Generation of highly stable 20 GHz transform-limited optical pulses from actively mode-locked Er3+-doped fibre lasers with an all-polarisation maintaining ring cavity

Abstract
Very high-speed, stable picosecond optical pulses are generated from an active harmonic mode-locked Er3+-doped fibre laser with a 16m long polarisation maintaining ring cavity. Resultant transform-limited, 3.5–10ps optical pulses with a time-bandwidth product of 0.31–0.33, are analysed at repetition rates from 2 to 20GHz. The authors confirm bit-error-free stable operation at up to 8 Gbit/s.