FIBER OPTICS DISTORTION MEASURING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a fiber optics distortion measuring apparatus which can measure a Brillouin spectrum waveform of an optical fiber as a whole in real time. SOLUTION: Output light of a light source 10 is made incident into an optical fiber 15 to be measured through an optical directional coupler 11, an optical switch 12, a light amplifier 13 and an optical directional coupler 14. The light also is incident into a polarization controller 16 from the optical directional coupler 11. The output light and the return light of the optical fiber 15 is made incident into a reception circuit 17. Both lights interfere with each other in a balance photodetection circuit 17 and the results are outputted. A fixed frequency or a frequency varying in a step is outputted by a control signal of a DC voltage generation circuit 19 or a saw-tooth wave voltage generation circuit 20 from a voltage control oscillator 18. An output of the balance photodetection circuit 17 and an output of the voltage control oscillator 18 are combined with a mixer 26 and processed by a signal processing part 24 through a lowpass filter 21, an amplifier 22 and an AD conversion part 23.