Wideband Phase Noise Measurement Using a Multifunctional Microwave Photonic Processor

A novel scheme for measuring the phase noise of microwave signal sources is proposed based on the delay-line method using a multifunctional microwave photonic processor, which can simultaneously implement the electrical-to-optical conversion, provide a time delay, and control the phase of the output microwave signal. Thanks to the microwave photonic processor, the requirement for accurate phase control is relaxed and a large operation bandwidth of the phase noise measurement system can be achieved. An experiment is performed. The phase noise measured by the proposed system agrees well with the result measured by a commercial spectrum analyzer, and the noise floor of the measuring system is lower than -130 dBc/Hz at 10 kHz frequency offset. The large operation bandwidth is also verified by measuring the phase noise of a wideband signal source in a frequency range from 5 to 40 GHz without rebuilding the system.