The Development Of High Power Double Cladding Fiber End Cap

End cap is a special type of high power device designed for handling with the output of high power fiber lasers and amplifiers. It can protect fiber end from damaging by reducing optical power density through expending beam aperture at output end. Theoretical and experimental research are discussed detialedly in this dissertation, in order to explore the making craft of an end cap. The primary coverage as follows:1. The history of development of fiber lasers and the main applications of end caps in high power fiber lasers are introduced. The present condition, develop trend of end caps as well as three essential making craft are expatiated on.2. Achieved the welding of a no-core end cap. The variation of the light spot of laser beams are modeling when propagate through a no-core end cap by using numerical simulations. We developed no-core end caps in experiments. The no-core end caps then are successfully used in fiber lasers or amplifiers. Finally, attained a specific method to package no-core end caps.3. Base on a system which can be used to weld the glass cone and the optical fiber, which is developed by our research group, we realized and fabricated the glass cone end cap. In experiments, the end cap of glass cone are tested with the strength, the loss, the affordable power and the quality of out-put beam. The experiment results indicate that the welded glass cone has the capacity of a high strength which can sustain a gravity of 40 g as well as a low loss of no more than 4% in total. The glass cone can endure an out-put power of 1kW in an experiment without water-cooling device. The particular process to package the glass cone is designed and achieved.4. Cascaded extract cladding light strippers are designed. The stripper can overcome localized heating, and have the capacity to remove the cladding light within a reasonable and consistent length. The experiment results indicate that the loss reach to 18 dB and the localized heating is not exceed 60℃ while coupling with the laser power of 150 W in a 30/250μm fiber.