A polarization filter of gold-filled photonic crystal fiber with regular triangular and rectangular lattices

Abstract

A modified structure of photonic crystal fiber (PCF) with gold-filled air holes is presented in this paper. It consists of two kinds of air holes, one part is arrayed in a regular triangular lattice and the other part is arrayed in a rectangular lattice with different hole pitches in x-pol and y-pol, respectively, which can enhance the birefringence of the PCF and the 1st order surface plasmon polariton (SPP) mode can also be separated by a large distance. The polarization filter is based on the phenomenon of surface plasmon resonance (SPR). Numerical simulations with a full vectorial finite element method demonstrate that the resonance peaks occur at different wavelengths in two orthogonal polarization states. It is possible to obtain a resonance strength as high as 407dB/cm at the communication wavelength of 1550nm in y-polarized direction while the loss is very low in x-polarized direction. This makes it a promising candidate for polarization filter devices.