Microjoule, Subpicosecond Pulse Generation from a Yb3+ - Doped Fiber Laser Using Frequency Shifted Feedback

We demonstrate the highest reported output power with a frequency-shifted feedback fiber laser. In the self starting and environmentally stable modelocked operation 120 nJ pulse energy was achieved, increasing to 1 muJ with simultaneous Q-switching with the intracavity frequency shifter. The pulses could be compressed to less than 1 ps duration.