光通信系统Q因子测量和原理

The Measure and Principle of Q Gene of Optical Fiber Communication System

１０Ｇｂｉｔ／ｓ及其以上速率光传输系统非线性效应很强，对系统最终的ＢＥＲ性能有着举足轻重的影响。人 们倾向采用Ｑ因子来衡量系统性能。Ｑ因子被定义为在接收机判决电路信噪比，这种检测到的电ＳＮＲ 最终决定物理层系统ＢＥＲ。可以适用于各种信号格式和速率的数字客户信号，而且不需要解开帧结构， 比较简单易行。本文具体讨论Ｑ因子的定义及与ＯＳＮＲ之间的关系。同时介绍ＩＴＵ关于Ｑ因子的测 试方法和对测试设备的要求。

The nonlinear distortion of 10Gbit/s and over 10Gbit/s optical fiber transmission system influences system's BER, Q gene measures signal to noise ratio at the sink, the measure result-SNR decides system's BER, is the same with all kinds of formats and rates of digital signals. The define of Q gene and the realtion between OSNR and Q gene are discussed, the measure method and equipment about Q gene of ITU are introduced.