CN211978116U - Fine spectrum detection device - Google Patents
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- CN211978116U CN211978116U CN202020848656.XU CN202020848656U CN211978116U CN 211978116 U CN211978116 U CN 211978116U CN 202020848656 U CN202020848656 U CN 202020848656U CN 211978116 U CN211978116 U CN 211978116U
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- 238000001228 spectrum Methods 0.000 title claims abstract description 77
- 238000001514 detection method Methods 0.000 title claims abstract description 27
- 239000013307 optical fiber Substances 0.000 claims abstract description 64
- 239000000835 fiber Substances 0.000 claims abstract description 61
- 230000035559 beat frequency Effects 0.000 claims abstract description 21
- 230000003287 optical effect Effects 0.000 claims abstract description 10
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims description 6
- 238000001914 filtration Methods 0.000 abstract description 2
- 230000003595 spectral effect Effects 0.000 description 9
- 238000000034 method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000010009 beating Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
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Abstract
The utility model discloses a fine spectrum detection device, which comprises a DFB laser, two fiber couplers, two phase modulators, two high-frequency signal sources, a fiber circulator, a fiber grating, a high-speed photoelectric detector and a spectrum analyzer; the utility model adopts the same DFB laser to output single-frequency laser, which is divided into two beams by an optical fiber coupler, one beam is processed with narrow-band filtering after passing through the phase modulation of higher frequency, and laser with certain wavelength deviation with the DFB light source is obtained; the other beam is subjected to phase modulation at a lower frequency; then the two laser beams are combined through another optical fiber coupler to form a beat frequency signal and transmitted to a high-speed photoelectric detector, the optical signal is converted into an electric signal through the high-speed photoelectric detector and finally transmitted to a spectrum analyzer, and a spectrum corresponding to the spectrum can be observed through the spectrum analyzer. The utility model has the advantages that: the influence caused by frequency jitter among different DFB lasers is avoided, stable beat signals can be formed, and fine spectrum detection is realized.
Description
Technical Field
The utility model relates to a laser technical field, specific saying so relates to a meticulous spectrum detection device.
Background
Spectra are parameters that describe the distribution of light energy in the frequency domain and are of great importance in optical applications. For broadband spectra, detection is usually performed by a spectrum analyzer, and the resolution of the commonly used spectrum analyzer is usually greater than 0.02nm, and fine measurement cannot be realized for spectra smaller than the resolution. For narrow-band spectra, fabry-perot interference filters are usually used for detection, the wavelength resolution of which can reach pm order, but the high resolution depends on the calibration accuracy of the fabry-perot cavity. High resolution can also be achieved by self-heterodyne beat frequency, by which the optical bandwidth is converted to the electrical domain by beating the signal light with a phase-delayed signal light, which is then detected by a spectrum analyzer, but this method relies on the stability of the modulated signal and the narrow line width. In addition, there is also a method of performing fine spectrum detection using stimulated brillouin scattering, which requires dynamic scanning of a wavelength and a high laser power, or a long transmission fiber, although it has a high resolution.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a meticulous spectral detection device for solve the defect that current spectral detection technique exists among the background art.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a fine spectrum detection device comprises a DFB laser, a 1x2 optical fiber coupler A, a 2x1 optical fiber coupler, a phase modulator A, a phase modulator B, a high-frequency signal source A, a high-frequency signal source B, an optical fiber circulator, an optical fiber grating, a high-speed photoelectric detector and a spectrum analyzer; the DFB laser is connected with the 1x2 optical fiber coupler, the 1x2 optical fiber coupler is respectively connected with the phase modulator A and the phase modulator B, the phase modulator A is respectively connected with the high-frequency signal source A and the optical fiber circulator, the phase modulator B is respectively connected with the high-frequency signal source B and the 2x1 optical fiber coupler, the optical fiber circulator is respectively connected with the optical fiber grating and the 2x1 optical fiber coupler, the 2x1 optical fiber coupler is further connected with the high-speed photoelectric detector, and the high-speed photoelectric detector is further connected with the spectrum analyzer;
when the fiber grating optical coupler is used, the DFB laser outputs single-frequency laser to a 1x2 fiber coupler, the single-frequency laser is divided into two beams by a 1x2 fiber coupler, one beam is modulated by a high-frequency signal f1 output by a high-frequency signal source A through a phase modulator A, then is input to a port A of the fiber circulator, then is output to a fiber grating from the port B of the fiber circulator, returns to the port B of the fiber circulator after being reflected by the fiber grating, and finally is output to a 2x1 fiber coupler from a port C of the fiber circulator; the other beam passes through a phase modulator B, is modulated by a high-frequency signal f2 output by a high-frequency signal source B, and is output to a 2x1 optical fiber coupler; and then combining the two laser beams through a 2x1 optical fiber coupler to form a beat frequency, injecting the beat frequency into a high-speed photoelectric detector, converting a beat frequency optical signal obtained by combining the two laser beams into an electric signal through the high-speed photoelectric detector, transmitting the electric signal into a spectrum analyzer for analysis, and finally observing a spectrum corresponding to the beat frequency spectrum in the spectrum analyzer.
In the technical scheme, the splitting ratio of the 1x2 optical fiber coupler is 50: 50-20: 80.
In the technical scheme, the splitting ratio of the 2x1 optical fiber coupler is 50: 50-20: 80.
In the above technical solution, the phase modulator a is a lithium niobate waveguide phase modulator.
In the above technical solution, the phase modulator B is a lithium niobate waveguide phase modulator.
In the above technical solution, the fiber grating is a narrow-band fiber grating, the reflection bandwidth of the fiber grating is smaller than that of the high-frequency signal f1 output by the high-frequency signal source a, and the reflection spectrum covers the left side or the right side of the first-order sideband of the laser modulated by the high-frequency signal f 1.
In the above technical solution, the output power of the high frequency signal source a is greater than 20 dBm.
In the above technical solution, the frequency of the high-frequency signal f1 output by the high-frequency signal source a is higher than the frequency of the high-frequency signal f2 output by the high-frequency signal source B, and the frequency of the high-frequency signal f1 is greater than 2 × the frequency of the high-frequency signal f 2.
In the above technical solution, the response bandwidth of the high-speed photodetector is greater than the high-frequency signal f1 output by the high-frequency signal source a.
Compared with the prior art, the beneficial effects of the utility model are that:
(1) the laser from the same DFB laser source is adopted for beat frequency, so that the influence caused by frequency jitter among different DFB lasers is avoided, a stable beat frequency signal can be formed after the two paths of laser are combined, and the detection of a fine spectrum can be realized;
(2) the conversion of laser wavelength is realized by combining the phase modulator and the narrow-band fiber grating, and a foundation is laid for the smooth realization of beat frequency.
The utility model discloses a main innovation point lies in: the method comprises the steps that a single-frequency laser is output by the same DFB laser light source and is divided into two beams through a 1x2 optical fiber coupler, wherein one beam is subjected to narrow-band filtering after being subjected to phase modulation with high frequency, and laser with certain wavelength deviation with the DFB laser light source is obtained; the other beam of laser is subjected to phase modulation with lower frequency to form narrow-band spectrum broadening; and then combining the two paths of lasers into beams through another 1x2 optical fiber coupler to form beat frequency signals, transmitting the beat frequency signals to a high-speed photoelectric detector, finally converting the optical signals into electric signals through the high-speed photoelectric detector, and transmitting the electric signals to a spectrum analyzer for observation of fine spectrums corresponding to the spectrums.
Drawings
FIG. 1 is a schematic view of the operation principle of the fine spectrum detection device of the present invention;
FIG. 2 is a simulated spectrum broadening and fiber grating reflection spectrum under the modulation of a high-frequency signal f 1;
FIG. 3 is a graph of simulated spectral broadening under modulation of a high frequency signal f 2;
FIG. 4 is a diagram of a frequency spectrum analysis of beat signals detected after the combination of two simulated lasers;
description of reference numerals: 1. a DFB laser; 2. 1x2 fiber coupler; 3. 2x1 fiber optic couplers; 4. a phase modulator A; 5. a phase modulator B; 6. a high-frequency signal source A; 7. a high-frequency signal source B; 8. a fiber optic circulator; 9. a fiber grating; 10. a high-speed photodetector; 11. and a spectrum analyzer.
Detailed Description
In order to make the technical means, the creation features, the achievement purposes and the functions of the present invention easy to understand and understand, how to implement the present invention is further explained below with reference to the accompanying drawings and the detailed description.
Referring to fig. 1, the utility model provides a fine spectrum detection device, include DFB laser 1, 1x2 fiber coupler 2, 2x1 fiber coupler 3, phase modulator a4, phase modulator B5, high frequency signal source a6, high frequency signal source B7, optical fiber circulator 8, fiber grating 9, high-speed photodetector 10 and spectrum analyzer 11; the DFB laser 1 is connected with a 1x2 optical fiber coupler 2, the 1x2 optical fiber coupler 2 is respectively connected with a phase modulator A4 and a phase modulator B5, the phase modulator A4 is respectively connected with a high-frequency signal source A6 and an optical fiber circulator 8, the phase modulator B5 is respectively connected with a high-frequency signal source B7 and a 2x1 optical fiber coupler 3, the optical fiber circulator 8 is also respectively connected with an optical fiber grating 9 and a 2x1 optical fiber coupler 3, the 2x1 optical fiber coupler 3 is also connected with a high-speed photoelectric detector 10, and the high-speed photoelectric detector 10 is also connected with a spectrum analyzer 11; when the fiber optic circulator is used, a single-frequency laser is output to a 1x2 fiber coupler 2 by a DFB laser 1, the single-frequency laser is divided into two beams by a 1x2 fiber coupler 2, one beam is input to a port A of a fiber optic circulator 8 after passing through a phase modulator A4 and being modulated by a high-frequency signal f1 output by a high-frequency signal source A6, then is output to a fiber grating 9 from the port B of the fiber optic circulator 8, returns to the port B of the fiber optic circulator 8 after being reflected by the fiber grating 9, and finally is output to a 2x1 fiber coupler 3 from a port C of the fiber optic circulator 8; the other beam is modulated by a high-frequency signal f2 output by a high-frequency signal source B7 through a phase modulator B5 and then is output to a 2x1 optical fiber coupler 3; then, combining the two lasers through the 2x1 optical fiber coupler 3 to form a beat frequency signal, injecting the beat frequency signal into the high-speed photodetector 10, converting the beat frequency optical signal obtained by combining the two lasers into an electrical signal through the high-speed photodetector 10, transmitting the electrical signal to the spectrum analyzer 11 for analysis, and finally observing a spectrum corresponding to the beat frequency spectrum in the spectrum analyzer 11.
Specifically, in the utility model, referring to fig. 1, the output end of DFB laser 1 is connected with the input end of 1x2 optical fiber coupler 2, two output ends of 1x2 optical fiber coupler 2 are connected with the input ends of phase modulator a4 and phase modulator B5, the output end of phase modulator a4 is connected with port a of optical fiber circulator 8, port B of optical fiber circulator 8 is connected with fiber grating 9, port C of optical fiber circulator 8 is connected with one input end of 2x1 optical fiber coupler 3, the output end of phase modulator B5 is connected with another input end of 2x1 optical fiber coupler 3, the output end of 2x1 optical fiber coupler 3 is connected with the input end of high-speed photodetector 10, and the output end of high-speed photodetector 10 is connected with spectrum analyzer 11; the high-frequency signal source a6 outputs a high-frequency signal f1 into the control voltage terminal of the phase modulator a4, and the high-frequency signal source B7 outputs a high-frequency signal f2 into the control voltage terminal of the phase modulator B5.
Specifically, in the present invention, the splitting ratio of the 1 × 2 optical fiber coupler 2 is 50:50 to 20:80, preferably 30: 70.
Specifically, in the present invention, the splitting ratio of the 2 × 1 optical fiber coupler 3 is 50:50 to 20:80, preferably 30: 70.
Specifically, in the present invention, the phase modulator a4 is preferably a lithium niobate waveguide phase modulator.
Specifically, in the present invention, the phase modulator B5 is preferably a lithium niobate waveguide phase modulator.
Specifically speaking, in the utility model discloses in, fiber grating 9 is narrowband fiber grating, and its reflection bandwidth is less than the high frequency signal f1 of high frequency signal source A6 output, and its reflection spectrum covers laser first order sideband left side or right side under the modulation of high frequency signal f 1.
Specifically speaking, in the utility model discloses in, high frequency signal source A6 output is greater than 20 dBm.
Specifically, in the present invention, the frequency of the high-frequency signal f1 output from the high-frequency signal source a6 is higher than the frequency of the high-frequency signal f2 output from the high-frequency signal source B7, and the frequency of the high-frequency signal f1 is > 2 × the frequency of the high-frequency signal f 2.
Specifically, in the present invention, the high-speed photodetector 10 responds to the high-frequency signal f1 with a bandwidth greater than that of the high-frequency signal source a 6.
As a preferred embodiment of the present invention: when the splitting ratio of the 1 × 2 fiber coupler 2 is 30:70, an output arm with a large beam ratio is connected to the phase modulator a4, and an output arm with a small beam ratio is connected to the phase modulator B5; when the splitting ratio of the 2 × 1 fiber coupler 3 is 30:70, an input arm having a large beam ratio is connected to the port C of the fiber optic circulator 8, and an input arm having a small beam ratio is connected to the phase modulator B5.
Adopt the utility model provides a pair of meticulous spectral detection device carries out spectral detection's process, specifically divide into following several steps:
Fig. 2 shows that, based on the fine spectrum detection device provided by the present invention, the simulated high-frequency signal f1 output by the high-frequency signal source a6 is the spectrum spread width modulated by 16GHz and the reflection spectrum of the fiber grating 8; in fig. 2, the abscissa represents the wavelength in nm; the ordinate represents the spectral intensity; the curve shown by the dotted line represents the reflection spectrum of the fiber grating 8; the rest represent the spectral spread.
Fig. 3 is a diagram showing the spectrum spread width of a high-frequency signal f2 output by a high-frequency signal source B7, which is simulated based on the fine spectrum detection device provided by the present invention, under the modulation of 1 GHz; in fig. 3, the abscissa represents the wavelength in nm; the ordinate represents the spectral intensity.
Fig. 4 shows a simulated frequency spectrum diagram of the beat signal detected by the spectrum analyzer 11 after the combination of two lasers based on the fine spectrum detection device provided by the present invention; in fig. 4, the abscissa represents the wave frequency in Hz; the ordinate represents the spectral intensity.
Finally, the above description is only the embodiments of the present invention, not limiting the scope of the present invention, all the equivalent structures or equivalent processes that are used in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.
Claims (9)
1. The fine spectrum detection device is characterized by comprising a DFB laser (1), a 1x2 optical fiber coupler (2), a 2x1 optical fiber coupler (3), a phase modulator A (4), a phase modulator B (5), a high-frequency signal source A (6), a high-frequency signal source B (7), an optical fiber circulator (8), an optical fiber grating (9), a high-speed photoelectric detector (10) and a spectrum analyzer (11); the DFB laser (1) is connected with the 1x2 optical fiber coupler (2), the 1x2 optical fiber coupler (2) is respectively connected with the phase modulator A (4) and the phase modulator B (5), the phase modulator A (4) is respectively connected with the high-frequency signal source A (6) and the optical fiber circulator (8), the phase modulator B (5) is respectively connected with the high-frequency signal source B (7) and the 2x1 optical fiber coupler (3), the optical fiber circulator (8) is also respectively connected with the fiber grating (9) and the 2x1 optical fiber coupler (3), the 2x1 optical fiber coupler (3) is also connected with the high-speed photoelectric detector (10), and the high-speed photoelectric detector (10) is also connected with the spectrum analyzer (11);
when the fiber grating optical coupler is used, single-frequency laser is output to a 1x2 fiber coupler (2) by the DFB laser (1), the single-frequency laser is divided into two beams by a 1x2 fiber coupler (2), one beam is input to a port A of a fiber circulator (8) after being modulated by a high-frequency signal f1 output by a high-frequency signal source A (6) through a phase modulator A (4), then is output to a fiber grating (9) from the port B of the fiber circulator (8), returns to the port B of the fiber circulator (8) after being reflected by the fiber grating (9), and finally is output to a 2x1 fiber coupler (3) from a port C of the fiber circulator (8); the other beam is modulated by a high-frequency signal f2 output by a high-frequency signal source B (7) through a phase modulator B (5) and then output to a 2x1 optical fiber coupler (3); then, after the two beams of laser are combined through the 2x1 optical fiber coupler (3), a beat frequency signal is formed and injected into the high-speed photoelectric detector (10), the beat frequency optical signal formed by combining the two beams of laser is converted into an electric signal through the high-speed photoelectric detector (10), the electric signal is transmitted to the spectrum analyzer (11) for analysis, and finally, the spectrum corresponding to the beat frequency spectrum can be obtained in the spectrum analyzer (11).
2. The fine spectrum detection device according to claim 1, wherein the splitting ratio of the 1x2 fiber coupler (2) is 50: 50-20: 80.
3. The fine spectrum detection device according to claim 1, wherein the splitting ratio of the 2x1 fiber coupler (3) is 50: 50-20: 80.
4. The fine spectrum detection device according to claim 1, wherein said phase modulator A (4) is a lithium niobate waveguide phase modulator.
5. The fine spectrum detection device according to claim 1, wherein said phase modulator B (5) is a lithium niobate waveguide phase modulator.
6. The fine spectrum detection device according to claim 1, wherein the fiber grating (9) is a narrow-band fiber grating, the reflection bandwidth of the fiber grating is smaller than that of the high-frequency signal f1 output by the high-frequency signal source A (6), and the reflection spectrum of the fiber grating covers the left side or the right side of the first-order sideband of the laser modulated by the high-frequency signal f 1.
7. The fine spectrum detection device of claim 1, wherein the output power of the high frequency signal source A (6) is greater than 20 dBm.
8. The fine spectrum detecting apparatus according to claim 7, wherein the high frequency signal source A (6) outputs a high frequency signal f1 having a frequency higher than that of the high frequency signal f2 output by the high frequency signal source B (7), and the frequency of the high frequency signal f1 is greater than 2x the frequency of the high frequency signal f 2.
9. The fine spectrum detecting apparatus according to claim 8, wherein the high-speed photodetector (10) responds to a high-frequency signal f1 having a bandwidth larger than that of the high-frequency signal source A (6).
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| CN202020848656.XU CN211978116U (en) | 2020-05-19 | 2020-05-19 | Fine spectrum detection device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111504456A (en) * | 2020-05-19 | 2020-08-07 | 宝宇(武汉)激光技术有限公司 | Fine spectrum detection device and method |
| CN113310575A (en) * | 2021-05-28 | 2021-08-27 | 中电科思仪科技股份有限公司 | Method and device for removing spectral signal substrate measured by Brillouin spectrometer |
-
2020
- 2020-05-19 CN CN202020848656.XU patent/CN211978116U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111504456A (en) * | 2020-05-19 | 2020-08-07 | 宝宇(武汉)激光技术有限公司 | Fine spectrum detection device and method |
| CN111504456B (en) * | 2020-05-19 | 2023-12-01 | 宝宇(武汉)激光技术有限公司 | Fine spectrum detection device and method |
| CN113310575A (en) * | 2021-05-28 | 2021-08-27 | 中电科思仪科技股份有限公司 | Method and device for removing spectral signal substrate measured by Brillouin spectrometer |
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Denomination of utility model: A fine spectrum detection device Effective date of registration: 20220310 Granted publication date: 20201120 Pledgee: Wuhan area branch of Hubei pilot free trade zone of Bank of China Ltd. Pledgor: Baoyu (Wuhan) laser technology Co.,Ltd. Registration number: Y2022420000056 |
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