LIGHT SHIELD MEMBER FOR OPTICAL FIBER

摘要

PROBLEM TO BE SOLVED: To prevent high order clad mode light from being emitted from the output end without affecting a first mode optical signal transmitting through an optical fiber, by setting the pore diameter of a through hole of a light shield member in specified times of a mode field diameter. SOLUTION: By inserting the plug part of an optical fixed attenuator into a connection part 15 of an adaptor 12, a ferrule is received by a guide part 17, and an engagement pawl 18 is engaged with a pair of engagement grooves. Thus, the optical fixed attenuator is connected attachably/detachably to the adaptor 12 of a photodetector 10 between the optical fiber and the photodetector 10. In this connection state, the output end of the optical attenuation fiber of the optical fixed attenuator is positioned so as to oppose to the through hole 20 provided on the light shield member 19. The pore diameter of the through hole 20 opposite to the output end of this optical attenuation fiber is set in a value of 2.5-5 times of the mode filed diameter of the optical attenuation fiber of the optical fixed attenuator.