Yb-Doped Fiber Amplification System Based On DFB Semiconductor Laser

In order to provide a good seed laser for thin-film regeneration and amplification,and obtain short-pulse or ultra-short-pulse laser output with high single-pulse energy and high average power,this paper proposes a seed source plus fiber amplification scheme.Feedback laser,DFB laser)is used as a seed source,and the erbium-doped fiber is used as an amplifier to perform optical amplification,namely the Master Oscillator Power Amplifier(MOPA)technology.The resulting amplification system is used as a seed source for the thin-film regenerative amplifier.MOPA technology injects the seed laser into a single-stage or multi-stage fiber amplification system to achieve power amplification.Its advantage is that the beam quality of the output laser can be determined by the seed source during the entire process,and the power of the final output light is determined by the gain of the amplifier.The article first numerically simulates erbium-doped fiber amplification based on DFB semiconductor laser.Without considering the amplification of spontaneous emission and the fiber’s own loss,the gain of the amplifier,the threshold power of the pump light,and the optimal fiber length are derived through the solution of the rate transmission equation.The gain and threshold of the amplifier are obtained by numerical simulation The relationship and interaction between power,optimal fiber length,erbium ion doping concentration,and signal optical power.Experimental research is carried out on this basis.In the first stage of amplification,the seed laser is amplified dozens of times in the MOPA system.When the pulse repetition frequency is 100 k Hz and the pulse duration is 20 ns,the average power is0.15 W.It achieved a peak power output of 85 W,and achieved a peak power of 1287 W after the second stage amplification.The center wavelength of the output light was 1030 nm,and the beam quality was consistent with the seed light.After obtaining the results of the ultra-short pulse(greater than 1 ns)amplification experiment,the amplifier’s output pulse was injected into the thin-film regeneration amplification experiment,and the scheme of semiconductor modulation plus fiber amplification and thin-film regeneration amplification was initially verified.The ultra-short pulse output with high single-pulse energy and high average power has laid the foundation for the development of ultra-fast lasers with higher output power and higher single-pulse energy.