1003 results about "Avalanche photodiode" patented technology

Arrangement (10) for measuring the distance to an object, comprising: a photonic source for illuminating said object using a continuous modulated photonic wave, a solid-state image sensor, comprising an array of avalanche photodiodes and a plurality of circuits for processing signals output by said avalanche photodiodes to yield data depending on the photonic wave reflected by said object onto said photodiodes. The circuit may comprise a multiplexer at the pixel level arranged so as to accumulate the signal output by the avalanche photodiode during different sub-periods in different storage devices.

A light wave rangefinder includes a light transmitting optical system for directing a laser pulse at a target, and a light receiving optical system for receiving reflected light from the target, including a Geiger-mode avalanche photodiode (APD) array and a non-imaging optical device. The non-imaging optical device is positioned between the received reflected light and the APD array, and is configured to uniformly distribute the received reflected light across the APD array. The APD array is uniformly illuminated by a single received reflected laser pulse, producing a plurality of Geiger-mode avalanche events.

Methods and systems for optoelectronics transceivers integrated on a CMOS chip are disclosed and may include receiving optical signals from optical fibers via grating couplers on a top surface of a CMOS chip, which may include a guard ring. Photodetectors may be integrated in the CMOS chip. A CW optical signal may be received from a laser source via grating couplers, and may be modulated using optical modulators, which may be Mach-Zehnder and / or ring modulators. Circuitry in the CMOS chip may drive the optical modulators. The modulated optical signal may be communicated out of the top surface of the CMOS chip into optical fibers via grating couplers. The received optical signals may be communicated between devices via waveguides. The photodetectors may include germanium waveguide photodiodes, avalanche photodiodes, and / or heterojunction diodes. The CW optical signal may be generated using an edge-emitting and / or a vertical-cavity surface emitting semiconductor laser.

A controller for controlling the reverse-bias voltage of an avalanche photodiode in a transceiver or receiver. The controller includes memory for storing information related to the avalanche photodiode, and analog to digital conversion circuitry for receiving an analog signal corresponding to the temperature of the avalanche photodiode, converting the received analog signal into a digital value, and storing the digital value in a predefined location within the memory. Control circuitry in the controller controls the operation of the avalanche photodiode in accordance with the digital value corresponding to the temperature of the avalanche photodiode and a temperature lookup table stored in the memory. A serial interface is provided to enable a host device to read from and write to locations within the memory. The invention is also implemented as a method for controlling the reverse-bias voltage of an avalanche photodiode in a transceiver or receiver and a method for calibrating a transceiver or receiver having an avalanche photodiode.

A photon-counting Geiger-mode avalanche photodiode intensity imaging array includes an array of pixels, each having an avalanche photodiode. A pixel senses an avalanche event and stores, in response to the sensed avalanche event, a single bit digital value therein. An array of accumulators are provided such that each accumulator is associated with a pixel. A row decoder circuit addresses a pixel row within the array of pixels. A bit sensing circuit converts a precharged capacitance into a digital value during read operations.

An apparatus and method for allowing avalanche photodiode based single-photon detectors to be driven by the same electrical circuit in gated and in free-running modes is proposed. The high-performance working of all the running modes relies on the capability of tuning the rise-time value of the electrical pulse driver which activates the avalanche photodiode in Geiger mode.

A Geiger-mode avalanche photodiode may include an anode, a cathode, an output pad electrically insulated from the anode and the cathode, a semiconductor layer having resistive anode and cathode regions, and a metal structure in the semiconductor layer and capacitively coupled to a region from the resistive anode and resistive cathode regions and connected to the output pad. The output pad is for detecting spikes correlated to avalanche events.

A transmitter emits high-frequency modulated optical radiation which is reflected by an object and is received by a measurement receiver. Part of the transmitter radiation is decoupled as reference radiation and guided via a calibration path to a reference receiver whose electrical signals are fed to a frequency mixer. The frequency mixer and avalanche photodiodes acting as measurement receivers of the measuring radiation are interconnected directly via an electrical connection line upon which a mixer frequency acts. As a result thereof, optoelectronic calibration which completely compensates for the temperature-dependent phase shifts of the avalanche photodiodes is possible. Additionally, the phase shifts generated in the reference and receiver signals by the temperature drifts of the transmitter compensate one another. The overall accuracy of the distance measurement can be increased, particularly for short measuring times and immediately after the apparatus has been switched on. Furthermore, in comparison with a successive mechanical calibration process, the measuring times are halved and advantages in terms of weight, cost, and reliability are afforded since a mechanical change-over device is dispensed with.

An avalanche photodiode device operated in Geiger-mode, the device comprising a P-N junction formed on a substrate with a first semiconductor region and a second semiconductor region with an anode and cathode. The device further comprising a third semiconductor region, the third semiconductor region in physical contact with the second region, not in physical contact with the first region, and being the same semiconductor-type as the first semiconductor region. Additionally comprising a diode on the second semiconductor region and having a turn-on voltage than the P-N junction.

An avalanche photodiode and a sensor array comprising an array of said avalanche photodiodes is disclosed. Then avalanche photodiode comprises a substrate of a first conductivity type; a first well of a second conductivity type formed within the substrate; a second well of the second conductivity type formed substantially overlying and extending into the first well; a heavily doped region of the first conductivity type formed substantially overlying and extending into the first well, the junction between the heavily doped region and the second well forming an avalanche multiplication region; a guard ring formed from a first conductivity material positioned substantially about the periphery of the multiplication region at least partially underlying the heavily doped region; and an outer well ring of the second conductivity type formed about the perimeter of the deep well and the guard ring. The sensor array comprises a plurality of pixel elements, each of the pixel elements being configured to operate on discrete value continuous time (DVCT) basis. Each of the pixel elements can include the avalanche photodiode previously described.

A lidar system capable of remotely identifying calibrated absolute aerosol backscatter coefficients of atmospheric aerosol particles by transmitting a beam of light and spectrally separating the intensity of Rayleigh and Mie backscattering is disclosed. The transmitter features high pulse energy to generate sufficient Rayleigh backscattering, enabling atmospheric scanning in a timely manner. The transmitter employs a seeded Nd:YAG laser and a seeded stimulated Raman scattering wavelength shifter to achieve narrow bandwidth, eye-safe laser pulses. The receiver employs a telescope, collimating lens, beam splitter, molecular absorption filter, focusing lenses, and avalanche photodiodes. Mie backscattering is blocked by the molecular absorption filter to provide a Rayleigh signal, which is used with knowledge of atmospheric density to calibrate the Mie signal. The system is intended for atmospheric research and aerosol monitoring applications where calibrated Mie scattering intensity is necessary to measure the optical depths of aerosol structures such as plumes, clouds, and layers.

A bi-directional transient voltage suppression (“TVS”) device (101) includes a semiconductor die (201) that has a first avalanche diode (103) in series with a first rectifier diode (104) connected cathode to cathode, electrically coupled in an anti-parallel configuration with a second avalanche diode (105) in series with a second rectifier diode (106) also connected cathode to cathode. All the diodes of the TVS device are on a single semiconductor substrate (301). The die has a low resistivity buried diffused layer (303) having a first conductivity type disposed between a semiconductor substrate (301) having the opposite conductivity type and a high resistivity epitaxial layer (305) having the first conductivity type. The buried diffused layer shunts most of a transient current away from a portion of the epitaxial layer between the first avalanche diode and the first rectifier diode, thereby reducing the clamping voltage relative to the breakdown voltage. The TVS device is packaged as a flip chip (202) that has four solder bump pads (211-214). The abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims pursuant to 37 C.F.R. §1.72(b).

A compact integrated APD device integrates the bias voltage and temperature compensation functions inside a standard 4-pin PIN package. The active components of the bias and temperature compensation circuits are integrated into a single ASIC using a high-voltage CMOS process and operated at frequencies of at least 1 MHz to greatly reduce the size of the passive components. To mount the relatively large ASIC chip inside the package with the APD chip, TIA chip and passives, the 4-pin package may be modified by either recessing the pins inside the can to facilitate surface mounting the ASIC or adding a spacer inside the can to facilitate three-dimensional packaging. Communication with the bias and temperature circuits is accomplished using a unique bi-directional 1-wire serial interface via the power supply pin. A clock signal is preferably embedded in the control data to synchronize the APD with an external controller.

The output of an avalanche photodiode (APD) comprises a “photocurrent” component comprising photon initiated events resulting from the interaction of photons with the APD and a “dark current” component comprising dark carrier events arising in the APD even when the APD is not exposed to light. Differences in the pulse height distributions of photon initiated events and dark carrier initiated events are used to statistically discriminate between photocurrent and dark current components of APD output.

A method for single photon counting transmission computed tomography (CT) is described. The method is based on an apparatus consisting of a radiation source and detectors on an opposite side of the subject from the source. The radiation source is for example an X-ray tube. The detectors are independently connected to parallel, fast, low-noise processing electronics capable of recording and counting individual X-ray photons at very high rate. In one embodiment of the invention, said detector is made of a scintillator coupled to a photodetector. The photodetector can be an avalanche photodiode (APD). The method comprises the steps of: directing the low energy radiation source toward the subject; detecting the radiation transmitted through the subject towards the detectors and recording the position and energy of each individual X-ray photon; rotating the radiation source and detectors around the subject; recording data for each position of the radiation source and detectors around the subject to form projections; and creating a CT image from the recorded projection data. The proposed method allows enhancing CT image contrast and reducing radiation dose to the patient by counting individual X-ray photons.

An aspect of the present invention is directed to an avalanche photodiode (APD) device for use in oil well drilling applications in harsh, down-hole environments where shock levels are near 250 gravitational acceleration (G) and / or temperatures approach or exceed 150° C. Another aspect of the present invention is directed to an APD device fabricated using SiC materials. Another aspect of the present invention is directed to an APD device fabricated using GaN materials. According to an embodiment of the present invention, an avalanche photodiode for detecting ultraviolet photons comprises a substrate having a first dopant; a first layer having the first dopant, positioned on top of the substrate; a second layer having a second dopant, positioned on top of the first layer; a third layer having a second dopant, positioned on top of the second layer; a passivation layer for providing electrical passivation on a surface of the avalanche photodiode; a phosphorous silicate glass layer for limiting mobile ion transport, positioned on top of the third layer; and a pair of metal electrodes for providing an ohmic contact wherein a first electrode is positioned below the substrate and a second electrode is positioned above the third layer; wherein the avalanche photodiode comprises a first sidewall and a second sidewall forming a sloped mesa shape; and wherein the avalanche photodiode operates in an environment comprising a temperature approximately equal to 150 degrees Celsius.

An avalanche photodiode detector is provided with a substrate including an array of avalanche photodiodes. An optical interface surface of the substrate is arranged for accepting external input radiation. There is provided at least one cross-talk blocking layer of material including apertures positioned to allow external input radiation to reach photodiodes and including material regions positioned for attenuating radiation in the substrate that is produced by photodiodes in the array. Alternatively at least one cross-talk blocking layer of material is disposed on the optical interface surface of the substrate to allow external input radiation to reach photodiodes and attenuate radiation in the substrate that is produced by photodiodes in the array. At least one cross-talk filter layer of material can be disposed in the substrate adjacent to the photodiode structures, including a material that absorbs radiation in the substrate that is produced by photodiodes in the array.

In order to operate a single photon detector in communication wavelength band at a high speed, a DC bias voltage 2 lower than the breakdown voltage is applied to an InGaAs / InP avalanche photodiode (APD) 1. A 500 MHz sine wave gating signal 3 is superimposed with the DC bias voltage 2 and applied to the APD 1 so as to exceed the breakdown voltage by about 4V in a fractional time of each period. The sine wave gating signal 3 passed through the APD 1 is substantially completely removed by a filter 4, thereby improving S / N and enabling to detect a single photon even if the avalanche multiplication time is shortened to reduce the after pulse and the detection period. As a result, it achieves to detect a single photon in the 1550 nm communication band at a high speed.

A photodiode is provided by the invention, including an n-type active region and a p-type active region. A first one of the n-type and p-type active regions is disposed in a semiconductor substrate at a first substrate surface. A second one of the n-type and p-type active regions includes a high-field zone disposed beneath the first one of the active regions at a first depth in the substrate, a mid-field zone disposed laterally outward of the first active region at a second depth in the substrate greater than the first depth, and a step zone connecting the high-field zone and the mid-field zone in the substrate.

The invention discloses a 10G single-fiber bidirectional optical module, which comprises a burst laser driver, a burst light power indicator, a microcontroller, a single-fiber bidirectional optical device, an avalanche photoelectric diode bias control circuit, a limiting amplifier, a receiving end light power monitor and an SFP+ connector, wherein the microcontroller is mainly used for controlling the burst laser driver and the limiting amplifier; the single-fiber bidirectional optical device is connected between the burst laser driver and the limiting amplifier to realize conversion between electrical signals and light signals; and the avalanche photoelectric diode bias control circuit supplies a high bias voltage to a receiving end avalanche photoelectric diode and performs voltage compensation on the receiving end avalanche photoelectric diode according to the temperature property. The 10G single-fiber bidirectional optical module has the advantages of low design cost, simple circuit design and capability of meeting the requirement of a 10G EPON ONU symmetrical scheme.

The present invention provides a front-illuminated avalanche photodiode (APD) with improved intrinsic responsivity, as well as a method of fabricating such a front-illuminated APD. The front-illuminated APD comprises an APD body of semiconductor material, which includes a substrate and a layer stack disposed on a front surface of the substrate. The layer stack includes an absorption layer, a multiplication layer, and a field-control layer. Advantageously, a back surface of the APD body is mechanically and chemically polished, and a reflector having a reflectance of greater than 90% at the absorption wavelength band is disposed on the back surface of the APD body. Thus, incident light that is not absorbed in a first pass through the absorption layer is reflected by the reflector for a second pass through the absorption layer, increasing the intrinsic responsivity of the front-illuminated APD.

The invention relates to an optical fiber near-infrared spectrometer in the technical field of medical devices. The optical fiber near-infrared spectrometer uses multi-tail optical fiber collimator as light source optical fiber, uses a number lock technology as a technical scheme for weak signal extraction, uses a laser diode with a PD as a light source for sinusoidal modulation, uses an avalanche photodiode (APD) or photomultiplier tube (PMT) as a detector, and uses thick core-diameter plastic optical fiber, liquid-core optical fiber, silica optical fiber, a silica optical fiber bundle or glass optical fiber bundle as detection optical fiber. The invention has the advantages that the instrument can conduct nondestructive real-time hemodynamic parameter detection to biological tissues sheltered by hairs, the noise level of the instrument is low, the time resolution is high, the stability is high, the price is cheap, the hardware circuit design is greatly simplified and the portability of the instrument is realized.

An avalanche photodiode is deposited and integrated directly on top of CMOS readout circuitry. The anode of the avalanche photodiode may be independently biased at high voltage so that the avalanche photodiode may be operated in an avalanche multiplication mode. The avalanche photodiode has a multi-layered structure which is not pixilated; and photo-carrier generation and carrier multiplication may take place in the same layer or in different layers. A constant-gate-bias transistor isolates the high-voltage avalanche photodiode from the low-voltage the CMOS readout circuitry.

A photodiode array includes a plurality of arrayed individual diode devices. The arrayed diode devices include at least one active photodiode and at least one reference diode. A bias control circuit for the array monitors operation of the reference diode at an applied first bias voltage and adjusts that applied first bias voltage until optimal reference diode operation is reached. A second bias voltage having predetermined relationship to the first bias voltage is applied to the active photodiode to optimally configure array operation. More specifically, an operational characteristic of the reference diode at the first bias voltage is monitored and compared to a reference value. As a result of this comparison, the circuit adjusts the applied first and second bias voltage in order to drive the reference diode measured characteristic to substantially match the reference value. The operational characteristic that is measured may comprise reference diode responsivity or reference diode output current, and may be based on either electrical or optical device operation. Each avalanche photodiode semiconductor structure may have a conventional reverse biased pn junction semiconductor structure providing a high field region as is well known in the art. An enhanced semiconductor structure may also be utilized wherein a heavily doped layer that is physically separate from the pn junction is also included to provide a source of charge carriers that are swept into the high field region.

Embodiments of the present invention include complementary metal-oxide-semiconductor (CMOS) readout architectures for photon-counting arrays with a photon-counting detector, a digital counter, and an overflow bit in each of the sensing elements in the array. Typically, the photon-counting detector is a Geiger-mode avalanche photodiode (APD) that emits brief pulses every time it detects a photon. The pulse increments the digital counters, which, in turn, sets the overflow bit once it reaches a given count. A rolling readout system operably coupled to each sensing element polls the overflow bit, and, if the overflow bit is high, initiates a data transfer from the overflow bit to a frame store. Compared to other photo-counting imagers, photon-counting imagers with counters and overflow bits operate with decreased transfer bandwidth, high dynamic range, and fine spatial resolution.