In this paper we review our work on birefringence compensated arrayed waveguide grating. We elaborate on a
birefringence compensation technique based on angled star couplers in arrayed waveguide grating (AWG) and discuss
several demonstrations both in low-index-contrast and high-index-contrast material systems. A 16-channel AWG with
100GHz channel spacing for DWDM application is designed and fabricated in silica-based low-index-contrast
waveguide. The experimental results confirm that the polarization-dependent wavelength shift (PDλ) can be tuned by
varying the incident/diffraction angle at the star couplers and a birefringence-free property can be achieved without
additional fabrication process as compared to conventional AWG. A further validation of this technique is demonstrated
in high-index-contrast silicon-on-insulator waveguide, in combination with different diffraction orders for TE and TM
polarizations. A birefringence compensated silicon nanowire AWG for CWDM optical interconnects is designed and
fabricated. The theoretical and experimental results show that the PDλ can be reduced from 380–420nm to 0.5–3.5 nm,
below 25% of the 3 dB bandwidth of the channel response in the wavelength range of 1500 to 1600nm.
The design and simulation results of temperature-insensitive arrayed waveguide gratings based on silicon nanowires are presented.
The temperature dependent wavelength shift is minimized by using negative thermo-optic coefficient material SU-8 as the
upper-cladding. Simulation results show that by using an appropriate thickness and width of the waveguide, quasi-athermal
operation can be achieved. For temperature varying from 0°C to 80°C, the TD-CWS can be controlled down to 0.036nm with
little polarization dependence for 272nm×253nm waveguide.