Ultra-low time jitter pulse source using mode-locked fiber laser as a high-Q resonator

Coupled optoelectronic oscillator (COEO) is a combination of a mode-locked fiber laser and an optoelectronic oscillator. The mode-locked laser (MLL) within the COEO acts like a narrow-band microwave resonator. Its input port is the electro-optic modulator input, and the output is the photodetector output. We used simple microwave oscillator model to show how it applies to the coupled optoelectronic oscillator, modeling the MLL as a microwave resonator. The phase noise measurement with injected microwave phase noise and direct measurement of the Leeson frequency using phase shift demonstrated that a quality factor of >2times106 is achieved with MLL. We are currently investigating the dependence of the quality factor on the MLL parameters, such as optical filter bandwidth, loop length, and loop loss as well as fundamental noise limits