Cut Back Method
| Cut Back Method | ||||
| POF Testing: Measuring Methods : Cut Back Method | ||||
| The following test method and diagram (Figure 6.11) is quoted from POF Data Book published in 1993 by MRC Techno Research Inc. in Tokyo, Japan (Page 37).
“ Among various attenuation testing methods, OTDR and cut-back methods are well known in the optical fiber field. In POF, the cutback method is the only method used in the industry. The OTDR is ineffective as a test method for POF because of higher attenuation such as 150 dB/km at visible wavelength. In this method, the factor of coupling loss between light source and fiber is neglected. Therefore, accuracies of the length and launching condition are the main factors affecting accuracy of the measurement.” Figures below illustrate the cutback methods of attenuation measurement. First, measure transmitted optical power ( ) of the fiber at certain length ( m), then cut the fiber to m (usually 2m or 1m) and measure transmitted optical power ( ) of the cut fiber in m. Where is attenuation dB/km. |
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