Highly efficient modified dual D-shaped PCF polarization filter.

• Highly efficient TE pass polarizer based on dual D-shaped PCF is reported. • D-shaped layers are coated by gold films to enhance the filtering characteristics. • The SP modes are strongly coupled to the TM core mode with high confinement loss. • An insertion loss of −0.39 and −0.57 dB/cm are achieved at λ = 1300 nm and 1550 nm. • Large bandwidth from λ = 1.2 µm to λ = 1.6 µm is obtained with crosstalk < −21 dB. In this work, a highly efficient transverse-electric (TE) pass polarizer based on dual D-shaped photonic crystal fiber (PCF) is designed and analyzed. The PCF birefringence between the two polarized modes is efficiently controlled by adjusting the core region. Additionally, the dual D-shaped layers are coated by gold films to enhance the filtering characteristics. Therefore, the surface plasmon (SP) modes at the metal/dielectric interface are strongly coupled to the quasi-transverse-magnetic (TM) core mode with high confinement loss in comparable to the conventional D-shaped PCF. However, no coupling occurs with the quasi-TE core mode. Thus, a TE-pass polarizer is realized with an insertion loss (IL) of −0.39 dB/cm and −0.57 dB/cm at the two-telecommunication wavelengths of 1300 nm and 1550 nm, respectively. Moreover, the reported device has a wide operation bandwidth that extends from λ = 1.2 µm to λ = 1.6 µm where the crosstalk (CT) is less than −21 dB. [ABSTRACT FROM AUTHOR]