994 resultados para 1995_12070321 Optics-7


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研究了一种侧面抽运双包层光纤的方法,从被剥除了外包层、端面为350μm×400μm的D型双包层光纤内包层上切下长度为3mm的一段柱体,并胶合在相同的双包层光纤内包层的侧面上,构成了柱体-光纤侧面耦合器。半导体激光器的抽运光从该柱体的一端入射并通过它耦合进入双包层光纤的内包层,实验测得耦合器最大耦合效率为85%。该方法适用于输出功率为数瓦的光纤激光器和放大器的侧面抽运。

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报道了一种MOPA式国产单频光纤放大器。该放大器采用连续波单频激光器作为主振荡器,采用我国自行设计和制造的大模场面积掺Yb双包层光纤作为功率放大器,在波长1064 nm处实现了最高7.3 W的连续激光输出,斜率效率为39%,光-光转换效率为26%。此外,对光谱特性及放大的自发发射的抑制也进行了探讨。

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Large numbers of fishing vessels operating from ports in Latin America participate in surface longline fisheries in the eastern Pacific Ocean (EPO), and several species of sea turtles inhabit the grounds where these fleets operate. The endangered status of several sea turtle species, and the success of circle hooks (‘treatment’ hooks) in reducing turtle hookings in other ocean areas, as compared to J-hooks and Japanese-style tuna hooks (‘control’ hooks), prompted the initiation of a hook exchange program on the west coast of Latin America, the Eastern Pacific Regional Sea Turtle Program (EPRSTP)1. One of the goals of the EPRSTP is to determine if circle hooks would be effective at reducing turtle bycatch in artisanal fisheries of the EPO without significantly reducing the catch of marketable fish species. Participating fishers were provided with circle hooks at no cost and asked to replace the J/Japanese-style tuna hooks on their longlines with circle hooks in an alternating manner. Data collected by the EPRSTP show differences in longline gear and operational characteristics within and among countries. These aspects of the data, in addition to difficulties encountered with implementation of the alternating-hook design, pose challenges for analysis of these data.