Wideband tunable, high-power, graphene mode-locked ultrafast lasers

Ultrafast passively mode-locked lasers with spectral tuning capability and high output power have widespread applications in biomedical research, spectroscopy and telecommunications. Currently, the dominant technology is based on semiconductor saturable absorber mirrors (SESAMs). However, these typically have a narrow tuning range, and require complex fabrication and packaging. A simple, cost effective alternative is to use Single Wall Carbon Nanotubes (SWNTs) and Graphene. Wide-band operation is possible using SWNTs with a wide diameter distribution. However, SWNTs not in resonance are not used and may contribute to unwanted insertion losses. The linear dispersion of the Dirac electrons in graphene offers an ideal solution for wideband ultrafast pulse generation. Here, we report graphene saturable absorbers (GSA) for wideband tunable and high power ultrafast pulse generation. Tunable ultrafast pulses are generated with an Erbium-doped fiber laser mode-locked by GSA.