Optical time-division space switches using tree-structured directional couplers

Abstract

The letter proposes two optical time-division space-switch structures using tree-structured directional couplers. First-order approximations show that they have an excellent signal/crosstalk ratio and low-loss properties in a large matrix dimension. An experiment on a 4 × 4 switch using Ti:LiNbO3 directional couplers is presented under the 128 Mbit/s condition.