Abstract

Dispersion-tuned, harmonically mode locked fiber ring lasers (DTHMLFRLs) are able to generate high-speed, picosecond optical pulses with smooth wavelength tuning.^1,2 However, large supermode noise (SMN) associated with harmonic mode locking significantly limits their applications.³ While several methods have been proposed to suppress the SMN in mode-locked fiber ring lasers,³⁻⁶ they cannot be used in a DTHML- FRL because the addition of filters prevents smooth wavelength tuning. We have reported a simple scheme to suppress the SMN in a DTHMLFRL by introducing a semiconductor optical amplifier (SOA) into the ring cavity.⁷ Biased at its low-gain regime, the SOA suppressed the SMN by 13 dB. Smooth wavelength tuning was achieved within 10 nm by varying the modulation frequency 0.25 MHz. 5.3-ps pulses were obtained at a repetition rate of 10 GHz. In this paper, we report the experimental study of this system at different driving currents of the SOA and compare some of the experimental data with result from numerical simulations.

© 2002 Optical Society of America