Research On MOPA Structured High Power Pulsed Fiber Laser

Master Oscillator Power Amplifier fiber laser system has the characteristics of stable structure,good beam quality,high output energy and wide application range.It was widely used in industrial production,space ranging,military and so on.Especially the high power pulsed fiber laser system with high peak power and high beam quality output has become a research hotspot.In this thesis,the Yb-doped high power pulsed fiber laser system with MOPA structure is experimentally studied,and the high peak power MOPA fiber laser system with low repetition rate pulse output is emphatically studied.The main points include:1.The basic principle of MOPA structure optical fiber laser system,the application prospect of optical fiber laser system and the development status at home and abroad are introduced.The amplification theory of Ytterbium-doped optical fibers is described,including the energy level structure and spectral characteristics of Yb³⁺.2.According to the theory of pulse pumping,the experimental platform of pulsed fiber laser is designed and built.Pulsed Ytterbium-doped fiber laser system with high power is experimentally studied.A low-frequency seed signal source was constructed,The signal source can generate 1064nm pulses of peak power from 0m W to 1000m W,pulse duration from 0ns to 1000ns and repetition from 1Hz to 1000Hz.The multi-stage amplification optical circuit is designed,three design schemes of synchronous pulse pump are proposed,and each scheme is analyzed.3.According to the experimental platform.The experiment of pulse pump characteristics of fiber laser has been completed.And the relationship between pulse energy and ASE with pump power and duration is studied.The multi-stage amplification experiment of MOPA optical fiber laser system has been completed,and the output characteristics of each stage amplification optical path have been studied,and make analysis.When the repetition of the signal is 80Hz,the pulse duration is 30ns and the pump pulse duration is 9ms,1064nm laser output with single pulse energy greater than 0.9mJ is obtained and the gain is greater than 53dB.