一、前言与半导体 DH 激光器相比,作为近红外光源的半导体 LED’S 有如下优点:1)光输出与工作电流之间有良好的线性关系;2)具有较好的温度稳定性;3)突然失效变化小,即寿命长,Zn 扩散 SH GaAs LED 就是一种这样的红外光源。虽然,在调制特性和效率方面,它比不上半导体 DH 激光器和 DH LED,但是,由于其结构简单,工艺难度小,所以还是一种得到广泛应用的器件。其效率高于同质结结构的同类器件,其截止频率 fc 也比掺 I. Introduction Compared with semiconductor DH lasers, the semiconductor LED’s as a near-infrared light source have the following advantages: 1) a good linear relationship between light output and operating current; 2) good temperature stability; 3) sudden failure Small changes, that is, long life, Zn diffusion SH GaAs LED is one such infrared light source. Although it is inferior to semiconductor DH lasers and DH LEDs in terms of modulation characteristics and efficiency, it is still a widely used device because of its simple structure and small process difficulty. Its efficiency is higher than homogeneous structure of similar devices, its cut-off frequency fc than doped