Optimal design of birefringent filter with a flat-top passband

摘要

Bandpass filters based on birefringent plates employed in optical communications and sensing for channel dropping are considered. A filter with a flat-top passband is designed based on the configuration of the Lyot birefringent filter. A genetic algorithm is employed for the optimization of the flat-top passband. Compared to the traditional Lyot birefringent filter, the designed filter has a wider bandwidth, sharp transition and low crosstalk. The fabrication tolerance is also discussed.