L-band femtosecond fibre laser based on Bi2Se3 topological insulator

We demonstrate a femtosecond erbium-doped fibre laser operating in the long wavelength band (L-band) in which topological insulator Bi2Se3-polyvinyl alcohol film is applied as a saturable absorber. It generates a ~360 fs soliton pulse at 1600 nm with a repetition rate of 35.45 MHz. To the best of our knowledge, this is the shortest pulse duration ever achieved with an L-band design employing Bi2Se3 as a saturable absorber. The result shows topological insulator Bi2Se3 could be a promising candidate to generate L-band ultrafast pulses for practical applications.