Photonic Instantaneous Frequency Measurement: Parallel Simultaneous Implementations in a Single Highly Nonlinear Fiber

A microwave photonic system that simultaneously implements multiple parallel instantaneous frequency measurement systems within a single highly nonlinear optical fiber is proposed and practically demonstrated. Three optical carriers of different wavelengths are modulated by the same radio-frequency (RF) signal and then delayed differentially. All three carriers are then mixed within a highly nonlinear optical fiber. The mixing products are separated, and the optical power of each is used to deduce input RF frequency. We demonstrate simultaneous acquisition of two distinct frequency measurement responses over the range from 1 to 40 GHz. This system is all-optical and requires no high-speed electronic components. Avenues for further increasing the number of simultaneous channels are identified.