用InGaAs/InP APD的红外单光子探测技术

由于在量子信息技术特别是量子密钥分配系统中的应用，以InGaAs／InP雪崩二极管为基础的红外单光子探测技术，近年来成为研究的热点之一。主要介绍了单光子探测用InGaAs／InP APD的选择和实现红外单光子探测器的关键技术：半导体制冷精密温控技术和APD的驱动控制技术，重点介绍了门控电路。     

High-speed InP/InGaAs avalanche photodiodes with a compositionallygraded quaternary layer

InP/InGaAs avalanche photodiodes (APDs) with a compositionally graded quaternary layer at the heterointerface between the InGaAs absorption and InP multiplication regions were fabricated and tested. A comparison of samples with the graded layer and with conventional three quaternary layers showed that the frequency characteristics for samples with the graded layer did not deteriorate at a low bias voltage even below -100°C, unlike APDs with three InGaAsP layers. Thus, no hole trapping occurred at the InP/InGaAs heterointerface with the graded layer. A sample with the graded layer showed a cutoff frequency exceeding 9 GHz at a low multiplication factor of 2. The authors found InP/InGaAs APDs with the compositionally graded quaternary layer to be useful over a wide temperature range     

Effect of impact ionization in the InGaAs absorber on excess noise of avalanche photodiodes

The effects of impact ionization in the InGaAs absorption layer on the multiplication, excess noise and breakdown voltage are modeled for avalanche photodiodes (APDs), both with InP and with InAlAs multiplication regions. The calculations allow for dead space effects and for the low field electron ionization observed in InGaAs. The results confirm that impact ionization in the InGaAs absorption layer increases the excess noise in InP APDs and that the effect imposes tight constraints on the doping of the charge control layer if avalanche noise is to be minimized. However, the excess noise of InAlAs APDs is predicted to be reduced by impact ionization in the InGaAs layer. Furthermore the breakdown voltage of InAlAs APDs is less sensitive to ionization in the InGaAs layer and these results increase tolerance to doping variations in the field control layer.     

宽带半导体可饱和吸收镜研制方法及选择腐蚀研究

介绍了用于固体激光器被动锁模自启动实现飞秒级脉冲输出的两种波长的带半导体可饱和吸收镜(800nm和1550 nm SESAMs)的研制方法和应用.制作宽带反射层的关键技术之一是AlGaAs/GaAs和InP/InGaAs/InGaAs的选择腐蚀.分别就几种湿法腐蚀和干法腐蚀进行了详细的分析和比较.     

Lateral n?p?n avalanche photodiode with an AlInAs multiplication layer

A quasi-planar AllnAs avalanche photodiode (APD) with a lateral n-p-n structure for optical fibre communications is reported. Although both the anode and the cathode contact the n-type regions, it is demonstrated that the n-p-n APD has the same performance as a normal p-n APD. The n-p-n structure enables the p-type conversion process of thermal Zn diffusion to be omitted, and AlInAs with a large gain bandwidth product and low noise to be utilised for a multiplication region. The n-p-n AlInAs APDs can provide better receiver sensitivity at 10 Gbit/s than commercially available InP APDs.     

Frequency response of InP/InGaAsP/InGaAs avalanche photodiodes

A theoretical model for the frequency response of InP/InGaAs avalanche photodiodes (APDs) is presented. Included in the analysis are resistive, capacitive, and inductive parasitics, transit-time factors, hole trapping at the heterojunction interfaces, and the avalanche buildup time. The contributions of the primary electrons, primary holes, and secondary electrons to the transit-time-limited response are considered separately. Using a measurement apparatus which consists of a frequency synthesizer and a spectrum analyzer controlled by a microcomputer, the frequency response of InP/InGaAsP/InGaAs APDs grown by chemical-beam epitaxy are measured. Good agreement with the calculated response has been obtained over a wide range of gains     

Effect of different etching processes on edge breakdown suppression for planar InP/InGaAs avalanche photodiodes

With the progress of semiconductor processing technology, avalanche photodiodes (APDs) based on InP/InGaAs are used for high-speed optical receiver modules. Planar-type APDs give higher reliability than mesa-type APDs. However, planar-type APDs struggle with a problem of intense electric field at the junction curvature, which causes edge breakdown phenomena at the junction periphery. In this paper, we focus our study on the effects of junction curvature for APDs performances by different etching processes followed by single diffusion to form p-n junction. The performance of each process is characterized by observing electric field profiles and carrier generation rates. From the results, it is understood that the optimum structure, which can minimize edge breakdown and improve the manufacturability, can be predicted.     

Multiplication-dependent frequency responses of InP/InGaAs avalanche photodiode

The intrinsic response time of InP/InGaAs APD has been reported. The multiplication factor dependent frequency responses were measured up to multiplication factor of 24. The results show the gain bandwidth of InP/InGaAs APDs is 10 GHz, and the intrinsic response time to be 16 ps.     

Optical properties of InGaAs/InGaAlAs quantum wells for the 1520–1580 nm spectral range

The optical properties of elastically strained semiconductor heterostructures with InGaAs/InGaAlAs quantum wells (QWs), intended for use in the formation of the active region of lasers emitting in the spectral range 1520–1580 nm, are studied. Active regions with varied lattice mismatch between the InGaAs QWs and the InP substrate are fabricated by molecular beam epitaxy. The maximum lattice mismatch for the InGaAs QWs is +2%. The optical properties of the elastically strained InGaAlAs/InGaAs/InP heterostructures are studied by the photoluminescence method in the temperature range from 20 to 140°C at various power densities of the excitation laser. Investigation of the optical properties of InGaAlAs/InGaAs/InP experimental samples confirms the feasibility of using the developed elastically strained heterostructures for the fabrication of active regions for laser diodes with high temperature stability.     

High-performance avalanche photodiode with separate absorption `grading? and multiplication regions

High-speed operation of avalanche photodiodes with separated absorption and multiplication regions has been achieved by incorporating an intermediate bandgap InGaAsP `grading? layer between the InP multiplication layer and the InGaAs absorption layer. These APDs also exhibit low dark currents, high quantum efficiencies and good avalanche gains. Sensitivity measurements have been made at 1.3 ?m and 1.55 ?m with one of these APDs in a high-speed optical receiver: at bit rates of 420 Mbit/s and 1 Gbit/s the minimum average powers required for 10?9 BER are ?43 dBm and ?38 dBm at 1.55 ?m, and ?41.5 dBm and ?37.5 dBm at 1.3 ?m, respectively.     

LPE制作平面型InGaAs/InP APD

叙述了用液相外延(LPE)制作 InGaAsP/InP 雪崩光电二极管(APD)的物理性能。分析了该器件的设计参数。介绍了器件结构、器件制作中 LPE 生长条件及器件性能。最后,评述了器件发展水平及改进意见。     

基于数字采样示波器的InGaAsP单光子雪崩二极管的特性

介绍了由带尾纤的InGaAs/InP雪崩光电二极管建立的近红外单光子探测系统.使用带宽50GHz的数字采样示波器,首次直观地展现了门模式(即盖革模式)工作状态下,单光子探测的模式和过程.并且在波长分别为1310和1550nm的情况下进行了定量研究.在1550nm,工作温度203K条件下,该探测器达到了暗计数概率2.4×10-3每门,量子效率52%,50kHZ的门信号重复频率;在工作温度为238K时,相应参数分别为8.5×10-3,43%和200kHz.     

A New Method to Investigate InGaAsP Single-Photon AvalancheDiodes Using a Digital Sampling Oscilloscope

介绍了由带尾纤的InGaAs/InP雪崩光电二极管建立的近红外单光子探测系统. 使用带宽50GHz 的数字采样示波器，首次直观地展现了门模式（即盖革模式）工作状态下，单光子探测的模式和过程. 并且在波长分别为1310和1550nm的情况下进行了定量研究. 在1550nm，工作温度203K条件下，该探测器达到了暗计数概率2.4E-3每门，量子效率52%, 50kHz的门信号重复频率；在工作温度为238K时，相应参数分别为8.5E-3,43%和200kHz.     

High-speed flip-chip InP/InGaAs avalanche photodiodes with ultralowcapacitance and large gain-bandwidth products

Planar InP/InGaAs avalanche photodiodes (APDs) have been fabricated by adopting a flip-chart configuration and a monolithic lens structure. These APDs exhibit an ultralow capacitance of 70 fF, a quantum efficiency of 80%, a wide bandwidth of 7 GHz, and a large gain-bandwidth product of 80 GHz     

Comprehensive Characterization of InGaAs–InP Avalanche Photodiodes at 1550 nm With an Active Quenching ASIC

We present an active quenching application-specific integrated circuit (ASIC), for use in conjunction with InGaAs–InP avalanche photodiodes (APDs), for 1550-nm single-photon detection. To evaluate its performance, we first compare its operation with that of standard quenching electronics. We then test four InGaAs–InP APDs using the ASIC, operating both in the free-running and gated modes, to study more general behavior. We investigate not only the standard parameters under different working conditions but also parameters such as charge persistence and quenching time. We also use the multiple trapping model to account for the afterpulsing behavior in the gated mode, and further propose a model to take account of the afterpulsing effects in the free-running mode. Our results clearly indicate that the performance of APDs with an on-chip quenching circuit significantly surpasses the conventional quenching electronics and makes them suitable for practical applications, e.g., quantum cryptography.      

High-speed InP/InGaAsP/InGaAs avalanche photodiodes grown bychemical beam epitaxy

High-performance InP/InGaAsP/InGaAs avalanche photodiodes (APDs) grown by chemical beam epitaxy are described. These APDs exhibit low dark current (less than 50 nA at 90% of breakdown), good external quantum efficiency (greater than 90% at a wavelength of 1.3 μm), and high avalanche gain (≃40). In the low-gain regime, bandwidths as high as 8 GHz have been achieved. At higher gains, a gain-bandwidth-limited response is observed; the gain-bandwidth product is 70 GHz     

Methods for Calculation and Control of the Impurity Difference Dose in Avalanche InGaAs/InP Structures

Methods for calculation and control of impurity difference dose Q_а during the planar procedure of fabrication of avalanche photodiodes (APDs) based on heteroepitaxial InGaAs/InP structures are presented. The developed methods for the difference dose control in avalanche InGaAs/InP structures have been used at various stages of APD fabrication. It has been demonstrated that a tighter impurity dose control from the manufacturer of epitaxial structures, coordination of dose measurement procedures, and correction of diffusion processes for specific impurity doses are needed.     

Design and Characteristics of Guardring-Free Planar AlInAs Avalanche Photodiodes

This paper reports a guardring-free planar AlInAs avalanche photodiode (APD) for optical fiber communications. AlInAs APDs can achieve a larger gain-bandwidth product (GBP) with lower excess noise than commercial InP APDs, and the guardring-free planar structure enables these superior AlInAs APDs to have both a low dark current and high reliability for practical use. We present the structure, fabrication, designs, APD characteristics, and receiver sensitivity, systematically. The guardring-free planar structure and its peculiarities are described, and we show APD designs for 2.5-Gb/s and 10-Gb/s applications and their characteristics. A 0.2-mum -thick AlInAs multiplication layer achieves a GBP of 120 GHz and an excess noise factor of 2.9 at a multiplication factor of 10. Their dark currents are less than 20 nA and their lifetime is evaluated to be 25 million hours at 85^degC. Lastly, we demonstrate that the guardring-free planar AlInAs APDs with a transimpedance amplifier achieve the remarkable sensitivity of -37.0 dBm at a bit error rate of 10^-10 for 2.5-Gb/s signals and of -29.9 dBm at a bit error rate of 10^-12 for 10-Gb/s signals. This performance indicates that the guardring-free planar AlInAs APDs have made great advances against commercial InP APDs and other AlInAs APDs.     

可见增强的32×32元平面型InGaAs/InP面阵探测器

为了实现In Ga As探测器响应波段向可见增强,在传统的外延材料中加入一层In Ga As腐蚀阻挡层,制备了32×32元平面型In Ga As面阵探测器,采用机械抛光和化学湿法腐蚀相结合的方法,去除了In P衬底.结果表明,探测器的响应波段为0.5~1.7μm,室温下在波长为500 nm处的量子效率约为16%,850 nm处量子效率约为54%,1 550 nm处量子效率约为91%.暗电流大小与衬底减薄之前基本保持一致.理论分析了材料参数对器件量子效率的影响,为进一步优化可见波段探测器的量子效率提供了依据.     

Incoupling waveguide hologram with reduced polarization sensitivity

An incoupling waveguide hologram (IWGH) with significantly reduced polarization sensitivity was designed and fabricated in InP for 1550 nm wavelength. The IWGH couples the light from an optical fiber, irrespectively of the state of polarization, into the InP waveguide and simultaneously focuses it to a desired position in the waveguide. Conventional IWGHs are strongly polarization sensitive with a measured 19 dB difference in the incoupling efficiency between the TE and TM mode. In contrast, although some design parameters turned out to be slightly in error, the fabricated IWGHs designed for reduced polarization sensitivity exhibited a 3.1 dB difference in the incoupling efficiency between the TE and TM modes