介绍了用于光纤传输系统的自动激光器切断（ＡＬＳ）功能模块的原理和开发过程．它可以在光缆线路发生故障时自动切断激光发送器，并在线路修复后自动恢复系统工作．该技术已应用于ＳＤＨ－１５５Ｍｂｉｔ／ｓ光接口实验系统，其性能完全满足ＩＴＵ－ＴＧ．９５８建议关于激光安全性的要求 The principle and development process of automatic laser off (ALS) function module for optical fiber transmission system are introduced. It automatically shuts off the laser transmitter when a fiber optic cable fails, and automatically resumes system operation after the line is repaired. The technology has been applied to SDH-155Mbit / s optical interface experimental system, its performance fully meet the ITU-TG. 958 Recommendations on laser safety requirements