Design of voltage controlled oscillator for fiber lasers application in microwave generation

A low-power and area-efficient 10 GHz LC- voltage controlled oscillator is designed for fiber lasers application in microwave signal generation from a free running mode-locked Er-fiber laser. In the stretched-pulse regime, the Er-fiber laser is designed at close-to-zero dispersion to minimize the phase noise of extracted microwaves. In order to suppress the excess phase noise in the opticalto- electronic conversion process, we synchronize a low-noise VCO to the fiber laser using a fiber Sagnac-loop-based optical-microwave phase detector. The proposed VCO circuit applies PMOS cross-coupled pairs LC circuits and implemented in TSMC 0.18-um CMOS process.