It is a madlab code for EDFA gain with length of optical fiber. Hope it will help to the students.

Low-Noise, High-Gain Si-Bipolar Preamplifiers for 10 Gb/s Optical-Fiber Links—Design and Realization

针对高增益的光通信用APD的边缘击穿，利用MATLAB得到APD的内部电场分布。运用该模型研究倍增层的厚度对边缘提前击穿特性的抑制程度。-The breakdown for the edge of the high-gain optical communication APD, using MATLAB APD internal electric field distribution. The use of the thickness of the multiplication layer of