Polarisation selective Bragg filters on silicon-on-insulator

Abstract

We report on the design and characterisation of integrated silicon-on-insulator Bragg filters for polarisation selective operation. We show how the design of side and top waveguide gratings can be independently optimised for TE and TM polarisation. Device measurements show filter extinction ratios up to 40dB, strong polarisation selectivity and accurate control over the stop-band width.

Integrated TE/TM grating filters with high extinction ratio

“…To this end, top surface relief waveguide gratings provide an interesting solution as they strongly interact with the TM mode with a negligible influence on the TE polarised mode (see Fig. 1b) [6]. In summary, we have investigated the limitations on the extinction ratio of side-wall gratings.…”