Tunable High-energy femtosecond soliton fiber laser based on hollowcore photonic bandgap fiber

We present an all-fiber high power tunable femtosecond soliton-based source incorporating a picosecond fiber laser and an 8 m long piece of hollow-core photonic bandgap fiber. Strongly chirped high energy 5.5 ps pulses produced by fiber amplification are compressed in the hollow core enabling formation of stable 520 fs-solitons with 77% conversion efficiency. Wavelength tunability was provided by exploiting Raman self-frequency shift of the solitons yielding 33nm tuning range. The transform limited output pulses were frequency doubled using a conventional nonlinear crystal with high conversion efficiency of 60%. Demonstration of a femtosecond green laser tunable from 534 nm to 548 nm with 180nJ pulse energy is also reported.