Analysis of Transmission Characteristics of Multi-mode Optical Fiber Endcap

Optical fiber endcap is an important device that can effectively suppress the fiber end face damage caused by high-power laser. Owing to the nonlinear effects, the power of single-mode optical fiber laser is limited by the core size. High-power laser based on multi-mode optical fiber can achieve higher-power. In this paper, transmission characteristics of light in multi-mode optical fiber endcap are investigated. The light outputted from multi-mode optical fiber is expanded very fast in the endcap, which is owing to the high numerical aperture and the large core size. The splicing angle and position deviation play strong impact on the transmission loss and the light spot, which implies the accurate splicing procedure should be applied in order to reduce the splicing loss and the mode spot factor.