CN202267497U - Multiplexing sensor with SMS (single-mode, multi-mode and single-mode) fiber structures - Google Patents
Multiplexing sensor with SMS (single-mode, multi-mode and single-mode) fiber structures Download PDFInfo
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- CN202267497U CN202267497U CN2011203967475U CN201120396747U CN202267497U CN 202267497 U CN202267497 U CN 202267497U CN 2011203967475 U CN2011203967475 U CN 2011203967475U CN 201120396747 U CN201120396747 U CN 201120396747U CN 202267497 U CN202267497 U CN 202267497U
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Abstract
The utility model relates to the technical field of optical fiber sensors, in particular to an optical fiber sensor based on multiplexing of SMS (single-mode, multi-mode and single-mode) fiber structures to realize simultaneous measurement of various parameters such as temperature, pressure, refractive rate and the like. An optical time domain reflectometer is connected with at least two SMS optical fiber structures to form the optical fiber sensor, wherein two ends of a multi-mode optical fiber are connected with single-mode optical fibers to form each SMS optical fiber structure. The SMS optical fiber structures can be serially connected. The SMS optical fibers are respectively connected onto different branches of a coupler. At least two SMS optical fiber structures are connected onto each branch of the coupler, and are serially connected. The length of the multi-mode optical fiber in each SMS optical fiber structure is equal to the self-image distance of the SMS optical fiber structure. By the aid of the optical fiber sensor, various parameters, such as temperature, pressure, refractive rate and the like, can be measured simultaneously, cost of a sensing system is lowered, and the optical fiber sensor is simple in structure, easy in manufacture and high in sensibility.
Description
Technical field
The present invention relates to technical field of optical fiber sensing, be specially the Fibre Optical Sensor of multi parameter simultaneous measurings such as the multiplexing realization temperature of a kind of SMS-Based optical fiber structure, stress, refractive index.
Technical background
Fibre Optical Sensor has many traditional incomparable advantages of sensor; As highly sensitive, volume is little, good insulating, can realize advantage such as distribution measuring, a lot of physical quantitys such as pressure, temperature, stress (strain), magnetic field, refractive index, deformation, little vibration, micrometric displacement and acoustic pressure etc. can both be carried out high-acruracy survey with optical fiber sensing technology.
Because the advantage of Fibre Optical Sensor itself constantly has novel sensor to come out.Wherein, Based on the multimode optical fiber sensor of single-mode fiber-multimode optical fiber-single-mode fiber (SMS) structure and swift and violent based on the distributing optical fiber sensing technical development speed of optical time domain reflection; This multimode optical fiber sensor most important parts is the SMS optical fiber structure, and sensing head is a multimode optical fiber.The SMS optical fiber structure is that multimode optical fiber is passed through single-mode fiber incoming fiber optic system, and the variation of external environment causes that this structure transmission performance changes, and realizes the measurement of environment parameter through the change of monitoring transmission performance.The fibre optic temperature sensor similar with the present invention that occurs at present is that this is simple in structure, and is easy to manufacture through the SMS optical fiber structure of encapsulation, the sensitivity of fibre optic temperature sensor reaches-and 3.915nm/ ℃.Yet this sensor can't be realized cascade, can only realize single parameter measurement, makes that the cost of sensor is very high.
The foundation of optical time domain reflectometer work is the backscattering principle of light.The backscattering of optical fiber is caused that by Rayleigh scattering and Fresnel scattered reflection Fresnel reflection is caused by variations in refractive index, generally occurs in the end face of splicing point, joint and optical fiber.Backscattering is owing in the inhomogeneous scattered light that causes of medium, understand some light and pass transmitting terminal back along the reverse direction of optic path.Optical time domain reflectometer utilizes that the backscattering light intensity has the principle of certain rule to measure in the optical fiber.
The most significant advantage of distribution type fiber-optic measuring technique based on optical time domain reflection (OTDR) is the information such as stress, temperature, vibration and damage that can measure exactly on the optical fiber any point along the line, need not to constitute the loop.Present disclosed Fibre Optical Sensor based on OTDR; Adopt special optical fiber; Separate through the optical time domain reflection method and to transfer to measure high temperature, OTDR is used for confirming the different losses along optical fiber diverse location place, reaches the purpose of real-time monitoring; But this method also can only be measured single parameter, can't carry out the measuring multiple parameters of circumstance complication.
Optical time domain reflectometer carries out data acquisition and processing (DAP) along fiber lengths; Accurate Analysis everywhere change in information; That is to say that optical time domain reflectometer can monitor a plurality of structures place intensity variations situation that is connected in real time, for realizing that multiplexing the providing of a plurality of Fibre Optical Sensors maybe.
Summary of the invention
The purpose of this invention is to provide a kind of Fibre Optical Sensor of realizing multi parameter simultaneous measuring by the feedback signal of a plurality of SMS optical fiber structures of optical time domain reflection method demodulation.
The objective of the invention is to realize like this:
Connect at least 2 SMS optical fiber structures by optical time domain reflectometer and form, wherein the SMS optical fiber structure by one section multimode optical fiber at two ends the connection single-mode fiber form.
The present invention can also comprise:
1. described SMS optical fiber structure links together with series system.
2. described SMS optical fiber structure is connected in the different shunt of coupling mechanism.
3. every coupling mechanism is gone up along separate routes and is connected at least 2 SMS optical fiber structures, and these SMS optical fiber structures link together with series system.
4. in the described SMS optical fiber structure length of multimode optical fiber be the SMS optical fiber structure from the picture point distance.
Advantage of the present invention is mainly reflected in:
The information such as stress, temperature, vibration and damage that this sensor can accurately be measured on the optical fiber any point along the line need not to constitute the loop.Demodulation is based on multimode interference principle; Variation through each SMS optical fiber structure place optical loss of real-time monitoring realizes the multiplexing of a plurality of SMS optical fiber structures, can measure simultaneously many reference amounts such as temperature, stress, refractive indexes; Reduced the cost of sensor-based system; Simple in structure, make easily, highly sensitive.
Description of drawings
Fig. 1 is the connect Fibre Optical Sensor synoptic diagram of multiplexing realization multi parameter simultaneous measuring of SMS optical fiber structure;
Fig. 2 is the Fibre Optical Sensor synoptic diagram of the multiplexing realization multi parameter simultaneous measuring of SMS optical fiber structure parallel connection;
Fig. 3 is the structural representation of SMS optical fiber structure;
Fig. 4 is the structural representation of the SMS optical fiber structure after corroding;
Fig. 5 is an optical time domain reflection loss exemplary plot.
Embodiment
Be described further in the face of the concrete technical scheme of the present invention down.
SMS optical fiber structure multiplied sensor adopts big core diameter multimode optical fiber to do sensing head, and importing end and deriving the single-mode fiber of holding is standard single-mode fiber.When the parameter of multimode optical fiber is suitable, single SMS optical fiber structure can be used to measure the variation of a certain parameters such as temperature, stress, refractive index, and a plurality of SMS optical fiber structures are multiplexing can realize that just a plurality of parameters measure simultaneously.Optical time domain reflectometer carries out data acquisition and processing (DAP) along fiber lengths; Can on-line real time monitoring and show the optical loss situation at each SMS optical fiber structure place; As the SMS optical fiber structure that is cascaded can monitor the isoparametric variation of refractive index, temperature or stress respectively, and the extraneous parameter size of optical loss everywhere that shows on the optical time domain reflectometer then that changes also can change thereupon.Variation through confirming optical loss comes quantitative test temperature, stress, the isoparametric situation of change of refractive index, finally realizes multi parameter simultaneous measuring.
For making the object of the invention, technical scheme and advantage clearer, combine concrete embodiment with reference to accompanying drawing, the present invention is carried out detailed explanation.
As shown in Figure 1, Fig. 1 is the connect Fibre Optical Sensor synoptic diagram of multiplexing realization multi parameter simultaneous measuring of SMS optical fiber structure.This figure shows is that the series connection of a plurality of SMS optical fiber structures is multiplexing, and these SMS optical fiber structures link to each other through single-mode fiber.Optical time domain reflectometer carries out data acquisition and processing (DAP) along fiber lengths, and the light intensity of the terminal output of each SMS optical fiber structure changes with the change of external condition, and is surveyed by optical time domain reflectometer.This demodulation is not to utilize the reflection of the welding end surface of single mode and multimode optical fiber, and is based on multimode interference principle, through the variation of each SMS optical fiber structure place optical loss of real-time monitoring, realizes the multiplexing of SMS optical fiber structure sensing.
As shown in Figure 2, Fig. 2 is the Fibre Optical Sensor synoptic diagram of the multiplexing realization multi parameter simultaneous measuring of SMS optical fiber structure parallel connection.What this figure showed is the parallelly connected multiplexing of a plurality of SMS optical fiber structure sensors; Because optical time domain reflectometer is to carry out data acquisition and processing (DAP) along fiber lengths, we guarantee that through the difference of control incident single-mode optical fiber length each SMS optical fiber structure is in the different position of length.When needed, adopt other connected mode also to be fine, such as SP combination etc.
As shown in Figure 3, Fig. 3 is the structural representation of SMS optical fiber structure.The SMS optical fiber structure is made up of two section single-mould fibers and one section multimode optical fiber being connected between them, and this structure adopts big core diameter multimode optical fiber to do sensing head, and importing end is standard single-mode fiber with the single-mode fiber of deriving end.For making sensing sensitive first watch, the core diameter of multimode optical fiber is 105um, and length equals to be about about 5cm from the picture point distance.When the external condition change, the transmission performance of SMS optical fiber structure sensor also changes, and causes changing from the light intensity of single mode output optical fibre output thereupon, accomplishes the measurement of environment parameter through the change of real-time monitoring light intensity.
As shown in Figure 4, Fig. 4 is the structural representation of the SMS optical fiber structure after corroding.When one of them SMS optical fiber structure is used for the measurement environment refractive index, measure for improving sensitivity, needing to use concentration is that 40% hydrofluorite corrodes the multimode optical fiber clad section, reduces cladding thickness.
As shown in Figure 5, Fig. 5 is an optical time domain reflection loss exemplary plot.Optical time domain reflectometer (OTDR) sends light pulse to tested optical fiber, when light pulse all can cause scattering along the each point on the fiber lengths during through Optical Fiber Transmission, can produce Fresnel reflection at disconnected fine point of optical fiber or end face.The scattered light of optical fiber each point is relevant with the luminous power that is transferred to this point with catoptrical power, so turn back to the reflection of input end and the power of scattered light has also just reflected the attenuation of signal along optical fiber.As shown in the figure; Optical time domain reflectometer can on-line monitoring and is shown the optical loss situation at optical fiber different distance place; The variation of optical loss reflects the variation of the extraneous parameter of each SMS optical fiber structure place induction in real time, also can change like the extraneous refractive index optical time domain reflection rate then of the changing optical loss size that shows on the optical time domain reflectometer then that changes thereupon.Optical time domain reflectometer sends light pulse to tested optical fiber, when light pulse all can cause scattering along the each point on the fiber lengths during through Optical Fiber Transmission, can produce Fresnel reflection at disconnected fine point of optical fiber or end face.The scattered light of optical fiber each point is relevant with the luminous power that is transferred to this point with catoptrical power, so turn back to the reflection of input end and the power of scattered light has also just reflected the attenuation of signal along optical fiber.
Above-described specific embodiment has been done further detailed description to concrete preparation method of the present invention.The present invention has solved the problem of a plurality of SMS optical fiber structure sensor multiplexings by the optical time domain reflection method, has realized multi parameter simultaneous measurings such as temperature, refractive index, stress, has reduced the cost of sensor-based system, and is simple in structure, makes easily, highly sensitive.
Claims (5)
1. SMS optical fiber structure multiplied sensor is characterized in that: connect at least 2 SMS optical fiber structures by optical time domain reflectometer and form, wherein the SMS optical fiber structure by one section multimode optical fiber at two ends the connection single-mode fiber form.
2. SMS optical fiber structure multiplied sensor according to claim 1 is characterized in that: described SMS optical fiber structure links together with series system.
3. SMS optical fiber structure multiplied sensor according to claim 1 is characterized in that: described SMS optical fiber structure is connected in the different shunt of coupling mechanism.
4. SMS optical fiber structure multiplied sensor according to claim 3 is characterized in that: every coupling mechanism is gone up along separate routes and is connected at least 2 SMS optical fiber structures, and these SMS optical fiber structures link together with series system.
5. according to each described SMS optical fiber structure multiplex optical fibre sensor in the claim 1 to 4, it is characterized in that: in the described SMS optical fiber structure length of multimode optical fiber be the SMS optical fiber structure from the picture point distance.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011203967475U CN202267497U (en) | 2011-10-18 | 2011-10-18 | Multiplexing sensor with SMS (single-mode, multi-mode and single-mode) fiber structures |
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| CN2011203967475U CN202267497U (en) | 2011-10-18 | 2011-10-18 | Multiplexing sensor with SMS (single-mode, multi-mode and single-mode) fiber structures |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393220A (en) * | 2011-10-18 | 2012-03-28 | 哈尔滨工程大学 | SMS (single mode-multimode-single mode) optical fiber structural duplexing sensor |
| CN103453940A (en) * | 2013-09-13 | 2013-12-18 | 天津理工大学 | Optical fiber sensor based on multi-mode structure |
| CN112188420A (en) * | 2020-09-28 | 2021-01-05 | 南京国电南自电网自动化有限公司 | Method and system for identifying fault section of optical fiber multiplexing channel by using short message |
-
2011
- 2011-10-18 CN CN2011203967475U patent/CN202267497U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393220A (en) * | 2011-10-18 | 2012-03-28 | 哈尔滨工程大学 | SMS (single mode-multimode-single mode) optical fiber structural duplexing sensor |
| CN103453940A (en) * | 2013-09-13 | 2013-12-18 | 天津理工大学 | Optical fiber sensor based on multi-mode structure |
| CN112188420A (en) * | 2020-09-28 | 2021-01-05 | 南京国电南自电网自动化有限公司 | Method and system for identifying fault section of optical fiber multiplexing channel by using short message |
| CN112188420B (en) * | 2020-09-28 | 2022-03-11 | 南京国电南自电网自动化有限公司 | Method and system for identifying fault section of optical fiber multiplexing channel by using short message |
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