Compact InP-based waveguide crossings with low crosstalk and low loss

Abstract

Optical waveguide crossings are becoming increasingly important due to the increasing complexity of optical chips. In switching matrices [1], multiwavelength add drop filters [2] and optical crossconnects [3] worst-case paths may contain more than five or even ten crossings. In fibre-matched waveguides structures as used in lithium niobate or silica-based technology, crossings with very low crosstalk and loss can be realised [4,5]. We have found that in highly integrated semiconductor devices crossings may contribute significantly to the loss and crosstalk performance. In this paper we present the results of a series of experiments for design of high-performance semiconductor waveguide crossings.