DEVICE FOR MEASURING ULTRASONIC USING OPTICAL FIBER IN WHICH CONTROL CIRCUIT CHANGES A PIEZOELECTRIC UNIT WOUND BY THE OPTICAL FIBER IN SUCH A MANNER THAT A HIGH FREQUENCY LIGHT DETECTOR OF THE DOPPLER SHIFT SENSOR DETECTS THE INTERFERENCE LIGHT IN AN OPTIMAL STATE

摘要

PURPOSE: A device for measuring ultrasonic using an optical fiber is provided to improve accuracy of a Doppler shift by lengthening the length of an optical fiber while minimizing the overall size. CONSTITUTION: A device for measuring ultrasonic using an optical fiber includes a condensing lens(10), a Doppler shift sensor(20), and a controller(60). The condensing lens(10) condenses scattered light generated by laser beam projected on an object to be measured. The Doppler shift sensor(20) has a high-frequency light detector(53) for detecting interference light passing through the optical fiber. The controller(60) includes a control circuit(42). The control circuit(42) changes a piezoelectric unit(40) wound by the optical fiber in such a manner that the high frequency light detector(53) of the Doppler shift sensor detects the interference light in an optimal state.