红外波段单光子探测器及其在量子通信领域中的应用

本文简要介绍了红外波段单光子探测器的种类，分析了InGaAs／InP雪崩光电二极管（InGaAs／InP APD）与超快超导单光子探测器（SSPD）的相关性能，并概述了二者在量子通信中的应用。     

用于高速量子密码系统的1.25 GHz InGaAs/InP单光子探测器的研制

随着量子密码领域的快速发展,近红外单光子探测器的研究已经成为该领域的研究重点和技术制高点。报道了一种基于正弦门控与滤波技术的InGaAs/InP雪崩光电二极管(APD)高速单光子探测器,门控频率达到1.25GHz。在探测效率为10.3%时,暗计数概率为1.3×10-6/gate,后脉冲概率为5.6×10-5/ns。这种高速单光子探测器将大幅度提升量子密码系统的两个关键指标——密钥率和传输距离,为下一代高速量子密码系统的实用化应用奠定了基础。     

高速近红外InGaAs/InP单光子探测器设计

量子信息技术的研究中大量采用单光子作为量子 信息的载体,因此单光子探测技术成为近来研究的 热点。目前基于InGaAs/InP雪崩光电二极管(APD)的单光子探测器(SPD)工作频率较低 且无法连续可 调。高速门控模式下,APD的容性效应会带来较强的尖峰噪声将光生雪崩信号湮没,导致探 测器的探测效 率也相对较低。为了提高单光子探测器的工作频率,降低后脉冲概率,设计了基于高速正弦 门控技术的 InGaAs/InP雪崩光电二极管淬灭-重置电路。为了抑制强大的背景噪声提高探测效率,设 计了双APD平衡 方案来提取有效雪崩信号。实验结果表明:设计的探测器工作频率连续可调;在－ 50℃、1～1.3GHz门控频率 条件下,最光子大探测效率为35%,暗计数率为4.2×10 －5/gate。探测效率为18%时 ,暗计数率仅为5.6×10－6/gate,后脉冲概率均低于5×10－6/ns。     

InGaAs单光子雪崩焦平面研究进展（特邀）

雪崩光电二极管（APD）是一种高灵敏度光电器件。按照工作电压的不同可分为线性APD和盖革APD。其中,盖革APD的工作电压高于击穿电压,利用半导体材料内部载流子的高雪崩增益可实现单光子级信号探测,也被称为单光子雪崩光电二极管（SPAD）。InGaAs材料SPAD在0.9~1.7 μm光谱范围内有高量子效率,是1.06、1.55 μm主动激光探测的理想探测器。通过将高效率InGaAs SPAD阵列芯片与CMOS计时/计数读出电路芯片集成封装,制备的雪崩焦平面探测器可对光子信号进行时间量化,在三维激光雷达、远距离激光通信、稀疏光子探测等领域有广泛应用。介绍了InGaAs单光子雪崩焦平面的器件结构及基本原理,在此基础上回顾了国内外雪崩焦平面技术的研究进展,并对未来发展方向进行了展望。     

基于InGaAs/InP低噪声GHz单光子探测器研究(特邀)

InGaAs/InP雪崩光电二极管(APD)体积小、功耗低、响应速度快,被广泛应用于近红外单光子检测。文中分析了APD雪崩及噪声信号的频谱分布特征,提出了正弦门控结合低通滤波级联方案,噪声抑制比超过40 dB,实现了1～2 GHz高性能探测。当工作速率为1.5 GHz,探测效率设置为20.0%时,后脉冲概率为6.6%,暗计数率仅为6.7×10^-7/gate。此外,集成了APD高速门控产生及延时调节模块,温度反馈稳定控制模块,实现了单光子探测器12 h稳定运行,计数标准差仅为1.0%。最后,为了更完整的描述探测器的量子特征,引入量子探测器层析技术进行标定,重新构建了其正值算符测度矩阵以及对应的Wigner函数,为其在量子通信、量子计算等量子信息技术的应用中提供支撑。     

InGaAs/InP红外雪崩光电探测器的研究现状与进展

近年来,量子卫星通信、主动成像等先进技术的应用取得了较大的进展,InGaAs/InP雪崩光电探测器作为信息接收端的核心器件起到了至关重要的作用。本文系统介绍了InGaAs/InP雪崩光电探测器的工作原理,分析了器件结构设计对暗电流特性的影响,对盖格模式下多种单光子探测电路进行了综述,同时对新型金属-绝缘体-金属结构设计的研究进展进行了介绍和展望。     

近红外1550 nm单光子探测器硬件电路设计

针对现有单光子探测器模块价格昂贵和体积大的不足,设计了基于 InGaAs／InP 雪崩光电二极管（APD）的便携式单光子探测器,给出了探测器温控模块和偏置电压源的设计电路,门控信号的产生和雪崩信号的提取由 FPGA 完成。实验结果表明：在200 MHz 门控条件且制冷温度为－55℃时,探测器的最大光子探测效率（PDE）约为16％,当探测效率为12％时,暗计数率（DCR）约为8．2×10－6／ns。     

InP基自由运行模式单光子APD

基于InGaAs/InP材料的雪崩二极管探测器工作响应波段范围0.9~1.67 μm,在盖革模式下探测效率较高,具有单光子量级的灵敏度,通过配置不同的偏置电路,可工作在门控和自由运行模式。目前主要采用门控模式的工作方式,门控模式可应用于光子到来时间已知的量子密钥分发。在激光测距、激光雷达成像等应用中当光子到达时间是未知的条件下,器件需工作在自由运行模式下。通过内部集成或片上集成自淬灭器件,探测器本身具有自淬灭或自恢复功能,无需外部淬灭电路,可工作在自由运行模式,大大拓展了InGaAs/InP单光子探测器的应用领域,同时对制备单光子探测器阵列具有优势。另外,采用InGaAs/GaAsSbⅡ类超晶格材料作为雪崩二极管的吸收层,可将探测器的截止波长进一步扩展为2.4 μm。首先对盖革模式APD进行了介绍,在此基础上对当前发展的自由运行模式以及扩展波长的InP基单光子探测器原理和性能进行了详细的阐述。     

量子通信中SAGM型单光子探测器性能分析

分析了InGaAs/InP光电雪崩二极管(SAGM-APD)在红外电信波段应用中的优良特性,阐述了在实际应用中一些关键参数和设计制造中的一些重要问题.在800～1700 nm波段,为了实现单光子探测,SAGM-APD应采用"盖格"工作模式并且论述了其中面临的一些问题.论述了量子保密通信中的门模抑制电路的工作原理及其工作过程中采用符合电路消除暂态信号的方法.     

GHz重复频率可调InGaAs/InP单光子探测器

InGaAs/InP雪崩光电二极管（avalanche photodiode APD）可实现近红外波段的单光子检测,具有集成度高功耗低等优势,被广泛应用于量子信息科学、激光测绘、深空通信等领域。通常,为了减小误计数,InGaAs/InP APD工作在门控盖革模式,其门控信号的重复频率直接决定了探测器的工作速率。基于此,采用低通滤波方案,结合集成了GHz正弦门控信号产生、雪崩信号采集、温度控制、偏置电压调节等功能的处理电路,搭建了GHz重复频率可调的高性能InGaAs/InP单光子探测器。GHz门控信号重复频率升高到2 GHz,其相位噪声仍优于-70 dBc/Hz@10 kHz,且尖峰噪声被抑制到热噪声水平,当探测效率为10%时,暗计数仅为2.4×10^-6/门。此外,还验证了该方案下探测器的长时间稳定性,测试了工作速率、偏置电压等对APD关键性能参数的影响,为GHz InGaAs/InP APD的进一步集成及推广奠定基础。     

短波红外单光子探测器的发展(特邀)

InP/InGaAs短波红外单光子探测器(SPAD)是目前制备技术较为成熟且获得广泛应用的单光子探测器,通过半导体热电制冷(TEC)即可达到的工作温度(-40℃左右),具有体积小、成本低,方便安装和携带的应用优势;另外,基于常规半导体二极管的芯片制造工艺很容易实现大面阵单光子阵列,除了探测信号,还具备三维数字成像功能。国外包括美国、瑞士、意大利、韩国、日本等对InP/InGaAs SPAD进行了长期持续的研究,目前已研制出单管的货架产品,性能还在不断的优化和改进之中,其单光子探测器阵列呈现了清晰的三维成像效果,正在逐步应用。国内包括重庆光电技术研究所、中国科学院上海技术物理所、西南技术物理研究所、中国科学技术大学、云南大学等对InP/InGaAs SPAD芯片先后进行了器件设计和器件制备研究,目前单管的性能已经达到与国外报道相当的性能。国内单光子探测器阵列的研究获得了一定的进展,但芯片规模和器件性能有待提升。文中对国内外InP/InGaAs短波红外单光子探测器的发展,在设计和研制中存在的问题,以及近10年来的优化改进进行了介绍,重点介绍了高温、高速以及单光子焦平面阵列的发展,并结合新颖...     

Degradation analysis of secondary lens system and its effect on performance of LED-based luminaire

Degradation of a secondary lens system and its effect on LED-based luminaire performance are investigated. A polycarbonate plastic lens system is selected as a test vehicle. The lens system is aged under an actual user condition using high power warm white LEDs. The spectral power distributions (SPDs) of the LED/lens assembly are obtained before and after 9500 h of continuous operation. A detailed SPD analysis is followed to identify the most critical parameter of the lens system degradation.     

Single Photon Detectors Based on SPADs: Circuit Solutions and Operating Modes

Russian Microelectronics - Single photon detectors (SPDs) are the most sensitive devices for detecting light. The rapid development of quantum communication over the past decades have given rise to...     

Thermal/luminescence characterization and degradation mechanism analysis on phosphor-converted white LED chip scale packages

According to the requirements on minimizing the package size, guaranteeing the performance uniformity and improving the manufacturing efficiency in LEDs, a Chip Scale Packaging (CSP) technology has been developed to produce white LED chips by impressing a thin phosphor film on LED blue chips. In this paper, we prepared two types of phosphor-converted white LED CSPs with high color rendering index (CRI > 80, CCT ~ 3000 K and 5000 K) by using two mixed multicolor phosphor materials. Then, a series of testing and simulations were conducted to characterize both short- and long-term performance of prepared samples. A thermal analysis through both IR thermometry and electrical measurements and thermal simulation were conducted first to evaluate chip-on-board heat dissipation performance. Next, the luminescence mechanism of multicolor phosphor mixtures was studied with the spectral power distribution (SPD) simulation and near-field optical measurement. Finally, the extracted features of SPDs and electrical current-output power (I-P) curves measured before and after a long-term high temperature accelerated aging test were applied to analyze the degradation mechanisms. The results of this study show that: 1) The thermal management for prepared CSP samples provides a safe usage condition for packaging materials at ambient temperature; 2) The Mie theory with Monte-Carlo ray-tracing simulation can be used to simulate the SPD of Pc-white LEDs with mixed multicolor phosphors; 3) The degradation mechanisms of Pc-white LEDs can be determined by analyzing the extracted features of SPDs collected after aging.     

Offline application of the fixed-frequency clamped-mode seriesresonant converter

The performance of the clamped-mode series resonant converters (CMSRC) is studied for an offline application. The CMSRC has the advantage of fixed-frequency operation, resulting in an easier design of magnetic components for resonant tank and filtering. Two prototypes were designed and tested experimentally, one to operate below resonant frequency (mode B) and the other to operate above resonant frequency (mode A). The efficiency is mainly determined by the rectifier losses and the switching losses. Where mode-B operation is implemented (below resonant frequency), the recovery of the diodes greatly increases the turn-on losses of the devices. The operation mode with four switches turned on at zero voltage, mode A' at above resonant frequency, shows better efficiency. Therefore, if higher frequencies of operation are desired, mode A' is the better choice among the four modes of operation discussed     

A Parallel Power Amplifier With a Novel Mode Switching Control

Two parallel operating power amplifiers (PAs) are controlled by a novel mode switch for high efficiencies at both the back-off power region and high power region. The mode switch is realized by the base-collector (BC) junction diode which reuses the dc current of the low power mode amplifier. A 836 MHz CDMA PA has been demonstrated using InGaP/GaAs heterojunction bipolar transistor with fully integrated matching component for small package and low cost. It shows a 13 mA idle current, 15.4% power added efficiency (PAE), ACPR1 at 16 dBm of the low power mode operation and a 40.5% PAE, ACPR1 at 28 dBm of the high power mode operation.     

Double-precision Dual Mode Logic carry-save multiplier

In this paper, a double-precision carry-save adder (CSA)-based array multiplier is designed using the Dual Mode Logic (DML) approach in a commercial 65-nm low-power CMOS technology. DML typically allows on-the-fly controllable switching at the gate level between static and dynamic operation modes. The proposed multiplier exploits this unique ability of DML to efficiently trade performance and energy consumption when considering on-demand double-precision (8 × 8-bit or 16 × 16-bit) operations. This occurs in the DML multiplier working in a mixed operation mode, i.e., by employing the static and dynamic mode for lower and higher precision operations, respectively. In fact, the use of the dynamic mode for higher precision operations ensures higher performance as compared to the standard CMOS circuit (16% gain on average) at the cost of higher energy consumption. Such energy penalty is counterbalanced at lower precision operations where the static mode is enabled in the DML circuit. Overall, the adoption of the mixed operation mode in the proposed DML multiplier proves to be beneficial to achieve a better performance/energy trade-off with respect to the standard CMOS implementation and to the case when using either the static or the dynamic mode for both operations at the two different precisions. When compared to its CMOS counterpart, our DML design operating in the mixed mode exhibits an average improvement of 15% in terms of energy-delay product (EDP) under wide-range supply voltage scaling. Such benefit is maintained over process-voltage-temperature (PVT) variations.     

Bipolar-FET hybrid-mode operation of quarter-micrometer SOI MOSFETs[MESFETs read MOSFETs]

A hybrid mode of device operation, in which both bipolar and MOSFET currents flow simultaneously, has been experimentally investigated using quarter-micrometer-channel-length MOSFET's which were fabricated on SIMOX silicon-on-insulator substrates. This mode of device operation is achieved by connecting the gate of a non-fully-depleted SOI MOSFET to the edges of its floating body. Both the maximum G _m and current drive at 1.5× higher than the MOSFET's normal mode. Bipolar-junction-transistor (BJT)-like 60-mV/decade turn-off behavior is also achieved. This mode of operation is very promising for low-voltage, low-power, very-high-speed logic as well as for on-chip analog functions     

Monolithically integrated 780-nm-band high-power and 650-nm-bandlaser diodes with real refractive index guided self-aligned structure

780-nm-band high-power and 650-nm-band laser diodes (LDs) with real refractive index guided self-aligned (RISA) structures are monolithically integrated for the first time. High-power and fundamental transverse mode operation at an output power of 100-mW continuous wave (CW) up to 80°C is attained for the 780-nm-band LD. For the 650-nm-band LD, high temperature and fundamental transverse mode operation at an output power of 10-mW CW up to 80°C is obtained     

Thermal-gradient enhanced current spreading in d.h. lasers

The observed differences in light output against current (P/I) curves between c.w. and short-pulse operation of (GaAl)As lasers have generally been considered as arising from the increase in active-region temperature under c.w. operation. This temperature increase results in a decrease in optical output at a given current level because of the reduced carrier confinement at the heterojunctions. However, by carefully compensating the temperature rise in the active region in the c.w. mode, we have experimentally established that, for exactly the same active-region temperature and total pumping current, the laser emits significantly less light in the c.w. mode than in the pulse mode of operation. This difference becomes larger as the input power increases. The thermoelectric (Seebeck) effect can explain this observation. The temperature gradient induced by c.w. operation causes current to flow away from the stripe region, leading to excess wasted current and reduced light output.