时分复用倍乘光脉冲重复率的新型光纤耦合器环状连接法分析

Analysis of a Novel Fiber Coupler Loop Connecting Method for Multiplying Optical Pulse Repetition Rates Based on TDM

提出并详细分析了一种基于时分复用技术倍乘光脉冲重复率的方法：在２×２光纤耦合器的一个输入口与一个输出口间，接入时延为脉冲列半周期奇数倍的一段光纤使之形成环状连接循环耦合，而在另一输出口获得光脉冲。详细分析了该系统中光纤耦合器耦合比、插入损耗、时延光纤长度的要求，偏差的影响及其调节法，给出了理论公式、结果的计算机模拟与实验介绍；与经典的马赫陈德尔干涉仪接法及近年提出的Ｓａｇｎａｃ环接法进行了比较。该方法特别适用于对窄脉冲列进行串接复用实现重复率的多次倍乘。

A novel connecting method for multiplying optical pulse repetition rate based on TDM(time division multiplexing) has been proposed and analyzed in detail. How to design the coupler′s coupling ratio as a function of its insertion loss, to select the length of loop fiber used as time delay line, to predict the effect of fiber length deviation from designed value and how to adjust precisely the loop fiber length have been indicated. Theoretical formulae, computer simulation to analyzed results and brief description of the experiment are given. The comparisons of the present connecting with the classical Mach Zehnder interferometer connecting and the Sagnac connecting exhibit that the present one has several advantages and superior behaviors, with which the high repetition rate of optical pulses from some giga Hertz to hundreds of giga Hertz can be better achieved by using the present method in series.