| With the development of optical fiber technology, the range of fiber applications is wider and wider. Especially in optical communications, optical fiber has become the most important optical waveguide. Semiconductor laser has been widely used in optical communication with advantages of a small size, long life, electro-optical conversion efficiency, modulation convenience, can be integrate and so on. Because the semiconductor laser active area is small, its output beam divergence angle of a great, fast-axis direction is generally 30°~ 40°, collimating and shaping the laser beam is need to improve the beam quality when coupled with the optical fiber. In order to improve reliability, reduce the coupling loss of encapsulation and installation difficulties, we can use micro-lens to reduce the beam divergence angle and increasing the numerical aperture of optical fiber. With the successful development and promotion application of high-power laser, the quality of optical fiber output beam constraints the application of optical fiber.The current research of degree of loss in fiber-coupled system is relatively small and mostly concentrated in the defense and military, so the research of degree of loss of capacity problem in high-power fiber-coupled semiconductor laser system has practical significance.In this paper, through a variety of research and comparison in shovel-shaped fiber-optic technology at home and abroad, we mainly have done the following tasks:1. Introduced the structure of semiconductor lasers, far-field pattern and the basic theory of optical fiber transmission, described the laser beam shaping methods and the methods of fiber numerical aperture. Have summarized the status of optical fiber coupler products, introduces the semiconductor laser and fiber coupling system and a brief description of common coupling.2. Given a brief introduction on the spade-shaped fiber preparation process and control parameters. Based on the theory of the optical fiber coupling, have expounded the analysis method and basic principles in shovel-shaped optical fiber coupled with the LD systems. Through the analysis of the beam divergence, coupling distance, fiber core diameter and the relationship between coupling efficiency, we got the best coupling efficiency and maximum coupling efficiency.3. Analyzed the degree of loss of capacity on the shovel-shaped optical fiber coupling system. Introduce the relationship between the characteristics of the system power loss on each dimension and the content error. Provide a theoretical guidance of reducing the difficulty of debugging and packaging, and thus give a great help to improve the shovel-shaped optical device development and application.4. Prepared the different cutting angle and cutting depth of the shovel-shaped fiber in accordance with the theoretical guidance, and with experimental measurement of prepared shovel-shaped fiber, and the results show: the improved shovel-shaped fiber may improve the coupling efficiency coupled with the LD. This result can provide theoretical guidance to the optimization design and practical application of shovel-shaped fiber. |
