Abstract: Optical sensing apparatus includes a transmitter, which transmits outgoing FM coherent optical radiation toward a target scene, and a receiver, including an array of detectors, which output electrical signals in response to photons that are incident on the detectors, and optics to image the target scene onto the array while diverting a part of the outgoing FM coherent optical radiation to form a local beam, which mixes with incoming optical radiation from the target scene. Processing circuitry processes the electrical signals output by the detectors to produce a 2D image of the target scene, to identify an object of interest in the 2D image, which is imaged onto an area within the array, to extract beat frequencies in response to the mixed optical radiation from the electrical signals output by the detectors in the area, and to measure a feature of the object of interest responsively to the beat frequencies.

Abstract: Optical sensing apparatus includes a transmitter, which is configured to emit FM coherent optical radiation toward a target. A receiver alongside the transmitter includes an array of optical detectors. An objective optic focuses optical radiation that is reflected from the target onto the receiver. A transparent slab over the transmitter and the receiver has a first face facing the substrate and an opposing second face, which includes a first diffractive structure intercepting the transmit axis and configured to deflect a part of the FM coherent optical radiation to form a local beam propagating diagonally within the transparent slab and reflecting from the second face toward the receive axis. A second diffractive structure on the second face intercepts the receive axis and projects the reflected local beam onto the array of detectors, whereby the local beam mixes at the array with the optical radiation reflected from the target.

Abstract: Optical sensing apparatus includes a transmitter, which emits frequency-modulated (FM) coherent optical radiation along a transmit axis toward a target, and a receiver, which is disposed alongside the transmitter and comprises an array of detectors. An objective optic focuses the optical radiation that is reflected from the target onto the receiver along a receive axis. A transparent slab, disposed over the transmitter and receiver, includes a diffractive surface, which deflects a part of the FM coherent optical radiation to form a local beam propagating diagonally within the transparent slab and reflecting from within the slab toward the receive axis. A collimating metasurface on the slab, intercepting the receive axis, deflects and collimates the reflected local beam onto the array of detectors, whereby the local beam mixes at the array with the optical radiation reflected from the target.

Abstract: Disclosed herein are photodetectors using arrays of pixels with single-photon avalanche diodes (SPADs). The pixel arrays may have configurations that include one or more control transistors for each SPAD collocated on the same chip or wafer as the pixels and located on a surface of the wafer opposite to the light gathering surface of the pixel arrays. The control transistors may be positioned or configured for interconnection with a logic chip that is bonded to the wafer of the pixel array. The pixels may be formed in a substrate having doping gradient. The control transistors may be positioned on or within the SPADs, or adjacent to, but isolated from, the SPADs. Isolation between the individual SPADs and the respective control transistors may make use of shallow trench isolation regions or deep trench isolation regions.

Abstract: Optical sensing apparatus includes a radiation source, which directs a series of optical pulses toward a target scene. A first array of single-photon detectors receives optical radiation that is reflected from the target scene and outputs electrical pulses in response to incident photons. A second array of counters aggregates and counts the electrical pulses output by the single-photon detectors over respective periods indicated by respective gating signals applied to the counters. Control logic applies the respective gating signals to the counters, in each of a sequence of image frames, so as to cause different ones of the counters to aggregate and count the electrical pulses output by one or more of the single-photon detectors over different, respective gating intervals relative to each of the optical pulses, and to sum the frame histograms generated with different temporal offsets so as to compute and output a cumulative histogram.

Abstract: A sensing device includes an array of sensing elements and a bias control circuit. Each sensing element of the array of sensing elements includes (i) a photosensitive material, which is configured to generate photoelectrons in response to incident optical radiation, and (ii) a plurality of avalanche diodes, which are disposed at different, respective locations within the sensing element in electrical communication with the photosensitive material and are configured, when reverse-biased, to generate electrical avalanches in response to the generated photoelectrons. The bias control circuit is configured to selectively set respective reverse-bias voltage levels of the avalanche diodes within each sensing element to different, respective values.

Abstract: Optical sensing apparatus includes a radiation source, which directs a series of optical pulses toward a target scene with a pulse repetition interval (PRI) equal to a first number p of sampling intervals defined by a sample clock. A first array of single-photon detectors output electrical pulses in response to photons reflected from the target scene that are incident thereon. A second array of time-to-digital converters (TDCs) detect the electrical pulses that are output by respective groups of the single-photon detectors in each of a sequence of the sampling intervals in a succession of sampling frames and output respective times of arrival of the electrical pulses. Each sampling frame contains a second number m of the sampling intervals such that p and m are co-prime. Control logic receives and aggregates the times of arrival output by the TDCs into a histogram.

Abstract: Disclosed herein are photodetectors using arrays of pixels with single-photon avalanche diodes (SPADs). The pixel arrays may have configurations that include one or more control transistors for each SPAD collocated on the same chip or wafer as the pixels and located on a surface of the wafer opposite to the light gathering surface of the pixel arrays. The control transistors may be positioned or configured for interconnection with a logic chip that is bonded to the wafer of the pixel array. The pixels may be formed in a substrate having doping gradient. The control transistors may be positioned on or within the SPADs, or adjacent to, but isolated from, the SPADs. Isolation between the individual SPADs and the respective control transistors may make use of shallow trench isolation regions or deep trench isolation regions.

Abstract: An optoelectronic assembly includes: (i) a substrate having a cavity, (ii) an optoelectronic device, which is disposed over the cavity and includes an array of multiple emitters configured to emit a predefined number of light beams in response to receiving one or more electrical signals, and (iii) an integrated circuit (IC), which is mounted within the cavity, between the substrate and the optoelectronic device, and is configured to drive the one or more electrical signals to the optoelectronic device.

Abstract: An optoelectronic device includes a first semiconductor die, having first and second surfaces and including a first array of transceiver elements. Each transceiver element includes an optical transducer, which directs outgoing coherent optical radiation through the first surface toward a target and to receive incoming optical radiation that has been reflected from the target. A single-photon optical detector outputs electrical pulses in response to photons of the incoming optical radiation. A waveguide conveys the incoming optical radiation from the optical transducer to the single-photon optical detector. A second semiconductor die is bonded to the second surface of the first semiconductor die and includes a second array of logic circuits, which are coupled to receive and process the electrical pulses output by the single-photon optical detectors in corresponding ones of the transceiver elements.

Abstract: Optical sensing apparatus includes a transmitter, which is configured to transmit outgoing frequency-modulated (FM) coherent optical radiation toward a target scene. A receiver includes an array of single-photon detectors, which are configured to output electrical pulses in response to photons that are incident on the detectors. Optics image the target scene onto the array while diverting a part of the outgoing FM coherent optical radiation to form a local beam, which mixes with incoming optical radiation from the target scene. Processing circuitry is configured to compute counts of the electrical pulses output as a function of time by the single-photon detectors in response to the mixed optical radiation, to extract beat frequencies from the computed counts, and to measure ranges of points in the target scene responsively to the beat frequencies.

Abstract: A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.

Abstract: An electronic device may include a proximity sensor under a cover layer. The proximity sensor may include a light-emitter, such as an infrared light source, and a light-detector, such as an array of single-photon avalanche diodes (SPADs). The SPADs may measure light that has reflected from an external object. However, some of the light may be reflected by the cover layer, creating cross-talk. To distinguish between the cross-talk and signals from the external object, processing circuitry may histogram measurements from the SPADs. In particular, the processing circuitry may histogram near-field and/or far-field measurements into different histograms. The measurements may be weighted and/or gated prior to histogramming. In this way, cross-talk may be distinguished from the near-field and far-field signals.

Abstract: A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.

Abstract: Sensing apparatus includes a radiation source, which emits pulses of optical radiation toward multiple points in a target scene. A receiver receives the optical radiation that is reflected from the target scene and outputs signals that are indicative of respective times of flight of the pulses to and from the points in the target scene. Processing and control circuitry selects a first pulse repetition interval (PRI) and a second PRI, greater than the first PRI, from a permitted range of PRIs, drives the radiation source to emit a first sequence of the pulses at the first PRI and a second sequence of the pulses at a second PRI, and processes the signals output in response to both the first and second sequences of the pulses in order to compute respective depth coordinates of the points in the target scene.

Abstract: Sensing apparatus includes a radiation source, which emits pulses of optical radiation toward multiple points in a target scene. A receiver receives the optical radiation that is reflected from the target scene and outputs signals that are indicative of respective times of flight of the pulses to and from the points in the target scene. Processing and control circuitry selects a first pulse repetition interval (PRI), a second PRI, greater than the first PRI, and a third PRI, greater than the second PRI, from a permitted range of PRIs, drives the radiation source to emit sequences of the pulses at the first PRI, the second PRI, and the third PRI, and processes the signals output by the receiver in response to the first, second, and third sequences of the pulses in order to compute respective depth coordinates of the points in the target scene.

Abstract: A method of building a moving average histogram of photon times of arrival includes, for each time interval in first and second subsets of time intervals, latching a time reference corresponding to a time of receipt of an avalanche timing output signal of a single-photon avalanche diode (SPAD), and advancing a count stored at a memory address corresponding to the latched time reference. The memory address corresponds to a range of time references. The method further includes reading and clearing a first set of counts after the first subset of time intervals; phase-shifting the sequence of time references with respect to a set of memory addresses after the first subset of time intervals; reading and clearing a second set of counts after the second subset of time intervals; and building the moving average histogram using at least the first and second sets of counts.

Abstract: A sensing device includes a first array of sensing elements, which output a signal indicative of a time of incidence of a single photon on the sensing element. A second array of processing circuits are coupled respectively to the sensing elements and comprise a gating generator, which variably sets a start time of the gating interval for each sensing element within each acquisition period, and a memory, which records the time of incidence of the single photon on each sensing element in each acquisition period. A controller sets, in each of at least some of the acquisition periods, different, respective gating intervals for different ones of the sensing elements.

Abstract: Optical sensing apparatus includes a radiation source, which directs a series of optical pulses toward a target scene. A first array of single-photon detectors receives optical radiation that is reflected from the target scene and outputs electrical pulses in response to incident photons. A second array of counters aggregates and counts the electrical pulses output by the single-photon detectors over respective periods indicated by respective gating signals applied to the counters. Control logic applies the respective gating signals to the counters, in each of a sequence of image frames, so as to cause different ones of the counters to aggregate and count the electrical pulses output by one or more of the single-photon detectors over different, respective gating intervals relative to each of the optical pulses, and to sum the frame histograms generated with different temporal offsets so as to compute and output a cumulative histogram.

Abstract: Disclosed herein are photodetectors using arrays of pixels with single-photon avalanche diodes (SPADs). The pixel arrays may have configurations that include one or more control transistors for each SPAD collocated on the same chip or wafer as the pixels and located on a surface of the wafer opposite to the light gathering surface of the pixel arrays. The control transistors may be positioned or configured for interconnection with a logic chip that is bonded to the wafer of the pixel array. The pixels may be formed in a substrate having doping gradient. The control transistors may be positioned on or within the SPADs, or adjacent to, but isolated from, the SPADs. Isolation between the individual SPADs and the respective control transistors may make use of shallow trench isolation regions or deep trench isolation regions.