Aberration theory of arrayed waveguide grating

The general aberration theory of arrayed waveguide grating (AWG) is propose d in this paper. The derived conclusions can be applied to any symmetrical AWGs, With the aberration theory, the spectral response can be optimized. S ome performances of an AWG, for example, crosstalk and channel number, are expected to be improved by reducing the aberrations. A common AWG with the Rowland geometry has low aberrations for the absence of the second-order ab erration, To further reduce the aberrations, nonstandard AWGs are considere d. The AWG based on three stigmatic points is proved to have a perfect perf ormance.