拉锥光纤端面耦合效率的研究

The Coupling Efficiency Study of Tapered Fiber End Faces

光纤端面形状对光纤耦合的相关指标影响较大。光纤传输系统的速率越高,反射光对系统的影响越大。反射光会沿着光纤反馈到系统的激光器光源中,引起系统的不稳定和噪声,使得光纤系统的传输信息不可靠。因此我们提出通过拉锥将光纤端面制成曲面,而锥体曲面与光纤系统匹配,可以与光纤线路进行低损耗连接,具有极低的后向反射,得到更高的回波损耗。基于光纤熔接机的熔接功能,在放电熔融时使夹具反向移动,使光纤在熔融状态下获得径向拉力,可以改变光纤径向尺寸分布,光纤平端面可形成具有一定锥体的曲面。本文测量了不同放电时间和放电强度条件下,相应形成的光纤端面的插入损耗和回波损耗值,并与光纤平端面对比, 得到回波损耗可达到36 dB,并通过测试和分析,我们首次提出插入损耗随耦合端面距离改变的变化规律的结论。

The shape of fiber end has a relatively vital effect on related indices of fiber coupling. The higher the fiber transmission system is, the greater the effect of reflected light is on the system. The reflected light can feed back into the laser source, causing instability and noise of system, which leads to unreliable transmission information. Then we put forward the idea that the end face can be made into curved surface by tapering to match with fiber system and be connected with low loss which has extremely low back reflection and gets higher return loss. On the basis of fusion function of fiber fusion splicer, the fixture moves reversely in the melt when it discharges and the fiber obtains radial tension in the molten state that can change the fiber radial size distribution. Then fiber end face can form a curved surface with a certain cone. In this paper we measure return loss and insert loss of fiber end faces respectively corresponding to different discharge time and intensity. In comparison with fiber flat end, we conclude that return loss of tapered fiber can reach 36 dB and to our knowledge, we first time put forward the rule that insert loss changes when the coupling end distance changes.