Broadband low-coherence light has been applied in many fields such as optical imaging, atmospheric optical communication and laser inertial confinement fusion(ICF). It’s meaningful to investigate the temporal shaping technology of broadband low-coherence light. We propose and experimentally demonstrate a scheme of achieving all-optical arbitrary temporal shaping of broadband low-coherence light based on saturable absorption effect. Compared to traditional temporal shaping schemes such as electro-optic modulation(EOM) shaping or acousto-optic modulation(AOM) shaping, the modulation on the shaped pulse profile is much smaller, reduced from 14% (by acousto-optic modulator) to 3%(close to the ASE noise). Furthermore, we explore the evolution of shaped pulse contrast (intensity ratio between front edge and end edge) with the pump energy and contrast changing. The contrast of shaped pulse can be adjusted from 1:1.32 to 1:1.02 when pump contrast is 1:2, and from 1:2.25 to 1:1.90 when pump contrast is 1:3. And the maximum contrast of shaped pulse can reach 1:17 within the measurement accuracy. By changing the energy and contrast of pump, the contrast of the shaped pulse can be controlled flexibly. It’s useful to achieve all-optical arbitrary temporal shaping and pre-compensation during pulse amplification.
With the development of fiber technologies, fiber lasers are able to deliver very high power beams and high energy pulses which can be used not only in scientific researches but industrial fields (laser marking, welding,…). The key of high power fiber laser is fiber amplifier. In this paper, we present a two-level master-oscillator power amplifier system at 1053 nm based on Yb-doped photonic crystal fibers. The system is used in the front-end of high power laser facility for the amplification of nano-second pulses to meet the high-level requirements. Thanks to the high gain of the system which is over 50 dB, the pulse of more than 0.89 mJ energy with the nearly diffraction-limited beam quality has been obtained.
A fiber-based，high precision long-term stable time synchronization system for multi-channel laser pulses is presented，using fiber pulse stacker combined with high-speed optical-electrical conversion and electronics processing technology. This scheme is used to synchronize two individual lasers including a mode-lock laser and a time shaping pulse laser system. The relative timing jitter between two laser pulses achieved with this system is 970 fs (rms) in five minutes and 3.5 ps (rms) in five hours. The synchronization system is low cost and can work at over several tens of MHz repetition rate.