Study On High Power Semiconductor Laser Multimode Optical Fiber Coupling

Because of the improved require of fiber-optic communications for the demand of semiconductor laser diode(LD) coupling with multi-mode fiber. This paper respectively designed single LD and LD array coupling with multi-mode fiber. In order to reduce the complexity of directly design in array’s coupling, author first design single LD coupling with optical fiber. It can divide the array’s coupling system into collimating system, shaping system and focusing system, and analysis and research to each system’s selection. Through the physical and mathematical models, calculate each system’s specific parameters on theoretical. Then, simulate the actual situation by Matlab and Zemax, and compared with the theoretical results.In the paper, the wavelength of LD is980nm, divergence angle is36°×10°, and the size of light emitting surface is1μm*150μm. The element spacing of LD array is0.5mm, and the unit number of19. The multi-mode optical fiber’s core diameter of0.2mm, and the numerical aperture of0.22. For the coupling of single LD with multi-mode optical fiber, by adding cylindrical lens and spherical end face of the optical fiber, and coated AR on every surface, finally, the efficiency of92%can be achieved. For the coupling of LD array with multi-mode optical fiber, author use collimating system, shaping system and focusing system. The collimating system select flat-convex collimating len of fast axis(aspheric treatment to the convex) and flat-convex collimating lens array of slow axis; the shaping system select the stack rectangular prism group; the focusing system based on the triplet lens, adding flat-convex collimating lens of slow axis. The efficiency of actual analog data reach94%at last.