CN2718522Y - Stress-strain transducer based on temperature unsensitivity of optical fiber grating - Google Patents

Stress-strain transducer based on temperature unsensitivity of optical fiber grating Download PDF

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Publication number
CN2718522Y
CN2718522Y CN 200420011658 CN200420011658U CN2718522Y CN 2718522 Y CN2718522 Y CN 2718522Y CN 200420011658 CN200420011658 CN 200420011658 CN 200420011658 U CN200420011658 U CN 200420011658U CN 2718522 Y CN2718522 Y CN 2718522Y
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Prior art keywords
fiber grating
optical fiber
stress
temperature
strain
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Expired - Fee Related
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CN 200420011658
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Chinese (zh)
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赵志勇
于永森
张玉书
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Jilin University
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Jilin University
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Abstract

The utility model relates to a stress-strain transducer based on temperature unsensitivity of optical fiber grating which belongs to the transducer field. The transmission type or the reflection type stress-strain transducer is composed of an illuminating source 4, an optical fiber grating 1, a detector 3. Only one optical fiber grating 1 is used, one segment of whose incident light terminal is fixed to the quartz plate 2, and the other corresponding segment is bare. Or the optical fiber grating 1 is made into a conical tube form. The diameter reduces gradually along the axial direction, or one segment of the incident light terminal is fixed to the quartz plate 2, and the other corresponding bare segment is made into a conical tube form. The detector 3 adopts a photoelectric detector or a power meter. The three sensing elements of the utility model can comprise the stress-strain transducer based on temperature unsensitivity with higher sensitivity and larger measurement range. In addition, by using one optical fiber grating of the sensing elements and without using the temperature control apparatus, the transducer structure is simple; the change of the optical fiber grating power only needs to be detected during the signal demodulation; the change of the wavelength don't need to be detected; the cost of the transducer is greatly reduced.

Description

Stress strain gauge based on the temperature-insensitive of fiber grating
Technical field
The utility model belongs to sensor field, particularly is used to make to the insensitive stress strain gauge based on fiber grating of temperature variation.
Background technology
Fiber grating is that the fiber core refractive index is subjected to periodically perturbation and a kind of novel full fiber optic passive device that forms.Because possess with the fibre system compatibility, insert that loss is low, simple in structure, volume is little, preparation technology is simple, with low cost, to temperature and strain unusual advantage such as sensitivity all, fiber grating has boundless application prospect at sensory field.Within the specific limits, the centre wavelength position of ordinary optic fibre grating not only can be along with the change of optical grating axial strain linear change, and change along with the change of environment temperature, so with optical fiber preparing grating stress strain gauge the time, the cross sensitivity of temperature and strain is the problem that must face.
With the close prior art of the utility model is a kind of sensor that mainly is made of light source, fiber grating, detecting device.Survey light and detect by detecting device, constitute transmission-type stress strain gauge or reflective stress strain gauge through fiber grating transmission or reflection.In order to solve temperature and strain cross sensitivity problem, use at least two fiber grating combinations, a fiber grating wherein uses attemperating unit to realize thermostatic control; By the structures shape of ordinary optic fibre grating, determine the size of ess-strain by detecting grating wavelength, detect surveying light so adopt wavemeter or spectrometer to make detecting device.
Background technology adopts fiber grating is placed the environment of constant temperature, and uses two or many methods such as fiber grating multiple measurement solution cross sensitivity problems, makes the sensor construction complexity.In addition, all be to determine the size of ess-strain by detecting grating wavelength, wavemeter or spectrometer that this just needs the price comparison costliness add attemperating unit, have increased the cost of sensor.
The utility model content
The technical problems to be solved in the utility model is: a kind of simple and practical stress strain gauge based on fiber grating is provided.Only use a fiber grating in sensitive element, sensor construction is simple; The more important thing is the light signal in the sensor is adopted power detection, reduce cost, solved strain and temperature cross sensitivity problem, produce the stress strain gauge of the realistic application requirements that sensitivity is higher, measurement range is bigger.
For arriving above-mentioned purpose, the structure of the stress strain gauge of the temperature-insensitive based on fiber grating of the present utility model constitutes transmission-type or reflective stress strain gauge by light source, fiber grating, detecting device, said fiber grating only uses one, fix with a quartz plate, and one section of the fiber grating incident light end fix with quartz plate, another section is exposed accordingly; Perhaps fiber grating is made into the Taper Pipe shape, promptly diameter reduces vertically gradually.Said detecting device can adopt photodetector or power meter.
Said light source adopts wideband light source, and photodetector can be used photodiode.
In order to improve detection sensitivity, a section of fiber grating incident light end can also be fixed with quartz plate, corresponding another exposed section is made into the Taper Pipe shape.
The leading portion of fiber grating, promptly one section of fiber grating short wavelength end is fixed on the quartz plate, and the quartz plate width is far longer than fibre diameter, such as, the quartz plate width can be 10~300 times of fibre diameter, and the back segment of fiber grating is exposed, promptly fixes without quartz plate.The fiber grating of this structure is when being subjected to along optical fiber axial stress or effects of strain, because leading portion is fixed on width and is far longer than on the quartz plate of fibre diameter, according to mechanics principle, the suffered strain of fiber grating leading portion diminishes, can ignore, so the reflection of fiber grating leading portion correspondence or transmission peak wavelength position do not change with added stress or strain; And the pairing wavelength of fiber grating back segment is subjected to the effect of stress or strain and moves to the long wave direction.This has just caused the reflection of fiber grating or transmitted spectrum to broaden, and reflective power increases or transmission power reduces, and in the middle of reflection or the transmission spectrum splitting takes place simultaneously, and the splitting width is also along with stress or strain variation, and causes that reflective power reduces or transmission power increases.Therefore within the specific limits, the general power of reflection or transmission spectrum is linear change with the change of stress or strain, so just can obtain the size of stress or strain by the measurement to reflection or transmission power.When the fiber grating environment temperature changes, because quartz plate has identical thermal expansivity with optical fiber, whole fiber grating has identical sensitivity coefficient to temperature, though optic fiber grating wavelength changes with variation of temperature, but reflection or transmission spectrum bandwidth are constant, and reflection or transmission power can not change yet.Therefore the measurement of counter stress or strain is a temperature-insensitive.Based on above structural design,, and be not subjected to influence of temperature change only by just can realizing the measurement of counter stress or strain to the power detection of signal.
Three kinds of sensitive elements in the utility model all constitute the temperature-resistant stress strain gauge that sensitivity is higher, measurement range is bigger, and only use a fiber grating in the sensitive element, all do not use attemperating unit, make sensor arrangement simple; Particularly, in the signal demodulation, only need the variation of detection fiber grating power, need not detect wavelength variations, reduce the sensor cost greatly.
Description of drawings
Fig. 1 is the reflective power detection system device synoptic diagram of the basic sensitive element of the utility model employing.
Fig. 2 is the transmission power detection system device synoptic diagram of the basic sensitive element of the utility model employing.
Fig. 3 is a highly sensitive Taper Pipe shape sensitive element device synoptic diagram of the present utility model.
Fig. 4 is that highly sensitive Taper Pipe shape of the present utility model adds fixedly sensitive element device synoptic diagram of quartz plate.
Embodiment
Below in conjunction with accompanying drawing the utility model is elaborated.
The device of the present invention that embodiment 1 adopts basic sensitive element to constitute.
Fig. 1 is the reflective power detecting system device synoptic diagram that adopts basic sensitive element.Sensitive element comprises a fiber grating 1 and a quartz plate 2 that diameter is identical, wideband light source 3 links to each other with fiber coupler 5 respectively with detecting device 4, the other end of fiber coupler 5 connects the fiber grating 1 as sensitive element, constitutes the ess-strain system of reflective power detection.Detecting device 4 adopts photodetector or power meter, is used for optical signal power and detects.
Fig. 2 is the transmission-type power detecting system device synoptic diagram that adopts basic sensitive element.The fiber grating 1 that wideband light source 3 is directly identical with diameter links to each other, and detects luminous powers at the other end of fiber grating with detecting device 4, and the leading portion of fiber grating 1 is fixed on the quartz plate 2, constitutes the ess-strain detection system of transmission-type power detection.
Embodiment 2 adopts Taper Pipe shape fiber grating as sensitive element.
In order to improve sensitivity, adopt sensitive element device as shown in Figure 3 based on the stress strain gauge of fiber grating.
In the sensitive element device shown in Figure 3, the fibre diameter of fiber grating 1 reduces vertically gradually.When fiber grating 1 is subjected to axial stress or effects of strain, the local strain that fibre diameter is more little is big more, corresponding grating wavelength to long wave move far away more, the spectral bandwidth of whole fiber grating 1 becomes bigger, more powerful (little) of detected reflection (or transmission) light signal.Within the specific limits, optical signal power is directly proportional with stress or strain size that fiber grating 1 is subjected to, and power detection is not acted upon by temperature changes equally, and therefore, the sensor of this temperature-insensitive has the sensitivity higher than basic sensitive element.
Embodiment 3 Taper Pipe shapes add the fixing sensitive element device of quartz plate.
In the sensitive element device shown in Figure 4, the structure of fiber grating 1 has been gathered the advantage of fiber grating 1 structure among Fig. 1 and Fig. 3, be that fiber grating 1 leading portion also is fixed on a width and is far longer than on the quartz plate 2 of fibre diameter, the diameter of back segment along fiber axis to reducing gradually.According to aforesaid principle, under identical axial stress effects of strain, this fiber grating 1 has the spectrum wideer than fiber grating among Fig. 1-3 1.More powerful (little) of reflection (or transmission) light signal, within the specific limits, optical signal power is directly proportional with stress or strain size that fiber grating is subjected to, therefore, has higher sensitivity based on the sensor of this optical fiber grating structure.

Claims (2)

1, a kind of stress strain gauge of the temperature-insensitive based on fiber grating, constitute transmission-type or reflective stress strain gauge by light source (4), fiber grating (1), detecting device (3), it is characterized in that, said fiber grating (1) only uses one, one section of its incident light end is fixing with quartz plate (2), corresponding another section is exposed, perhaps fiber grating (1) is made into the Taper Pipe shape, and promptly diameter reduces vertically gradually; Said detecting device (3) adopts photodetector or power meter.
2, according to the stress strain gauge of the described temperature-insensitive based on fiber grating of claim 1, it is characterized in that, said fiber grating (1), a section of its incident light end is fixing with quartz plate (2), and corresponding another exposed section is made into the Taper Pipe shape.
CN 200420011658 2004-03-12 2004-03-12 Stress-strain transducer based on temperature unsensitivity of optical fiber grating Expired - Fee Related CN2718522Y (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 200420011658 CN2718522Y (en) 2004-03-12 2004-03-12 Stress-strain transducer based on temperature unsensitivity of optical fiber grating

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Application Number Priority Date Filing Date Title
CN 200420011658 CN2718522Y (en) 2004-03-12 2004-03-12 Stress-strain transducer based on temperature unsensitivity of optical fiber grating

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CN2718522Y true CN2718522Y (en) 2005-08-17

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108871388A (en) * 2018-05-10 2018-11-23 刘正勇 Optical fiber touch sensor and sensor array

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108871388A (en) * 2018-05-10 2018-11-23 刘正勇 Optical fiber touch sensor and sensor array
CN108871388B (en) * 2018-05-10 2021-04-09 刘正勇 Optical fiber touch sensor and sensing array

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