SPOT SIZE MEASUREMENT FOR OPTICAL FIBER

摘要

PURPOSE:To measure the spot size of an optical fiber at a high speed with a high accuracy, by measuring and memorizing factors for causing measuring errors such as uneven light receiving sensitivity and an (r) value of a TV camera beforehand to correct the actually measured value of the spot size by the data thus memorized. CONSTITUTION:A step type optical fiber 7 is set at the position of a fiber 6 to be measured to admit a parallel light into an incident end from a light source 1 and the position sensitivity characteristic on the whole screen of a TV camera 11 is memorized into a CPU14 varying the level of a light attenuator 3. Then, the fiber 7 is removed and the fiber 6 being measured is set at the position thereof to measure the intensity of light on the end face with the TV camera 11. The results are computed with the CPU14 to be corrected by the portion of the position sensitivity characteristic previously measured and the measured value following the correction is outputted. The radius, namely, the spot size is measured to the point where the intensity of light decreases to one-(e)th of the maximum from the center at which the intensity reaches the maximum from the measured value.