A Study On Practical Technology For Complement Coupling Between Laser Diode And Multi-mode Optical Fiber

Laser Diode(LD) has the advantages of small volume, light weight, longevity of service, high electro-optic convert efficiency and direct modulate etc. Now it is more widely used in the fields of information, energy, therapeutic, material, entrainment and so on. And the technological level of its material and devices has improved mostly. But its light waveguide is strong asymmetry with a very big difference between perpendicular and parallel to the junction plane. So most applications are limited and coupling efficiency between LD and the optical fiber is affected. The researches on the coupling between LD and the optical fiber have been focusing on and becoming a very important research project.The methods of coupling between LD and optical fiber can be divided into direct and indirect coupling according to whether optical devices exist between them. For various types of LD and optical fiber, every coupling method has its advantages and disadvantages.Based on in-depth analyses existing coupling methods and its'application conditions, this paper includes the following segments:1. The basic theories are offered on the optical transmission in fiber and the characteristic of LD's optical field. Set forth the coupling model in theory between LD and optical fiber, light coupling theory and model coupling one.2. Coupling systems between LD and optical fiber are separated into two categories: micro-lens optical fiber system and disjunct lens one. And in micro-lens optical fiber system mainly analysis the structure of the end face of optical fiber and it's coupling efficiency. Then introduce the process in making the micro-lens optical fiber. Considering the technics and coupling efficiency, optical fiber with sphere end is priority due to it's simple technics and easy facture.3. Because traditional coupling system composed with cylinder lens and focus lens has the disadvantages of difficult to encapsulation and modulate, a new practical method brings forward: the output light from laser diode is collimated using a section of optical fiber with the diameter of 600μm instead of cylinder lens, and a sphere–end lens...