CN102095523A - Light pulse external modulation type distributed optical fiber temperature sensing device - Google Patents
Light pulse external modulation type distributed optical fiber temperature sensing device Download PDFInfo
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- CN102095523A CN102095523A CN2010106191220A CN201010619122A CN102095523A CN 102095523 A CN102095523 A CN 102095523A CN 2010106191220 A CN2010106191220 A CN 2010106191220A CN 201010619122 A CN201010619122 A CN 201010619122A CN 102095523 A CN102095523 A CN 102095523A
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Abstract
The invention discloses a light pulse external modulation type distributed optical fiber temperature sensing device. An external modulation light-emitting unit is used for outputting the high-power narrow pulsed light needed by the system. The device has the following advantages and positive effects: the effects caused by instability of the light source and coupling loss, optical fiber splice loss, optical fiber bending loss, optical fiber transmission loss and the like in the optical fiber transmission process can be effectively eliminated by adopting Rayleigh scattering light as the contrast signal; and the Raman scattering light after combination and the Rayleigh scattering light are stronger, and the stronger scattering light signal can be detected if the input light source power is lower, thus overcoming the contradiction between the incident light power and the nonlinearity of scattering light and improving the temperature measuring sensitivity of the system.
Description
Technical field
The present invention relates to technical field of optical fiber sensing, relate in particular to the distributed optical fiber temperature sensor technology field.
Background technology
The index of incident pulse laser is the key factor that influences the distributed fiberoptic sensor performance, be the pacing items that distributed fiberoptic sensor can the response light scattering changes, and pulsed light is narrow more, and spectrum width is stable more, and the sensitivity of system is just high more; The drift of minimum light source frequency spectrum is also extremely important, and curve is shaken because frequency drift can cause the distributed optical fiber temperature sensor back scattering, and the variation of the back scattering curve that temperature causes is submerged, and has a strong impact on the performance of system.
High-power incident pulse laser plays an important role for long-distance sensing, and use too much light amplification meeting to introduce to a certain degree noise (being mainly derived from spontaneous emission noise), therefore, the incoming signal that uses in the system is pulsed light, just must carry out optical modulation to light.The method of the simplest modulation light intensity is internal modulation, realizes by changing LED or laser drive current.But when modulation rate was increased to 200MHz, this method had run into many restrictions, and signal is held high two-forty, average output power and extinction ratio and all is restricted.In addition, directly modulation can cause the simulating signal distortion and the output wavelength of pulse is offset, promptly said " warbling " effect.
Summary of the invention
In order to solve the problem of above-mentioned existence, the present invention has designed a kind of light pulse external modulation type distributed optical fiber temperature sensing device.
The technical solution adopted in the present invention is as follows: a kind of light pulse external modulation type distributed optical fiber temperature sensing device, comprise the external modulation luminescence unit, fiber coupler, detection optical fiber, wave filter, wavelength division multiplexer and high-speed, high precision distributed temperature measuring processing host, the external modulation luminescence unit links to each other with fiber coupler, fiber coupler one side connects detection optical fiber, one side connects three wave filters, two wave filters that filter Raman diffused light are connected on the wavelength division multiplexer, and the wave filter and the wavelength division multiplexer that filter Rayleigh scattering light are connected to high-speed, high precision distributed temperature measuring processing host.
The external modulation luminescence unit comprises continuous light source, electrooptic modulator, burst pulse driving circuit, fiber amplifier, continuous light source links to each other with electrooptic modulator, the burst pulse driving circuit is connected on the electrooptic modulator, electrooptic modulator links to each other with fiber amplifier, and fiber amplifier links to each other with subsequent probe optical fiber.
The continuous light that continuous light source sends is exported burst pulse light after entering electrooptic modulator under the driving of burst pulse driving circuit, burst pulse light enters fiber amplifier, fiber amplifier is exported required high-power narrow pulsed light as required, high-power narrow pulsed light is injected detection optical fiber through fiber coupler, high-power narrow pulsed light can produce rear orientation light when transmitting in detection optical fiber, rear orientation light enters wave filter by fiber coupler, isolate stokes scattering light, anti Stokes scattering light and Rayleigh scattering light, isolated stokes scattering light and anti Stokes scattering light are combined into Raman diffused light through wavelength division multiplexer, Raman diffused light and described Rayleigh scattering light enter high-speed, high precision distributed temperature measuring processing host and carry out subsequent treatment, finally obtain the temperature information of detection optical fiber measured zone.
In distributed optical fiber temperature sensing device, the Raman diffused light temperature influence is bigger, therefore actual temperature signal is just entrained by the Raman diffused light in the detection optical fiber, anti Stokes scattering light temperature influence is bigger in the Raman diffused light, stokes scattering light temperature influence is less, the Raman diffused light that the process wavelength division multiplexer closes behind the ripple is compared single anti Stokes scattering light, and it is big that luminous power becomes.Because Rayleigh scattering light is than 3-4 magnitude of Raman scattering light intensity, noise superposes, and the temperature measurement accuracy of described distributed optical fiber temperature sensing device is determined by signal to noise ratio (S/N ratio), so adopt Rayleigh scattering light as the reference signal.
The present invention is owing to adopted above-mentioned technical scheme, make it compared with prior art, have following advantage and good effect: employing Rayleigh scattering light signal as a comparison can be eliminated the instability of light source and the influence that coupling loss, opticalfiber splicing loss, bending loss of optical fiber and fiber transmission attenuation etc. in the Optical Fiber Transmission process are brought effectively.Because the Raman diffused light and the Rayleigh scattering of closing behind the ripple are all stronger, input light source power urine can detect stronger scattered light signal, thereby the incident optical power that has solved and the contradiction of scattered light non-linear phenomena have improved the sensitivity of thermometry of system.
Description of drawings
Fig. 1 is an apparatus structure synoptic diagram of the present invention;
Embodiment
Further specify concrete implementation step of the present invention below in conjunction with accompanying drawing.
A kind of light pulse external modulation type distributed optical fiber temperature sensing device, as shown in Figure 1, comprise the external modulation luminescence unit that continuous light source 1, electrooptic modulator 2, burst pulse driving circuit 3, fiber amplifier 4 are formed, fiber coupler 5, detection optical fiber 6, wave filter 7,8,9, wavelength division multiplexer 10 and high-speed, high precision distributed temperature measuring processing host 11; Continuous light source 1 links to each other with electrooptic modulator 2, burst pulse driving circuit 3 is connected on the electrooptic modulator 2, electrooptic modulator 2 links to each other with fiber amplifier 4, fiber amplifier 4 links to each other with fiber coupler 5, fiber coupler 5 one sides connect detection optical fiber 6, one side connects three wave filters 7,8,9, two wave filters 7,8 that filter Raman diffused light are connected on the wavelength division multiplexer 10, and the wave filter 9 and the wavelength division multiplexer 10 that filter Rayleigh scattering light are connected to high-speed, high precision distributed temperature measuring processing host 11.
2 inputs of continuous light source 1 output termination electrooptic modulator, burst pulse driving circuit 3 control electrooptic modulators 2 provide drive pulse signal, circuit modulator 2 amplifies the burst pulse light input optical fibre amplifier 4 of output, exports required high-power narrow pulsed light and enters follow-up sensor-based system.
Light source 1 is a kind of continuous laser source.Electrooptic modulator 2 is a kind of high speed electro-optical converters, and electrooptic modulator drives through burst pulse driving circuit 3 will import the required burst pulse light of continuous light modulation output.Burst pulse driving circuit 3 can be electrooptic modulator 2 drive pulse signal is provided.The burst pulse driver module also comprises synchronous signal output end, notifies described high-speed, high precision distributed temperature measuring processing host to begin the digital conversion collection in order to the output synchronizing signal.Image intensifer 4 is a kind of optical amplifier devices, and the gain that present embodiment is selected for use is 30dB.
Here description of the invention and application is illustrative, is not to want with scope restriction of the present invention in the above-described embodiments.Here the distortion of disclosed embodiment and change are possible, and the various parts of the replacement of embodiment and equivalence are known for those those of ordinary skill in the art.Those skilled in the art are noted that under the situation that does not break away from spirit of the present invention or essential characteristic, and the present invention can be with other forms, structure, layout, ratio, and realize with other elements, material and parts.Under the situation that does not break away from the scope of the invention and spirit, can carry out other distortion and change here to disclosed embodiment.
Claims (3)
1. light pulse external modulation type distributed optical fiber temperature sensing device, comprise external modulation luminescence unit, fiber coupler, detection optical fiber, wave filter, wavelength division multiplexer and high-speed, high precision distributed temperature measuring processing host, it is characterized in that: the external modulation luminescence unit links to each other with fiber coupler, fiber coupler one side connects detection optical fiber, one side connects three wave filters, two wave filters that filter Raman diffused light are connected on the wavelength division multiplexer, and the wave filter and the wavelength division multiplexer that filter Rayleigh scattering light are connected to high-speed, high precision distributed temperature measuring processing host.
2. light pulse external modulation type distributed optical fiber temperature sensing device according to claim 1, it is characterized in that: described external modulation luminescence unit comprises continuous light source, electrooptic modulator, burst pulse driving circuit, fiber amplifier.
3. light pulse external modulation type distributed optical fiber temperature sensing device according to claim 1, it is characterized in that: described external modulation luminescence unit is configured to: continuous light source links to each other with electrooptic modulator, the burst pulse driving circuit is connected on the electrooptic modulator, and electrooptic modulator links to each other with fiber amplifier.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010106191220A CN102095523A (en) | 2010-12-29 | 2010-12-29 | Light pulse external modulation type distributed optical fiber temperature sensing device |
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| CN2010106191220A CN102095523A (en) | 2010-12-29 | 2010-12-29 | Light pulse external modulation type distributed optical fiber temperature sensing device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103616090A (en) * | 2013-12-06 | 2014-03-05 | 山东大学 | Brillouin distributed type optical fiber sensing temperature measurement system for eliminating optical fiber attenuation |
| CN105043586A (en) * | 2015-05-28 | 2015-11-11 | 华中科技大学 | Few-mode fiber based Raman distributed temperature measurement system and temperature measurement method |
-
2010
- 2010-12-29 CN CN2010106191220A patent/CN102095523A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103616090A (en) * | 2013-12-06 | 2014-03-05 | 山东大学 | Brillouin distributed type optical fiber sensing temperature measurement system for eliminating optical fiber attenuation |
| CN105043586A (en) * | 2015-05-28 | 2015-11-11 | 华中科技大学 | Few-mode fiber based Raman distributed temperature measurement system and temperature measurement method |
| CN105043586B (en) * | 2015-05-28 | 2018-01-09 | 华中科技大学 | A kind of Raman distributed temp measuring system and temp measuring method based on less fundamental mode optical fibre |
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Application publication date: 20110615 |