Externally mounted fibers for integrated optics interconnections

Abstract

A variety of input–output coupling problems remain central to the development of fiber and integrated optics communication systems. This paper discusses an externally mounted fiber consisting of a high index rectangular waveguide mounted on a larger low index support fiber. These fibers can be used to provide coupling between linear integrated optic guides and fibers or laser sources. Tapered (crossed-β) couplers are discussed in this context, and a simple expression for their coupling efficiency is presented. Externally mounted fibers have been fabricated, and experimental efficiencies of 70% for fiber–fiber and integrated optic linear waveguide–fiber coupling obtained.