Ultrafast Raman Fiber Laser Based on Cavity Matching Scheme and Heavily Germania-Core Fiber

We experimentally demonstrate the large-energy short-pulsed Raman fiber laser by pumping heavily GeO2-doped fiber (GDF) with a dissipative soliton resonance (DSR) mode-locked Yb-doped fiber laser. By exploiting the large Raman gain of GDF and the exotic properties of the DSR mode-locked pulses, the cavity matching condition can be facilely fulfilled with high mismatch tolerance and simple cavity design. The Raman fiber laser therefore initiates at 1118 nm and generates pulses with narrow pulse width of 647 ps or pulse energy upto 22 nJ. The novel Raman fiber laser system cannot only achieve synchronization between the Raman laser pulses and the pump waves without delay line, but also features readily tunable pulse duration and peak power. This proofof-principle work may provide a potential useful route to ultrafast, energy-scalable, and wavelength-versatile (e.g., mid-infrared) pulse generation directly in fiber lasers with low cost, easy-accessibility along with compact structure.