光纤通信第五章课件.ppt

Fig. 5-1: Emission-pattern coordinate system Fig. 5-2: Lambertian radiance pattern Fig. 5-3: Source-to-fiber coupling Two modal distributions Mechanical misalignments Longitudinal offset effect Comparison of misalignment effects Fiber-to-Fiber Joints CHAPTER5.3 5.1 SOURCE-TO-FIBER POWER LAUNCHING 5.2 LENSING SCHEMES FOR COUPLING IMPROVEMENT 5.3 FIBER-TO-FIBER JOINTS 5.4 LED COUPLING TO SINGLE-MODE FIBERS 5.5 FIBER SPLICING 5.6 OPTICAL FIBER CONNECTORS Power Launching and Coupling CHAPTER5 Power Launching and Coupling CHAPTER5 In an optical fiber link, two major system are: How to launch optical power into a particular fiber? How to couple optical power from one fiber into another? Consideration in optical power launching Numerical aperture Core size Refractive-index profile Core-cladding index difference Size, radiance, angular power distribution of source Power Launching and Coupling CHAPTER5 Power Launching and Coupling CHAPTER5 5.1.1Source Output Pattern To determine the optical power-accepting capability of a fiber, the spatial radiation pattern of the source must first be known. by R, θ, and ф, with the normal to the emitting surface being the polar axis. The radiance may be a function of both θ and ф, and can also vary from point to point on the emitting surface. A reasonable assumption for simplicity of analysis is to take the emission to be uniform across the source area. Source-to-Fiber Power Launching CHAPTER5.1 Source-to-Fiber Power Launching CHAPTER5.1 5.1.1Source Output Pattern To determine the optical power-accepting capability of a fiber, the spatial radiation pattern of the source must first be known. by R, θ, and ф, with the normal to the emitting surface being the polar axis. The radiance may be a function of both θ and ф, and can also vary from point to point on the emitting surface. A reasonable assumption for simplicity of analysis is to take the emi