Polarization insensitive, low-loss, low-crosstalk wavelength multiplexer modules

A method for compensating polarization sensitivity of arrayed waveguide gratings (AWG's) based on silica-on-Si waveguide technology using stress release grooves and its realization are described. These stress release grooves compensate fabrication-induced waveguide birefringence without performance degradation. An advanced design for low-loss, low-channel imbalance, and low-crosstalk multiplexer is given and results of the realized modules are presented. The TE/TM passband shift could be reduced from 0.7 nm to below 0.05 nm. Insertion loss of the fully packaged wavelength multiplexer modules is <5 dB and adjacent channel crosstalk is as low as <-40 dB.