InGaAs Avalanche Photodiodes Research Articles

Radiation damage of InGaAs avalanche photodiode under gamma ray irradiation

The γ-ray irradiation characteristics of InGaAs avalanche photodiode (APD) in a space radiation environment have been comprehensively investigated through an in-depth study. The results show that γ-ray can cause the dark current and low frequency noise of InGaAs APD to increase, while the avalanche breakdown characteristics, multiplication gain, spectral response and capacitance of the device are less affected by irradiation, and almost no obvious changes occur, which suggests that these parameters are insensitive to ionizing radiation. In addition, the activation energy of the device under different bias voltages is significantly increased by the ionization damage after irradiation. Finally, the annealing experiments at different temperatures after irradiation were carried out. It is found that the interface state induced by radiation is the main factor leading to the increase of dark current, low frequency noise and activation energy of InGaAs APD. Reducing the interface state can improve the device’s ability to inhibit ionizing radiation damage.

Illumination Induced Negative Differential Resistance in InGaAs Avalanche Photodiode

Illumination Induced Negative Differential Resistance in InGaAs Avalanche Photodiode

Resonant InGaAs Detectors and Emitters for Passive and Active Imaging Application

In this work, we design an InGaAs avalanche photodiode (APD) with a higher photocurrent to dark current ratio than a conventional APD. The improvement is based on optical confinement in an optical resonator, which increases the optical intensity in the detector volume and thus its quantum efficiency. With optical confinement, the absorbing layer can be 20 times thinner than the conventional APD, reducing the intrinsic generation-recombination dark current by the same amount and still be able to produce 90.9% of the photocurrent. The photocurrent to intrinsic dark current ratio can thus be increased theoretically by 18.2 times in concomitant with a lower operating voltage. Higher photocurrent can also be obtained using a thicker absorber. Besides APDs, the optical resonator structure can also be applied to p-i-n photodiodes for similar improvement. To further increase the detection sensitivity, we design an efficient InGaAsP light emitting diode (LED) having a similar resonator geometry. The resonator geometry enables more collimated emission and increases the optical power theoretically by more than 36 times compared to a conventional LED. Integrating the resonant APD and LED together will yield a powerful SWIR transceiver for various low light, LIDAR, and 3-dimensional imaging applications.

Double-Pulse Superposition Technique for Avalanche Extraction From Gated InGaAs/InP Single-Photon Detectors

Gated InGaAs avalanche photodiodes are often used for synchronous single-photon detection in the near-infrared wavelengths of 1310 and 1550 nm for optical fiber communication. However, one of the main obstacles limiting their application is the difficulty in extracting a weak photon-induced avalanche pulse from background noise. Here, we describe a double-pulse superposition technique to detect the signal, which uses a synchronized pulse to raise the avalanche signal above the discriminating threshold so the avalanche signal can be easily detected. This technique provides a simple idea for a practical gated single-photon detector to sense avalanche signals since the parasitic capacitance signal from an applied external circuit is unavoidable and will always be coupled to the avalanche signal. Under the same measurement conditions, a comparison was made with the conventional capacitive balance technique, and the experimental results showed a high agreement between the effects of the two signal extraction techniques under several nanoseconds scale gating widths, and the double-pulse superposition technique is highly efficient and easy to implement even under complicated background noise.

A review on III-V compound semiconductor short wave infrared avalanche photodiodes.

The on-chip avalanche photodiodes (APDs) are crucial component of a fully integrated photonics system. Specifically, III-V compound APD has become one of the main applications of optical fiber communication reception due to adaptable bandgap and low noise characteristics. The advancement of structural design and material choice has emerged as a means to improve the performance of APDs.Therefore, it is inevitable to review the evolution and recent developments on III-V compound APDs to understand the current progress in this field. To begin with, the basic working principle of APDs are presented. Next, the structure development of APDs is briefly reviewed, and the subsequent progression of III-V compound APDs (InGaAs APDs, AlxIn1-xAsySb1-y APDs) is introduced. Finally, we also discuss the key issues and prospects of AlxIn1-xAsySb1-y digital alloy avalanche APDs that need to be addressed for the future development of ≥2µm optical communication field.

Hybrid Design of an Optical Detector for Terrestrial Laser Range Finding

This paper presents the integration of an InGaAs avalanche photodiode (APD)with the first amplification stage, comprised of a low capacitance silicon N-channel dual-gate MOS-FET and associated passive components, in the APD case. This combined linear mode optical hybrid detector is used in the field of terrestrial laser range finding. In this case, a reduction of input capacitance by 0.7 pF and an improvement of signal-to-noise ratio (SNR) at lowbackground noise conditions by 32 percent when compared to the equivalent discrete detector was measured. When integrated in a laser range finding system at very strong daylight conditions an improvement in SNR by approximately 10 percent was achieved. Furthermore a significant improvement in immunity to electromagnetic interference (EMI) is shown. Finally, when used in an eye-safe mobile laser range finding system, ranging beyond 10 km with an accuracy of ±2 m on non-cooperative targets using this hybrid detector is demonstrated.

InGaAs avalanche photodiode thermometry

The infrared detector is the most important component within any radiation thermometry-based system, with its choice determining the wavelength, response time and, ultimately, the temperature measurement capabilities of the instrument. To improve upon the existing generation of radiation thermometers, more sensitive detector technologies are required. In this work, we demonstrate a direct comparison between an indium gallium arsenide (InGaAs) photodiode and an InGaAs avalanche photodiode (APD) for 1.6 µm radiation thermometry. The high internal gain of the InGaAs APD increases the sensitivity of the radiation thermometer, enabling the measurement of a target temperature more than 50 °C lower than is typical with commercially available InGaAs photodiode thermometers. The more sensitive InGaAs APD provides faster response time measurements, hence improving the thermometer’s temporal resolution. Finally, the InGaAs APD is shown to produce a quantitative thermal image with lower measured temperature fluctuation across the scene when incorporated within a highly aperture limited scanning system.

Temperature effects on characteristics and performance of near-infrared wide bandwidth for different avalanche photodiodes structures

In this paper, the influences of thermal and spectral variations on various structures of avalanche photodiodes (APDs) have been deeply investigated. The characteristics and performance of Silicon (Si), Gallium Arsenide (GaAs) and Indium Gallium Arsenide (InGaAs) avalanche photodiodes have been evaluated under effects of different temperature degrees. The impacts of different temperature levels on the band gap energy, detector responsivity, noise equivalent power (NEP), cut-off wavelength, dark current and the photocurrent are studied and analyzed in details. The signal to noise ratio (SNR) and Bit Error Rate (BER) of these APDs are also computed and measured under the influences of different temperature levels and spectral variations. The aim of this paper is to determine the most efficient avalanche photodiode achieving the best performance according to the maximum SNR and minimum BER at high temperature environments. The analysis of the proposed model is performed by MATLAB. It was found that the experimental measured results endorse the analytical computed results. Further, it was observed that the APD (InGaAs) provides performance better than other APD structures in terms of larger SNR and less BER at higher temperature levels. Also, the temperature has a slight effect on the performance of APD (GaAs). So, it is seemed to be stable more than other APD structures and recommended to be used in warm environments and for high temperature applications.

10-Mb/s Quantum Key Distribution

We report the first quantum key distribution (QKD) systems capable of delivering sustainable, real-time secure keys continuously at rates exceeding 10 Mb/s. To achieve such rates, we developed high speed post-processing modules, achieving maximum data throughputs of 60 MC/s, 55 Mb/s, and 108 Mb/s for standalone operation of sifting, error correction and privacy amplification modules, respectively. The photonic layer of the QKD systems features high-speed single photon detectors based on self-differencing InGaAs avalanche photodiodes, phase encoding using asymmetric Mach-Zehnder interferometer, and active stabilization of the interferometer phase and photon polarisation. An efficient variant of the decoy-state BB84 protocol is implemented for security analysis, with a large dataset size of $10^8$ bits selected to mitigate finite-size effects. Over a 2 dB channel, a record secure key rate of 13.72 Mb/s has been achieved averaged over 4.4 days of operation. We confirm the robustness and long-term stability on a second QKD system continuously running for 1 month without any user intervention.

Best-Practice Criteria for Practical Security of Self-Differencing Avalanche Photodiode Detectors in Quantum Key Distribution

Fast gated avalanche photodiodes (APDs) are the most commonly used single photon detectors for high bit rate quantum key distribution (QKD). Their robustness against external attacks is crucial to the overall security of a QKD system or even an entire QKD network. Here, we investigate the behavior of a gigahertz-gated, self-differencing InGaAs APD under strong illumination, a tactic Eve often uses to bring detectors under her control. Our experiment and modelling reveal that the negative feedback by the photocurrent safeguards the detector from being blinded through reducing its avalanche probability and/or strengthening the capacitive response. Based on this finding, we propose a set of best-practice criteria for designing and operating fast-gated APD detectors to ensure their practical security in QKD.

Breakdown flash at telecom wavelengths in InGaAs avalanche photodiodes.

Quantum key distribution (QKD) at telecom wavelengths (1260 - 1625 nm) has the potential for fast deployment due to existing optical fibre infrastructure and mature telecom technologies. At these wavelengths, Indium Gallium Arsenide (InGaAs) avalanche photodiode (APD) based detectors are the preferred choice for photon detection. Similar to their Silicon counterparts used at shorter wavelengths, they exhibit fluorescence from recombination of electron-hole pairs generated in the avalanche breakdown process. This fluorescence may open side channels for attacks on QKD systems. Here, we characterize the breakdown fluorescence from two commercial InGaAs single photon counting modules, and find a spectral distribution between 1000 nm and 1600 nm. We also show that by spectral filtering, this side channel can be efficiently suppressed.

Realistic Device Imperfections Affect the Performance of Hong-Ou-Mandel Interference With Weak Coherent States

Measurement-device-independent quantum key distribution (MDI QKD) is a promising and practical protocol for remote secret sharing, where the Hong-Ou-Mandel (HOM) type interference in the measurement side provides a simple and economic way to resist malicious attacks on the measurement devices. Because the HOM interference greatly indicates the performance of MDI QKD system, its interferential behavior in practical situations deserve to be studied. In this work, we analyzed HOM visibility with several practical imperfections, such as the deviation of the beam splitting ratio, detection efficiency mismatch of detectors, inconsistent intensities of two incident pulses. In particular, we discussed the afterpulse effect of InGaAs avalanche photodiode detectors with a non-Markovian model, where we take the avalanche history into consideration and provide a new and more accurate perspective for afterpulse analysis. Simulation results indicate that the afterpulse effect in practical situation has a greater impact on the HOM performance than other imperfections. The results exhibit its value in realistic high-speed MDI QKD systems as well as other fiber-based HOM applications.

High sensitivity narrowband wavelength mid-infrared detection at room temperature.

We report an upconversion experiment using an orientation-patterned gallium arsenide (OP-GaAs) crystal to detect small mid-infrared signals on an InGaAs avalanche photodiode. A conversion efficiency up to 20% with a nonpolarized pulsed fiber pump is demonstrated. Our uncooled setup is favorably compared in terms of noise equivalent power, dynamic range, and response time to cryogenically cooled HgCdTe detectors. Its dependence on the polarization of both the pump and signal beams is also investigated.

Detector with internal gain for short-wave infrared ranging applications

Highly sensitive photon detectors are regarded as the key enabling elements in many applications. Due to the low photon energy at the short-wave infrared (SWIR), photon detection and imaging at this band are very challenging. As such, many efforts in photon detector research are directed toward improving the performance of the photon detectors operating in this wavelength range. To solve these problems, we have developed an electron-injection (EI) technique. The significance of this detection mechanism is that it can provide both high efficiency and high sensitivity at room temperature, a condition that is very difficult to achieve in conventional SWIR detectors. An EI detector offers an overall system-level sensitivity enhancement due to a feedback stabilized internal avalanche-free gain. Devices exhibit an excess noise of unity, operate in linear mode, require bias voltage of a few volts, and have a cutoff wavelength of 1700 nm. We review the material system, operating principle, and development of EI detectors. The shortcomings of the first-generation devices were addressed in the second-generation detectors. Measurement on second-generation devices showed a high-speed response of ∼6 ns rise time, low jitter of less than 20 ps, high amplification of more than 2000 (at optical power levels larger than a few nW), unity excess noise factor, and low leakage current (amplified dark current ∼10 nA at a bias voltage of −3 V and at room temperature. These characteristics make EI detectors a good candidate for high-resolution flash light detection and ranging (LiDAR) applications with millimeter scale depth resolution at longer ranges compared with conventional p-i-n diodes. Based on our experimentally measured device characteristics, we compare the performance of the EI detector with commercially available linear mode InGaAs avalanche photodiode (APD) as well as a p-i-n diode using a theoretical model. Flash LiDAR images obtained by our model show that the EI detector array achieves better resolution with higher signal-to-noise compared with both the InGaAs APD and the p-i-n array (of 100×100 elements). We have designed a laboratory setup with a receiver optics aperture diameter of 3 mm that allows an EI detector (with 30-μm absorber diameter) to be used for long-range LiDAR imaging with subcentimeter resolution.

Systematic afterpulsing-estimation algorithms for gated avalanche photodiodes.

We present a method designed to efficiently extract optical signals from InGaAs avalanche photodiodes (APDs) operated in gated mode. In particular, our method permits an estimation of the fraction of counts that actually results from the signal being measured, as opposed to being produced by noise mechanisms, specifically by afterpulsing. Our method in principle allows the use of InGaAs APDs at high detection efficiencies, with the full operation bandwidth, either with or without resorting to the application of a dead-time. As we show below, our method can be used in configurations where afterpulsing exceeds the genuine signal by orders of magnitude, even near saturation. The algorithms that we have developed are suitable to be used either in real-time processing of raw detection probabilities or in post-processing applications, after a calibration step has been performed. The algorithms that we propose here can complement technologies designed for the reduction of afterpulsing.

All-Optical Fiber Hanbury Brown &Twiss Interferometer to study 1300 nm single photon emission of a metamorphic InAs Quantum Dot.

New optical fiber based spectroscopic tools open the possibility to develop more robust and efficient characterization experiments. Spectral filtering and light reflection have been used to produce compact and versatile fiber based optical cavities and sensors. Moreover, these technologies would be also suitable to study N-photon correlations, where high collection efficiency and frequency tunability is desirable. We demonstrated single photon emission of a single quantum dot emitting at 1300 nm, using a Fiber Bragg Grating for wavelength filtering and InGaAs Avalanche Photodiodes operated in Geiger mode for single photon detection. As we do not observe any significant fine structure splitting for the neutral exciton transition within our spectral resolution (46 μeV), metamorphic QD single photon emission studied with our all-fiber Hanbury Brown & Twiss interferometer could lead to a more efficient analysis of entangled photon sources at telecom wavelength. This all-optical fiber scheme opens the door to new first and second order interferometers to study photon indistinguishability, entangled photon and photon cross correlation in the more interesting telecom wavelengths.

(Invited) Spectral Triangulation: A Novel 3D Method for Locating Single-Walled Carbon Nanotubes In Vivo

Nanomaterials with luminescence in the short-wave infrared (SWIR) region are of special interest for biological research and medical diagnostics because of relatively favorable tissue transparency in that region. Single-walled carbon nanotubes (SWCNTs) show sharp SWIR spectral signatures and therefore have the potential for noninvasive detection and imaging of cancerous tumors when linked to selective targeting agents such as antibodies. However, such applications face the challenge of detecting and localizing the source of light emission from inside tissues. We present here a new method, called spectral triangulation, for sensitively locating SWCNT emission sources in three dimensions using only optical measurements at the specimen surface. SWCNTs inside tissue phantoms are excited by an LED array, and resulting SWIR emission is captured by a scanning fiber optic probe coupled to an InGaAs spectrometer or avalanche photodiode detector. Because of water absorption, attenuation of the SWCNT fluorescence in tissues is strongly wavelength-dependent. We can therefore gauge the distance between SWCNTs and probe by analyzing differential changes in the measured SWCNT emission spectra. SWCNT fluorescence is clearly detected though as much as 22.5 mm of tissue phantom, and the three-dimensional locations of SWCNT samples are deduced with sub-millimeter accuracy at depths up to 10 mm. Our method can also distinguish and locate dual SWCNT sources within tissues.

Room temperature single-photon detectors for high bit rate quantum key distribution

We report room temperature operation of telecom wavelength single-photon detectors for high bit rate quantum key distribution (QKD). Room temperature operation is achieved using InGaAs avalanche photodiodes integrated with electronics based on the self-differencing technique that increases avalanche discrimination sensitivity. Despite using room temperature detectors, we demonstrate QKD with record secure bit rates over a range of fiber lengths (e.g., 1.26 Mbit/s over 50 km). Furthermore, our results indicate that operating the detectors at room temperature increases the secure bit rate for short distances.

Geiger Mode로 동작하는 3차원 LADAR 광수신기 개발

본 논문에서는 3차원 영상 획득을 위한 LADAR(LAser Detection And Ranging)용 광수신기 모듈을 설계-제작하고 측정한 결과를 보고한다. 광수신기 모듈은 1 km 이상의 거리에서도 신호를 측정할 수 있도록 디지털모드(Geiger Mode)에서 동작하는 InGaAs APD(Avalanche Photodiode)로 설계하였으며, <TEX>$16{\pm}16$</TEX> FPA(Focal Plane Array)로 설계-제작하였다. 디지털모드(Geiger Mode)는 항복전압 이상의 영역에서 동작하여 작은 광에 대해 반응 할 수 있게 큰 증폭률을 가지게 된다. 1ns의 FWHM(Full Width at Half Maximum)을 갖는 펄스를 수광할 수 있고, 배열 크기는 <TEX>$16{\pm}16$</TEX>, Geiger Mode 동작 등의 특성을 만족하도록 광수신기를 구성하기 위해 ROIC(Read Out Integrated Circuit)를 자체적으로 설계-제작하였다. 제작된 광수신기 모듈은 원거리 표적정보 획득이 가능하며, PDE(Photon Detection Efficiency)는 28%, DCR(Dark Count Rate)은 140 kHz 이하의 특성을 보였으며, LADAR 시스템에서 3차원 영상을 획득하였다. 이는 <TEX>$16{\pm}16$</TEX> FPA APD를 이용한 광수신기에서 가장 우수한 특성을 나타낸 것이다. In this paper, we report the design, fabrication and characterization of the 3-Dimensional optical receiver for a Laser Detection And Ranging (LADAR) system. The optical receiver is composed of three parts; <TEX>$16{\pm}16$</TEX> Geiger Mode InGaAs Avalanche Photodiode (APD) array device operated at 1560 nm wavelength, Read Out Integrated Circuit (ROIC) measuring the Time-Of-Flight (TOF) of the return signal reflected from target objects, a package and cooler maintaining the proper operational condition of the detector and control electronics. We can confirm that the LADAR system can detect the signal from a target up to 1.2 km away, and it showed low Dark Count Rate (DCR) of less than 140 kHz, and higher than 28%-Photon Detection Efficiency (PDE). This is considered to be the best performance of the <TEX>$16{\pm}16$</TEX> FPA APD optical receiver for a LADAR system.

대면적 APD를 이용한 LADAR용 광대역 광수신기

본 논문에서는 3차원 영상을 위한 LADAR(LAser Detection And Ranging)용 광검출기 모듈을 설계-제작하고 그 특성을 측정한 결과를 보고한다. 광검출기 모듈은 광파이버 어레이와 접속될 수 있도록 200 um 직경을 갖는 InGaAs APD(Avalanche Photodiode)로 설계-제작하였으며, 선형모드 동작 특성을 만족하도록 TIA(Trans-impedance Amplifier)를 설계-제작하였다. 광검출기 모듈을 구성하는 핵심부품들은 12개의 lead pin을 갖는 TO8 상에 집적되었으며, 집적에 필요한 APD 서브마운트 및 TIA 회로 등을 자체적으로 설계-제작하여 사용하였다. 제작한 광검출기 모듈은 450 ps의 rising time과 780 MHz의 대역폭 특성을 보였으며, 0.8 mV 이하의 잡음 특성과, 150 nW의 MDS(Minimum Detectable Signal) 신호 크기에 대해 15 이상의 신호대 잡음비(SNR)를 보임으로써 설계한 모든 특성을 만족하였는데, 이는 저자들이 아는 한 200 um 직경의 대면적 InGaAs APD를 이용한 광수신기에서 가장 우수한 특성을 나타낸 것이다. In this paper, we report design, fabrication and characterization of the WBRM (Wide Band Receiver Module) for LADAR (LAser Detection And Ranging) application. The WBRM has been designed and fabricated using self-made APD (Avalanche Photodiode) and TIA (Trans-impedance Amplifier). The APD and TIA chips have been integrated on 12-pin TO8 header using self-made ceramic submount and circuit. The WBRM module showed 450 ps of rise time, and corresponding 780 MHz bandwidth. Furthermore, it showed very low output noise less than 0.8 mV, and higher SNR than 15 for 150 nW of MDS(Minimum Detectable Signal). To the author's knowledge, this is the best performance of an optical receiver module for LIDAR fabricated by 200 um InGaAs APD.