Polarization-independent all-fiber multiwavelength-switchable filter based on a polarization-diversity loop configuration

In this paper a polarization-independent all-fiber multiwavelength-switchable filter based on a polarization-diversity loop configuration is newly proposed. The proposed apparatus consists of a polarization beam splitter, high birefringence fibers, and polarization controllers. Our theoretical analysis shows that the apparatus exhibits unique feature which allows it to operate as a polarization-independent multiwavelength periodic filter with a good channel isolation and to make its channel wavelength switchable by varying effective birefringence of the polarization-diversity loop through the proper adjustment of the polarization controllers contained within the loop. Theoretical prediction was experimentally verified.