Timing jitter reduction of ultrashort tunable pulses using a mode-locked fiber laser in soliton regime

A stable, passively made-lacked erbium-doped fiber ring resonator is developed to generate tunable optical pulses with durations of 270-325 fs in the soliton regime pumped by a semiconductor laser diode. The lasing wavelength is tuned continuously over a wavelength range of 60 nm by rotating a bulk band-pass filter inserted in the resonator with a repetition frequency of 45.4 MHz. We reduced the timing jitter by minimizing the intensity fluctuation of the pump source using a feedback loop, and by controlling the influence of airflow and temperature fluctuation of the resonator in a sealed box. The root-mean-square value of timing jitter is estimated to be below 31 parts in 10(6) of the round-trip time (0.7 ps) at a center wavelength of 1.558 mu m, and to be below 86 parts in 10(6) (1.8 ps) over a 25 nm wavelength tuning range, using a power spectrum technique in the offset frequency span of 30-3000 Hz.