Brillouin optical time domain reflectormeter method and device based on parallel data processing technique

Abstract

The invention provides a brillouin optical time domain reflectormeter method and a device based on a parallel data processing technique. The temperature and / or stress of each position along a measured optical fiber are measured through detection for changes of brillouin scattering spectra center frequency returned through a detection optical pulse in the measured optical fiber. Brillouin scattered light signals are coherent with single-frequency local oscillation light to produce coherent medium-frequency signals, and therefore the brillouin scattered signals are changed into brillouin electric frequency spectra from optical spectra. High-speed signal collection and parallel data processing schemes are adopted in the measurement of the brillouin electric frequency spectra, and accordingly complete brillouin spectra are obtained in each detection pulse cycle. Dynamic measurement for the temperature and / or the stress of each position along the measured optical fiber is benefited.

Description

technical field

[0001] The invention relates to a distributed optical fiber sensing method and device for monitoring temperature and / or stress by using the spontaneous Burrillouin scattering effect in the optical fiber, and belongs to the field of sensing technology. Background technique

[0002] The transmission of single-frequency light pulses in the optical fiber will generate self-Brillouin scattered light, part of which will return along the optical fiber, and this part of the Brillouin signal is called the back Brillouin scattered signal. The Brillouin signal is Lorentzian, and its 3dB bandwidth is about 35MHz in ordinary single-mode fiber, and the continuous range of the spectrum is greater than 200MHz, so the Brillouin scattering signal is also called the Brillouin scattering spectrum. The Brillouin scattering spectrum in the fiber is sensitive to the temperature and stress at the scattering position on the fiber, and the change of temperature and stress will cause t...

Examples

Embodiment 1

[0034] See figure 1 , a method of Brillouin optical time domain reflectometer based on parallel data processing technology provided by the embodiment of the present invention, the detailed content of the method is as follows:

[0035] The laser light emitted by the single-frequency laser source is divided into two paths by the coupler, one path is modulated into optical pulses by the optical pulse modulator, and the other path is used as single-frequency local oscillator light;

[0036] The optical pulse is first injected into the optical fiber under test after the peak power is increased by the optical amplifier, and the local oscillator light is shifted by a frequency shifter to make the difference frequency of the self-published Brillouin scattering signal generated by the optical pulse in the optical fiber under test falls within the bandwidth of the detector;

[0037] The spontaneous Brillouin scattering signal generated by the optical pulse in the optical fiber under te...

Embodiment 2

[0041] See figure 2 , the embodiment of the present invention provides a Brillouin optical time domain reflectometer method and device based on parallel data processing technology, the method and device details are as follows:

[0042] The light source module 101 is composed of a single-frequency laser and a 90:10 Y-type coupler. The single-frequency laser is divided into two beams by the coupler. One beam with high power is used as the probe light, while the other beam is used as the local oscillator light and Direct access to the coherent detection module 104;

[0043]The continuous detection light enters the modulation module 102, the modulation module 102 is composed of an electro-optic modulator and its drive, the continuous detection light is modulated into a detection light pulse and its frequency is shifted up by about 10.8 GHz, so that the pulse generated in the optical fiber under test The anti-Stokes spectrum in the spontaneous Brillouin scattered light is close t...

Embodiment 3

[0053] See image 3 , the embodiment of the present invention provides a Brillouin optical time domain reflectometer method and device based on parallel data processing technology, the method and device details are as follows:

[0054] The light source module 101 is composed of a single-frequency laser and a 90:10 Y-type coupler. The single-frequency laser is divided into two beams by the coupler. One beam with high power is used as the probe light, while the other beam is used as the local oscillator light and Direct access to the coherent detection module 104;

[0055] The continuous detection light enters the modulation module 102, the modulation module 102 is composed of an electro-optic modulator and its drive, the continuous detection light is modulated into a detection light pulse and its frequency is shifted up by about 10.8 GHz, so that the pulse generated in the optical fiber under test The anti-Stokes spectrum in the spontaneous Brillouin scattered light is close t...

technical field

[0001] The invention relates to a distributed optical fiber sensing method and device for monitoring temperature and / or stress by using the spontaneous Burrillouin scattering effect in the optical fiber, and belongs to the field of sensing technology. Background technique

[0002] The transmission of single-frequency light pulses in the optical fiber will generate self-Brillouin scattered light, part of which will return along the optical fiber, and this part of the Brillouin signal is called the back Brillouin scattered signal. The Brillouin signal is Lorentzian, and its 3dB bandwidth is about 35MHz in ordinary single-mode fiber, and the continuous range of the spectrum is greater than 200MHz, so the Brillouin scattering signal is also called the Brillouin scattering spectrum. The Brillouin scattering spectrum in the fiber is sensitive to the temperature and stress at the scattering position on the fiber, and the change of temperature and stress will cause t...

Examples

Embodiment 1

[0034] See figure 1 , a method of Brillouin optical time domain reflectometer based on parallel data processing technology provided by the embodiment of the present invention, the detailed content of the method is as follows:

[0035] The laser light emitted by the single-frequency laser source is divided into two paths by the coupler, one path is modulated into optical pulses by the optical pulse modulator, and the other path is used as single-frequency local oscillator light;

[0036] The optical pulse is first injected into the optical fiber under test after the peak power is increased by the optical amplifier, and the local oscillator light is shifted by a frequency shifter to make the difference frequency of the self-published Brillouin scattering signal generated by the optical pulse in the optical fiber under test falls within the bandwidth of the detector;

[0037] The spontaneous Brillouin scattering signal generated by the optical pulse in the optical fiber under te...

Embodiment 2

[0041] See figure 2 , the embodiment of the present invention provides a Brillouin optical time domain reflectometer method and device based on parallel data processing technology, the method and device details are as follows:

[0042] The light source module 101 is composed of a single-frequency laser and a 90:10 Y-type coupler. The single-frequency laser is divided into two beams by the coupler. One beam with high power is used as the probe light, while the other beam is used as the local oscillator light and Direct access to the coherent detection module 104;

[0043]The continuous detection light enters the modulation module 102, the modulation module 102 is composed of an electro-optic modulator and its drive, the continuous detection light is modulated into a detection light pulse and its frequency is shifted up by about 10.8 GHz, so that the pulse generated in the optical fiber under test The anti-Stokes spectrum in the spontaneous Brillouin scattered light is close t...

Embodiment 3

[0053] See image 3 , the embodiment of the present invention provides a Brillouin optical time domain reflectometer method and device based on parallel data processing technology, the method and device details are as follows:

[0054] The light source module 101 is composed of a single-frequency laser and a 90:10 Y-type coupler. The single-frequency laser is divided into two beams by the coupler. One beam with high power is used as the probe light, while the other beam is used as the local oscillator light and Direct access to the coherent detection module 104;

[0055] The continuous detection light enters the modulation module 102, the modulation module 102 is composed of an electro-optic modulator and its drive, the continuous detection light is modulated into a detection light pulse and its frequency is shifted up by about 10.8 GHz, so that the pulse generated in the optical fiber under test The anti-Stokes spectrum in the spontaneous Brillouin scattered light is close t...

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