Improved arrayed waveguide grating

摘要

In an arrayed waveguide grating (AWG) comprising fist and second slab waveguides and an array of waveguides optically coupled therebetween, the angle of the array waveguides at the slab waveguides is chirped according to the following equation: &thetas;i = ArcSine (i. DELTA &thetas;), where i = -(N-1)/2, -(N-1)/2 +1, ..., +(N-1)/2 where i is the array waveguide number, N is the number of array waveguides, and DELTA &thetas; is a constant. The chirping removes third-order aberration (COMA) which would otherwise cause asymmetry in the AWG output channel signals, especially where the AWG has a flattened passband.