Surface plasmon induced polarization filter of the gold-coated photonic crystal fiber with a liquid core

•There is one strong resonance peak over the wavelength range of 0.6–2 μm.•The peak loss in y polarization is 536.25 dB/cm at 1.55 μm with t = 0.0195 μm.•The peak loss in y polarization is 412.91 dB/cm at 1.31 μm with t = 0.055 μm.•The loss in x polarization is low to few.

A new gold-coated photonic crystal fiber (PCF) which can achieve a specific wavelength filter has been proposed. The polarization filter characteristics of the PCF based on the finite element method are investigated. Numerical results show that moving the two gold-coated holes toward the central core in longitudinal direction and filling pure water in the central defected air-hole can effectively enhance polarization extinction ratio around the resonance wavelength. The resonance strength in y-polarized case is far stronger than that in x-polarized case, the peak loss of the PCF with different coating thickness in y polarization can reach 536.25 dB/cm and 412.91 dB/cm at the communication wavelength of 1.55 μm and 1.31 μm, respectively, while the losses are very low in x polarization. This is beneficial for the study and application in many polarization filter devices.