850nm光波段高速雷射光能轉換器

Abstract

我們成功製作了一個可在順向偏壓下操作的高速光偵測器，在接收訊號的同時也可以將部分雷射光能轉換成電能，兼具傳統高速光偵測器與雷射光能轉換器的功能，我們稱之為高速雷射光能轉換器(High-Speed Laser-Power-Converter)，並利用串聯元件的方式進一步的提升整體元件的響應速度。在元件磊晶中，我們使用單載子傳輸光偵測器的設計原理，以電子為主要載子，利用電子在小電場(<10KV/cm)依然擁有高速的漂移速度的優異特性，成功的打破傳統高速光偵測器必須操作在逆向偏壓下的需求，並證明在順向偏壓下依然擁有一定的訊號傳輸速度。在實驗中，我們實驗團隊是第一個達到並成功製作可以在順向偏壓下操作的高速光偵測器。串聯的高速雷射光能轉換器(LC-LPC)當操作在+1V順向電壓下，可以達到10GBite/s的訊號傳輸量並同時擁有20%的光轉換效率，而且我們從數據中發現在順向偏壓下，元件的頻率響應主要是由載子的傳輸速度所對應的頻率響應來決定，與寄生電容(RC)效應無關。

In this thesis, we demonstrate a novel device: linear cascade GaAs/AlGaAs based high-speed laser power converter (LC-LPC). The working principal of such device is based on the concept of uni-traveling-carrier photodiode (UTC-PD). During operation of our demonstrated LPC, only electron is the active carrier, which can exhibit a high drift-velocity even under a low electric field (<10kV/cm). The high-speed with reasonable quantum efficiency performance of our LPC can thus be expected under forward bias operation, which is necessary for DC electrical power generation. This result overthrows the rule of high-speed PDs, which states that it must be operated under reverse bias regime and be a power-consumed device. By use of cascade structure, error-free 10 Gbit/sec data detection and 20% optical-to-electrical power generation efficiency can be achieved simultaneously at +1 V forward bias and 850nm optical wavelength. Furthermore, by use of device modeling technique, we found that the dominant bandwidth limiting factor of our demonstrated LPC under forward bias operation is internal carrier transient time instead of RC-limited bandwidth.