METHOD AND INSTRUMENT FOR MEASURING OPTICAL FIBER TRANSMISSION BAND

摘要

PURPOSE:To measure the transmission band characteristics of an optical fiber in a short time from one terminal of the optical fiber to be measured by varying and stabilizing the repetitive frequency of pulses generated by a pulse generation part. CONSTITUTION:The pulse waveform of reflected light from the far terminal of the optical fiber f1 to be measured is inputted to a photodetection and analysis part 18. The repetitive frequency fp of a light pulse Op and the operation start timing of the photodetection and analysis part 18 are adjusted for the generation timing of a repetitive light pulse according to the reciprocal propagation time tauL of the light pulse Op in the optical fiber f1. Then at least one delay time tauM of a delay circuit part 14 is varied to make an equation hold (where tauL is the reciprocal pulse propagation time (sec) in the optical fiber to be measured, tau0 reference delay time (sec) in the absence of the optical fiber to be measured, fp the repetitive frequency (Hz) of the light pulse, and INT an integer processing function), thereby measuring frequency characteristics while the repetitive period 1/fp of the light pulse Op is smaller than the reciprocal pulse propagation time tauL in the optical fiber to be measured.