| 摘要 |
The objective of the present invention is to offer an optical fiber strain-measuring apparatus, which allows the measurement of the strain at an arbitrary position within an optical fiber. An optical frequency conversion section 3 shifts, in a step-wise manner for prescribed frequencies, the frequencies of a continuous light emitted from a light source 1. A sound-light switch 4 coverts into pulses the continuous light forwarded from the optical frequency conversion section 3. When those light pulses are entered into a test optical fiber, back-scattered light is generated. An optical directional coupler 11 branches and forwards to an optical ring circuit and to an optical directional coupler 13 the back-scattered light. A photo-electric converter 14 receives employing heterodyne detection and converts into electric signals the synthesized light signals of the back-scattered light forwarded from the optical directional coupler 11 and the continuous light forwarded from the optical directional coupler 2. A signal processing section 18 reads at an arbitrary timing the electric signals, performs necessary processes, and obtains the amount of strain of the test optical fiber 7.
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