Study On 1550nm High-Power Fiber Amplifier

In recent years,because the traditional linear cavity fiber laser has complex structure,and it is difficult to get high-power,narrow line and high repetition rate laser output,the master-oscillator power-amplifier(MOPA)scheme becomes the main choice of high energy,high peak power pulsed laser systems due to its many advantages,such as high slope efficiency and easily manageable output pulse characteristics via the control of the seed source.to get high power Er/Yb co-doped pulsed fiber laser,the thesis studied many contents,include theory analysis,numerical analysis and experiment study,the main work are summarized as follows:1.We introduced the typical structure of MOPA system on the basis of the key technique,Based on equation and power propagation of Er/Yb co-doped fiber amplifier(EYDFA),we simulated the output of EYDFA with the different input parameters(signal power,pump power)by MATLAB software.2.We designed a nanosecond Er/Yb co-doped pulse fiber laser based on an all-fiber MOPA structure,where a directly electric-modulated 1550 nm laser diode(LD)and a high-gain double-cladding Er-Yb co-doped fiber are used as the seed source and the second-stage gain medium,respectively.The fiber laser will have a great potential to be widely applied in laser radar,laser medicine,laser ranging,etc.The output characteristic·of single-pass and double-pass Er-doped fiber amplifiers(EDFA),Er/Yb co-doped fiber amplifier(EYDFA)under forward and backward pumping are compared.and the ASE,nonlinear effect and gain saturation on the fiber amplifier are analyzed.3.We designed a high power sub-nanosecond Er/Yb co-doped pulse fiber laser based on an all-fiber 3-stage MOPA structure,where a directly electric-modulated 1550 nm FP laser diode(FP-LD)and a high-gain double-cladding Er-Yb co-doped fiber are used as the seed source and the second-stage gain medium,respectively.The output characteristics of Pre-amplifier,medium-amplifier and power main-amplifier are analyzed.The sub-nanosecond fiber laser will have a great potential to be widely applied in laser radar,laser ranging,precision machining etc.