Instantaneous microwave frequency measurement using dual drive Mach-Zehnder Modulator

A technique for instantaneous microwave frequency measurement using dual drive Mach-Zehnder Modulator is proposed and demonstrated. In the proposed technique a microwave signal for which frequency is to be use is phased modulated on the two optical carriers. These carrier wavelength are extracted from the side bands of dual drive LiNbO₃ Mach-Zehnder Modulator, and this modulated signal passed through dispersive optical fiber and detected at two photo detector. Dispersive fiber provide the chromatic dispersion and two microwave signal will experience different power fading, which leads to different power level at different frequency. A fixed relation between power and unknown frequency is obtained. The microwave frequency is estimated by measuring the microwave power.