Comprehensive method to reduce PDW in arrayed-waveguide grating

Stress induced birefringence is the source of polarisation dependent wavelength (PDW) in AWGs. The reduction of thermally induced residual stress (the effective stress of the AWG device and the stress balance on the core and surrounding cladding) during the waveguide fabrication process is the key to minimizing PDW. Top clad stress, grating waveguide width and core density are the major parameters that influence the stress and resulting birefringence. Low PDW (less than 0.01 nm) can be manufactured by suitably selecting these parameters.