砷化銦鎵光崩潰二極體於單光子偵測器之應用

Abstract

本論文主要目的為建立一套可在1100nm~1600nm波段的光纖通訊中使用的單光子偵測系統。首先我們對於操作在Geiger-Mode的砷化銦鎵光崩潰二極體的特性做一分析與驗證，且比較單光子偵測器與傳統的光二極體偵測器兩者對於光分析方式的不同之處，然後實際製作與分析了能使APD重複偵測的Quenching電路。於此之後我們架設了單光子偵測系統並透過改變超額電壓、操作溫度、重複速度、脈衝寬度來分析與尋找單光子偵測系統的最佳偵測環境。實驗中我們使用了NEC(NR8300)製造的光崩潰二極體，且分析其對1300nm波長光源的偵測表現。在Gated-Mode操作環境中先透過分析溫度與重複速度之間的關傒，來剔除各溫度下After pulsing效應對量測結果所造成的錯誤與失真，且在100KHz的重複速度下藉著變化脈衝寬度(20ns、40ns、60ns)來計算 Detection efficiency之間的差異，並經由計算得出在170K以及高於170K的溫度所得到的After pulsing probability in 20ns皆小於5%，因此在100KHz的重複速度下此些溫度的量測結果是正確的。最後藉著增加超額電壓與縮小脈衝寬度的方式得出在190K的溫度下的最佳Detection efficiency結果為60% , Dark count probability為1%而NEP值則為7x10-16 WHz-1/2。另一方面在Passive-Quenching對連續光源的偵測中，我們成功的分辨了10-12W、10-13W、10-14W三種光量。

The goal of this work is to setup a single-photon-detector system for fiber-optics communication in the range of 1100-1600nm. First, we figured out the characteristic of InGaAs Avalanche photodiode (APD) operating in Geiger mode. The difference between single photon detector and traditional photodetector in light detection was compared. After that, the quenching circuit for subsequent detection of APD was built and analyzed in detail. With the knowledge, we setup the measurement system for characterizing the single photon detector and found the best parameters for detection performance, including the excess voltage, the operation temperature, the repetition rate and the gated width. In our experiment, the APD (NEC-NR8300) was analyzed its performance at the source wavelength of 1300nm. In gated mode, we studied the relationship between repetition rate and temperature to minimize the after pulsing effect. By calculating the difference of detection efficiencies in different gated widths at 100KHz repetition rate, the after pulsing probability under 5% was obtained in 20ns gated width at 170K and higher temperatures. Because of that, the detection efficiency results at these temperatures are correct. Finally, by increasing the excess bias and shorting the gated width, the best performance, detection efficiency 60%, dark count probability 1% and noise-equivalent-power (NEP) 7x10-16 WHz-1/2, was achieved at 190K. On the other hand, by using passive quenching for the detection of continuous-wave (CW) light source, we were successful to distinguish three different power levels, 10-12 W、10-13 W、10-14 W.