Novel photonic broadband microwave frequency measurement based on intensity-modulated link with output microwave interference detection

A novel photonic approach for measuring microwave frequency over a wide bandwidth, based on intensity-modulated link with output microwave interference detection, is proposed. In this simple measurement system, a tunable laser and a fixed-wavelength laser are used with a single-mode fiber as the dispersive medium. By scanning the wavelength of a tunable laser, the frequency of the modulated microwave signal can be obtained directly through analyzing the interference intensity of the microwave signal at the output of the photodetector. The proposed approach is demonstrated experimentally by obtaining the unknown microwave frequency in the range of 1 to 20 GHz with a measurement accuracy of several tens of MHz. (C) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.OE.51.1.019001]