Tunable Optoelectronic Oscillator Incorporating a High-Q Spectrum-Sliced Photonic Microwave Transversal Filter

A tunable optoelectronic oscillator implemented employing a high-Q-factor spectrum-sliced photonic microwave transversal filter without using any electronic microwave filters is proposed and experimentally demonstrated for the first time to our knowledge. The high-Q-factor photonic microwave transversal filter is implemented using a sliced broadband optical source and a dispersive element, to perform frequency-tunable microwave frequency selection. The central frequency of the microwave filter is a function of the wavelength spacing of the sliced optical source and the chromatic dispersion of the dispersive element. Therefore, the oscillation frequency can be tuned by changing either the channel spacing of the sliced broadband optical source or the chromatic dispersion of the dispersive element. A proof-of-concept experiment is performed. An optoelectronic oscillator with a tunable frequency range of 9.7 GHz is achieved. The generated microwave signal exhibited a good phase noise performance with a phase noise of -120 dBc/Hz at an offset of 10 kHz.