High-efficiency, single-longitudinal-mode ring fibre laser

Abstract

A novel single-longitudinal-mode erbium-doped ring fibre laser is proposed and demonstrated experimentally. It combines a narrow-linewidth fibre Bragg grating (FBG) with several Mach-Zehnder mode filters (MZF) to obtain a single-frequency emission. It yields a power conversion efficiency of 16%. It is shown that the sidemodes are suppressed when one inserts the series of MZFs inside the cavity. At 1547 nm, the output power measures over 15 dBm, with a sidemode suppression ratio of 50 dB and a linewidth of no more than 7 kHz.