Supermode beat suppression in harmonically mode-lockederbium-doped fibre ring lasers with composite cavity structure

Abstract

Stable 6.8 GHz actively modelocked pulses were generated from composite cavity Er-doped fibre ring lasers. The composite cavity fibre lasers operate as virtually short cavity lasers, and thus modelocking at a lower harmonic number can be possible. The cavity mode spacing of the laser is over 10 times larger than usual ring cavity mode spacing with the same cavity length.