4 mJ Rectangular- Envelope GHz-Adjustable Burst-Mode Fiber-Bulk Hybrid Laser and Second-Harmonic Generation

We demonstrate a high peak power and high burst energy linear-polarization, narrowband, GHz-adjustable burst-mode fiber-bulk hybrid laser with central wavelength of 1064 nm and its second-harmonic generation. The active modulated burst-mode seed provides the tunability of temporal parameters and the pre-compensation of burst envelope distortion. Three-stage polarization maintained fiber amplifier cascading bulk amplifier promote the burst energy to 4 mJ at a burst duration of 100 ns and intra-burst duty of 50%. To the best of our knowledge, this is the highest reported output energy of burst-mode fiber-bulk hybrid laser with ~ hundred nanoseconds burst duration. Also, the pre-compensation for rectangular burst envelope is investigated by iteration method. Type I, non-critical phase matching lithium borate (LBO) is employed for second-harmonic generation and 1.8 mJ burst energy is achieved, corresponding to a conversion efficiency of 45%. The 3 dB spectral width of green light at maximal burst energy is 90 pm. The immediate application of this laser system is the generation of high peak power frequency-adaptive microwave.