阶跃光纤低阶线偏振模的M^2因子分析  

M^2 Factor of Linear Polarization Modes in a Step-index Fiber

作　　者：傅玉青[1] 冯国英[1] 张大勇[2] 陈建国[1] 周寿桓[1] 

机构地区：[1]四川大学电子信息学院,成都610064 [2]华北光电技术研究所,北京100015

出　　处：《光子学报》2008年第7期1342-1345,共4页Acta Photonica Sinica

基　　金：国家自然科学基金(10676023);固体激光国防重点实验室基金

摘　　要：针对阶跃光纤输出低阶线偏振模(Linear Polarization,LP),利用二阶距定束宽,多点拟合法计算了几个低阶LPmn模相干和非相干叠加时的M2因子.结果表明,对同一LPmn模式,光纤的归一化频率参量V减小到截止频率时,M2因子出现峰值;当V远离截止频率时M2因子趋于一定值.低阶LPmn模非相干叠加时,叠加后的较高阶模成分越大,合成光束的光束质量越差,光束在一定的条件下可能比基模更接近于理想高斯光束;而相干叠加时,合成后的M2因子可以大于参与叠加的较高阶模的光束质量因子.Using the second order moment method to determine the beamwidth and multipoint fitting methor,the Me factor in the case of incoherent and coherent superposition of several low order LPmn modes, which are outputed from the step-index fiber, have been calculated. The results indicate that, for an individual LPmn mode,the value of the Me factor takes its maximum value when the normalized frequency parameter V of the fiber approaches to the cut-off frequency and it gradually goes to a constant value when V apparted from its cut-off frequency. In the case of incoherent superposition, under certain circumstance, the beam that comprises few lowest order LP modes may become even smaller and closer to the ideal Gaussian beam than that value of the Me factor ma here could be helpful for of the fundamental mode. However y be greater than that of the application of the hig case of the coherent superposition,the he higher order constituent mode. The results reported power fiber systems.

关 键 词：M^2因子 线偏振模 阶跃光纤 

分 类 号：TN252[电子电信—物理电子学]