Abstract:
The present invention may include an optical modulation unit which produces first and second optical signals including a sideband signal by diffracting light from light sources, which modulates the second optical signal using a modulation signal, and which applies the first optical signal and the modulated second signal to both ends of test optical fiber; and an optical detection unit optically connected to the test optical fiber to detect Brillouin scattering light produced by the first and second optical signals. At this moment, the modulation signal has first and second sections alternating with each other according to a first frequency. The first section may be a sinusoidal signal having a second frequency. [Reference numerals] (210) Optical splitter; (225) Signal generator; (530) Phase locking amplifier
Abstract:
PURPOSE: A distribution type optical fiber sensor and a method for controlling beat noise of the distribution type optical fiber sensor are provided to measure physical changes and the temperature of a large building, a bridge, an aircraft, and a railway vehicle by using a brillouin optical correlation domain analysis. CONSTITUTION: A distribution type optical fiber sensor comprises a test optical fiber(30), a light source unit(10), a light modulation unit(20), and an optical detecting unit(50). The light source unit outputs lights modulated into a first frequency. The light modulation unit generates first optical signals including sideband signals and second optical signals chirped into a second frequency having a preset ratio with respect to the first frequency by utilizing the light emitted by the light source unit and applies the first and second optical signals respectively to both ends of the test optical fiber. The optical detecting unit detects brillouin scattered light generated by the first and second optical signals from the test optical fiber. [Reference numerals] (210) Light distributor; (225) Signal generator; (530) Phase lock amplifier; (AA) Probe; (BB) Pump
Abstract:
분포형 광섬유 센서는, 시험 광섬유; 제1 주파수로 변조된 광을 출력하는 광원부; 상기 광원부에 의해 출력된 광을 이용하여, 측대역 신호를 포함하는 제1 광신호 및 상기 제1 주파수에 대해 미리 설정된 비율을 갖는 제2 주파수로 처핑된 제2 광신호를 생성하고, 상기 제1 광신호 및 상기 제2 광신호를 상기 시험 광섬유의 양단에 각각 인가하는 광변조부; 및 상기 시험 광섬유에서 상기 제1 광신호 및 상기 제2 광신호에 의하여 생성된 브릴루앙(Brillouin) 산란광을 검출하는 광검출부를 포함할 수 있다. 제2 광신호를 제1 주파수에 대해 소정의 비율로 처핑(chopping) 함으로써, 분포형 광섬유 센서에서 발생할 수 있는 비트 노이즈(beat noise)를 억제하여 브릴루앙 이득 스펙트럼의 왜곡 현상을 피할 수 있다.