Detailed Analysis of All-Optical Clock Recovery at 10 Gb/s Based on a Fiber Optical Parametric Oscillator
We demonstrate all-optical clock recovery of input return-to-zero ON-OFF-keyed signals operating at 10 Gb/s using a fiber optical parametric oscillator (FOPO). We first characterize an actively mode-locked FOPO, which serves as the basis for all-optical clock recovery. 12.5-ps pulses with a timing jitter of around 450 fs are generated. Afterward, the characteristics of the recovered clock (timing jitter, pulsewidth, and time-bandwidth product) are investigated as a function of the duty cycle, average power, extinction ratio, and optical signal to noise ratio (OSNR) of the input signal. The wavelength tunability of the recovered clock is also investigated. The results show that the FOPO can recover a good quality clock over a large range of input signal characteristics, namely, duty cycle from 33% to 60%, average input power from -23 to 6 dBm, extinction ratio above 8.7 dB, and an OSNR larger than 27 dB. The wavelength of the recovered clock signal can be tunable over 8 nm.