基于CCD的光斑能量分布测量及特性分析

摘要

光纤技术应用于自由空间激光通信系统有诸多优点,而且应用前景广阔.空间光与光纤的耦合效率问题是其应用中的首要问题.本文论述了光斑半径与耦合效率的关系,对有无大气影响时的光斑形状进行的仿真,分析了大气湍流对光斑形状以及半径的影响,采用CCD对激光光斑进行测量,分析CCD采集到的激光光斑的能量分布、光斑半径等特性,特别针对当采集到的光斑中央最大光功率超出CCD的探测范围,根据已知的光斑能量分布,推算出光斑中央的光功率,用以拟合出实际光斑能量分布,确定光斑半径大小.对光斑半径大小的研究有助于合理选择光纤的芯径及数值孔径,评估空间光到光纤的耦合效率.%There are many advantages and extensive application prospect in applying optical fiber technology to free space laser communication system.Unfortunately, it is difficult to coupled spatial light to fiber.And then the coupling efficiency is the key of the application.In this paper,we simulated the effect of atmosphere turbulent on the facula shape,and measured the facula with CCD, analyzed the characteristics of facula, such as the energy distribution and the size of the facula, especially when the maximum light power in the centre of the facula is beyond the range of CCD.Based on the distribution what we had got previously, we calculated the light power in the centre of the facula.Then we could fit the energy distribution actually, and then we can get the radius of the facula.The research of the facula's characteristies is very essential.It offers the theoretic foundation for choosing the adequate fiber core's diameter and numerical aperture(NA).And it can also be used to estimate the coupling efficiency of spatial light to fiber.