Wavelength interrogator based on arrayed waveguide gratings

A novel wavelength interrogator that employs an arrayed waveguide grating (AWG) is proposed and its operating features are investigated in detail theoretically. Wavelength detection can be easily achieved by using traditional means of detecting light intensity of AWG´s output signal in this method. An explicit formula based on the Gaussian approximation is given and used to model the characteristics of the proposed interrogator. The result shows that: the wavelength signal to be detected can be linearly described by the logarithm of adjacent channels´ power ratio; the wavelength detection sensitivity can be improved by decreasing channel spacing or 3dB bandwidth of AWG. This method is not sensitive to the insertion loss ripple of AWG.