CN202748042U - High-speed wavelength demodulating system based on transmission grating spectrometer - Google Patents
High-speed wavelength demodulating system based on transmission grating spectrometer Download PDFInfo
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- CN202748042U CN202748042U CN 201220396965 CN201220396965U CN202748042U CN 202748042 U CN202748042 U CN 202748042U CN 201220396965 CN201220396965 CN 201220396965 CN 201220396965 U CN201220396965 U CN 201220396965U CN 202748042 U CN202748042 U CN 202748042U
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Abstract
The utility model relates to a high-speed wavelength demodulating system based on a transmission grating spectrometer. The system comprises a wideband light source, an optical circulator, an optical switch, a fiber bragg grating, the transmission grating spectrometer and a signal processing unit, wherein the transmission grating spectrometer comprises a collimating lens, a first-level diffraction grating, a second-level diffraction grating, an aspherical mirror and an optical detector array. Therefore, a reflecting light signal of the fiber bragg grating enters the transmission grating spectrometer and is formed into parallel light beams by the collimating lens; the parallel light beams are projected onto the first-level diffraction grating; a part of diffraction light beams penetrating through the first-level diffraction grating is projected onto the second-level diffraction grating; a part of diffraction light beams penetrating through the second-level diffraction grating is imaged onto the optical detector array by the aspherical mirror; the imaging position and the imaging strength are read by the signal processing unit; and the grating wavelength value is demodulated according to system parameters. Through the first-level diffraction grating and the second-level diffraction grating, the diffraction angle of the diffraction light beams is increased, the wavelength definition is improved, and high precision of the system is ensured.
Description
Technical field
The utility model relates to a kind of optic fiber grating wavelength demodulation techniques, relates in particular to a kind of high speed Wavelength demodulation system based on the transmission grating spectrometer.
Background technology
The signal intensities such as temperature, stress, vibration can cause fiber Bragg grating sensor centre wavelength to change, and between two variations of front and back fixed relationship are arranged, and therefore can realize the measurement of respective environment parameter by surveying its wavelength variable quantity.General sensor-based system requires demodulating system to have the wavelength resolution of micromicron magnitude and the wavelength measurement scope of tens nanometers.
In order to be used for the detection of Practical Project, the demodulation techniques of Fiber Bragg Grating FBG have been carried out a large amount of research both at home and abroad, multiple demodulation method has been proposed.But these demodulation method response speeds are slow, and precision is lower, and can't realize that multipoint multiplexing detects.
The utility model content
In view of this, be necessary to provide a kind of high precision, high-speed, multipoint multiplexing to detect and Wavelength demodulation system with low cost.
The utility model is achieved through the following technical solutions:
High speed Wavelength demodulation system based on the transmission grating spectrometer, comprise wideband light source (1), be provided with optical port (2-1,2-2, optical circulator 2-3) (2), fiber grating (4), the signal processing unit (6) of transmission grating spectrometer (5) and demodulation wavelength, the light beam of wideband light source (1) is through optical port (2-1), optical port (2-2) is transmitted to fiber grating (4), enter transmission grating spectrometer (5) by fiber grating (4) reflection by optical port (2-3), transmission grating spectrometer (5) signal connects signal processing unit (6), and described transmission grating spectrometer (5) comprises collimation lens (5-1), first-order diffraction grating (5-2), second-order diffraction grating (5-3), aspheric mirror (5-4) and photodetector array (5-5).
Described high speed Wavelength demodulation system also comprises the photoswitch (3) that is positioned between optical circulator (2) and the fiber grating (4).
Described photoswitch (3) comprises the passage that can switch at a high speed more than 2.
Described signal processing unit (6) signal connects photoswitch (3).
Serial connection at least one fiber grating (4) on each passage of described photoswitch (3).
Described first-order diffraction grating (5-2) and second-order diffraction grating (5-3) are the transmission-type diffraction grating.
Described aspheric mirror (5-4) is convergent mirror.
Described photodetector array (5-5) is the InGaAs linear array detector.
Described wideband light source (1) is optical fiber source or super-radiance light emitting diode.
But described high speed Wavelength demodulation system also comprises the communication interface of external equipment.
The beneficial effects of the utility model are:
High speed Wavelength demodulation system based on the transmission grating spectrometer described in the utility model, comprise wideband light source, be provided with the optical circulator of optical port, fiber grating, the signal processing unit of adjusting wavelength is taken into account in the transmission grating light splitting, the light beam of wideband light source is through optical port 2-1, optical port 2-2 is transmitted to fiber grating, enter the transmission grating spectrometer by the fiber grating reflection by optical port 2-3, transmission grating spectrometer signal connects signal processing unit, and described transmission grating spectrometer comprises collimation lens, the first-order diffraction grating, the second-order diffraction grating, aspheric mirror and photodetector array.So, the reflected light signal of fiber grating enters the transmission grating spectrometer by optical port 2-3, by projecting on the first-order diffraction grating behind the collimation lens formation parallel beam, part diffracted beam by the first-order diffraction grating projects on the second-order diffraction grating, then the part diffracted beam by the second-order diffraction grating is imaged onto on the photodetector array by aspheric mirror, read image space and intensity by signal processing unit again, and according to systematic parameter demodulation grating wavelength value.The utility model grating wavelength demodulating system has increased the angle of diffraction of diffracted beam by the two-stage diffraction grating, has improved the wavelength resolution of demodulating system, guarantees the high precision of this system.Signal processing unit adopts high-speed digital signal process chip and programmable logic chip in addition, i.e. DSP and FPGA, and system's dynamic response is fast, can be used for the high frequency kinetic measurement of multiple physical quantity.
High speed Wavelength demodulation system described in the utility model also comprises the photoswitch between optical circulator and fiber grating, and this photoswitch comprises the passage that can switch at a high speed more than 2, and the signal processing unit signal connects photoswitch.So, control at high speed switching channel of photoswitch by signal processing unit, realized that the multipoint multiplexing of this system detects.
Further, at least one fiber grating of serial connection on each passage of described photoswitch.Can be connected in series at most 30 fiber gratings, so form the distributed fiber grating array, guarantee the effect of its multiple spot distributed measurement.
First-order diffraction grating described in the utility model and second-order diffraction grating are the transmission-type diffraction grating.So, when light beam passed through, the angle of diffraction of different wave length line was different, thereby can with the different wave length line according to the wavelength size separately, realize the demodulation to light beam.
But high speed Wavelength demodulation system described in the utility model also comprises the communication interface of external equipment.So, so that native system can be realized communication with external device (as: computing machine), improved the using value of this system.
Description of drawings
Below in conjunction with accompanying drawing the utility model is described in further detail.
Fig. 1 is the theory diagram of the utility model high speed Wavelength demodulation system embodiment one;
Fig. 2 is the theory diagram of the transmission grating spectrometer of Fig. 1;
Fig. 3 is the theory diagram of the utility model high speed Wavelength demodulation system embodiment two.
Embodiment
Below in conjunction with drawings and Examples the utility model is described in further detail:
Embodiment one:
See also Fig. 1, the utility model shown in Figure 2 is based on the embodiment one of the high speed Wavelength demodulation system of transmission grating spectrometer, comprise wideband light source 1, be provided with optical port 2-1,2-2, the optical circulator 2 of 2-3, photoswitch 3, fiber grating 4, the signal processing unit 6 of transmission grating spectrometer 5 and demodulation wavelength, the light beam of wideband light source 1 is through optical port 2-1, optical port 2-2, photoswitch 3 is transmitted to fiber grating 4, enter transmission grating spectrometer 5 by fiber grating 4 reflections by optical port 2-3, transmission grating spectrometer 5 signals connect signal processing unit 6, and described transmission grating spectrometer 5 comprises collimation lens 5-1, first-order diffraction grating 5-2, second-order diffraction grating 5-3, aspheric mirror 5-4 and photodetector array 5-5.
Described wideband light source 1 is the higher optical fiber source of flatness.
Described photoswitch 3 is the photoswitch of 1 * n passage.Be at least the passage that can switch at a high speed more than 2 in the present embodiment, be connected in series at least a fiber grating 4 on each passage.Certainly, according to the test needs, each passage can be connected in series respectively 1～30 fiber grating that does not wait 4, to form the distributed fiber grating array, realizes the multiple spot distributed measurement.
Described transmission grating spectrometer 5 comprises collimation lens 5-1, first-order diffraction grating 5-2, second-order diffraction grating 5-3, aspheric mirror 5-4 and photodetector array 5-5.This first-order diffraction grating 5-2, second-order diffraction grating 5-3 are the transmission-type diffraction grating, adopt the two-stage diffraction grating, Effective Raise the wavelength resolution of this system.This aspheric mirror 5-4 is convergent mirror.This photodetector array 5-5 is the linear array of the InGaAs detector of rapid photoelectric response.
Described signal processing unit 6 signals connect photoswitch (3), realize the passage switching controls to 1 * n passage photoswitch 3.This signal processing unit 6 comprises digital signal processing chip and programmable logic chip.In addition, but this high speed Wavelength demodulation system also comprises the communication interface (figure do not look) of external equipment.Signal processing unit 6 is by communication interface and external device 7(such as computing machine etc.) the realization communication.This communication interface can be the interfaces such as USB interface or RS232/485.
The principle of work of the high speed Wavelength demodulation system based on the transmission grating spectrometer described in the utility model is: the light beam that wideband light source 1 sends is through the optical port 2-1 of optical circulator, be transmitted into the adjustable 1 * n photoswitch 3 of passage that links to each other with the optical port 2-2 of optical circulator, again by after fiber grating 4 reflections, optical port 2-3 through optical circulator enters transmission grating spectrometer 5, by projecting on the first-order diffraction grating 5-2 behind the collimation lens 5-1 formation parallel beam, part diffracted beam by first-order diffraction grating 5-2 projects on the second-order diffraction grating 5-3, then the part diffracted beam by second-order diffraction grating 5-3 is imaged onto on the photodetector array 5-5 by aspheric mirror 5-4, position and intensity with fiber grating 4 reflectance spectrum imagings transfers to signal processing unit 6 again, carried out the noise restraints such as filtering by 6 pairs of spectral signals of signal processing unit after, sample through the A/D sampling section, again through DSP, communicating by letter etc. the wavelength of the high speed process chip demodulating fiber bragg gratings such as FPGA, and realize simultaneously passage switching controls and and external device 7(such as computing machine etc. to 1 * n passage photoswitch 3 etc.).
The utility model has adopted diffraction grating, and when light beam passed through, the angle of diffraction of different wave length line was different, thereby can with the different wave length line according to the wavelength size separately, realize the demodulation to light beam; Adopt the two-stage diffraction grating, Effective Raise the wavelength resolution of system.
And because the light path part of whole demodulating system inside all is relatively-stationary parts, so dynamic response is very fast, can be used for the high frequency kinetic measurement, has larger actual use value.
In the present embodiment, adjust roughly light path by the infrared phenomena card, make the focus point of the light of the focus point of light of longer wavelength and shorter wavelength be radiated at respectively two end points of photodetector array, corresponding in the middle of the focus point of light of wave band between the two ends of photodetector array.Then, through calibration, can obtain the corresponding relation of the photodetector array pixel of wavelength of light, again by signal processing unit according to calibrating parameters demodulation grating wavelength value.
In the present embodiment, signal processing unit adopts at a high speed and accurately digital signal processing chip and software fitting algorithm.Process chip is DSP and FPGA, and software algorithm comprises threshold value, binomial fitting, Gauss curve fitting etc., processes and sensing assays for system has realized high-speed data-flow.
High speed Wavelength demodulation system based on the transmission grating spectrometer of the present utility model has the Wavelength demodulation resolution of micromicron magnitude, the wavelength measurement scope of tens nanometers and the dynamic frequency response of upper KHz.
Be appreciated that described wideband light source also can be super-radiance light emitting diode.The nonessential variation of so this utility model is also within the utility model protection domain.
Embodiment two:
See also the utility model shown in Figure 3 based on the second embodiment of the high speed Wavelength demodulation system of transmission grating spectrometer, the distinctive points of itself and embodiment one is: described high speed Wavelength demodulation system based on the transmission grating spectrometer is single channel, the light beam that is wideband light source 1 directly is transmitted to fiber grating 4 through optical port 2-1, optical port 2-2, enter transmission grating spectrometer 5 by fiber grating 4 reflection by optical port 2-3, again by signal processing unit 6 according to calibrating parameters demodulation grating wavelength value.
In the present embodiment, take single pass pattern, realize high precision, the Wavelength demodulation system that high-speed, multipoint multiplexing detects, reduced the use of multichannel optical switch, cost further reduces.
All the other structures are all consistent with embodiment one with beneficial effect in the present embodiment, give unnecessary details no longer one by one here.
Claims (10)
1. based on the high speed Wavelength demodulation system of transmission grating spectrometer, comprise wideband light source (1), be provided with optical port (2-1,2-2, optical circulator 2-3) (2), fiber grating (4), the signal processing unit (6) of transmission grating spectrometer (5) and demodulation wavelength, the light beam of wideband light source (1) is through optical port (2-1), optical port (2-2) is transmitted to fiber grating (4), enter transmission grating spectrometer (5) by fiber grating (4) reflection by optical port (2-3), transmission grating spectrometer (5) signal connects signal processing unit (6), and it is characterized in that: described transmission grating spectrometer (5) comprises collimation lens (5-1), first-order diffraction grating (5-2), second-order diffraction grating (5-3), aspheric mirror (5-4) and photodetector array (5-5).
2. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 1, it is characterized in that: described high speed Wavelength demodulation system also comprises the photoswitch (3) that is positioned between optical circulator (2) and the fiber grating (4).
3. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 2, it is characterized in that: described photoswitch (3) comprises the passage that can switch at a high speed more than 2.
4. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 3 is characterized in that: described signal processing unit (6) signal connection photoswitch (3).
5. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 4 is characterized in that: at least one fiber grating of serial connection (4) composition optical fiber optical grating array on each passage of described photoswitch (3).
6. such as the described high speed Wavelength demodulation system based on the transmission grating spectrometer of claim 1 to 5 any one, it is characterized in that: described first-order diffraction grating (5-2) and second-order diffraction grating (5-3) are the transmission-type diffraction grating.
7. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 6, it is characterized in that: described aspheric mirror (5-4) is convergent mirror.
8. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 7, it is characterized in that: described photodetector array (5-5) is the InGaAs linear array detector.
9. such as claim 7 or 8 described high speed Wavelength demodulation systems based on the transmission grating spectrometer, it is characterized in that: described wideband light source (1) is optical fiber source or super-radiance light emitting diode.
10. the high speed Wavelength demodulation system based on the transmission grating spectrometer as claimed in claim 9 is characterized in that: but described high speed Wavelength demodulation system also comprises the communication interface of external equipment.
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| CN 201220396965 CN202748042U (en) | 2012-08-11 | 2012-08-11 | High-speed wavelength demodulating system based on transmission grating spectrometer |
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| CN 201220396965 CN202748042U (en) | 2012-08-11 | 2012-08-11 | High-speed wavelength demodulating system based on transmission grating spectrometer |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105403236A (en) * | 2015-11-18 | 2016-03-16 | 中国矿业大学 | Optical fiber sensing device and method of mechanical state of coal cutter |
| CN108680193A (en) * | 2018-04-18 | 2018-10-19 | 中山水木光华电子信息科技有限公司 | A kind of optical fiber code recognition methods based on light splitting matrix demodulation |
| CN109682474A (en) * | 2018-12-27 | 2019-04-26 | 佛山科学技术学院 | Spectrometer dispersive elements and spectrometer |
| CN114111909A (en) * | 2021-11-30 | 2022-03-01 | 上海大学 | Fiber Bragg grating temperature and stress dual-parameter integrated sensing and demodulating system based on diffraction grating |
-
2012
- 2012-08-11 CN CN 201220396965 patent/CN202748042U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105403236A (en) * | 2015-11-18 | 2016-03-16 | 中国矿业大学 | Optical fiber sensing device and method of mechanical state of coal cutter |
| CN105403236B (en) * | 2015-11-18 | 2017-02-08 | 中国矿业大学 | Optical fiber sensing device and method of mechanical state of coal cutter |
| CN108680193A (en) * | 2018-04-18 | 2018-10-19 | 中山水木光华电子信息科技有限公司 | A kind of optical fiber code recognition methods based on light splitting matrix demodulation |
| CN109682474A (en) * | 2018-12-27 | 2019-04-26 | 佛山科学技术学院 | Spectrometer dispersive elements and spectrometer |
| CN114111909A (en) * | 2021-11-30 | 2022-03-01 | 上海大学 | Fiber Bragg grating temperature and stress dual-parameter integrated sensing and demodulating system based on diffraction grating |
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Granted publication date: 20130220 |