High power chirped pulse Yb fiber amplifier seeded by mode-locked fiber laser oscillator with multimode interference based saturable absorber

In this research, we demonstrate a novel femtosecond fiber laser system which comprises of ytterbium (Yb) doped mode-locked fiber laser oscillator using nonlinear multimode interference (NL-MMI) based saturable absorber (SA) seeded into a chirped pulse fiber amplifier. The laser pulses from the oscillator centered at a wavelength of 1033.2 nm with a pulse duration of 2.4 ps. Correspondingly, the pulse energy is 120 pJ at the fundamental repetition rate of 21.35 MHz. By integrating the laser oscillator with the amplification system, an output average power of 11 W with compressed pulse duration of 340 fs and pulse energy of 0.51 μJ is achieved. The pulse possesses high stability with signal-to-noise ratio up to 58 dB. These characteristics evince that the fiber amplifier system seeded with NL-MMI based mode-locked laser oscillator results in a highly stable femtosecond laser.