Saturable absorption performance of large area monolayer MoS2 coated planarized optical waveguide

Abstract

The development of compact waveguide-based pulsed lasers has been of great interest in the past two decades. This is supported by the rapid development of two-dimensional (2D) materials saturable absorbers (SAs). In this paper, we integrate a large area monolayer molybdenum disulphide (MoS2) on a planarized silica optical waveguide and studied its performance as an SA. A single layer MoS2 film on polydimethylsiloxane substrate is mechanically transferred to the planarized optical waveguide. The single layer MoS2 can interact with the evanescent field of the waveguide core mode, thus achieving SA. The MoS2-coated waveguide is then integrated into an erbium-doped fibre laser cavity that operates in the telecommunication wavelength region. Q-switching is achieved with a repetition rate, pulse duration and maximum pulse energy of 22.5 kHz, 5.24 µs and 4.1 nJ, respectively at a pump power of 122.8 mW. The results show that 2D material thin films can be integrated onto a planarized optical waveguide to act as SAs. These findings show the potential of using 2D materials in developing compact, integrated waveguide pulsed laser sources.