Single frequency, 5 ns, 200 μJ, 1553 nm fiber laser using silica based Er-doped fiber

A 1553 nm Er-doped fiber master-oscillator-power-amplifier (MOPA) laser system providing pulses with a 6 kHz repetition rate, 5 ns duration, ~210 μJ energy, ~300 MHz linewidth, and with a near diffraction limited beam quality, was developed. A gain fiber as short as 0.7 m in length was utilized in order to relax the SBS effect. To the best of our knowledge, thus generated peak power of 40 kW is the highest one obtained from a single frequency Er-doped silica fiber laser. The pulse quality was verified by frequency conversion with a periodically poled lithium niobate nonlinear crystal (PPLN) for second harmonic generation. A pulse energy as high as ~100 μJ was achieved at 776.6 nm with a moderate incident energy of 133 μJ, indicating an energy conversion efficiency of 75%.