4-nJ Erbium All-Fiber Hybrid Highly Chirped Dissipative Soliton Oscillator

Ultrafast fiber lasers with a high pulse energy at 1550 nm wavelength are important for a range of applications: from CARS [1], few-cycle pulse generation [2] and frequency metrology to THz-wave generation. These applications require not only the high pulse energy, but also short duration, and high generation stability. Highly chirped (chirp parameter > 10) dissipative soliton (HCDS) generation technique (HCDS) driven by the nonlinear polarization evolution (NPE) effect meets all the above requirements. Substantial HCDS energy increase has been obtained previously in Yb-fiber all-fiber NPE mode-locked cavity containing polarization maintaining (PM) and non-PM parts [3]. We have implemented this approach for 1.5 microns wavelength area for the first time in [4] demonstrating 165 fs dechirped duration and 0.93 nJ energy HCDS. We also observed a multi-pulse generation regime caused by NPE overdriving. In this work we extend our results and increase the single HCDS energy by significantly lengthening the all-fiber cavity.