Wavelength Demodulation Approach Based on Dispersion-Induced Microwave Power Fading for Optical Sensor

An approach based on the dispersion-induced microwave power fading is proposed and experimentally demonstrated to perform wavelength demodulation. In the demodulation approach, the received optical signal with its wavelength to be interrogated is firstly modulated by a microwave signal under the small-signal modulation condition, resulting in a double-sideband modulation. The modulated optical signal is then coupled into two channels with different chromatic dispersions. At the output of each channel a wavelength-dependent microwave power suffering dispersion-induced microwave power fading is detected and the two microwave powers of the two channels have different dispersion-induced microwave fadings. The wavelength can be demodulated from the ratio of the two microwave powers, leading to a fast and robust demodulation for optical fiber sensors.