| 摘要 |
PURPOSE:To make it possible to simply measure a connection length in a range from a short connection length to a long one with high accuracy, by selecting the wavelength of light from a white light source by a spectroscope to allow said light to be incident to a polarization surface preservation fiber and calculating a connection length from the wavelength characteristics of the polarization degree of emitted light. CONSTITUTION:The white light from a white light source 1 is spectrally diffracted by a spectroscope 2 and monochromatic light with a selected specific wavelength is incident to a polarization surface preservation fiber 4 through a polarizer 3. The emitted light from said fiber 4 is guided to Ge-APD7 by a multimode fiber 6 while passes through an analyser 5 and the output voltage thereof is measured by a voltmeter 8. At this time, the analyser 5 is rotated and the transmitted polarized light direction thereof is changed to measure voltage values and, on the basis of the max. value P1 and min. value P2 thereof, the polarization degree P=(P1-P2)/(P1+P2) of the emitted light is calculated. The polarization degree P is repeatedly calculated by changing the selected wavelength by the spectroscope 2 and, if a range from a wavelength lambda1 to a wavelength lambda2 is one cycle, the connection length L of the polarization surface preservation fiber 4 can be calculated from L=2L0(1-lambda1/lambda2) (wherein L0 is the length of the fiber 4). |
