High Power Sub-picosecond All Fiber Er³⁺/Yb³⁺ Co-doped Laser Source

High power, high repetition rate ultrafast laser sources operating at 1.56 ?m have extensive applications in medicine, industry, and military,because of its short pulse duration, high peak power and wide spectrum. Among them, the fiber laser system has been studied a lot due to its compact structure, high stability to environmental change, and can be directly pumped by low cost high brightness laser diodes for high efficiency laser operation.In this paper, we mainly focused on chirped pulse amplification. The whole system is fully fiberized except for the compression part. Explored the mechanisms in fiber and discussed their influence on pulse duration, spectrum width and energy. Make a future prospect on how to improve all fiber laser amplifer.The main contents of this thesis can be devided into three parts:1?The development of ultrafast fiber laser, basic theory of mode-locked fiber lasers, dispersion compensation mechanisms and principles of several commonly used fiber amplifier. Among them, the chirped pulse amplification stand out for its output stability. Establish the nonlinear propagation model in fiber based on the combined effects of gain, dispersion and self-phase modulation.2?Set up numerical model with matlab, simulate the dynamic process of the fiber chirped pulse amplification. Verify and optimize the parameters to obtain the shortest pulse width. After compression, the pulse width is 700 fs. To further study spectrum broadening mechanism, Exchange the position of preamplifier stage and dispersion compensating fiber.3?Demonstrated an all fiber, high power ultrafast laser source utilized a fiber chirped pulse amplification(FCPA) configuration operating at 1563 nm. The system is highly stable and achieved self-starting mode-locking. The main power amplifier was based on a cladding-pumped Er-Yb co-doped fiber with 8 ?m active single mode core diameter. The laser source output 3.4 W average power at 75 MHz repetition rate,the spectrum was broadened to 11 nm. The pulses were compressed to 765 fs by a low loss transmission grating pair. Exchange the position of preamplifier stage and dispersion compensating fiber, self-similar evolution accured in the dispersion compensating fiber, the spectrum was 14 nm, wider than before. However the pulse quality was influenced because of the overage nonlinear chirp and the limitation of compression elements. This result perfectly matches the simulation results, confirming the reliability of the all fiber amplification system.