Geiger-mode Avalanche Photodiode Arrays Research Articles

Long-Range Daytime 3D Imaging Lidar With Short Acquisition Time Based on 64×64 Gm-APD Array

This paper reports a complete solution for short-acquisition-time, flood-illumination, and non-scanning 3D imaging. Based on an InGaAs/InP 64×64 Geiger-mode avalanche photodiode array, we developed a single-photon imaging Lidar with a field of view of 19.2 mrad. A spatiotemporal dominant imaging method was also applied for depth estimation under high daytime background noise conditions. In the field tests, 3D imaging information was effectively extracted from objects with strong solar background light. An acquisition time of only 0.5 ms to 4 ms was needed for a building target approximately 1300 m away. The experimental results show that the Lidar and its data processing method have the potential for dynamic scenarios that require high performance 3D imaging, such as vehicle navigation, airborne mapping, and moving target monitoring.

Coherent sensing performance comparison of framed and asynchronous GMAPD arrays.

Single photon counting Geiger mode avalanche photodiode (GMAPD) arrays are typically used for high-resolution 3D ranging. These high-gain, high-bandwidth detectors are also feasible for coherent sensing. GMAPD arrays have two different readout architectures: asynchronous and synchronous (or framed). The individual pixels in asynchronous GMAPD arrays operate independently, reducing the loss due to blocking during the reset time. In contrast, framed GMAPD arrays are prone to saturation as they reset the entire array of pixels simultaneously. This study presents a performance comparison of asynchronous and framed GMAPD arrays for coherent sensing as a function of common system parameters. Expressions for the arm probability and blocking loss are defined to contrast the mechanisms of missed detection opportunities for both types of GMAPD detectors.

A Full CMOS Quenching Circuit With Fuse Protection for InGaAs/InP Single Photon Detectors

This brief presents a new quenching circuit with a metal fuse that aims to protect readout integrated circuit (ROIC) from breakdown due to unexpectedly high voltage from Geiger-mode avalanche photodiode (GmAPD) arrays. Fuse resistances in states of pre-burnout and post-burnout are investigated to satisfy requirements of rapid quenching and high voltage protection, respectively. Several fuse options using commercial mixed-signal CMOS processes, such as metal and polysilicon, are compared in detail. Meander metal fuse is the most suitable candidate according to measurement results. A rapidly quenching circuit integrated with metal fuse is developed using a 0.18 $\mu \text{m}$ CMOS process. After being bonding with GmAPDs and resistors, test results show that this circuit could endure a high voltage of 75 V, demonstrating that this innovative design can contribute in a low-cost and high-reliable way to high-yield large-format GmAPD arrays.

Discrete probabilistic detection model for a Geiger-mode avalanche photodiode array with crosstalk.

A discrete-time probability model is proposed to predict the detection performance of the Geiger-mode avalanche photodiode array. This model is established by considering multiple influencing factors, and crosstalk is characterized in the form of a transition matrix during the modeling process. The verification experiment shows that the results are consistent with previous results for a crosstalk-free scenario. The performance analysis also indicates that the array detection performance decreases approximately linearly with the increase of crosstalk probability. When the crosstalk probability is 20%, compared with the scenario without considering crosstalk effects, the deviation of array detection probability reaches up to 27.05%.

Development of an optical photon-counting imager with a monolithic Geiger Avalanche Photodiode array

Abstract We have developed a sensor system based on an optical photon-counting imager with high timing resolution, aiming for highly time-variable astronomical phenomena. The detector is a monolithic Geiger-mode avalanche photodiode array customized in a Multi-Pixel Photon Counter with a response time on the order of nanoseconds. This paper evaluates the basic performance of the sensor and confirms the gain linearity, uniformity, and low dark count. We demonstrate the system’s ability to detect the period of a flashing light-emitting diode, using a data acquisition system developed to obtain the light curve with a time bin of 100 μs. The Crab pulsar was observed using a 35-cm telescope without cooling, and the equipment detected optical pulses with a period consistent with the data from the radio ephemeris. Although improvements to the system will be necessary for more reliability, the system has been proven to be a promising device for exploring the time-domain optical astronomy.

Three-Dimensional Laser Imaging Based on a Photon-Counting Avalanche Photodiode Array

Photon-counting detector array is very desired for high-resolution laser imaging based on direct time-of-flight measurement. Such systems have potential applications in remote sensing with long distances. We will perform three-dimensional imaging using a large InGaAs Geiger-mode avalanche photodiode array which has single-photon sensitivity. To improve the image quality with only a few photon detections, the photon counting imaging process is analyzed and a regularization method based on pixel spatial correlation is employed for image reconstruction. The performance of the method is compared with that of conventional maximum likelihood estimation on intensity and range image reconstructions of a building about six hundred meters away.

Photon-counting panoramic three-dimensional imaging using a Geiger-mode avalanche photodiode array

A lidar system based on a photon-counting Geiger-mode avalanche photodiode (GmAPD) array can provide high range resolution three-dimensional imaging. The small number of pixels in the GmAPD array limits the size of measured scenes compared to passive cameras. Here, the performance of rapid panoramic imaging of larger scenes is investigated. Controlled environment indoor measurement at up to 24 m range is used to validate the principle. Outdoor daylight measurements of natural targets at 230 to 340 m range are performed to test the capability of the measurement system. A 20 deg by 1.8 deg scene is imaged with 0.25-mrad lateral resolution in 4 s. The standard deviation of point to plane distances for a flat wall in the outdoor measurement is 10.6 mm, giving an estimate of the achievable relative range accuracy, even if this will depend on the signal-to-noise ratio. A radiometric model is used to estimate the performance of an upgraded optimized system and the necessary laser power for imaging at longer ranges in both day and night conditions.

Error performance analysis of a non-ideal photon counting array receiver system for optical wireless communication.

In order to detect weak light from background radiation, utilizing an array of Geiger-mode avalanche photodiodes (GM-APDs) as a detector in the receiver is researched. First, the principle of a GM-APD operated in gated mode is analyzed. Based on the Poisson random process of arrival of photons, the trigger probability of a single GM-APD has been computed. Then, according to the trigger probability, a new bit error rate (BER) model of a photon-counting array receiver system is built, and the expression of BER is derived based on the quantum efficiency, signal photons, background photons, dark carriers, and the number of GM-APDs in array. Using the BER expression, the error performance of a new photon-counting array receiver system can be predicted rapidly. Furthermore, the error performance of a system based on an array of GM-APDs is investigated. The simulation results indicated that maintaining the ratio of signal photons and background photons above 1 is necessary for system operation. When background noise is limited to the acceptable range, maintaining a certain scale of GM-APDs (above 20) in array can greatly reduce the demand of transmitting power. Compared with achieving target BERs of 10-6 and 10-9, preserving a BER of 10-3 and making use of error correction coding can further improve the receiving sensitivity to 5-8dB.

Large-Format Geiger-Mode Avalanche Photodiode Arrays and Readout Circuits

Over the past 20 years, we have developed arrays of custom-fabricated silicon and InP Geiger-mode avalanche photodiode arrays, CMOS readout circuits to digitally count or time stamp single-photon detection events, and techniques to integrate these two components to make back-illuminated solid-state image sensors for lidar, optical communications, and passive imaging. Starting with 4 × 4 arrays, we have recently demonstrated 256 × 256 arrays, and are working to scale to megapixel-class imagers. In this paper, we review this progress and discuss key technical challenges to scaling to large format.

Optical attenuator for Geiger mode avalanche photodiode laser detection systems

This paper presents a method to estimate the optical attenuator according to the false firing percentage of Geiger Mode Avalanche Photodiode array detection system only under background light. The effect of the dark current and the gate setting are discussed. The efficiency of the Geiger mode avalanche photodiode detection system is improved by the optical attenuator by simulation analysis, that the false probability is reduced in all cases, and the detection probability increases accorindgly when the signal is larger than the total noise. Finally, the imaging simulation experiments show that the average ranging accuracy increase by using optical attenuator.

Simulation study of PET detector configuration with thick light guide and GAPD array having large-area microcells for high effective quantum efficiency

Background and ObjectivesLight sharing PET detector configuration coupled with thick light guide and Geiger-mode avalanche photodiode (GAPD) with large-area microcells was proposed to overcome the energy non-linearity problem and to obtain high light collection efficiency (LCE). MethodsA Monte-Carlo simulation was conducted for the three types of LSO block, 4 × 4 array of 3 × 3 × 20 mm3 discrete crystals, 6 × 6 array of 2 × 2 × 20 mm3 discrete crystals, and 12 × 12 array of 1 × 1 × 20 mm3 discrete crystals, to investigate the scintillation light distribution after conversion of the γ-rays in LSO. The incident photons were read out by three types of 4 × 4 array photosensors, which were PSPMT of 25% quantum efficiency (QE), GAPD1 with 50 × 50 µm2 microcells of 30% photon detection efficiency (PDE) and GAPD2 with 100 × 100 µm2 of 45% PDE. The number of counted photons in each photosensor was analytically calculated. The LCE, linearity and flood histogram were examined for each PET detector module having 99 different configurations as a function of light guide thickness ranging from 0 to 10 mm. ResultsThe performance of PET detector modules based on GAPDs was considerably improved by using the thick light guide. The LCE was increased from 24 to 30% and from 14 to 41%, and the linearity was also improved from 0.97 to 0.99 and from 0.75 to 0.99, for GAPD1 and GAPD2, respectively. As expected, the performance of PSPMT based detector did not change. The flood histogram of 12 × 12 array PET detector modules using 3 mm light guide coupled with GAPDs was obtained by simulation, and all crystals of 1 × 1 × 20 mm3 size were clearly identified. PET detector module coupled with thick light guide and GAPD array with large-area microcells was proposed to obtain high QE and high spatial resolution, and its feasibility was verified. ConclusionsThis study demonstrated that the overall PET performance of the proposed design was considerably improved, and this approach will provide opportunities to develop GAPD based PET detector with a high LCE.

Multiple-return single-photon counting of light in flight and sensing of non-line-of-sight objects at shortwave infrared wavelengths.

Time-of-flight sensing with single-photon sensitivity enables new approaches for the localization of objects outside a sensor's field of view by analyzing backscattered photons. In this Letter, the authors have studied the application of Geiger-mode avalanche photodiode arrays and eye-safe infrared lasers, and provide experimental data of the direct visualization of backscattering light in flight, and direct vision and indirect vision of targets in line-of-sight and non-line-of-sight configurations at shortwave infrared wavelengths.

Development of Fuses for Protection of Geiger-Mode Avalanche Photodiode Arrays

Current-limiting fuses composed of Ti/Al/Ni were developed for use in Geiger-mode avalanche photodiode arrays for each individual pixel in the array. The fuses were designed to burn out at ∼4.5 × 10−3 A and maintain post-burnout leakage currents less than 10−7 A at 70 V sustained for several minutes. Experimental fuse data are presented and successful incorporation of the fuses into a 256 × 64 pixel InP-based Geiger-mode avalanche photodiode array is reported.

InP-Based Single-Photon Detectors and Geiger-Mode APD Arrays for Quantum Communications Applications

To meet the increasing demand from quantum communications and other photon starved applications, we have developed various InP-based single-photon detectors, including discrete single-photon avalanche diodes (SPADs), negative feedback avalanche diodes (NFADs), and Geiger-mode avalanche photodiode (GmAPD) arrays. A large quantity of InP SPADs have been fabricated. Out of 1000 devices with a 25-μm active area diameter, operated under gated mode at temperature of 233 K, with a pulse repetition rate of 1 MHz and pulse width of 1 ns, the average dark count rate and afterpulsing probability are 30 kHz and 8 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> , respectively. Smaller (16-μm active area diameter) and larger (40-μm active area diameter) discrete devices have been fabricated as well, and their performances are presented along with the 25-μm diameter devices. NFAD devices can operate in free running mode and photon detection efficiency of 10-15% can be achieved without applying any hold-off time externally. When the temperature decreases from 240 to 160 K, the noise equivalent power (NEP) decreasesfrom1.9 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-16</sup> to 1.8 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-18</sup> WHz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1/2</sup> , with the activation energy being 0.2 eV. The very low NEP at 160 K makes NFAD devices an ideal choice for long distance, entanglement-based quantum key distributions. GmAPD arrays provide an enabling technology for many active optical applications, such as 3-D laser detection and ranging (LADAR) and photon starved optical communications. Both 32 × 32 and 128 × 32 GmAPD arrays have been fabricated with high performance and good uniformity. GmAPD focal plane arrays (FPAs) with framed readout mode have enabled very high-performance flash LADAR systems. GmAPD FPAs with asynchronous readout mode will enable high rate quantum key distributions and other quantum communications applications.

Development of PET/MRI with insertable PET for simultaneous PET and MR imaging of human brain

The purpose of this study was to develop a dual-modality positron emission tomography (PET)/magnetic resonance imaging (MRI) with insertable PET for simultaneous PET and MR imaging of the human brain. The PET detector block was composed of a 4 × 4 matrix of detector modules, each consisting of a 4 × 4 array LYSO coupled to a 4 × 4 Geiger-mode avalanche photodiode (GAPD) array. The PET insert consisted of 18 detector blocks, circularly mounted on a custom-made plastic base to form a ring with an inner diameter of 390 mm and axial length of 60 mm. The PET gantry was shielded with gold-plated conductive fabric tapes with a thickness of 0.1 mm. The charge signals of PET detector transferred via 4 m long flat cables were fed into the position decoder circuit. The flat cables were shielded with a mesh-type aluminum sheet with a thickness of 0.24 mm. The position decoder circuit and field programmable gate array-embedded DAQ modules were enclosed in an aluminum box with a thickness of 10 mm and located at the rear of the MR bore inside the MRI room. A 3-T human MRI system with a Larmor frequency of 123.7 MHz and inner bore diameter of 60 cm was used as the PET/MRI hybrid system. A custom-made radio frequency (RF) coil with an inner diameter of 25 cm was fabricated. The PET was positioned between gradient and the RF coils. PET performance was measured outside and inside the MRI scanner using echo planar imaging, spin echo, turbo spin echo, and gradient echo sequences. MRI performance was also evaluated with and without the PET insert. The stability of the newly developed PET insert was evaluated and simultaneous PET and MR images of a brain phantom were acquired. No significant degradation of the PET performance caused by MR was observed when the PET was operated using various MR imaging sequences. The signal-to-noise ratio of MR images was slightly degraded due to the PET insert installed inside the MR bore while the homogeneity was maintained. The change of gain of the 256 GAPD/scintillator elements of a detector block was <3% for 60 min, and simultaneous PET and MR images of a brain phantom were successfully acquired. Experimental results indicate that a compact and lightweight PET insert for hybrid PET/MRI can be developed using GAPD arrays and charge signal transmission method proposed in this study without significant interference.

A method to stabilize the temperature dependent performance of G-APD arrays

This paper presents a compensation method to stabilize the temperature dependent performance of Geiger-mode Avalanche Photodiode (G-APD) arrays for Positron Emission Tomography (PET). The compensation method is used to identify the bias voltage range that provides stable performance even at different temperatures using the G-APD’s characteristics, and to control the photo-peak variation as a function of temperature using the preamplifier gain within the identified bias voltage range. A pair of G-APD detectors and temperature sensors were located in the temperature chamber and the preamplifiers which can control the gain of the detectors using the digital potentiometer were positioned outside the chamber. The performance of the G-APD detector, especially energy resolution and coincidence timing resolution, was characterized as a function of bias voltage at different temperatures from 20°C to 40°C at 5°C increments; the energy resolution, coincidence timing resolution, and photo-peak position of all channels of G-APD PET detectors before and after the preamplifier gain correction were then measured and compared. The results of this study demonstrated that the optimal bias voltage range providing the good energy and coincidence timing resolution, 12.1±1.2% and 1.30±0.09ns, respectively, could be identified at the temperature range and the photo-peak variation and the performance at different temperatures could be stabilized by adjusting the preamplifier gain within the identified bias voltage range. We concluded the proposed method to be reliable and useful for the development of the PET system using G-APD arrays.

Development of a position decoder circuit for PET consisting of GAPD arrays

Use of channel reduction techniques that reduce the number of signals transmitted to a data acquisition (DAQ) module can lead to more efficient use of the DAQ module for PET with numerous readout channels. The purpose of this study was to develop a position decoder circuit (PDC) with a capacity to output the digital address and analog pulse of one interacted channel from numerous PET outputs. A PDC capable of reducing the number of readout channels by a factor of 32 was designed and fabricated. PET detector modules consisting of an LYSO scintillator, a 4×4 array Geiger-mode avalanche photodiode (GAPD), and a 16-channel preamplifier were also constructed to evaluate the performance of the PDC developed for this study. The output signal from the PET detector module was transmitted to the DAQ module after a 45ns delay by the PDC. Using the gain correction circuit implemented in the PDC, gain uniformity for all channels of the PET detector module was improved by 80%. Energy resolution in the PET detector was 20.4% with the PDC and 20.8% without the PDC. Timing resolution was 2.2ns with the PDC and 1.5ns without the PDC. A hot-rod phantom image was successfully acquired using proof-of-principle PET with the PDC developed for this study. Experimental results indicate that the PDC developed for this study is not only useful for the reduction of the readout channel number from the PET detector module consisting of GAPD arrays, but also for PET signal processing and PET imaging.

A Geiger-mode avalanche photodiode array for X-ray photon correlation spectroscopy

X-ray photon correlation spectroscopy (XPCS) provides an opportunity to study the dynamics of systems by measuring the temporal fluctuations in a far-field diffraction pattern. A two-dimensional detector system has been developed to investigate fluctuations in the frequency range of several Hz to kHz. The X-ray detector system consists of a thin 100 microm scintillation crystal coupled to a Geiger-mode avalanche photodiode array. In this article the elements of the system are detailed and the detector for XPCS measurements is demonstrated.

InP-based single-photon detector arrays with asynchronous readout integrated circuits

We have developed and demonstrated a high-duty-cycle asynchronous InGaAsP-based photon counting detector system with near-ideal Poisson response, room-temperature operation, and nanosecond timing resolution for near-infrared applications. The detector is based on an array of Geiger-mode avalanche photodiodes coupled to a custom integrated circuit that provides for lossless readout via an asynchronous, nongated architecture. We present results showing Poisson response for incident photon flux rates up to 10 million photons per second and multiple photons per 3-ns timing bin.

Crosstalk Characterization in Geiger-Mode Avalanche Photodiode Arrays

Following our work on Geiger-mode avalanche photodiode arrays, we have recently been dealing with the crosstalk issue in newly developed dense arrays with a minimum distance between pixel centers of 84 mum. In this paper, we present our crosstalk measurement approach, including the experimental setup and the offline calculation methods. Different characterizations of the crosstalk probability PCT versus capacitance have been performed to extrapolate the PCT when no measurement setup loads the pixels. We also present results regarding the crosstalk probability versus pixel distance and bias. Moreover, by adopting a slightly different approach, the probability density decay time has been measured to investigate about crosstalk origin.