Multiple microwave frequencies measurement based on stimulated Brillouin scattering with ultra-wide range

By utilizing two pump signals with the frequency space by twice the stimulated Brillouin frequency shift, a single and multiple microwave frequency measurement scheme can be achieved with ultra-wide range. The unknown signal is modulated by the phase modulator, and the pump signal is the modulated sweep signal which is generated by vector network analyzer. When the phase matching conditions is satisfied, the stimulated Brillouin scattering will be occurred by the pump signal and the phase modulated signal, the conversion of phase modulation to amplitude modulation can be achieved, the unknown signal is ultimately measured. By the application of two pumps, the measurement range of the system is extended from 2VB to 4VB; which is demonstrated by numerical simulation. As a result, the measurement resolution and error are 39.93 MHz and 1.6 MHz respectively when the two frequencies are input simultaneously.