Optical modulators using fibreoptic Sagnac interferometers

We propose, and present a theoretical and experimental investigation of optical modulators using fibreoptic Sagnac interferometers. Several possible modulator configurations have been investigated and compared. An optical modulator using the ceramic material PLZT as the electrooptic modulating element has been experimentally demonstrated to show the feasibility of this new type of modulator structure. Preliminary experimental results show that the optical modulators using fibre Sagnac interferometer have a number of useful features such as input polarisation independence, readily adjustable phase bias, and suitability for forming fibre-to-fibre devices.