High-energy, wavelength-tunable picosecond all-fiber laser based on active mode-locking

A high-energy, wavelength-tunable all-fiber picosecond MOPA laser is reported. The seed is provided by an active mode-locked oscillator which can be continuously tuned from 1030 nm to 1080 nm. The seed pulses with duration of 212 ps and average power of 3 mW are injected into a two-stage amplifier. The nonlinear effect in the main amplifier is alleviated by using a large mode area gain fiber, to avoid pulse distortion and spectral broadening. Over 10 W average output power ranged from 1030 nm to 1080 nm is achieved with the FWHM bandwidth and spectral signal-to-noise ratio of 0.2 nm and 30 dB, respectively. Measured pulse duration is less than 350 ps at repetition rate of 536 kHz. The maximum peak power and single pulse energy reaches 54 kW and 18 nJ, respectively. The source is then used to pump a self-designed multi-core photonic crystal fiber (PCF) for supercontinuum generation. By tuning the wavelength of the laser to approach the zero-dispersion wavelength of the PCF, a broadband supercontinuum covering the wavelength range from shorter than 400 nm to longer than 2400 nm is achieved. The experimental results are in consistent with the theoretical analysis, which benefit from the wavelength continuously tunable property and the high peak power of the picosecond laser.