| 摘要 |
PURPOSE:To improve measuring accuracy, by providing at least two light receiving surfaces in a light-amount detecting means, and forming detected light- amount signals in correspondence with the amounts of the received lights from the light receiving surfaces. CONSTITUTION:The light emitted from a cut end 43 of a cut optical fiber 4' to be measured is detected with a photodetector 5. The photodetector 5 forms individual detected light-amount signals corresponding to the incident-light amounts through at least two light receiving surfaces. The signals are supplied to a control device 9. The device 9 processes and operates each of the input signals and judges whether or not the optical coupling between the cut end 43 and the photodetector 5 is good. When the coupling is good, an attenuating amount of light is obtained and a transmission loss is determined. When the coupling is inadequate, the device 9 sends a driving signal to a moving stage 8 so as to move the photodetector. Thus the coupling with the cut end 43 is adjusted. When the coupling does not improve, the device 9 sends a reject signal (a) so as to indicate that this optical fiber 1 is not suitable for measurement. In this way the measuring accuracy can be improved. |
