Abstract

A well known characteristic of optical fibres is that they do not maintain the polarisation of the transmitted light. Therefore an important requirement of integrated optical circuits in optical fibre systems is that they have to be polarisation independent, i.e. their operation is the same for all polarisations of the incoming light. Unfortunately, integrated optical waveguides always show modal birefringence. In an optical bandpass-filter based on interference this causes for example a shift in the wavelength for maximal transfer between TE and TM modes.

© 1996 Optical Society of America