基于硅光集成技术的激光雷达研究进展

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We present, to the best of our knowledge, the first demonstration of coherent solid-state light detection and ranging (LIDAR) using optical phased arrays in a silicon photonics platform. An integrated transmitting and receiving frequency-modulated continuous-wave circuit was initially developed and tested to confirm on-chip ranging. Simultaneous distance and velocity measurements were performed using triangular frequency modulation. Transmitting and receiving optical phased arrays were added to the system for on-chip beam collimation, and solid-state beam steering and ranging measurements using this system are shown. A cascaded optical phase shifter architecture with multiple groups was used to simplify system control and allow for a compact packaged device. This system was fabricated within a 300 mm wafer CMOS-compatible platform and paves the way for disruptive low-cost and compact LIDAR on-chip technology.

We present the demonstration of an integrated frequency modulated continuous wave LiDAR on a silicon platform. The waveform calibration, the scanning system, and the balanced detectors are implemented on a chip. Detection and ranging of a moving hard target at upto 60 m with less than 5 mW of output power is demonstrated in this paper.

We present the demonstration of two novel chip-scale FMCW LiDAR optical engines in which all photonic components, including the laser sources, were integrated on single silicon chips. Using the first LiDAR chip design, with an integrated distributed Bragg reflector laser and grating couplers as input/output ports for the receive/transmit light, we demonstrated a maximum range of 28 m limited by transmit light output power of 2 mW. We further demonstrated a maximum range of 75 m using a second LiDAR chip architecture having an on-chip sampled grating distributed Bragg reflector master laser with integrated power amplifier in which the local oscillator light was obtained from the laser back facet. This maximum range can be further increased by improving the laser linewidth. The measured range dependence of the FMCW signal level for both LiDAR chips agreed well with theory. The chip-scale FMCW LiDAR optical engines can be used in conjunction with a variety of off-chip two dimensional beam scanners to realize a chip-scale scanning LiDAR solution. To the best of our knowledge, this is the first published demonstration of fully integrated FMCW LiDAR optical engines on a single silicon chip.

We report a LiDAR transmitter incorporating both a hybrid-integrated tunable external cavity laser and a high-resolution 2-D optical phased array beam-steerer. Widely tunable single-mode lasing over a span of approximately 100 nm is achieved with >42 dB side-mode-suppression-ratio, 18 mW output power, and 2.8 kHz linewidth. Two-dimensional beam steering in a field-of-view of 140° × 16° exhibits a beam divergence of 0.051° × 0.016° measured in full width at half maximum. Leveraging the low propagation loss, negligible nonlinear loss, and low thermal sensitivity of silicon nitride, and combining the high mode confinement and efficient thermal tuning of silicon, the device affirms the feasibility of high-power on-chip lasing, power bottleneck elimination, and low on-chip insertion loss. It represents the first demonstration of a fully integrated LiDAR transmitter on the multi-layer silicon-nitride-on-silicon photonic platform, revealing the potential of complementary integration in the effort toward a LiDAR transmitter of sufficient optical power budget.

We present a photonic integrated circuit (PIC) transceiver for frequency modulated continuous wave (FMCW) LiDAR applications. The transmitter consists of a widely tunable sampled grating distributed Bragg reflector laser (SGDBR) and a frequency discriminator which combines multimode interference couplers, a tunable asymmetric Mach-Zehnder Interferometer (a-MZI), and balanced photodiodes. The frequency discriminator converts frequency fluctuations of the laser to amplitude fluctuations of the photodiode currents. This provides an error signal for feedback into the laser cavity for frequency stabilization. Frequency modulation is obtained by a phase shifter in the a-MZI which tunes the quadrature point of the filter and the frequency where the error is zero. An on-chip receiver couples power from the transmitter to self-heterodyne with the time-delayed echo of a distant object. The generated beat frequency of the self-heterodyne measurement gives the echo signals time-of-flight to obtain the distance and velocity of the reflecting object. The theory of the components is described, and characterization of the transmitter and receiver is presented.

We present recent results towards the development of an integrated photonic LIDAR system. Through the use of nanophotonic phased arrays, silicon photonics enables high-speed (>100kHz) beam-steering to be performed without moving parts in the same manner as electronically steerable microwave phased arrays. Already, we have demonstrated the ability to beam-steer over a 51-degree angular range and have separately demonstrated the ability to implement the required LIDAR optical signal processing on-chip and perform basic ranging measurements. Increasingly it is becoming apparent that chip-based LIDAR will become a reality, facilitating high-resolution 3D imaging for applications such as autonomous vehicles.

We demonstrate the highest yet-reported element count actively-steered optical phased array with record low array power consumption of <1.8W. We show 2D steering over a 70 x 14 degree field of view while pumped by an integrated InP/silicon laser.

We present the first integrated coherent LiDAR system with experimental ranging demonstrations operating within the eye-safe 1550nm band. Leveraging a unique wafer-scale 3D integration platform which includes customizable silicon photonics and nanoscale CMOS, our system seamlessly combines a high-sensitivity optical coherent detection front-end, a large-scale optical phased array for beamforming, and CMOS electronics in a single chip. Our prototype, fabricated entirely in a 300mm wafer facility, shows that low-cost manufacturing of high-performing solid-state LiDAR is indeed possible, which in turn may enable extensive adoption of LiDARs in consumer products, such as self-driving cars, drones, and robots.

Photonic crystal slow-light gratings fabricated using Si photonics enable high-speed, high-resolution, and wide field-of-view two-dimensional beam scanning via the thermo-optic effect. In this paper, we built a frequency-modulated continuous-wave light detection and ranging system on a chip by combining a beam scanner with Ge photodiodes for delay homodyne coherent detection. Emitting and scanning frequency-swept laser beam, point cloud images of 154 × 32 = 4928 points were obtained. The real-time operation and velocity imaging were also demonstrated. This device is expected to detect Lambertian targets over long distances in the 100-m class by reasonably reducing chip and optics losses and suppressing internal noise components.

This work reports the first realization of a combined radar&lidar system based on silicon-on-insulator photonic integrated circuit (PIC). The software-defined architecture comprises a frequency-flexible and simultaneous multi-band radar operation and an advanced lidar with coherent detection for range and velocity measurements. Both systems are implemented within a single chip, allowing a coherent radar and lidar parallel data acquisition in order to take advantage of their complementary characteristics. This feature potentializes the study of complex environments providing a more complete cognition of the target or scene under observation. Here, we present the first sets of results of the radar and lidar subsystems characterization without any auxiliary frontend that confirms the large frequency flexibility of the radar system and the great potentiality for high resolution range and velocity measurements of the lidar system. These results open the way to an innovative generation of transceivers in the field of microwave photonics, potentially outperforming current systems thanks to its multiband and multifunction capability owing to a unique hybrid radar&lidar coherent architecture. Moreover, by operating in the photonic domain, radar and lidar subsystems are able to share the same optical source and digital electronics unit, allowing for an ultimate reduction of size, weight, and power consumption, thus making the proposed architecture suitable for the most stringent applications.

Frequency-modulated continuous-wave LIDAR is demonstrated with a silicon photonic device consisting of transmitting and receiving waveguides and photodetectors. A 20 mm resolution and 2 m range is shown. Simultaneous distance and velocity measurements are achieved.

A photonics-based radar-lidar integrated system is proposed, which consists of a photonics-based radar and a frequency-modulated continuous-wave (FMCW) lidar. Since the photonic generation of RF signals is used, the transmitter can simultaneously generate linear frequency-modulated (LFM) radio-frequency (RF) and optical signals. Meanwhile, similar data acquisition methods are shared by the radar and lidar subsystems because FMCW ranging method is used in both of them. In the integrated system, the lidar subsystem provides high-resolution 3D images and velocity distributions, while the radar subsystem can implement real-time imaging with high frame rates. An experiment is carried out, in which a system consisting of a K-band radar and a 1550-nm FMCW lidar is used. The bandwidth of the radar and lidar subsystems are 8-GHz and 4-GHz. The standard deviations of displacements between the measured and the expected distances are 0.342 cm and 0.997 cm for the radar and lidar subsystems, respectively. For multi-sensor fusion applications, the 3D image and velocity distribution of a static cardboard and a spinning disk are obtained by the lidar subsystem, while the inverse synthetic aperture (ISAR) imaging for the spinning disk is achieved by the radar subsystem. Since some parts of the system are shared by the lidar and radar subsystems, the integrated system has a compact configuration, which is a potential configuration of the on-chip radar-lidar fusion system. Moreover, the performance of the lidar and radar subsystems are higher than the commonly used radar-lidar fusion system, which can be further enhanced by sophisticated data fusion algorithms.

Light detection and ranging (LiDAR) serves as one of the key components in the fields of autonomous driving, surveying mapping, and environment detection. Conventionally, dense points clouds are pursued by LiDAR systems to provide high-definition 3D images. However, the LiDAR is typically used to produce abundant yet redundant data for scanning the homogeneous background of scenes, resulting in power waste and excessive processing time. Hence, it is highly desirable for a LiDAR system to “gaze” at the target of interest by dense scanning and rough sparse scans on the uninteresting areas. Here, we propose a LiDAR structure based on an optical phased array (OPA) with reconfigurable apertures to achieve such a gaze scanning function. By virtue of the cascaded optical switch integrated on the OPA chip, a 64-, 128-, 192-, or 256-channel antenna can be selected discretionarily to construct an aperture with variable size. The corresponding divergence angles for the far-field beam are 0.32°, 0.15°, 0.10°, and 0.08°, respectively. The reconfigurable-aperture OPA enables the LiDAR system to perform rough scans via the large beam spots prior to fine scans of the target by using the tiny beam spots. In this way, the OPA-based LiDAR can perform the “gaze” function and achieve full-range scanning efficiently. The scanning time and power consumption can be reduced by 1/4 while precise details of the target are maintained. Finally, we embed the OPA into a frequency-modulated continuous-wave (FMCW) system to demonstrate the “gaze” function in beam scanning. Experiment results show that the number of precise scanning points can be reduced by 2/3 yet can obtain the reasonable outline of the target. The reconfigurable-aperture OPA (RA-OPA) can be a promising candidate for the applications of rapid recognition, like car navigation and robot vision.

This paper presents the design, modeling, fabrication, and testing of an optical phased array (OPA) based scanner utilizing microelectromechanical system (MEMS) micromirrors with in-plane pitch tuning capability for high-speed and high-resolution laser beam steering. A pair of lateral comb-drive actuators are located at both sides of the free-standing structure of the micromirror array and used to generate the force required for in-plane motion of the micromirrors. Identical folded-beam flexures on both sides of the moving part of each comb-drive actuator allow for the precisely guided lateral motion and reduction of the in-plane mechanical stiffness. The mirror-positioned flexures enable a symmetrical structure which helps to reduce side instability as well as levitation during lateral comb-drive actuation. Analytical models of the OPA structure are presented for estimations of the micro actuator performance as well as the optical characteristics. A prototype for the proposed OPA system with polysilicon as structural material and gold as optically reflective surface is fabricated using a surface micromachining process. The optical path difference is realized by slightly elevating every other micromirrors along the array in order to form the required optical phase shift. The aperture size of the OPA based scanner is about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$195\,\,\mu \text{m}\,\,\times 185\,\,\mu $ </tex-math></inline-formula> m and the fill factor of the array is 40-57%. Pitch tuning due to the electrostatic actuation results in an optical steering range of 0.06° with angular resolution of 0.002° at 30 V and a laser wavelength of 650 nm. [2021-0070]

We present high-performance integrated optical phased arrays along with first-of-their-kind light detection and ranging (LiDAR) and free-space data communication demonstrators. First, record-performance optical phased array components are shown with low-power phase shifters and high-directionality waveguide grating antennas. Then, one-dimensional (1-D) 512-element optical phased arrays are demonstrated with record low-power operation (<;1 mW total), large steering ranges, and high-speed two-dimensional (2-D) beam steering (<;30 μs phase shifter time constant). Next, by utilizing optical phased arrays, we show coherent 2-D solid-state LiDAR on diffusive targets with simultaneous velocity extraction at a range of nearly 200 m. In addition, the first demonstration of 3-D coherent LiDAR with optical phased arrays is presented with raster-scanning arrays. Finally, lens-free chip-to-chip free-space optical communication links up to 50 m are shown, including a demonstration of a steerable transmitter to multiple optical phased array receivers at a 1 Gb/s data rate. This paper shows the most advanced silicon photonics solid-state beam steering to date with relevant demonstrators in practical applications.

LIDAR in automotive systems typically uses 905nm or 940nm wavelength light for short to medium range mapping. The fabrication of an Optical Phase Array (OPA) for LIDAR applications at 905nm wavelength on a silicon nitride platform using metal heaters for beam steering is reported here.

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This study presents the comprehensive design, optimization, and experimental validation of an advanced silicon photonic delay line tailored for nonlinearity calibration in frequency-modulated continuous-wave (FMCW) LiDAR systems. The novel delay line employs a hybrid architecture combining Archimedes' and Euler's spirals, which significantly minimizes connection loss and higher-order mode crosstalk, resulting in a low-loss, high-density optical path. Fabricated using a standard CMOS multiple project wafer (MPW) process, the delay line achieves 0.24 dB/cm loss and 7.56 ns optical delay within a compact 1 × 3 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area, representing a substantial 41.5% improvement in delay density over our prior designs. Experimental outcomes validate the engine's capability for nonlinearity calibration, demonstrating a notable enhancement in signal-to-noise ratio and linewidth narrowing post-calibration. This work paves the way for the development of multifunctional, highly integrated FMCW LiDAR optical-electrical engines through the optimization of essential packaging and circuit functionalities.

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A high performance optical phased array (OPA) combined with frequency-modulated continuous-wave (FMCW) technology is essential for coherent all-solid-state light detection and ranging (LiDAR). In this work, we propose and experimentally demonstrate a coaxial transceiver based on a single OPA for a LiDAR system, which releases the off-chip circulator and collimator. The proposed scheme is demonstrated on the commonly used silicon-on-insulator (SOI) platform. For realizing the long optical grating antenna with only one-step etching, the bound state in the continuum is harnessed to simplify the fabrication process and ease the fabrication precision. Experimental results indicate that the OPA is with 0.076° vertical beam divergence under a 1.5 mm-long grating antenna. The measured field of view (FOV) is 40° × 8° without grating lobes under a wavelength band of 60 nm. The coaxial transceiver of the single OPA is also demonstrated with the FMCW method for ranging measurement at different angles.

Accurate 3D imaging is essential for machines to map and interact with the physical world1,2. While numerous 3D imaging technologies exist, each addressing niche applications with varying degrees of success, none have achieved the breadth of applicability and impact that digital image sensors have achieved in the 2D imaging world3-10. A large-scale twodimensional array of coherent detector pixels operating as a light detection and ranging (LIDAR) system could serve as a universal 3D imaging platform. Such a system would other high depth accuracy and immunity to interference from sunlight, as well as the ability to directly measure the velocity of moving objects11. However, due to difficulties in providing electrical and photonic connections to every pixel, previous systems have been restricted to fewer than 20 pixels12-15. Here, we demonstrate the first large-scale coherent detector array consisting of 512 (32×16) pixels, and its operation in a 3D imaging system. Leveraging recent advances in the monolithic integration of photonic and electronic circuits, a dense array of optical heterodyne detectors is combined with an integrated electronic readout architecture, enabling straightforward scaling to arbitrarily large arrays. Meanwhile, two-axis solid-state beam steering eliminates any tradeoff between field of view and range. Operating at the quantum noise limit16,17, our system achieves an accuracy of 3.1 mm at a distance of 75 meters using only 4 mW of light, an order of magnitude more accurate than existing solid-state systems at such ranges. Future reductions of pixel size using state-of-the-art components could yield resolutions in excess of 20 megapixels for arrays the size of a consumer camera sensor. This result paves the way for the development and proliferation of low cost, compact, and high-performance 3D imaging cameras, enabling new applications from robotics and autonomous navigation to augmented reality and healthcare.

Light detection and ranging (LiDAR) is widely thought to be the next big market for silicon photonics after data and telecommunications. In this talk, we will present some recent progress silicon photonics made in miniaturization of LiDAR systems, including heterogeneous III-V/Si OPA, integrated Pockels laser with fast chirping capabilities and microcomb sources with wide chirping range.

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The performance of silicon photonic components and integrated circuits has improved dramatically in recent years. As a key enabler, heterogeneous integration not only provides the optical gain which is absent from native Si substrates and enables complete photonic functionalities on chip, but also lays the foundation of versatile integrated photonic device performance engineering. This paper reviews recent progress of high-performance silicon photonics using heterogeneous integration, with emphasis on ultra-low-loss waveguides, single-wavelength lasers, comb lasers, and photonic integrated circuits including optical phased arrays for LiDAR and optical transceivers for datacenter interconnects.

We fabricated a frequency-modulated continuous-wave light detection and ranging (FMCW LiDAR) chip that integrates a slow-light grating (SLG) beam scanner and an optical interferometer for k-clock generation using silicon photonics. Beam scanning and FMCW light generation were performed simultaneously through a wavelength sweep, while the sweep nonlinearity was compensated by resampling the ranging signal using the k-clock. The interferometer incorporated a 24-cm-long Si waveguide delay line, facilitating ranging up to 7.1 m and the capture of point cloud images. The possibility of ranging longer distances by lengthening the waveguide and increasing the interpolation is discussed.

Silicon photonics based lidar sensors can enable chip scale sensors for high volume 3D sensing applications. These sensors require narrow linewidth and high optical power semiconductor devices to power long range lidars. Experimental results from 1550nm high power SOAs and narrow linewidth lasers are presented.

LIDAR on a silicon chip holds strong potentials for LIDAR system solutions featuring low cost, small size, and high robustness. In line with this effort, on-chip circulators are of great interest as they bring significant benefit for system complexity reduction and SNR improvement by enabling the LIDAR transmitter and receiver to share a single common aperture. Here, we present our recent study on passive silicon photonics nonlinear switches as conditional circulators for LIDAR applications. We propose a device implementation to address the nonlinear switch working principle by controlling waveguide nonlinear coefficient using sub-wavelength gratings. This implementation is foundry-compatible using only regular passive silicon waveguide components and are fully demonstrated in the experiment. In addition, we propose a sub-splitting coupler-based switch potentially can achieve a better fabrication tolerance than sub-wavelength grating-based switch. This work builds up signal processing functions in silicon photonics technology for optical communication and sensing applications. In particular, for LIDAR applications, this work contributes to the critical components of important use, and the easy integration with other existing functions such as optical phased arrays and spectral filters pronounces the potential for LIDAR on a silicon chip.

Optical phased arrays are a promising beam-steering technology for ultra-small solid-state lidar and free-space communication systems. Long-range, high-performance arrays require a large beam emission area densely packed with thousands of actively phase-controlled, power-hungry light emitting elements. To date, such large-scale phased arrays have been impossible to realize since current demonstrated technologies would operate at untenable electrical power levels. Here we show a multi-pass photonic platform integrated into a large-scale phased array that lowers phase shifter power consumption by nearly 9 times. The multi-pass structure decreases the power consumption of a thermo-optic phase shifter to a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow class="MJX-TeXAtom-ORD"><mml:msub><mml:mrow class="MJX-TeXAtom-ORD"><mml:mi mathvariant="normal">P</mml:mi></mml:mrow><mml:mi>π</mml:mi></mml:msub></mml:mrow></mml:math> of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow class="MJX-TeXAtom-ORD"><mml:mn>1.7</mml:mn></mml:mrow><mml:mspace width="thickmathspace"/><mml:mrow class="MJX-TeXAtom-ORD"><mml:mi mathvariant="normal">m</mml:mi><mml:mi mathvariant="normal">W</mml:mi><mml:mrow class="MJX-TeXAtom-ORD"><mml:mo>/</mml:mo></mml:mrow></mml:mrow><mml:mi>π</mml:mi></mml:math> without sacrificing speed or optical bandwidth. Using this platform, we demonstrate a silicon photonic phased array containing 512 actively controlled elements, consuming only 1.9 W of power while performing 2D beam steering over a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mrow class="MJX-TeXAtom-ORD"><mml:mn>70</mml:mn></mml:mrow><mml:mo>∘</mml:mo></mml:msup><mml:mo>×</mml:mo><mml:msup><mml:mrow class="MJX-TeXAtom-ORD"><mml:mn>6</mml:mn></mml:mrow><mml:mo>∘</mml:mo></mml:msup></mml:math> field of view. Our results demonstrate a path forward to building scalable phased arrays containing thousands of active elements.

LIDAR (Light Detection and Ranging) is emerging as a necessity for fully automated self-driving automotive applications. In order to sample the far field with sufficient resolution for this application the system must incorporate many optical elements, leading to challenges for manufacturability and size. Due to the density of optical components required, LIDAR is well suited for photonic integration in order to achieve miniaturization and scalable manufacturability. This talk will give an overview of LIDAR, the components required for a chip-scale solution, and silicon photonics progress with respect to this goal.

Silicon photonics is one of the most prominent technology platforms for integrated photonics and can support a wide variety of applications. As we move towards a mature industrial core technology, we present the integration of silicon nitride (SiN) material to extend the capabilities of our silicon photonics platform. Depending on the application being targeted, we have developed several integration strategies for the incorporation of SiN. We present these processes, as well as key components for dedicated applications. In particular, we present the use of SiN for athermal multiplexing in optical transceivers for datacom applications, the nonlinear generation of frequency combs in SiN micro-resonators for ultra-high data rate transmission, spectroscopy or metrology applications and the use of SiN to realize optical phased arrays in the 800–1000 nm wavelength range for Light Detection And Ranging (LIDAR) applications. These functionalities are demonstrated using a 200 mm complementary metal-oxide-semiconductor (CMOS)-compatible pilot line, showing the versatility and scalability of the Si-SiN platform.

We demonstrate a four-channel dual-polarization FMCW LiDAR receiver module using a silicon photonic coherent receiver chip. The sensitivity of the module is better than -80dBm. The ranging operation within a distance of 81.9m is demonstrated.

Heterogeneous silicon photonics is uniquely positioned to address the photonic sensing needs of upcoming autonomous cars and provide the necessary cost reduction for widespread deployment. This is because it allows for wafer-scale active/passive integration, including optical sources. We present our recent research and the development of interferometric optical gyroscopes and LiDAR sensors. More specifically, we show a fully integrated gyroscope front-end occupying an area of only 4.5 mm². We also show the first dense pitch optical phased array using heterogeneous phase shifters. The 4 µm pitch heterogeneous phase shifters provide very low V_2π of only 0.35-1.4 V across 200 nm, low residual amplitude modulation of only 0.1-0.15 dB for 2π phase shift, extremely low static power consumption (<3 nW), and high speed (> 1 GHz). All of these factors make them ideal for next-generation LiDAR systems that employ optical phased arrays.

We present recent advancements of optical phased array LiDAR with record-performance system demonstrations. First, we give an overview of the technology and how it combines the benefits of coherent LiDAR with the integration capabilities of silicon photonics. Then, an 8192-element optical phased array is shown with individually-addressed elements driven by custom CMOS electronics. This compact chip-scale beam-steering engine is enabled by flip-chip attached ASICs on the photonic integrated circuit. The optical phase shifters and emitters in the array have a 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m pitch to enable a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$100^{\circ }\times 17^\circ$</tex-math></inline-formula> field of view. This unprecedented number of active elements forms a near centimeter-scale aperture. Next, a high-performance laser uniquely suited for optical phased array LiDAR is demonstrated. Due to the silicon photonics cavity, it simultaneously supports a large tuning range (60 nm), low linewidth ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 50 kHz), and fast linear chirp (1.3 GHz in 17.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> s). Finally, a solid-state coherent LiDAR system is realized with transmit/receive optical phased arrays coupled to an on-chip coherent receiver while being driven by the demonstrated laser. Ranging is shown on diffusive targets while simultaneously extracting velocity at each point in the point cloud. To the best of our knowledge, this single-unit compact system represents the state-of-the-art in optical phased array LiDAR technology.

In this paper we present the first integration of a 2D Optical Phased Array (OPA) for 905nm LIDAR applications on our 300mm SWIR photonic platform DAPHNE, based on Si &amp; SiN components.

Abstract Technologies for efficient generation and fast scanning of narrow free-space laser beams find major applications in three-dimensional (3D) imaging and mapping, like Lidar for remote sensing and navigation, and secure free-space optical communications. The ultimate goal for such a system is to reduce its size, weight, and power consumption, so that it can be mounted on, e.g. drones and autonomous cars. Moreover, beam scanning should ideally be done at video frame rates, something that is beyond the capabilities of current opto-mechanical systems. Photonic integrated circuit (PIC) technology holds the promise of achieving low-cost, compact, robust and energy-efficient complex optical systems. PICs integrate, for example, lasers, modulators, detectors, and filters on a single piece of semiconductor, typically silicon or indium phosphide, much like electronic integrated circuits. This technology is maturing fast, driven by high-bandwidth communications applications, and mature fabrication facilities. State-of-the-art commercial PICs integrate hundreds of elements, and the integration of thousands of elements has been shown in the laboratory. Over the last few years, there has been a considerable research effort to integrate beam steering systems on a PIC, and various beam steering demonstrators based on optical phased arrays have been realized. Arrays of up to thousands of coherent emitters, including their phase and amplitude control, have been integrated, and various applications have been explored. In this review paper, I will present an overview of the state of the art of this technology and its opportunities, illustrated by recent breakthroughs.

We demonstrate, for the first time, a monolithically integrated biaxial LiDAR on a silicon photonic platform, combining an optical phased array emitter with fast on-chip calibration, and a focal plane array with coherent pixel receivers.

This paper reports on large field-of-regard, high-efficiency, and large aperture active optical phased arrays (OPAs) for optical beam steering in LIDAR systems. The fabricated 5 mm-long silicon photonic OPA with a 1.3 μm waveguide pitch achieved adjacent waveguide crosstalk below -12dB. A relatively large and uniform emission aperture has been achieved with a low-contrast silicon nitride assisted grating (~20 dB/cm) whose emission profile can be further optimized using an apodized design. The fabricated silicon-photonic OPA demonstrated > 40° lateral beam steering with no sidelobes in a ± 33° field-of-regard and 3.3° longitudinal beam steering via wavelength tuning by 20 nm centered at 1550 nm. We have fully integrated the silicon photonic OPA device with electronic controls and successfully demonstrated 2-dimensional coherent optical beam steering of pre-planned far-field patterns. Future improvements include placement of a distributed Bragg reflector (DBR) underneath the grating emitter in order to achieve nearly a factor of two improvement in emission efficiency.

This paper reports on the experimental demonstration of a fully integrated frequency-modulated continuous-wave (FMCW) LiDAR sensing system, operating at 2.0 µm. It makes use of a widely tunable hybrid external cavity laser based on the combination of GaSb gain chip and silicon waveguide circuits. The single-frequency laser operation over the full spectral bandwidth of the gain chip is secured using a frequency-selective filter, consisting of two sequential microring resonators in a Vernier configuration. To increase the mode-hop free wavelength tuning range while preserving the linewidth of the laser, the heater of the phase section placed along the bus waveguide is synchronously controlled with two independent heaters placed on each microring resonator. This laser is then implemented for the development of an FMCW LiDAR, consisting of all-optical fiber-based two independent unbalanced Mach-Zehnder interferometers: k-space interferometer for the linearization of continuously swept laser frequency and main interferometer for the measurement of the distributed back-reflection over the distance. The optical frequency of the laser is continuously swept over a ∼100 GHz range (or Δλ=1.47 nm at the operating wavelength) at a modulation speed of 100 Hz. Using this wavelength tunable laser, a light detection and ranging system (LiDAR) is experimentally demonstrated, showing a very high axial resolution of 1.36 mm in air with an extremely high precision of ∼9 µm at a 100 Hz measurement rate.

Frequency modulated continuous wave laser ranging (FMCW LiDAR) enables distance mapping with simultaneous position and velocity information, is immune to stray light, can achieve long range, operate in the eye-safe region of 1550 nm and achieve high sensitivity. Despite its advantages, it is compounded by the simultaneous requirement of both narrow linewidth low noise lasers that can be precisely chirped. While integrated silicon-based lasers, compatible with wafer scale manufacturing in large volumes at low cost, have experienced major advances and are now employed on a commercial scale in data centers, and impressive progress has led to integrated lasers with (ultra) narrow sub-100 Hz-level intrinsic linewidth based on optical feedback from photonic circuits, these lasers presently lack fast nonthermal tuning, i.e. frequency agility as required for coherent ranging. Here, we demonstrate a hybrid photonic integrated laser that exhibits very narrow intrinsic linewidth of 25 Hz while offering linear, hysteresis-free, and mode-hop-free-tuning beyond 1 GHz with up to megahertz actuation bandwidth constituting 1.6 × 10¹⁵ Hz/s tuning speed. Our approach uses foundry-based technologies - ultralow-loss (1 dB/m) Si₃N₄ photonic microresonators, combined with aluminium nitride (AlN) or lead zirconium titanate (PZT) microelectromechanical systems (MEMS) based stress-optic actuation. Electrically driven low-phase-noise lasing is attained by self-injection locking of an Indium Phosphide (InP) laser chip and only limited by fundamental thermo-refractive noise at mid-range offsets. By utilizing difference-drive and apodization of the photonic chip to suppress mechanical vibrations of the chip, a flat actuation response up to 10 MHz is achieved. We leverage this capability to demonstrate a compact coherent LiDAR engine that can generate up to 800 kHz FMCW triangular optical chirp signals, requiring neither any active linearization nor predistortion compensation, and perform a 10 m optical ranging experiment, with a resolution of 12.5 cm. Our results constitute a photonic integrated laser system for scenarios where high compactness, fast frequency actuation, and high spectral purity are required.

Chip-scale integration is a key enabler for the deployment of photonic technologies. Coherent laser ranging or FMCW LiDAR, a perception technology that benefits from instantaneous velocity and distance detection, eye-safe operation, long-range, and immunity to interference. However, wafer-scale integration of these systems has been challenged by stringent requirements on laser coherence, frequency agility, and the necessity for optical amplifiers. Here, we demonstrate a photonic-electronic LiDAR source composed of a micro-electronic-based high-voltage arbitrary waveform generator, a hybrid photonic circuit-based tunable Vernier laser with piezoelectric actuators, and an erbium-doped waveguide amplifier. Importantly, all systems are realized in a wafer-scale manufacturing-compatible process comprising III-V semiconductors, silicon nitride photonic integrated circuits, and 130-nm SiGe bipolar complementary metal-oxide-semiconductor (CMOS) technology. We conducted ranging experiments at a 10-meter distance with a precision level of 10 cm and a 50 kHz acquisition rate. The laser source is turnkey and linearization-free, and it can be seamlessly integrated with existing focal plane and optical phased array LiDAR approaches.

A new method for solid-state beamsteering using MEMS grating switches integrated on a Si-PIC has been demonstrated. This method provides fast random access switching, simple digital control, extremely low side-lobes, and is scalable to large arrays, large apertures, and long ranges.

Monolithic microwave phased arrays are turning mainstream in automotive radars and high-speed wireless communications fulfilling Gordon Moores 1965 prophecy to this effect. Optical phased arrays enable imaging, lidar, display, sensing, and holography. Advancements in fabrication technology has led to monolithic nanophotonic phased arrays, albeit without independent phase and amplitude control ability, integration with electronic circuitry, or including receive and transmit functions. We report the first monolithic optical phased array transceiver with independent control of amplitude and phase for each element using electronic circuitry that is tightly integrated with the nanophotonic components on one substrate using a commercial foundry CMOS SOI process. The 8 × 8 phased array chip includes thermo-optical tunable phase shifters and attenuators, nano-photonic antennas, and dedicated control electronics realized using CMOS transistors. The complex chip includes over 300 distinct optical components and over 74,000 distinct electrical components achieving the highest level of integration for any electronic-photonic system.

We demonstrate millimeter-scale optical waveguide grating antennas with unidirectional emission for integrated optical phased arrays. Unidirectional emission eliminates the fundamental problem of blind spots in the element factor of a phased array caused by reflections of antenna radiation within the substrate. Over 90% directionality is demonstrated using a design consisting of two silicon nitride layers. Furthermore, the perturbation strength along the antenna is apodized to achieve uniform emission for the first time, to the best of our knowledge, on a millimeter scale. This allows for a high effective aperture and receiving efficiency. The emission profile of the measured 3 mm long antenna has a standard deviation of 8.65% of the mean. These antennas are state of the art and will allow for integrated optical phased arrays with blind-spot-free high transmission output power and high receiving efficiency for LIDAR and free-space communication systems.

A silicon photonic integrated chip was designed to further miniaturize the CO 2 gas- gas-measurement LiDAR seed laser. The optical links of the laser frequency stabilization loop (FSL), optical phase-locked loop (OPLL), and thermo-optical switch (TOS) are integrated into a photonic integrated circuit (PIC). The frequency stabilization loop built by the silicon photonics chip stabilizes the center frequency of the reference laser (RL) to the R-18 absorption line of carbon dioxide gas (1572.0179 nm). The long-term relative stability of the laser wavelength reached at 1000 s averaging time, and the RMS was 113 kHz. The frequency reference is a 15 m anti-resonant hollow-core optical fiber (HCF) filled with CO 2 gas at a pressure of 40 bar. By using OPLL, we locked the center frequency of the seed laser (slave laser) at 1572.0237 nm, and its Allan deviation is 38.2 kHz at 1000 s averaging time, and the RMS was 206 kHz. The wavelength stability of the RL and seed laser satisfies the requirements of CO 2 measurement LiDAR, which requires laser long-term stability better than 300 kHz (Allan standard deviation). The MZI-structured thermo-optic switch operated with a switching period of 400 µs, a rise/fall time of approximately 20 µs was obtained, and the dynamic extinction ratio reached 26 dB.

With the growing demand for automotive LiDAR and the maturation of silicon photonics platforms, optical phased arrays (OPAs) have emerged as a key technology for solid-state optical beam-steering. In order to meet realistic automotive specifications with OPAs, >500 antenna elements should work reliably under tight power and cost budgets. Existing multi-chip solutions necessitate expensive packaging and assembly to achieve high interconnect density. Even with 2-D monolithic integration, high-voltage drivers to deliver sufficient power to resistive phase shifters typically result in significant overhead in die area and limited power efficiency. In this article, we introduce a single-chip OPA realized through wafer-scale 3-D integration of silicon photonics and CMOS. Flexible and ultra-dense connections with through-oxide vias (TOVs) in our platform resolve the I/O density issue. Moreover, low-voltage L-shaped phase shifters and compact, efficient switch-mode drivers, connected vertically using TOVs, remove wiring/placement overhead and achieve a large active array aperture within a compact die. Our OPA prototype achieves wide-range 2-D steering over 18.5°×16° by leveraging wavelength tuning and phase control, and array scaling up to 125 elements with a large aperture size of 0.5 mm×0.5 mm and 0.15°×0.25° beamwidth while consuming 20 mW/element average power. Since our system supports per-element independent phase control, increased sensitivity to process variations in L-shaped shifters is fully compensated by a simple calibration process.

Narrow-linewidth semiconductor lasers, micro-optics, silicon photonics (SiP), low noise electronics and high-density packaging are key elements for the development of compact high-end light sources for sensing. A laser module for the interrogation of an RFOG (Resonant Fiber-Optic Gyroscope) includes three distributed feedback lasers coupled with micro-lenses to a multi-component SiP chip that performs beat note detection and several other functions. The lasers and SiP chip are packaged in a 2.6 cm³ multi-layer ceramic package, a 4x volume reduction over a first generation module. The package interfaces with 92 electrical pins and two fiber pigtails, one carrying the signals from a master and slave lasers, another carrying that from a second slave laser. The complete laser source including electronics is 60 mm in diameter and 23 mm in height, a 10x volume improvement over a previous version. The master laser can be locked to the RFOG resonator with a loop bandwidth greater than 1 MHz. The slave lasers are offset frequency locked to the master laser with loop bandwidths greater than 100 MHz. This high performance source is compact, automated, robust, and remains locked for days. A lighter version of this laser module for FM-CW LIDAR applications produces an output optical frequency that varies linearly as a function of the electrical drive. A triangular modulation at 100 kHz with a greater than 1 GHz amplitude has been demonstrated with a linearity noise near 1 MHz as measured through a 150 m unbalanced interferometer.

Silicon Photonics foundry based Extended-Distributed Bragg Reflector (E-DBR) lasers for automotive FMCW LiDAR systems are described, demonstrating record Lorentzian linewidths &lt;240Hz, promising the performance of discrete, commercial, E-DBR lasers, together with low- cost, high-volume, high-reliability manufacturing.

Optical phased arrays (OPAs) implemented in integrated photonic circuits could enable a variety of 3D sensing, imaging, illumination, and ranging applications, and their convergence in new lidar technology. However, current integrated OPA approaches do not scale—in control complexity, power consumption, or optical efficiency—to the large aperture sizes needed to support medium- to long-range lidar. We present the serpentine OPA (SOPA), a new OPA concept that addresses these fundamental challenges and enables architectures that scale up to large apertures. The SOPA is based on a serially interconnected array of low-loss grating waveguides and supports fully passive, 2D wavelength-controlled beam steering. A fundamentally space-efficient design that folds the feed network into the aperture also enables scalable tiling of SOPAs into large apertures with a high fill-factor. We experimentally demonstrate, to the best of our knowledge, the first SOPA using a 1450–1650 nm wavelength sweep to produce 16,500 addressable spots in a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mn>27</mml:mn> <mml:mo>×</mml:mo> <mml:mn>610</mml:mn> </mml:math> array. We also demonstrate, for the first time, far-field interference of beams from two separate OPAs on a single silicon photonic chip, as an initial step towards long-range computational imaging lidar based on novel active aperture synthesis schemes.

Optical beam steering can find applications in several domains such as laser scanning, LiDAR (Light Detection And Ranging), wireless data transfer and optical switches and interconnects. As present beam steering approaches use mechanical motion such as moving mirrors or MEMS (MicroElectroMechanical Systems) or molecular movement using liquid crystals, they are usually limited in speed and/or performance. Therefore we have studied the possibilities of the integrated silicon photonics platform in beam steering applications. In this paper, we have investigated a 16 element one-dimensional optical phased array on silicon-on-insulator with a field-of-view of 23. Using thermo-optic phase tuners, we have shown beam steering over the complete field-of-view. By programming the phase tuners as a lens, we have also shown the focusing capabilities of this one-dimensional optical phased array. The field-of-view can easily be increased by decreasing the width of the waveguides. This clearly shows the potential of silicon photonics in beam steering and scanning applications.

Typical integrated optical phase tuners alter the effective index. In this paper, we explore tuning by geometric deformation. We show that tuning efficiency, Vπ L, improves as the device size shrinks down to the optimal bend radius, contrary to conventional index-shift based approaches where Vπ L remains constant. We demonstrate that this approach is capable of ultra-low power tuning across a full FSR in a low-confinement silicon nitride based ring resonator of 580 μm radius. We demonstrate record performance with V_FSR = 16 V, Vπ L = 3.6 V dB, Vπ Lα = 1.1 V dB, tuning current below 10 nA, and unattenuated tuning response up to 1 MHz. We also present optimized designs for high confinement silicon nitride and silicon based platforms with radius down to 80 μm and 45 μm, respectively, with performance well beyond current state-of-the-art. Applications include narrow-linewidth tunable diode lasers for spectroscopy and non-linear optics, optical phased array beamforming networks for RF antennas and LIDAR, and optical filters for WDM telecommunication links.

We demonstrate a monolithically integrated line-scan optical phased array with focal plane array coherent receivers to realize a compact FMCW LiDAR system. A frame rate of 10 fps is experimentally achieved using thermo-optic phase shifters, with a theoretical upper limit of 62 fps.

This paper describes the design, fabrication, and record performance of a new class of ultra-wideband wavelength tuning, ultra-low noise semiconductor laser, the Integrated Coherent Tunable Laser (ICTL). The ICTL device is designed for, and fabricated in, a CMOS foundry based Silicon Photonics platform, utilizing heterogeneous integration of III-V material to create the integrated gain section of the laser&#x2013;enabling high-volume mass-market manufacturing at low cost and with high reliability. The ICTL incorporates three or more ultra-low loss micro-ring resonators, with large ring size, in a Sagnac loop reflector geometry, creating exceptional laser reflector performance, plus an extended laser cavity length that enables highly-coherent output; ultra-low linewidth and phase noise. This paper describes record integrated laser performance; 118 nm wavelength tuning, covering S-, C- and L-bands, with Lorentzian linewidth &lt;100 Hz, and with excellent relative intensity noise (RIN) of &#x2264; &#x2212;155 dBc&#x002F;Hz. The remarkable performance of the ICTL device, coupled with the high volume&#x002F;low cost capability of the Silicon Photonics platform enables next-generation applications including ultra-wideband WDM transmission systems, fiber-optic and medical-wearable sensing systems, and automotive FMCW LiDAR systems utilizing wavelength scanning.

Electro-optic modulators transform electronic signals into the optical domain and are critical components in modern telecommunication networks, RF photonics, and emerging applications in quantum photonics, neuromorphic photonics, and beam steering. All these applications require integrated and voltage-efficient modulator solutions with compact form factors that are seamlessly integrable with silicon photonics platforms and feature near-CMOS material processing synergies. However, existing integrated modulators are challenged to meet these requirements. Conversely, emerging electro-optic materials heterogeneously and monolithically integrated with Si photonics open up a new avenue for device engineering. Indium tin oxide (ITO) is one such compelling material for heterogeneous integration in Si exhibiting formidable electro-optic effect characterized by unity-order index change at telecommunication frequencies. Here we overcome these limitations and demonstrate a monolithically integrated ITO electro-optic modulator based on a Mach Zehnder interferometer featuring a high-performance half-wave voltage and active device length product of VπL = 0.52 V mm. We show that the unity-strong index change enables a 30 μm-short π-phase shifter operating ITO in the index-dominated region away from the epsilon-near-zero point for reduced losses. This device experimentally confirms electrical phase shifting in ITO enabling its use in applications such as compact phase shifters, nonlinear activation functions in photonic neural networks, and phased array applications for LiDAR.

Frequency-modulated continuous wave (FMCW) LiDAR can achieve long-distance and high-precision measurement, and the ranging error mainly comes from the nonlinearity of the laser frequency sweep. In this study, a high-precision silicon-integrated FMCW LiDAR is proposed. An equal frequency hypercube network is established by the stable free spectral range (FSR) of the microresonator to calibrate the nonlinearity of FMCW, and the distance matrix is obtained by analyzing the phase difference matrix of the FMCW signal. A standard length-based microresonator FSR calibration scheme is used to further improve the LiDAR accuracy. The feasibility of the scheme is verified by ranging and three-dimensional (3D) imaging. The ranging is carried out indoors and outdoors. In the indoor environment of a distance of 4 m, the minimum Allan deviation is 65 nm at 10.24 s. In the outdoor environment, the minimum Allan deviation at 438 m is 420 nm at 10.24 s. The 3D imaging can reconstruct the spatial point cloud of the objects and identify the spatial targets. This scheme has good on-chip integration capability and can be further combined with lens-assisted beam steering and optical phased array, laying the foundation for compact, large bandwidth, long-range, and high-precision LiDAR.

Silicon nitride (SiN) optical phased arrays (OPAs) have emerged as a potential alternative to their silicon counterparts, owing to their low nonlinearity, easy scalability, and low propagation loss. However, the development of SiN OPAs for light detection and ranging (LiDAR) applications has attracted less attention due to the low thermo-optic (TO) effect of SiN. Moreover, SiN OPAs are considered to be undesirable for transmitters in LiDAR systems because of the limited longitudinal tuning efficiency of SiN grating antenna. We present a hybrid integrated SiN-polymer OPA for realizing an efficient LiDAR. Owing to the large TO effect of polymer, the proposed OPA with polymeric phase modulators resolves the power dissipation drawback of the SiN devices. The polymeric modulators are integrated with a SiN power splitter and grating antenna, and the coupling loss is alleviated via a spot-size converter. Additionally, a steering angle magnifying lens is used to enhance the tuning efficiency of the antenna, expanding the longitudinal beam steering range. The prepared OPA transmitter equipped with the lens exhibits decent two-dimensional beam steering, featuring stable emission characteristics over a 12° × 30° field of view. With the transmitter, efficient time-of-flight based LiDAR is demonstrated to provide a detection range of 10 m under a peak optical power of 55 dBm. The proposed SiN-polymer OPA is highly anticipated to circumvent the challenges of conventional SiN counterparts and potentially spearhead the development of a prominent OPA platform for advanced LiDAR schemes.

This paper discusses recent advances on the newly developed high-density three-dimensional photonic integrated circuits (3-D PICs). In particular, we introduce our efforts in design, fabrication, and characterization toward a silicon photonic wafer-scale light detection and ranging (LIDAR) system populated by 3-D PIC unit cells. The 3-D PIC unit cell includes vertical U-shaped photonic couplers created by a combination of anisotropic etching, vertical α-silicon via formation, and wafer bonding. Using the U-shaped photonic couplers, the 3-D PIC unit cell forms a 120-channel folded single tile optical phased array (OPA) with 2-μm pitch. Ultracompact vertical U-shaped coupler arrays with 1-μm pitch are also fabricated and tested. The 3-D PIC unit cells will be tiled on a wafer-scale interposer, transmitting and receiving signals through equal-power splitters with pathlength-matched waveguides, and 3-D arbitrarily shaped waveguides or evanescent couplers. Designs of such interposers are shown and low-loss and misalignment tolerant chip-to-interposer coupling using evanescent coupler is demonstrated. Loss values of arbitrarily shaped waveguides fabricated by ultrafast laser inscription on the deposited-SiO2 cladding and their alignment tolerance to conventional silicon nitride edge couplers are reported. A path toward realizing 3-D integrated LIDAR is discussed.

No abstract

An ultra-compact half-wavelength pitch silicon waveguide array with very low crosstalk is proposed and analyzed in this work. We first show the design of a pair of low-crosstalk silicon waveguides with only half-wavelength spacing, where the placement of two thin silicon strips asymmetrically in between the waveguides is key to having very low crosstalk. We next extend this nano-structured two-waveguide design to form a low-crosstalk half-wavelength pitch silicon waveguide array. Coupled-mode theory shows that, for an array length of 1 mm, the insertion loss of the input waveguide is as low as -0.13 dB for the TE-like mode at 1550 nm, and the crosstalk in all other waveguides remains below about -18 dB. This half-wavelength pitch waveguide array also exhibits a favorable fabrication error tolerance when taking into account the waveguide width variations in practice. It offers a promising platform for realization of integrated optical phased arrays for solid-state lidars with a large field of view.

Free-space beam steering using optical phased arrays is a promising method for implementing free-space communication links and Light Detection and Ranging (LIDAR) without the sensitivity to inertial forces and long latencies which characterize moving parts. Implementing this approach on a silicon-based photonic integrated circuit adds the additional advantage of working with highly developed CMOS processing techniques. In this work we discuss our progress in the development of a fully integrated 32 channel PIC with a widely tunable diode laser, a waveguide phased array, an array of fast phase modulators, an array of hybrid III-V/silicon amplifiers, surface gratings, and a graded index lens (GRIN) feeding an array of photodiodes for feedback control. The PIC has been designed to provide beam steering across a 15&deg;x5&deg; field of view with 0.6&deg;x0.6&deg; beam width and background peaks suppressed 15 dB relative to the main lobe within the field of view for arbitrarily chosen beam directions. Fabrication follows the hybrid silicon process developed at UCSB with modifications to incorporate silicon diodes and a GRIN lens.

Optical phased array (OPA) technology is considered a promising solution for solid-state beam steering to supersede the traditional mechanical beam steering. As a key component of the LIDAR system for long-range detection, OPAs featuring a wide steering angle and high resolution without beam aliasing are highly desired. However, a wide steering range requires a waveguide pitch less than half of the wavelength, which is easily subjected to cross talk. Besides, high resolution requires a large aperture, and it is normally achieved by a high count number of waveguides, which complicates the control system. To solve the mentioned issues, we design two high-performance 128-channel OPAs fabricated on a multilayered SiN-on-SOI platform. Attributed to the nonuniform antenna pitch, only 128 waveguides are used to achieve a 4 mm wide aperture. Besides, by virtue of innovative dual-level silicon nitride ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>Si</mml:mi> </mml:mrow> <mml:mn>3</mml:mn> </mml:msub> <mml:msub> <mml:mi mathvariant="normal">N</mml:mi> <mml:mn>4</mml:mn> </mml:msub> </mml:mrow> </mml:math> ) waveguide grating antennas, the fishbone antenna OPA achieves a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"> <mml:mrow> <mml:mn>100</mml:mn> <mml:mo>°</mml:mo> <mml:mo>×</mml:mo> <mml:mn>19.4</mml:mn> <mml:mo>°</mml:mo> </mml:mrow> </mml:math> field of view (FOV) with divergence of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m3"> <mml:mrow> <mml:mn>0.021</mml:mn> <mml:mo>°</mml:mo> <mml:mo>×</mml:mo> <mml:mn>0.029</mml:mn> <mml:mo>°</mml:mo> </mml:mrow> </mml:math> , and the chain antenna OPA realizes a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m4"> <mml:mrow> <mml:mn>140</mml:mn> <mml:mo>°</mml:mo> <mml:mo>×</mml:mo> <mml:mn>19.23</mml:mn> <mml:mo>°</mml:mo> </mml:mrow> </mml:math> FOV with divergence of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m5"> <mml:mrow> <mml:mn>0.021</mml:mn> <mml:mo>°</mml:mo> <mml:mo>×</mml:mo> <mml:mn>0.1</mml:mn> <mml:mo>°</mml:mo> </mml:mrow> </mml:math> . To our best knowledge, 140° is the widest lateral steering range in two-dimensional OPA, and 0.029° is the smallest longitudinal divergence. Finally, we embed the OPA into a frequency-modulated continuous-wave system to achieve 100 m distance measurement. The reflected signal from 100 m distance is well detected with 26 dBm input transmitter power, which proves that OPA serves as a promising candidate for transceiving optical signal in a LIDAR system.

Light detection and ranging (lidar) sensors provide high resolution and high accuracy for diverse applications such as autonomous vehicles and three-dimensional imagers. Over the past few years, there has been significant development towards compact, low-power, and low-cost realization of lidars. Recently, silicon-based large-scale optical phased arrays operating at around 1550nm [1 -4] along with their application in lidar [5] [6] have been demonstrated. A major challenge associated with large-scale optical phased arrays is the inevitable mismatches across the array that necessitate array calibration. At present, all large-scale arrays are calibrated by using an external optical detector for measuring focused far-field beam spot intensity [3] or infrared image sensors for measuring the far-field radiation patterns in the lab [1] [2] [6]. This solution, which requires an external detector at a far-field distance, naturally does not lend itself to large-scale field deployment of optical phased arrays for commercial applications with a compact form factor.

No abstract

Beam engineering is one of the most important functionalities in light detection and ranging (LiDAR). In this work, a silicon optical phased array (OPA) is employed to control the beam profile. Machine-learning-based genetic algorithm optimization is utilized to suppress the sidelobes of the far field pattern assuming the random distribution of aperiodic arrays. The optimized mainlobe position versus wavelength relationship in two-dimensional aperiodic arrays is distinctly different from prior works. Analysis was performed to show the effect of fabrication error of arrays on the side mode suppression ratio. Our study provides an effective pathway to optimize the random distributed OPAs within a controllable time frame among the vast number of parameters.

LiDAR has attracted increasing attention because of its strong anti-interference ability and high resolution. Traditional LiDAR systems rely on discrete components and face the challenges of high cost, large volume, and complex construction. Photonic integration technology can solve these problems and achieve high integration, compact dimension, and low-cost on-chip LiDAR solutions. A solid-state frequency-modulated continuous-wave LiDAR based on a silicon photonic chip is proposed and demonstrated. Two sets of optical phased array antennas are integrated on an optical chip to form a transmitter-receiver interleaved coaxial all-solid-state coherent optical system which provides high power efficiency, in principle, compared with a coaxial optical system using a 2 × 2 beam splitter. The solid-state scanning on the chip is realized by optical phased array without a mechanical structure. A 32-channel transmitter-receiver interleaved coaxial all-solid-state FMCW LiDAR chip design is demonstrated. The measured beam width is 0.4° × 0.8°, and the grating lobe suppression ratio is 6 dB. Preliminary FMCW ranging of multiple targets scanned by OPA was performed. The photonic integrated chip is fabricated on a CMOS-compatible silicon photonics platform, providing a steady path to the commercialization of low-cost on-chip solid-state FMCW LiDAR.

Recent advancements in ultra-low-loss silicon nitride (Si 3 N 4 )-based photonic integrated circuits have surpassed fiber lasers in coherence and frequency agility. However, high manufacturing costs of DFB and precise control requirements, as required for self-injection locking, hinder widespread adoption. Reflective semiconductor optical amplifiers (RSOAs) provide a cost-effective alternative solution but have not yet achieved similar performance in coherence or frequency agility, as required for frequency modulated continuous wave (FMCW) LiDAR, laser locking in frequency metrology, or wavelength modulation spectroscopy for gas sensing. Here, we overcome this challenge and demonstrate an RSOA-based and frequency-agile fully hybrid integrated extended distributed Bragg reflector (E-DBR) laser with high-speed tuning, good linearity, high optical output power, and turn-key operability. It outperforms Vernier and self-injection locked lasers, which require up to five precise operating parameters and have limitations in continuous tuning and actuation bandwidth. We maintain a small footprint by utilizing an ultra-low-loss 200 nm thin Si 3 N 4 platform with monolithically integrated piezoelectric actuators. We co-integrate the DBR with a compact ultra-low-loss spiral resonator to further reduce the intrinsic optical linewidth of the laser to the Hertz-level—on par with the noise of a fiber laser—via self-injection locking. The photonic integrated E-DBR lasers operate at 1550 nm and feature up to 25 mW fiber-coupled output power in the free-running and up to 10.5 mW output power in the self-injection locked state. The intrinsic linewidth is 2.5 kHz in the free-running state and as low as 3.8 Hz in the self-injection locked state. In addition, we demonstrate the suitability for FMCW LiDAR by showing laser frequency tuning over 1.0 GHz at up to 100 kHz triangular chirp rate with a nonlinearity of less than 0.6% without linearization by modulating a Bragg grating using monolithically integrated aluminum nitride (AlN) piezoactuators.

Lidar (light detection and ranging) technology has the potential to revolutionize the way automated systems interact with their environments and their users. Most lidar systems in the industry today rely on pulsed (or, "time-of-flight") lidar, which has reached limits in terms of depth resolution. Coherent lidar schemes, such as frequency-modulated continuous-wave (FMCW) lidar, offer significant advantage in achieving high depth resolution, but are often too complex, too expensive, and/or too bulky to be implemented in the consumer industry. FMCW, and its close cousin, swept-source optical coherence tomography (SS-OCT) are often targeted towards metrology applications or medical diagnostics, where systems can easily cost upwards of $30,000. &lt;p&gt;In this dissertation, I present my work in chip-scale integration of optical and electronic components for application in coherent lidar techniques. First, I will summarize the work to integrate a typically bulky FMCW lidar control system onto an optoelectronic chip-stack. The chip-stack consists of an SOI silicon-photonics chip and a standard CMOS chip. The chip was used in an imaging system to generate 3D images with as little as 10um depth precision at stand-off distances of 30cm. &lt;p&gt;Second, I will summarize my work in implementing and analyzing a new post-processing method for FMCW lidar signals, called "multi-synchronous re-sampling" (MK-re-sampling). This involved Monte Carlo studies of laser phase noise under non-linear signal processing schemes, so I will show stochastic simulations and experimental results to demonstrate the advantages of the new re-sampling method. QS-re-sampling has the potential to improve acquisition rate, accuracy, SNR, and dynamic depth range of coherent imaging systems.

We propose a high-resolution frequency-modulated continuous-wave (FMCW) ranging system using multi-source stitching, which can effectively solve the contradiction between detection depth and scanning bandwidth. The system only needs a photodetector to simultaneously detect the measurement signal corresponding to each laser source, and can effectively correct the frequency modulation nonlinearity, the system structure is simplified while reduces the amount of data acquisition and enhances real-time. In this paper, ten tunable laser sources are set up for simulation measurements, which increases the resolution of the system by a factor of 10 and increases the signal-to-noise ratio (SNR). Demonstration experiments are performed with two lasers, the results show that the measurement error at 2.6 m was usually less than 10 μm and the maximum error is 20 μm. In addition, this system is very promising to be combined with silicon photonics to achieve chip-scaled LiDAR, which will enhance its application potential greatly.

Light detection and ranging (LIDAR) has emerged as an indispensable tool in autonomous technology. Among its various techniques, frequency-modulated continuous wave (FMCW) LIDAR stands out due to its capability to operate with ultralow return power, immunity to unwanted light, and simultaneous acquisition of distance and velocity. However, achieving a rapid update rate with submicrometer precision remains a challenge for FMCW LIDARs. Here, we present such a LIDAR with a sub-10-nanometer precision and a 24.6-kilohertz update rate by combining a broadband Fourier domain mode-locked (FDML) laser with a silicon nitride soliton microcomb. An ultrahigh-frequency chirp rate up to 320 petahertz per second is linearized by a 50-gigahertz microcomb to reach this performance. Our theoretical analysis also contributes to resolving the challenge of FMCW velocity measurements with nonlinear frequency sweeps and enables us to realize velocity measurement with an uncertainty below 0.4 millimeter per second. Our work shows how microcombs can unlock the potential of ultrafast frequency sweeping lasers.

Frequency-modulated continuous-wave (FMCW) LiDAR systems are drawing increasing interest due to their potential applications in autonomous driving, machine perception, rapid prototyping, and medical diagnostics. The nonlinearity of a laser’s input-output transfer function can degrade the performance of an FMCW LiDAR. However, traditional discrete-time electro-optical phase-locked loops (DT-EOPLLs) face an unfavorable trade-off between chirp bandwidth and Mach-Zehnder delay. We present an integrated continuous-time electro-optic phase-locked loop (CT-EOPLL) to address this problem. The proposed EOPLL is very wideband, with its loop bandwidth equal to its reference frequency. This feature enables it to relax the trade-off between chirp bandwidth and Mach-Zehnder (MZ) delay by 10× in dB scale, which consequently reduces the area and loss associated with the silicon photonic delay implementation. It also does not suffer from the challenging issue of spurs in wideband PLLs because it features image and harmonic spur suppression in the loop using single-sideband (SSB) and harmonic-reject (HR) mixing techniques. The electrical part of this EOPLL is implemented in 65nm CMOS technology, and its optical integrated circuit is fabricated using a silicon photonic process. Featuring more than 25dB of suppression of the highest spur, this EOPLL is utilized in a high precision LiDAR sensor that shows an RMS depth precision of 558μm at 2m distance, and a 9.4mm RMS depth resolution at ranges exceeding 3.3m.

Recent advances in the development of ultra-low loss silicon nitride integrated photonic circuits have heralded a new generation of integrated lasers capable of reaching fiber laser coherence. However, these devices are presently based on self-injection locking of distributed feedback laser diodes, increasing both the cost and requiring tuning of laser setpoints for their operation. In contrast, turn-key legacy laser systems use reflective semiconductor optical amplifiers (RSOAs). While this scheme has been utilized for integrated photonics-based lasers, so far, no cost-effective RSOA-based integrated lasers exist that are low noise and simultaneously feature fast, mode-hop-free, and linear frequency tuning as required for frequency modulated continuous wave (FMCW) LiDAR or for laser locking in frequency metrology. Here we overcome this challenge and demonstrate a RSOA-based, frequency agile integrated laser, that can be tuned with high speed, with high linearity at low power. This is achieved using monolithic integration of piezoelectrical actuators on ultra-low loss silicon nitride photonic integrated circuits in a Vernier filter-based laser scheme. The laser operates at 1550 nm, features a 6 mW output power and a 400 Hz intrinsic laser linewidth, and allows ultrafast wavelength switching within 7 ns rise time and 75 nW power consumption. In addition, we demonstrate the suitability for FMCW LiDAR by showing laser frequency tuning over 1.5 GHz at 100 kHz triangular chirp rate with a nonlinearity of 0.25% after linearization and use the source for measuring a target scene 10 m away with a 8.5 cm distance resolution.

The interference between a frequency-modulated continuous-wave (FMCW) light detection and ranging (LiDAR) and other LiDARs or sunlight was theorized, considering the spatial overlap, frequency overlap, and intensity ratio. It has been concluded that the interference probability between LiDARs can be lower than a safety standard value for autonomous vehicles when the number of the resolution points of a single LiDAR is increased sufficiently and that the interference with incoherent sunlight does not occur. Due to the coherent detection of FMCW, such ambient light immunity is much better than time-of-flight LiDAR. The dependence of the interference on the wavelength range, sweep bandwidth, and sweep period was also observed experimentally using a silicon (Si) photonics FMCW LiDAR chip incorporating slow-light grating beam scanners. It was shown that the interference can be suppressed by increasing the number of resolution points and changing their common parameters moderately. Regarding the contamination of sunlight, unwanted beam shift due to heating was observed, although it will be suppressed simply by wavelength filtering.

No abstract

We demonstrate an integrated optical-electrical calibration module for improving the nonlinearity of the optical source for frequency-modulated continuous-wave (FMCW) LiDAR applications. The linearity of the light source has a considerable influence on FMCW LiDAR range performance, and calibration is typically necessary. However, a majority of existing calibration techniques are based on separate devices, resulting in high cost and limited integration. Our module is made up of a silicon photonic chip with a long optical delay line, a tunable phase shifter, two balanced photodetectors, and some passive components. For this module, we also built the aided amplification and voltage bias circuits. After packaging this module, we used it with our nonlinearity calibration algorithm to analyze the laser's relative nonlinearity. After nonlinearity calibration, the laser relative nonlinearity 1-r² could be improved to 10^-6∼10^-7. In the future, the calibration result of nonlinearity could be enhanced further by increasing the length of the on-chip optical delay line.

LiDAR (Light Detection and Ranging) captures high-definition real-time 3D images of the surrounding environment through active sensing with infrared lasers. It has unique advantages that can compensate the fundamental limitations in camera-based 3D imaging via vision algorithms or RADARs, which makes it an important sensing modality to guarantee robust autonomy in self-driving cars. However, high price tag of existing commercial LiDAR modules based on mechanical beam scanners and intensity-based detection scheme makes them unusable in the context of mass produced consumer products.The focus of thesis is on the integrated coherent LiDAR with optical phased array-based solid-state beam steering, which has great potential to dramatically bring down the cost of a LiDAR module. It begins with an overview of LiDAR implementation options and system requirements in the context of autonomous vehicles, which leads us to conclude that beam-steering coherent FMCW LiDAR in optical C-band is indeed the best implementation strategy to realize low-cost automotive LiDARs. Motivated by this observation, a quantitative framework for evaluating FMCW LiDAR performance is also introduced to predict the design that satisfies car-grade performance requirements. Then the thesis presents the silicon implementation results from our single-chip optical phased array and integrated coherent LiDAR prototype. Our implementations leverage the 3D heterogeneous integration platform, where custom silicon photonics and nanoscale CMOS fabricated at a 300 mm wafer facility are combined at the wafer-scale to minimize the unit cost without I/O density issues. After discussing remaining challenges and possible ways to enhance the operating range and system reliability, this thesis finally addresses the problem of fundamental trade-off between phase noise and wavelength tuning in FMCW laser source, and present circuit- and algorithm-level techniques to enable FMCW measurements beyond inherent laser coherence range limit.

Optical single sideband (OSSB) modulation is widely used in radio-over-fiber (RoF) system, nanophotonic phase noise filter, frequency-modulated continuous wave (FMCW) lidar and so on. We demonstrate a silicon dual-parallel Mach-Zehnder modulator (DP-MZM) with tunable optical power splitting ratio to generate OSSB signal with ultra-high sideband suppression ratio (SSR). To mitigate the SSR deterioration caused by the limited extinction ratios (ER) of the two sub-MZMs due to the process tolerance and the imbalance in their RF driving powers in practical RF links, we adjust the distribution of the incident optical power between the two sub-MZMs with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 2$ </tex-math></inline-formula> switch. With this technique, the SSR measured at 20 GHz is better than 39.1 dB. A theoretical analysis is also provided to explain how the unwanted sideband is suppressed by adjusting the optical power splitting ratio.

An integrated continuous-time electro-optic phase-locked loop (CT-EOPLL) is presented that features image and harmonic spur suppression, and is used in a frequency-modulated continuous-wave (FMCW) LIDAR. The proposed EOPLL has its loop bandwidth equal to its reference frequency, which enables it to relax the trade-off between chirp bandwidth and Mach-Zehnder (MZ) delay and consequently reduce the area and loss associated with the silicon-photonic delay implementation by 10×. Image and harmonic spurs are rejected through single-sideband (SSB) and harmonic-reject (HR) mixing techniques. This EO-PLL is integrated in 65nm CMOS technology, suppresses the highest spur by more than 25dB, and is used in a LIDAR system that can detect an object at ranges exceeding 3.3 meters with an RMS depth precision of 558μm at 2m distance and 9.4mm depth resolution.

The Hilbert transform can resample the signal to compensate for the nonlinear frequency sweeping phenomenon and precisely measure a distance and velocity through frequency-modulated continuous-wave (FMCW). Instead of an additional auxiliary interferometer, the direct Hilbert-transform resampling on the main interferograms of a silicon platform could correct the optical-source phase error to form compact light detection and ranging (LiDAR) systems in the characterizations of distances and velocities. More than two samples in an interferogram period will be a criterion in the sampling rate-limited FMCW distance tests. 876.86 cm and 18.058 cm ranging limits are demonstrated through 5 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> and 1x10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> samples per second from the data acquisition, respectively, in a process-insensitive Mach-Zehnder directional coupler for FMCW-based LiDAR applications. The velocity of 200 mm per second was also illustrated in 5 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> samples per second. Moreover, the Hilbert-transform resampled on the main interferometer is superior to the peak-valley approach in the resampling data points, ranging accuracy, and low noise.

This talk discusses the application of silicon photonics technology to LiDAR using the Frequency Modulated Continuous Wave (FMCW) method. The presentation will feature measurement results from silicon photonic-based FMCW LiDAR systems and will highlight future developments for the technology. Additionally, real results, as demonstrated by the first fully integrated silicon photonics FMCW chip, will be shared with a focus on the value of critical vector measurements of polarization intensity, velocity and motion. The presentation will explain how coherent 4D imaging can take full advantage of all of the information that the light carries back when interacting with objects.

LiDAR sensors are key to ensure safety and efficiency of autonomous vehicles and mobile robotic systems. But current commercial LiDAR technologies cannot face the issues in terms of costs, reliability and form factors that are hindering widespread adoption. Steerlight, a CEA-Leti spin-off, develops a new generation of on-chip LiDARs that relies on Frequency Modulated Continuous Wave (FMCW) and Silicon Photonics. FMCW provides instantaneous depth and velocity acquisition while Silicon Photonics enables the integration of the optical and electronics functionalities on a single chip. This paper will first describe the proposed silicon photonics based architecture. Subsequently, various demonstrations will illustrate the roadmap towards miniature and scalable LiDARs. Such features will contribute to making a wide range of devices smarter and safer, beyond the automotive and robotics markets.

Abstract Recently, light detecting and ranging (LiDAR) technology has gained significant attention due to its wide‐ranging applications, particularly in 3D terrain mapping, atmospheric measurement, and autonomous driving. Most commercially available LiDAR systems employ mechanical beam steering, which presents limitations such as slower scanning speeds, lower reliability, and larger device size. In contrast, solid‐state LiDAR is emerging as a viable alternative, offering enhanced performance and integration potential. Among the various techniques, frequency‐modulated continuous wave (FMCW) LiDAR stands out, especially for its suitability in velocity measurements and its compatibility with silicon‐based integration. This work introduces a new bridge‐balanced photodetector (Bridge‐BPD) for enhanced performance in FMCW LiDAR systems. By integrating optical couplers and Germanium‐Silicon photodetectors (Ge/Si PDs), this BPD improves the common‐mode rejection ratio (CMRR) by up to 12.8 dB compared to traditional methods, achieving 45.8 dB at a wavelength of 1550 nm. With FMCW LiDAR systems, high detection sensitivity is demonstrated and a detection probability of 90% at −98 dBm. This novel BPD offers results comparable to commercial InP‐based detectors, paving the way for further optoelectronic integration in LiDAR applications.

硅光电倍增管(SiPM)光子数分辨性能受限于暗计数、光学串扰及高频信号堆积等，无法满足高速光子检测的需求。我们基于被动淬灭SiPM，采用了高通滤波放大与低噪声射频放大结合的方案，增强信号幅度的同时抑制基线漂移，在保障信号完整性的前提下提升多光子雪崩事件的分辨率，实现了雪崩信号的大动态范围线性提取。高通滤波后，雪崩信号的下降时间从50.4 ns减小到3.7 ns，减少了雪崩的堆叠效应，拓宽了器件的响应带宽。在激光重复频率为10 MHz的条件下，实现了最多25个光子的光子数分辨。此外，SiPM输出信号的有效采集对其分辨性能至关重要，我们通过调节示波器垂直采样分辨率，确定了最适合信号采样的区间，为后续SiPM光子数可分辨探测器的集成设计以及动态范围优化提供支持。

半导体激光器因其效率高、体积小、发光范围广、价格低廉等优势一直作为激光器中最重要、最实用的一类，其中1.5 μm附近是半导体激光器中非常重要的一个波段，目前该波段已经在医疗、激光雷达、光纤通信、保密通信、军工等领域有广泛应用。1.5 μm附近半导体激光器在结构上一般使用分布式反馈型和分布式布拉格光栅型结构，在有源区上，量子阱结构目前发展得最为成熟，量子点结构也在不断研究过程中。本文围绕1.5 μm波段的半导体激光器，主要讨论量子阱激光器和量子点激光器，其中包含DFB和DBR结构，叙述纳米低维结构激光器的技术发展，分析其技术特点，对1.5 μm波段的半导体激光器的技术发展趋势进行了展望。

可调谐外腔半导体激光器具有调谐范围宽、线宽窄、输出功率高、单模输出等优良特性，在白光干涉测量技术、波分复用系统、相干光通信、光纤传感等领域有着广泛的应用。本文首先介绍了可调谐外腔半导体激光器的基本原理, 对衍射光栅结构、光纤布拉格光栅结构、波导结构三种主要的TECDL结构进行了详细的综述和比较。阐述了各种可调谐外腔半导体激光器的国内外发展状况，分析了不同外腔结构的优缺点，最后总结可调谐外腔半导体激光器的不足，展望了可调谐外腔半导体激光器的发展前景。

传统光纤在引导光方面具有优异的性能，已广泛应用于长距离光通信。虽然光纤可以有效地传输光，但其功能受到铁芯和包层材料(如锗掺杂硅和硅玻璃)介电性能的限制。光纤通过在光纤尖端集成超表面，正在成为纳米光子学和光纤领域的重要光耦合平台。为了提高对自旋电磁波的控制，本研究设计了一种可直接在光纤端面集成的超表面。在1550 nm波长的入射光照射下，可实现偏振无关的双焦点聚焦，焦距为10 um。同时，通过改变超表面周围的介质折射率还可以实现连续变焦功能，使得空间光场的连续调制成为可能。随着通信能力的提高，具有多自旋光束的独立操控光纤超表面能够在多目标探测雷达系统和多目标多输入多输出(MIMO)通信中得到实际应用。

通过对近几年研究单位报道的VCSEL的研究成果以及目前各大公司的商用VCSEL产品进行分析总结，重点介绍了VCSEL的商用产品以及研究领域其性能优化情况，综述了近几年VCSEL的研究进展。

随着微波光子学和相控阵天线技术的广泛应用，因相控阵天线的窄带宽的缺点，目前尚未能很好与传统的电子对抗系统进行融合，本文引入光学延时方式，使得光控相控阵具有宽带的特点，工作频率覆盖2~18 GHz，满足电子对抗领域需求。本文提出的基于宽带光控相控阵的电子对抗系统实现了电扫描、高增益、灵巧波束控制以及小型化低功耗方面的功能，性能进一步提升。并在此系统的基础之上，提出了一种基于宽带光控相控阵的电子对抗方法。