Q-switched erbium-doped fibre laser using graphene-based saturable absorber obtained by mechanical exfoliation

Abstract

A stable passively Q-switched erbium-doped fibre laser (EDFL) operating at 1536.5 nm is developed, using a 1 m long erbium-doped fibre as a gain medium and a simple graphene-based saturable absorber (SA). Using mechanical exfoliation, a single layer of graphene is obtained and deposited on the end facet of an optical fibre ferrule, which is then connected to another ferrule to form the SA. The SA is integrated into an EDFL cavity to achieve a stable pulse train at the threshold pump power of 42.3 mW. When the pump power increases from 42.3 to 63.5 mW, the pulse train repetition rate increases from 10.3 to 32.4 kHz, while the pulse width varies from 10.7 to 31.0 μs. The highest energy, 166.2 nJ, is achieved at the pump power of 42.3 mW.