Reduction in dispersion of silica-based AWG using photosensitive phase trimming technique

The dispersion of a 25 GHz-spaced 64-channel silica-based arrayed waveguide grating (AWG) is reduced using a photosensitive phase trimming technique. The dispersion at the centre wavelength was reduced from about 170 to 30 ps/nm. Furthermore, we confirmed the same improvement in the dispersion for all 64 ports. The trimming technique is useful for realising fine AWGs with low crosstalk and dispersion.