| 摘要 |
A method of determining the optical loss in reflected radiation in a fibre-optic light guide under study, using an idle guide, comprises the steps of providing establishment of a stationary-mode distribution of radiation in forward and return paths thereof through the idle guide, introducing radiation from a source into the idle guide, measuring by a transducer of the power P0 of radiation reflected by the output end face of the idle guide, mating of the output end face of the idle guide with the input end face of the guide under study to obtain the maximum power of the radiation which has entered the guide under study from the idle guide and has returned by the same path to the transducer after reflection from the output end face of the guide under study, measuring of the power P1 of radiation reflected from the output end face of the guide under study, and finding, from the measured parameters, of the optical loss in the guide under study. Besides, if a high-quality mating of the end faces of the guides cannot be provided, the optical loss at the joint therebetween is determined from the measured values of powers P01 and P02 of the radiation which has entered the idle guide and has been scattered respectively in a first and a second points thereof located near the joint, and of powers P11 and P12 of the radiation which has entered the guide under study and has been scattered respectively in a first and a second points thereof, also located near the joint.
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