不同入射角激光束在大芯径SI-PDF光纤中的传输损耗

摘要

为得到纯石英阶跃光纤(SI-PDF)中漏泄模式光线功率的传输特性,应用光线投影积分法,推导了不同入射角的激光束在大芯径SI-PDF光纤中的传输功率计算公式,在不同入射角激光束照射下,分别对3、67、140 m SI-PDF光纤的输出功率特性进行了理论和实验研究,用最小二乘法原理对对数坐标下的实验数据进行拟合,得出了损耗系数.结果表明:入射角在0～12°内时,不同入射角功率输出和损耗系数近似一常量,其中损耗系数约为13 dB/km;入射角＞12°时,不同入射角光功率随入射角增加呈指数衰减规律,其损耗系数随入射角增大而增大,在12°时损耗系数值为26 dB/km,在28°时达到了82 dB/km.%In order to obtain transmission property of tunneling rays in a short length large-core SI-PDF fiber,a formula is derived by a light-ray projection integral method to calculate the power coupled from laser beam with different incident angles in the SI-PDF fiber.The output power characteristics of laser beams of 3,67,140 m length fibers at different incident angles are achieved respectively by measurements and theoretic calculations.The loss coefficiens are obtained by the least square fitting to experimental data at a logarithm coordinate.Results show that the coupled power and the loss coefficients with different incident angles in the SI-PDF fiber keep almost a constant at 0～12°and the coupled power goes down exponentially with different incident angles beyond 12° Moreover,the loss coefficients increase with increase of incident angles,it is 26 dB/km at 12° and 82 dB/km at 28°