Design of a Compact Photonic-Crystal-Based Polarization Channel Drop Filter

We design a compact photonic-crystal-based polarization channel drop filter (PhC-PCDF) using the triangular lattice air holes PhC, which would be an essential device in future integrated polarization and wavelength-division-multiplexed (PWDM) system. The PhC-PCDF contains two line waveguides and a resonating system between them. In the line waveguide, the transverse-electric (TE) polarization and the transverse-magnetic (TM) are guided by photonic bandgap effect and total internal reflection effect, respectively. By resonating the system, a narrow bandwidth TE polarization is dropped from one waveguide to the other, leaving other components of the PWDM signal without any disturbance. The transmission efficiency for TM polarization and TE polarization are both over 95%. The quality factor of the TE PCDF is about 1800. The whole size of the designed PhC-PCDF can be $20a\times 12a$.