多波长主动式相干合成中光程差对合成效果的影响

Influence of Optical Path Difference on Combination Effect in Multi-wavelength Active Coherent Beam Combination

为了对多波长激光主动式相干合成做出初步的理论描述,揭示影响合成效果的关键因素,根据相干合成的基本原理,建立了计算模型。并以9波长7路相干合成系统为实例,仿真计算了光程差取不同值的情况下,各频率成分的合成效果和总体合成效果。当各路间存在较大的光程差时,只有中心频率成分实现了相干相长,其他频率成分处于"混乱"状态,总体合成效果退化到接近非相干合成的状态;各路间的光程差减小后,实现相干相长的频率成分增多,总体合成效果得到改善。在多波长主动式相干合成中光程差是影响合成效果的重要因素,要实现好的合成效果需先将光程差控制在较小的范围内,再进行锁相控制。

In order to make a theoretical description of the multi-wavelength active coherent beam combination（CBC）,and to figure out the significant factors influencing the combination effect,a mathematical model was established based upon the fundamentals of CBC.The combination effect of each frequency component and the whole combination effect are obtained on the calculation of the nine-wavelength seven-channel CBC example with various optical path differences.Only the central frequency component is coherently enhanced and the whole combination effect degenerates to non-coherent beam combination on the condition of large optical path difference.More components are coherently enhanced and the whole combination effect is improved when the optical path difference is small.The optical path difference is the key in multi-wavelength active CBC.To achieve excellent combination effect,the optical path difference should be adjusted to the same and then the phase of each channel is locked.