Ultra-broadband polarization filter covering OÂ +Â EÂ +Â SÂ +Â CÂ +Â LÂ +Â U telecom wavebands based on Au-coated photonic crystal fiber

An ultra-broadband polarized filtering Au-coated photonic crystal fiber (PCF) is proposed by finite-element method with the software of Comsol Multiphysics. The pattern is further used to discuss the consequences on the operation of the PCF for the two polarized directions when the sizes of the cladding air holes d, the Au-coated enlarged air hole dl, and the thickness of the Au film t are varied. Numerical analyses have been simulated for the influence of the structural parameters on the performance of the designed polarization filter. A broadband of 1310 nm (from 1190 to 2500 nm) covering the two communication wavelengths of 1.31 μm and 1.55 μm for the crosstalk as high as 20 dB is obtained, providing a wavelength coverage of six bands in the O + E + S + C + L + U telecom wavebands over a 500-μm-long PCF simultaneously. This report presents an extensive application in the development of high-capacity, ultra-broadband, and integrated optical communication systems.