LiDAR Range and Sensitivity Enhancement

A light detection and ranging (LIDAR) sensor system for autonomous vehicles that uses an integrated light source to improve range and performance. The system has two devices: a laser source that generates an optical signal associated with a local oscillator (LO) signal, and an optical amplifier array device that amplifies the optical signal. The amplified signal is transmitted and receives reflected light. This allows longer ranges compared to using just the laser. The LO signal is also received to determine range and velocity. The integrated light source enables higher energy output from the laser and amplifier for better sensing.

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Adaptive lidar system that can dynamically focus the lasers to optimize imaging of objects and scenes. The system uses high-resolution, high-bandwidth digital micromirror arrays to steer the laser beams. This allows arbitrary pointing and focusing rather than fixed scanning. The micromirrors can independently steer each laser to focus on specific areas of interest. The system can switch between focusing modes to adapt to priorities and conditions. This enables more efficient and effective lidar imaging compared to fixed scanning.

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A low-cost, integrated lidar system using a 1550nm laser and a rotating mirror for scanning instead of a galvanometer. The system simplifies the lidar design by eliminating the galvanometer and using a rotating mirror for scanning. It also uses a frequency multiplier to reduce the wavelength of the reflected signal to match the sensitivity of lower-cost silicon detectors. The simplified design allows low-cost, integrated lidar with a longer detection range compared to 905nm lidar.

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Lidar sensor with non-uniform instantaneous field of view to improve target detection and identification distance. The lidar has a receiving system with changing field of view angles per pixel. The maximum field of view is multiple times the minimum. This compresses the field of view where targets are farther while expanding closer fields. It allows larger entrance pupils for distant targets without affecting nearby ones. The non-uniform FoV improves recognition distance compared to uniform FoV lidars.

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Lidar system with dynamic range optimization to enable reliable detection of objects with varying reflectivities at different distances. The lidar system uses a combination of attenuation, lens design, and detector placement to address issues like optical saturation and false detections due to dynamic range. The system includes a lens setup to concentrate the laser beam onto the detector, an attenuator before the detector to adjust transmissivity, and an aperture to block unwanted components. This allows optimizing the detection of weakly reflective objects at distance without saturation or false detections from bright objects close by.

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Lidar system with improved ranging accuracy and range by using multiple exit areas with different modulation frequencies and emission powers. The system has an emission array with multiple areas that can individually control the modulation frequency and power of the laser signal they emit. This allows optimizing the energy density and modulation frequency for each area to match the detection requirements of near and far fields. By having areas with lower frequency and higher energy density for far field detection and higher frequency and lower energy density for near field, it improves both range and accuracy compared to a single modulation frequency.

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Hybrid pulse/coherent lidar system that combines pulse lidar and coherent lidar techniques to improve sensitivity and range compared to traditional pulse lidar. The system uses a pulse lidar setup with a laser and receiver, but adds a separate coherent light source and detector to mix with the returning pulse. This coherent mixing term provides additional signal that can boost sensitivity for distant or low reflectivity targets. By separately controlling the pulse and coherent light levels, the system can optimize performance for different scenarios.

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Solid-state lidar with multiple transmission modules to improve uniformity and reduce errors in distance measurements. The lidar has multiple transmitting modules arranged around a central receiving module. Each transmitting module contains multiple light emitting units, with lasers arranged in a strip shape. This reduces the length of the emitting units compared to a single long strip. The shorter units have more uniform light emission. Multiple modules allow covering a wide field of view with shorter uniform emitting areas. This reduces distance measurement errors compared to long non-uniform emitting areas. The lidar can also have gap-filling lasers on the module edges to cover blind zones. The modules have electrodes to simultaneously drive all lasers.

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Laser radar system, laser transceiver, and autonomous driving equipment with improved light utilization for longer range and better accuracy. The system uses microlenses or optical shaping to concentrate the laser beams onto the small photosensitive areas of each pixel in the receiver array. This prevents wasted light outside the pixels and increases signal intensity and detection sensitivity.

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A lidar system and method with improved range, resolution, and accuracy compared to conventional lidar. The technique involves using a multiple-beam lidar setup with overlapping beams. Instead of waiting for each pulse to return before emitting the next one, multiple beams are emitted simultaneously in a sweep. This allows faster data acquisition with shorter latency. The overlapping beams provide better resolution and accuracy by reducing angular spacing between adjacent points. However, it does have tradeoffs like reduced range due to shorter dwell time at each beam orientation.

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Lidar system with separate transmitters for long and short range measurements to reduce internal crosstalk interference. The lidar has two transmitters, one for long range and one for short range. An optical system reflects the short range transmitter's beam to a different area on the mirror compared to the long range transmitter's beam, preventing internal crosstalk between the two transmissions. This reduces errors in short range measurements caused by crosstalk light from the long range transmitter.

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Lidar system with adaptive illumination and detection configurations to improve angular resolution and performance when the number of emitter elements is limited. The system has a transmitter with adjustable optical path between the emitters and lens, allowing changing the emitter-lens distances. This enables flood illumination with shorter paths or mixed illumination with longer paths. A control module adjusts emitter activation, exposure times, and lens movement based on scene requirements. This dynamically configures the system for optimal performance in different scenarios. The receiver also has adjustable exposure.

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A lidar system that scans in a constant direction without spreading the beam. The system uses a non-mechanical light transmitting module that drives individual light emitting elements to irradiate light in a specific direction. The light is transmitted through optical systems and received by a corresponding number of photodetector cells. This allows focused beam scanning without mechanical movement. The system combines optical signals from adjacent cells to increase sensitivity. The light emitting elements and photodetectors are arranged in arrays. The light is modulated at different frequencies by one array and demodulated at the same frequencies by the other array.

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Target detection in FMCW LIDAR systems using noise calibration and compensation to improve accuracy and reliability. The method involves estimating the LIDAR system noise in a calibration state and comparing it to the baseband signal in target detection. The comparison determines the likelihood of a signal peak indicating a target. Calibration includes measuring noise with no targets, low power startup, occluded view, and target absent. The calibration provides noise energy, moments, and impulse noise tracking. Masking frequencies below/above thresholds reduces reflections/aliasing.

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Optimizing the resolution, dynamic range, and signal-to-noise ratio of a lidar system by selectively limiting the illumination area compared to the detection area. The lidar has multiple lasers with smaller fields of view than the detectors. An adaptive shutter limits the illumination to a smaller transparent area. The ratio of transparent area to laser fields is chosen for desired lidar performance metrics like resolution, dynamic range, and SNR.

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Light detection and ranging (LIDAR) system that improves performance by adaptively determining the number of laser pulses and timing between pulses based on factors like environmental conditions and measurement requirements. This allows optimizing metrics like signal-to-noise ratio and confidence level. The decision on pulse count and timing is made dynamically during operation.

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Coaxial lidar design with improved accuracy and reliability by eliminating interference in the optical path. The coaxial lidar has a unique optical layout that reduces interference between the outgoing and returning light beams. This improves measurement accuracy by preventing interference that can degrade distance measurements. The coaxial lidar design includes features like coherent cancellation, phase shifting, and optical couplers to achieve this.

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Expanding the field of view and reducing optical signal loss in laser radars using a specialized optical system configuration. The laser radar has a transceiver module, fiber coupling module, conjugate system module, scanning module, and beam expansion module. The conjugate system focuses the emitted laser and adjusts the distance between its focal point and the scanning module to expand the scanning field. During reception, the conjugate system brings the focal point closer to the scanning module to reduce offset. This balances expanding view with minimizing offset for better performance.

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Laser radar receiving device, system, stray light elimination method and storage medium that reduces blind spots in short range laser radar. The key idea is to distinguish between stray light signals and actual echoes by controlling the bias voltage applied to the photoelectric conversion unit. Before ranging, the device collects the stray light signal and sets a lower bias voltage. During ranging, it increases the bias voltage to enhance the conversion gain. This allows separating the weaker echoes from the stronger stray signals based on waveform differences.

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A lidar sensor design to improve accuracy and reduce pixel count for lidar sensors with small, closely-spaced pixels. The design addresses issues of parallax, distortion, and light collection efficiency in lidar sensors with small pixels. It involves limiting the observation area to the actual field of view where reflected light is expected, instead of the entire sensor area. This reduces unnecessary collection of ambient light or noise from pixels. The sensor also compensates for lens distortion by adjusting the expected projected shape and position of the light on the focal plane. This improves accuracy by accounting for the non-ideal lens behavior. By limiting the observation area and accounting for distortion, it reduces the number of pixels needed compared to using the full sensor area. This can significantly lower pixel count and cost while still providing high accuracy.

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A 3D LiDAR sensor with improved accuracy by reducing noise caused by stray light. The sensor uses baffles and shields around the light transmission and reception paths to limit the angles of light entering the sensor. This prevents stray light from reaching the detector and distorts distance measurements.

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Time-of-flight lidar system for improved environmental scanning using coherent detection. The system sends a narrow band laser beam and splits it into short pulses and the residual beam. The pulses are scanned using a fast switching module like an acousto-optic modulator. The residual beam is used for coherent detection by amplifying weak signals. This allows amplifying faint returns without increasing overall laser power. The coherent detection improves weak signal sensitivity compared to direct detection.

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Compensating for internal reflections and Doppler shifts in optical rangefinding systems like LIDAR. The system adds a non-carrier pilot tone to the output signal to enable Doppler correction. It also subtracts internal reflections from the returned signal using a hybrid mixer and digitizers. This improves range accuracy by mitigating negative effects from internal optics. The subtraction is done by mixing the returned signal with a reference and detecting the real part. The complex portion is then digitally reconstructed to find the range.

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Reducing crosstalk in lidar sensors to improve accuracy by using separate detection devices in the receiver. The lidar sensor has a separate, spatially distinct second detection device in addition to the main detector. During operation, the main detector is used for normal scanning and data acquisition. But when a strongly reflective object is detected, the second separate detector is activated to capture the reflected light. This avoids crosstalk between pixels caused by saturation of the main detector by bright objects. The separate detector provides more accurate and detailed data for those objects without contamination from surrounding reflective surfaces.

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Laser radar with improved dynamic range by widening the light spot received from targets. The radar has a transmitting module to emit signal light and a receiving optical module to widen the light spot from echoes. This widening is done by projecting the expanded spot onto the detection module. The widening can be horizontal or vertical. By spreading the light, it allows detecting fainter echoes and expands the radar's dynamic range. The spreading is done by strobing subsets of the light sources in the array according to surface areas.

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Lidar system with improved vertical resolution without increasing the number of detector channels. The lidar uses time division multiplexing (TDM) to transmit and receive laser signals sequentially in time slots. This allows reducing the number of detector channels compared to simultaneous reception. The TDM technique involves transmitting from multiple channels in separate time slots and receiving in corresponding time slots using the same number of channels. This enables higher vertical resolution without needing more detector channels. The vertical scan is performed by scanning the transmitted laser beams in time slots without overlap. The received signals are amplified and detected to calculate distances. The TDM technique allows increasing vertical resolution without increasing detector channels compared to simultaneous reception.

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LIDAR system for autonomous vehicles that improves detection of nearby objects by using secondary laser beams to supplement the main beam. The system has optical elements along the transmit path that divert a portion of the primary laser beam as a wide, diffused secondary beam towards the receive path. This secondary beam illuminates nearby objects not fully covered by the main beam due to offset between transmitter and receiver. It increases detection of objects in the near field, reducing parallax errors.

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Dual receiver lidar system that combines laser pulse transmission and dual receiver capability using optimized optical designs. The system allows separate laser pulse emitters with different parameters to be combined in a common optical path. It uses specialized mid-range, long-range, and short-range receiver optics with small apertures and wide fields of view. This enables high probability single-photon detection at different ranges using microelectromechanical (MEMS) mirrors, single-photon avalanche diodes (SPADs), and scanning mirrors.

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Combining laser pulse transmissions in a LiDAR system to enable dual-receiver LiDAR with improved resolution and range compared to single-receiver LiDAR. The LiDAR uses a common optical path for both laser transmitters and receivers. It has separate short-range and long-range optical systems for each receiver. The short-range system has a small aperture and wide FOV, while the long-range system has a large aperture and small FOV. This allows combining multiple laser pulses with different characteristics like wavelength, width, and timing. The dual-receiver LiDAR improves resolution by separating nearby and distant reflections, and extends range by using the long-range optics.

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LiDAR system that can simultaneously detect objects at both short and long ranges, overcoming limitations of conventional LiDARs. The system has separate transmitters for short-range and long-range illumination. The short-range transmitter emits a flash before the main transmitter to detect nearby objects without dazzle. The short-range returns are sampled during a period avoided by dazzle. This allows near-field detection without interference. The long-range transmitter is used for distant objects. The short-range and long-range returns are combined for complete 3D mapping.

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Lidar for autonomous vehicles that improves ranging accuracy and adds communication capabilities while reducing noise compared to direct detection lidar. The lidar uses coherent detection with a mixer, power divider, and detector to process signals. It sends laser light with polarization different from the return signal to a mixer. The mixed signal is detected and split into multiple signals. Processing those signals provides range measurements and communication data. The coherent detection reduces lidar noise compared to direct detection.

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3D imaging LiDAR system using single-photon detectors and signal processing to improve range, resolution, and dynamic range compared to existing LiDAR systems. The system integrates photon arrival times to estimate average arrival time. It uses selective strobing of detector subsets to separate signal and background photons and correlation to isolate photons associated with the emitted pulse.

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Operating a LiDAR system to improve performance in bright environments or with reflective objects by using two measurement areas on the detector. The first measurement area is used for normal operation, but if bright conditions or reflective objects are detected, the second measurement area is activated. This reduces saturation and improves accuracy in challenging conditions. A control unit switches between the areas based on input signals.

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Enhanced high dynamic range lidar that can see further and more accurately by capturing and fusing short and long distance data. The lidar has separate near and far dynamic range capture capabilities. It filters out low confidence short distances and high confidence long distances to leave only reliable data. Then it combines the remaining short and long distances to provide enhanced high dynamic range data. This allows seeing further into scenes with mixed objects like close reflective objects and distant low reflective objects.

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A compact and reliable LiDAR system with multiple transmitter and receiver channels that improves scanning resolution and reduces complexity compared to conventional LiDAR designs. The system uses arrays of closely spaced transmitter optical fibers and a collimation lens to generate collimated beams at desired angular spacing. Multiple receiver channels share a collection lens and flexibly positioned detector assemblies to reduce crosstalk and alignment errors. This allows compact LiDARs with improved scanning performance and reliability.

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Frequency-modulated lidar system with differential reception to increase detection distance and reduce noise. The system uses a laser, modulator, scanner, transmitting-receiving coaxial optical unit, and differential receiver. The modulator frequency-modulates the laser light. The scanner reflects the modulated light to the target. The coaxial unit splits and recombines the light. The differential receiver receives the reflected light and subtracts the original modulated signal to extract the range difference. This improves range by avoiding self-interference and reduces noise compared to direct reception.

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A LiDAR system that adapts the emitted light beam properties based on the distance to the object to optimize the signal-to-noise ratio at the receiver. The LiDAR system can focus the light beams before emission using elements like SLMs or LCMs to optimize SNR at specific object distances. This allows customizing the light beam characteristics like radius to maximize SNR at the receiver for each distance.

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Adaptive threshold setting for lidar and rangefinding receivers to improve noise rejection and range accuracy. The threshold for detecting reflected pulses is adjusted based on ambient light levels and noise characteristics. This allows optimizing false trigger rates while maintaining low noise levels. The threshold is lowered during calibration cycles to compensate for changing noise levels. In range mode, the threshold is further adjusted based on ambient light measurements to account for changing light conditions. This avoids overly high thresholds that miss weak returns or underly thresholds that trigger on noise.

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LiDAR system for improved range response and sensitivity in scanning LiDAR systems. The system uses two sets of optics, with the laser beam directed along one optical axis and the receiver optics imaging the received light onto a perpendicular plane. A spatial filter is placed in this second plane to filter the received light onto the detector. This configuration allows efficient collection of both near and far field light, improving the LiDAR range response compared to single-axis systems.

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A lidar system and method for object detection that uses encoded light signals instead of pulsed light to improve performance compared to traditional lidar systems. The encoded light signals have asynchronous phase delays that depend on distance to objects. This allows using phase differences to determine distances instead of waiting for pulse round trips. The encoding scheme uses phase-bounded low cross-correlation codes that have low correlation within a phase range but higher correlation outside it. This enables reliable distance measurement with low interference between encoded signals.

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Combining multiple functions of a LIDAR system to support autonomous vehicles. The LIDAR system uses techniques like dual polarization, time division multiplexing, and fiber coupling to reduce size and power consumption while maintaining range and accuracy. It involves transmitting and receiving multiple channels of light beams from the environment using a single laser source. The reflected beams are combined with local oscillator signals to generate output signals. This allows simultaneous detection of horizontal and vertical polarizations using a single transceiver. It also reduces fiber requirements for scaling LIDAR systems by integrating transmit and receive channels.

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LiDAR system for improved resolution and stability by introducing wavefront-deforming components into the laser path, particularly at the entrance pupil of the receiver. These components have periodic or random surface deformations that cause beam deflections. By adding these elements, it reduces the spreading of the modulation transfer function curves. The wavefront deformation is selected to fit the pupil diameter and be on the order of the laser wavelength.

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LiDAR systems use an image sensor that can detect both faint and bright echo signals accurately over a wide dynamic range. The image sensor has Geiger-mode photodiodes that generate electrical signals when biased beyond breakdown voltage. The signals are independent of the optical power of the incident photons. This allows the detection of both very dim and very bright echo signals with high temporal accuracy. The sensor also uses textured and/or diffractive optical elements in each pixel to direct incident photons to different photodiodes, spreading the photon flux across multiple detectors to avoid saturation and increase dynamic range.

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LIDAR system with improved spatial mixing efficiency for detecting objects using coaxial local oscillator (LO) and target return signals. The LO is generated by partially reflecting a portion of the transmitted optical beam at a focal plane. The LO and target return signals are focused at a conjugate focal plane to mix efficiently in photodetectors. This compensates for mirror motion during round trip times by aligning LO and target signals at the mixer.

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Dynamic LiDAR scanning with adjustable laser power and sensitivity to optimize object detection range and resolution while maintaining eye safety. The system scans a field of view by moving a deflector to vary the light flux and angle. It uses initial scans to identify areas without objects, then increases light power and sensitivity in those areas to detect more distant or low-reflectivity objects.

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Solid state lidar system with noise reduction for improved range and reliability in automotive applications. The system uses multiple lasers and detectors with optimized pulse sequences to achieve the desired signal-to-noise ratio. By pulsing lasers in multiple cycles and limiting detector noise, it allows using lower power lasers for eye safety while still detecting far enough. The detectors have dedicated electronics and filters to reduce solar noise. The lidar also uses wavelength-separated lasers and receivers for better resolution. This enables solid state lidar with no moving parts and longer ranges compared to flash lidar.

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Integrated photonic circuit-based 3D imaging system using LiDAR for compact, high-performance 3D imaging. The system has a photonic integrated circuit (PIC) transmitter and receiver array, both in a focal plane configuration with lenses. The PIC transmitter generates a chirped optical signal and scans it using an array of couplers. The PIC receiver array detects the frequency difference between the return signal and a local copy using coherent detection for each pixel. The lenses focus the transmitted and received light onto the arrays. This enables compact, scalable, and high-performance LiDAR 3D imaging using integrated optics.

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Frequency modulated continuous wave (FMCW) LIDAR system with extended range capability by delaying the reference signal compared to the output signal. This reduces the effective round-trip delay for longer range operation without needing improved laser performance. The reference signal is tapped from the LIDAR output and delayed using a path delay. The delayed reference is then combined with the returning signal for processing. This reduces delay-dependent degradations like laser phase noise and chirp non-linearities for longer range operation.

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Lidar receiver to reduce blind zones near objects. It controls the bias voltage applied to the photodetector during laser ranging to prevent false signals from stray light reflections. The voltage is initially lower than breakdown until after the predicted arrival time of the stray signal. This prevents excitation and recovery time. Then the voltage increases to normal for the reflected signal. This allows detecting near range reflections without blind zones.

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A compact, integrated laser transmission and reception module for LiDAR systems in autonomous vehicles that uses optical phased array (OPA) devices. The module has an OPA transmitter to emit laser light in a 2D area, an OPA receiver to capture reflected light, and a mixing device between them. The OPA transmitter and receiver are integrated as a single silicon chip, unlike separate emitters and receivers. This allows a compact, robust, and high-performance LiDAR system with improved distance measurement capability.

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