Optimization of widely tuneable hybrid erbium-Raman-gain random fibre laser: theoretical investigation

Abstract

In this study, we investigated the realization of maximum tuning range of a random fibre laser by adjusting the pump wavelength and power as well as changing the lengths of single-mode and erbium-doped fibres (SMF and EDF) to achieve hybrid erbium-Raman gain. With this hybrid gain, the widest tuning range was 90 nm (1524–1614 nm), optimal pump wavelength was 1489 nm, optimal SMF length was 10 km, and optimal EDF length was 15 m. The lasing power flatness is greatly improved with this optimization. Numerical results indicate that the optical conversion efficiency is as high as 71.1%, with a pump power of 2.7 W and an optical signal-to-noise ratio over 55 dB. Hence, this work effectively optimizes and inspires the exploration of and new schemes for broad wavelength tuneable and high-efficiency random fibre lasers.