Optical fiber characteristic measuring device

An optical fiber characteristic measuring device comprising:

• a coherent light supply device which supplies a coherent light with a second frequency which is almost equal to the frequency of coherent light with a first frequency and the frequency of returning light emitted from this optical fiber when the coherent light with the first frequency is incident to the optical fiber as an object to be measured;
• a light pulse generating device which converts the coherent light with the first frequency which is supplied by the coherent light supply device to light pulse and emits a light pulse which is converted;
• a wave mixing device which mixes the wave of returning light emitted from the optical fiber and the wave of the coherent light with the second frequency supplied from the coherent light supply device when the light pulse emitted by the light pulse generating device is incident to the optical fiber as an object to be measured and emits the mixed light;
• a opto-electrical converting device which converts the mixed light emitted from the wave mixing device to an electric signal and outputs the electric signal which is converted;
• a processing device which calculates a shifting amount to the frequency of the returning light emitted from the optical fiber from the first frequency of coherent light which is incident to the optical fiber as an object to be measured according to the electric signal which is output from the opto-electrical converting device and determines characteristic of the optical fiber from the calculated shifting amount.