基于APD的弱光信号探测系统的设计及其相关特性研究毕业设计.docVIP

外 文 翻 译 毕业设计题目： 基于APD的弱光信号探测系统的设计及其相关特性研究 原文1：Design and Characterization of Single Photon APD Detector for QKD Application 译文1：用于量子密钥的单光子APD探测器设计  原文2：High Performance 10 Gb/s PIN and APD Optical Receivers 译文2：10 Gb / s的高性能PIN和APD光接收器 Design and Characterization of Single Photon APD Detector for QKD Application Abstract Modeling and design of a single photon detector and its various characteristics are presented. It is a type of avalanche photo diode (APD) designed to suit the requirements of a Quantum Key Distribution (QKD) detection system. The device is modeled to operate in a gated mode at liquid nitrogen temperature for minimum noise and maximum gain. Different types of APDs are compared for best performance. The APD is part of an optical communication link, which is a private channel to transmit the key signal. The encrypted message is sent via a public channel. The optical link operates at a wavelength of 1.55μm. The design is based on InGaAs with a quantum efficiency of more than 75% and a multiplication factor of 1000. The calculated dark current is below 10-12A with an overall signal to noise ratio better than 18dB. The device sensitivity is better than -40dBm, which is more than an order of magnitude higher than the dark current, corresponding to a detection sensitivity of two photons in pico-second pulses. I. INTRODUCTION Photon detectors sensitive to extremely low light levels are needed in a variety of applications. It was not possible to introduce these devices commercially several years ago because of the stringent requirements of QKD. Research efforts however resulted in photon detectors with reasonably good performance characteristics. The objective here is to model a single photon detector of high sensitivity, suitable for a QKD system. The detector is basically an APD, which needs cooling to very low