Frequency-domain measurement of phase error distribution in narrow-channel arrayed waveguide grating

The authors report a method for measuring the phase error of an arrayed-waveguide grating (AWG) in the frequency domain, using an interferometer with a continuously tuned laser. An interferogram of the AWG, obtained using the optical low coherence method, is derived numerically as a function of the optical delay. Since any large optical delay value is given in the calculation, the new method is suited to an AWG with a longer step increment or a channel spacing of 1 to 10 GHz. The phase error distribution of an AWG with 10 GHz channel spacing is successfully measured