An Ultra-broadband Single Polarization Filter Based on Plasmonic Photonic Crystal Fiber with a Liquid Crystal Core

An ultra-broadband single polarization filter based on plasmonic photonic crystal fiber with a liquid crystal core is investigated using the full-vectorial finite element method. Numerical simulations show that the loss of x-polarized core mode is better than 248.95 dB/cm in a 1.25–2.1 μm wavelength range, while the corresponding loss of y-polarized core mode is lower than 0.21 dB/cm. The high polarization extinction ratio is obtained at the communication wavelength of 1.3 μm, where the losses of x- and y-polarized core modes are 433.25 and 0.0064 dB/cm, respectively. When the fiber length is 1 mm, a broad bandwidth of 850 nm with an extinction ratio lower than −20 dB is obtained. Moreover, the proposed single polarization filter exhibits a better tolerance of realistic fabrication.