A Polarization Insensitive Three-Dimensional Waveguide Interleaver

We propose and demonstrate a polarization insensitive polymer waveguide interleaver with a channel spacing of 100 GHz, which has a three-dimensional (3-D) structure with two layers of optical waveguides: the lower waveguides layer comprise a complete light circuits of interleaver based on Mach-Zehnder interferometers (MZI) and the upper layer just one waveguide and with a electrode heater on top of it. The realization of the polarization insensitivity is by providing partly different optical path to TE and TM polarization light signal in one arm of MZI. The fabricated interleaver exhibits complete polarization insensitivity in aspect of center wavelength and channel spacing. It also exhibits the isolation more than 18 dB and the insertion loss lower than 8.8 dB for TE and TM polarization. The polarization dependent loss is ~0.8 dB.