CN202836592U - Optical fiber optical grating sensing device - Google Patents
Optical fiber optical grating sensing device Download PDFInfo
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- CN202836592U CN202836592U CN 201220516123 CN201220516123U CN202836592U CN 202836592 U CN202836592 U CN 202836592U CN 201220516123 CN201220516123 CN 201220516123 CN 201220516123 U CN201220516123 U CN 201220516123U CN 202836592 U CN202836592 U CN 202836592U
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Abstract
The utility model provides an optical fiber optical grating sensing device. A reflection-type semiconductor optical amplifier is driven by a pulse signal with different frequency. A resonant cavity is formed by the optical fiber optical grating sensing device and different sensors. Reading of different sensors signals is realized. The way that the sensors are visited by time division is adopted. The problems that the number of a wavelength division multiplexing technology sensors of the traditional optical fiber optical grating is limited by light source bandwidth. Sensing signals can be enlarged in the cavity due to the fact that the resonant cavity technology is adopted. The problems that noises of the sensing signal of the traditional time division multiplexing technology are low are solved. Combining a combined multiplexing technology of the time division multiplexing and the wavelength division multiplexing, the sensors are grouped. A sensor group is visited in the way of a mutual collocation in series connection and in a parallel connection. Multiplexing capacity of the sensors of the system is greatly increased.
Description
Technical field
The utility model relates to cheaply fiber grating sensing system of a kind of large capacity.
Background technology
Fiber-optic grating sensor is the light sensitive characteristic that utilizes optical fiber core material, forms the structure that refractive index becomes period profile by UV-irradiation at fibre core, is satisfying under the condition of phase matching, produces wavelength selectivity thereby coupling occurs between the resonant wavelength pattern.The resonant wavelength of fiber grating is subjected to the impact of the external environment conditions such as temperature and strain, so it can be used as sensor and change by wavelength variations perception external environment condition parameter, realizes the measurement of various parameters.Except have that the ordinary optic fibre sensor has lightweight, be not subjected to electromagnetic interference (EMI), the advantage such as highly sensitive, anticorrosive the characteristics such as easy networking is measured, large capacity-sharing, Wavelength demodulation that it also has.
The optical fiber optical grating multiplexing technology is the basis that makes up optical fiber sensing network, and common optical fiber optical grating multiplexing technology has wavelength-division multiplex (WDM), time division multiplex (TDM), space division multiplexing (SDM) and their hybrid multiplex technology.These multiplex techniques exist the cost that consists of sensor-based system relatively high at present, and power system capacity is limited, the problems such as inconvenient operation.Optical fiber sensing technology Future Development direction is low cost, high-performance, large capacity and networking, therefore increases the system multiplexing capacity sensor and reduce the optical fiber sensing system cost to be significant.
Wavelength-division multiplex: each sensor takies certain spectral range, the operation wavelength non-overlapping copies, and the identification of sensor is to judge according to wavelength coverage.The multiplexing number of sensors of wavelength-division multiplex technique is determined by dynamic range and the light source bandwidth of measurement point, common wideband light source bandwidth is 40 ~ 60nm, the quantity of limited light source limit bandwidth sensor can realize the multiplexing of 15 ~ 20 sensors on the common single optical fiber.Advantage: the sensor signal to noise ratio (S/N ratio) is high; Shortcoming: multiplexing negligible amounts, dynamic range of sensor is little, and cost is higher.
Time division multiplex: this technology adopts light-pulse generator, and each working sensor is in identical wavelength coverage, and the identification of sensor is to rely on the time interval that is reflected back signal.Only need a mask plate to make the antiradar reflectivity grating of same period, the sensor reflected signal is faint.Number of sensors is not subjected to the light source limit bandwidth, and each sensor all can use whole light source bandwidth.Because each sensor wavelength is identical, therefore can reflect the signal section of all the other sensors and generation signal attenuation, sensor is more, and attenuated optical signal is also faster.Advantage: cost is lower, and multiplexing capacity is large, and dynamic range of sensor is large; Shortcoming: the sensor signal to noise ratio (S/N ratio) is low.
Space division multiplexing: need the photoswitch switching channel, realize the selection of different sensors array, because there is insertion loss in photoswitch, the more insertion loss of space division multiplexing cascade level are larger, and are longer during interchannel addressing, and system configuration is complicated.Advantage: signal to noise ratio (S/N ratio) is higher; Shortcoming: system complex, cost is higher.
Fiber grating sensing system is mainly take wavelength-division multiplex technique as main at present, the most representative is the fiber grating sensing system of Micron Optics company, this system adopts wavelength-division multiplex technique and tunable laser source to realize multichannel simultaneously scanning, owing to adopt wavelength-division multiplex technique, the quantity of each channel sensor and dynamic range are subjected to the light source limit bandwidth, in high-capacity optical fiber Application in Sensing occasion, need several system to work simultaneously or adopt photoswitch to realize the passage expansion, the method for this increase capacity causes sensor-based system too complicated and expensive.Therefore, in conjunction with the advantage of various multiplex techniques, structure possesses that system architecture is simple, dependable performance, multiplexing optical fiber sensing system capacious are to reduce system cost, promotes the key that optical fiber sensing technology is used in each field.
The utility model content
The purpose of this utility model provides the multiplexer of a kind of low cost and jumbo fiber-optic grating sensor, and it is higher to solve current fiber grating sensing system cost, the problem that capacity is less.
A kind of fiber bragg grating sensing device of the utility model comprises a pulse signal generator, a wavelength measurement module, one first coupling mechanism, optical fiber, at least one time delay optical fiber and a sensor array.This fiber bragg grating sensing device further comprises a reflection type semiconductor image intensifer RSOA and one second coupling mechanism, described the second coupling mechanism is connected between the first coupling mechanism and the time delay optical fiber, described sensor array is connected in parallel on described the second coupling mechanism by a plurality of sensor groups and forms, every group of sensor internal is in series by a plurality of antiradar reflectivity sensors, and each sensor group all interconnects by a time delay optical fiber and described the second coupling mechanism.
In sum, this fiber bragg grating sensing device drives reflection type semiconductor image intensifer and different sensings formation resonant cavities by the pulse signal of different frequency, realizes reading of different sensors signal.Its adopts the mode of timesharing access sensors, has solved the problem that traditional fiber grating wavelength-division multiplex technique number of sensors is subjected to the light source limit bandwidth.Because adopt the resonant cavity technology, transducing signal can be exaggerated, therefore solved the low problem of traditional time-division multiplex technology transducing signal signal to noise ratio (S/N ratio) in the chamber.In conjunction with the hybrid multiplex technology of time division multiplex and wavelength-division multiplex, sensor is divided into groups, with mode access sensors group in parallel, that series connection is arranged in pairs or groups mutually, greatly increased the sensor multiplexing capacity of system.
Description of drawings
Fig. 1 is a structural representation of a kind of fiber bragg grating sensing device of the utility model.
Fig. 2 is a fundamental diagram of a kind of fiber bragg grating sensing device of the utility model.
Fig. 3 is another structural representation of a kind of fiber bragg grating sensing device of the utility model.
Embodiment
By describing technology contents of the present utility model, structural attitude in detail, reached purpose and effect, below hereby exemplify embodiment and cooperate that accompanying drawing is detailed to give explanation.
See also Fig. 1, a kind of fiber bragg grating sensing device of the utility model comprises: a reflection type semiconductor image intensifer RSOA1, a pulse signal generator 2, a wavelength measurement module 3, one first coupling mechanism 4, optical fiber (not indicating among the figure), one second coupling mechanism 6, at least one time delay optical fiber 7 and a sensor array 8.
Please continue and consult Fig. 1, the control input end of described reflection type semiconductor image intensifer RSOA1 is connected with the output terminal of pulse signal generator 2; The optical fiber I/O end of reflection type semiconductor image intensifer RSOA1 links to each other with the input end of the first coupling mechanism 4.
Described the first coupling mechanism 4 is the coupling mechanism of 1*2.It is the coupling mechanism of 10:90 that described the first coupling mechanism 4 adopts splitting ratio, and wherein, the port of splitting ratio 10% is connected with wavelength measurement module 3; The port of splitting ratio 90% is connected with the input end of the second coupling mechanism 6.
Described the second coupling mechanism 6 connexons are between the first coupling mechanism 4 and time delay optical fiber 7.
See also Fig. 3, in other preferred embodiments, between the first coupling mechanism 4 and the second coupling mechanism 6, further be connected with a time delay optical fiber 7.
Described the second coupling mechanism is the coupling mechanism of 1*M, and M is the natural number more than or equal to 3.
Described sensor array 8 is connected in parallel on described the second coupling mechanism 6 by a plurality of sensor groups and forms (for ease of describing, be set with m sensor group, wherein m is the natural number greater than 1), every group of sensor internal consists of series connection (for ease of describing by the identical a plurality of antiradar reflectivity sensors of centre wavelength, be set with n sensor, wherein n is the natural number greater than 1).Described each sensor group all interconnects by a time delay optical fiber and described the second coupling 6, and the optical fiber with 2-5 rice connects between inner each sensor of sensor group.Centre wavelength between each sensor group can be identical, also can be different.
The input end of described each sensor group links to each other with a time delay optical fiber one free end respectively, and another free end of time delay optical fiber is connected with each port of the second coupling mechanism 6 light splitting ends.
In the utility model specific embodiment, the reflectivity of the sensor that a kind of fiber bragg grating sensing device 100 adopts is 1%-5%.
In the utility model specific embodiment, the optical fiber with 2 to 5 meters between each sensor of sensor group inside couples together.
In the utility model specific embodiment, the length of time delay optical fiber 7 has significant time-lag action greater than the length of sensor group optical fiber.It is different that each organizes time delay optical fiber length, can make the signal of respectively organizing sensor constantly arrive the wavelength measurement module in difference.Certainly, the operation that also can adopt other device that light pulse signal is had time-lag action that light pulse signal is delayed time.
A kind of fiber bragg grating sensing device 100 of the utility model utilizes Programmable pulse generator 2 to produce a pulsewidth and adjustable pulse signal of cycle drives reflection type semiconductor image intensifer RSOA1, and described reflection type semiconductor image intensifer RSOA1 sends frequency, the pulsewidth broadband optimal pulse corresponding with pulse signal under pulse signal drives.
The broadband optimal pulse that described reflection type semiconductor image intensifer RSOA1 sends is divided into the light pulse of m beamwidth band after through the second coupling mechanism and enters respectively time delay optical fiber
,
,
, after time-delay, enter each sensor group.M broadband optimal pulse propagated in each sensor group, propagates by the second coupling mechanism 6 retroreflection type semiconductor optical amplifier RSOA1 directions after being reflected successively by the sensor in each sensor group.
Described broadband optimal pulse is propagated in optical fiber, part signal is reflected when running into sensor, light signal by the reflection of the sensor in the sensor group arrives reflection type semiconductor image intensifer RSOA1 successively, when the cycle that pulse signal is set and light signal when equate to two-way time between a sensor and the reflection type semiconductor image intensifer RSOA1 therein, the light signal that is then reflected by this sensor can enter reflection type semiconductor image intensifer RSOA1 and be exaggerated, and the light pulse signal of other sensor reflection then can't enter reflection type semiconductor image intensifer RSOA1; After the transducing signal that enters reflection type semiconductor image intensifer RSOA1 is exaggerated, enter the wavelength measurement module through the coupling unit signal of the first coupling mechanism 4, realize the wavelength measurement of the transducing signal that selected sensor is sent.
Pulsewidth and the cycle adjustable module of described pulse signal generator 2 for adopting the FPGA programming device to realize, the pulse minimum widith can reach for 10 nanoseconds.
See also Fig. 2, the below propagates in first group of sensor as example take light pulse signal and describes.A kind of fiber bragg grating sensing device basic functional principle of the utility model is as follows: pulse signal generator 2 produces the pulse signal that frequency is adjustable, when first pulse is applied to reflection type semiconductor image intensifer RSOA1, reflection type semiconductor image intensifer RSOA1 since self-excitation radiation (ASE) send a broadband optimal pulse and propagate along the sensor array column direction, this broadband optimal pulse is divided into the light pulse of m beamwidth band after through the second coupling mechanism, when broadband optimal pulse runs into each sensor in the same sensor group, the part luminous power is reflected, the wavelength of the light pulse signal of each sensor reflection is to wavelength that should sensor, the light pulse signal that is reflected arrives reflection type semiconductor image intensifer RSOA1 successively, wherein, light pulse signal arrives sensor
,
,
,
Time be respectively
,
,
,
When cycle of pulse signal generator 2 and light pulse signal at reflection type semiconductor image intensifer RSOA1 and sensor
Between when come and go equating, i.e. pulse producer cycle
The time, then by sensor
When the light pulse signal of reflection arrived reflection type semiconductor image intensifer RSOA1, reflection type semiconductor image intensifer RSOA1 was in conducting state, and transducing signal
Can enter reflection type semiconductor image intensifer RSOA1 is exaggerated and reflects again propagate to the sensor array column direction.The light pulse signal that this moment, reflection type semiconductor image intensifer RSOA1 sent is by self-excitation radiation (ASE) broadband optimal pulse that produces and the sensor signal that is exaggerated
Be formed by stacking.Repeat above process, because the utility model fiber bragg grating sensing device 100 adopts the reflection type semiconductor image intensifer RSOA1 that can amplify to input optical signal 18dB, transducing signal
Repeatedly enter reflection type semiconductor image intensifer RSOA1 by the saturated output of gradual magnification to reflection type semiconductor image intensifer RSOA1, enter the optic fiber grating wavelength demodulation module through the first coupling mechanism 4 part transducing signals, realize the measurement of sensor wavelength.Sensor
With
Between connect with the optical fiber of 2-5 rice, the travel-time of light pulse signal between the two is
, reflected signal
,
Mistiming be
For with sensor signal
,
Separately, then the width of light pulse signal satisfies:
When the signal of other sensor reflection arrives reflection type semiconductor image intensifer RSOA1, because pulse signal cycle and sensor are unequal two-way time, this moment, reflection type semiconductor image intensifer RSOA1 was in closed condition, the light pulse signal of other sensor reflection is absorbed, so realized sensor
Access, and then can draw light pulse signal at sensor
,
,
,
And be respectively two-way time between the reflection type semiconductor image intensifer RSOA1
,
,
The cycle of pulse signal generator 2 adjusted to each sensor equate two-way time, then can realize the access of each sensor.If equidistantly, the travel-time of light pulse signal between adjacent sensors is between the sensor
, then the pulse signal cycle of addressing individual sensor is respectively:
,
...,
, then can realize access to all the sensors in the sensor array 8 by the frequency that changes pulse signal generator 2.
In the sensor permutation, the length of described time delay optical fiber must satisfy following condition: the length of rear one group of time delay optical fiber is greater than length and the last sensor group fiber lengths sum of last group of time delay optical fiber, and also, the length of time delay optical fiber will satisfy following condition:
+
Wherein
Be that the input end of first sensor of i-1 group sensor is to the length of the optical fiber of last transducer tip.So time delay optical fiber is arranged
,
,
The time delay that produces causes that respectively to organize sensor accessed in different time ranges.
In sum, fiber bragg grating sensing device drives reflection type semiconductor image intensifer and different sensors formation resonant cavity by the pulse signal of different frequency, realizes reading of different transducing signals.It adopts the mode of timesharing access sensors, solved the problem that traditional fiber grid light WDM technology number of sensors is subjected to the light source limit bandwidth, owing to adopt the resonant cavity technology, faint transducing signal can amplify in the chamber, therefore also solved the low problem of traditional time-division multiplex technology transducing signal signal to noise ratio (S/N ratio), hybrid multiplex technology in conjunction with time division multiplex and wavelength-division multiplex, sensor is divided into groups, with mode access sensors group in parallel, that series connection is arranged in pairs or groups mutually, greatly increased the multiplexing capacity of system for sensor.
Above-described technical scheme only is the preferred embodiment of a kind of fiber bragg grating sensing device 100 of the utility model, within any equivalent transformation or the scope of the claim that is included in of replacement doing on a kind of fiber bragg grating sensing device of the utility model 100 bases.
Claims (10)
1. fiber bragg grating sensing device, comprise a pulse signal generator, one wavelength measurement module, one first coupling mechanism, optical fiber, at least one time delay optical fiber and a sensor array, it is characterized in that: this fiber bragg grating sensing device further comprises a reflection type semiconductor image intensifer RSOA and one second coupling mechanism, described the second coupling mechanism is connected between the first coupling mechanism and the time delay optical fiber, described sensor array is connected in parallel on described the second coupling mechanism by a plurality of sensor groups and forms, every group of sensor internal is in series by a plurality of antiradar reflectivity sensors, and each sensor group all interconnects by a time delay optical fiber and described the second coupling mechanism.
2. a kind of fiber bragg grating sensing device according to claim 1 is characterized in that: reflection type semiconductor image intensifer RSOA adopts and can amplify the reflection type semiconductor image intensifer RSOA of 18dB as light source and photoswitch gating device to the input optical pulse signal.
3. a kind of fiber bragg grating sensing device according to claim 1, it is characterized in that: the second coupling mechanism is the coupling mechanism of 1*M, and M is the natural number more than or equal to 3.
4. a kind of fiber bragg grating sensing device according to claim 1, it is characterized in that: every group of sensor internal consists of series connection by the identical a plurality of antiradar reflectivity sensors of centre wavelength, and the centre wavelength between each sensor group can be identical, also can be different.
5. a kind of fiber bragg grating sensing device according to claim 1, it is characterized in that: in the sensor array, the length of described time delay optical fiber must satisfy following condition: the length of rear one group of time delay optical fiber is greater than length and the last sensor group fiber lengths sum of last group of time delay optical fiber.
6. a kind of fiber bragg grating sensing device according to claim 1, it is characterized in that: the first coupling mechanism is the coupling mechanism of 1*2, further is connected with a time delay optical fiber between the first coupling mechanism and the second coupling mechanism.
7. a kind of fiber bragg grating sensing device according to claim 1 is characterized in that: it is the coupling mechanism of 10:90 that described the first coupling mechanism adopts splitting ratio, and the port of splitting ratio 10% is connected with the wavelength measurement module; The port of splitting ratio 90% is connected with the input end of the second coupling mechanism.
8. a kind of fiber bragg grating sensing device according to claim 1 is characterized in that: pulsewidth and the cycle adjustable module of pulse signal generator for adopting the FPGA programming device to realize, the pulse minimum widith can reach for 10 nanoseconds.
9. a kind of fiber bragg grating sensing device according to claim 1, it is characterized in that: the reflectivity of sensor is 1% ~ 5%.
10. a kind of fiber bragg grating sensing device according to claim 1 is characterized in that: the wavelength measurement module adopts the spectral measurement module based on the CCD technology, perhaps based on the wavelength measurement meter of edge filter technology.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102879025A (en) * | 2012-10-09 | 2013-01-16 | 成都阜特科技股份有限公司 | Fiber Bragg grating sensing device |
| CN103808342A (en) * | 2014-03-05 | 2014-05-21 | 武汉理工大学 | High-speed demodulation method and device for high-capacity weak grating sensing network |
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2012
- 2012-10-09 CN CN 201220516123 patent/CN202836592U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102879025A (en) * | 2012-10-09 | 2013-01-16 | 成都阜特科技股份有限公司 | Fiber Bragg grating sensing device |
| CN103808342A (en) * | 2014-03-05 | 2014-05-21 | 武汉理工大学 | High-speed demodulation method and device for high-capacity weak grating sensing network |
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Granted publication date: 20130327 Termination date: 20181009 |