An integrated optical coupler used in a fibre interferometry system for on-line surface measurements

In this paper, an integrated optical (IO) coupler produced using the technique of silica-on-silicon was described. A fibre interferometry system using the IO coupler was then developed and its performance was tested. The environmental noise and disturbances in this system were reduced significantly after combining a reference interferometer and an all fibre polarisation scrambler so as to produce good stability and repeatability. Furthermore, the measurement mirror was mounted on a piezoelectric transducer (PZT) and disturbances were introduced in the system in order to simulate on-line surface measurements. Both a commercial fibre and the IO couplers were compared using this method. Better experimental results were achieved when the system using the IO coupler than using the fibre one.