Optical wavelength interrogator employing the free spectral range of an arrayed waveguide grating

A method to increase the multiplex capacity of an arrayed waveguide grating (AWG) based interrogator is proposed that makes use of the spectral recurring feature of AWG due to its free spectral range. Using a single AWG, interrogation for two different wavelength regions of 1310nm and 1550nm was performed with a high performance of the standard deviation of the level of sub-pico-meter for 2nm dynamic range. The proposed method is very helpful to reduce the cost of the AWG interrogator.