CN111947793B - Time domain-frequency domain converter for ultrafast process detection - Google Patents
Time domain-frequency domain converter for ultrafast process detection Download PDFInfo
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- CN111947793B CN111947793B CN202010691433.1A CN202010691433A CN111947793B CN 111947793 B CN111947793 B CN 111947793B CN 202010691433 A CN202010691433 A CN 202010691433A CN 111947793 B CN111947793 B CN 111947793B
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- 238000000034 method Methods 0.000 title claims abstract description 26
- 238000001514 detection method Methods 0.000 title claims abstract description 23
- 230000003287 optical effect Effects 0.000 claims abstract description 24
- 239000004065 semiconductor Substances 0.000 claims abstract description 17
- 239000000835 fiber Substances 0.000 claims abstract description 10
- 239000013307 optical fiber Substances 0.000 claims description 28
- 239000006185 dispersion Substances 0.000 claims description 17
- 238000012423 maintenance Methods 0.000 abstract 1
- 238000001228 spectrum Methods 0.000 description 12
- 238000005259 measurement Methods 0.000 description 4
- 239000002609 medium Substances 0.000 description 3
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 230000003252 repetitive effect Effects 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000035559 beat frequency Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012984 biological imaging Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
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- 238000009532 heart rate measurement Methods 0.000 description 1
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- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J11/00—Measuring the characteristics of individual optical pulses or of optical pulse trains
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/0218—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using optical fibers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
Abstract
The invention discloses a time domain-frequency domain converter for ultrafast process detection, which comprises a first layer and a second layer; the first layer includes single mode semiconductor laser and optical flat plate, single mode semiconductor laser 7 is connected with first space collimator 2 through first fiber connector 6, receive by second space collimator 3 through one section space light route, be equipped with the shutter between first space collimator and the second space collimator, the shutter control ware is connected to the shutter, single mode semiconductor laser connects the light source switch, the second layer is including the signal source that awaits measuring, signal source one end that awaits measuring is passed through second fiber connector and is connected with second space collimator, the other end passes through third fiber connector and connects three port beam splitters, first output port is connected to three port beam splitters, second output port and third output port. The invention has the advantages of high detection speed, high resolution, simple structure, low cost, strong anti-interference capability and simple maintenance.
Description
Technical Field
The invention belongs to the technical field of ultra-short pulse measurement, and relates to a time domain-frequency domain converter for ultra-fast process detection.
Background
In recent years, the ultrashort laser pulse technology is rapidly developed in the scientific and technical fields of signal processing, optical communication, biological imaging and the like, however, how to realize the measurement of ultrashort pulses is a key problem in the ultrafast laser field, and particularly, the real-time measurement of the ultrafast process is the most challenging problem. Because the traditional spectrometer measures the signal spectrum by using the modes of converting a slit, moving a grating, a charge coupled device and the like, the detection rate of the traditional spectrometer is limited by machinery or electricity and is difficult to improve, so that the traditional spectrometer cannot acquire real-time spectrum information of ultrashort laser pulses and cannot detect non-repeated transient information in complex systems such as physics, chemistry, biology and the like based on the ultrashort pulses as information carriers.
The dispersion Fourier transform method based on the dispersion management method can overcome the speed limit of the traditional spectrometer and realize the real-time measurement of frequency domain information. When this method is used to study the start-up process of a mode-locked fiber laser, a new phenomenon such as spectral beat frequency can be found. The method can also be used for researching transient processes of non-repetitive phenomena such as noise, instability, giant wave solitons and the like in the optical nonlinear medium. When the two-dimensional images are mapped onto the time sequence by the method, the two-dimensional images to be measured can be obtained by adopting a photoelectric detector and analog-to-digital conversion, and the frame rate of shooting is more than 1000 times higher than that of a common CCD. Therefore, the development of the time domain-frequency domain converter based on the method has high application value and commercial value.
Disclosure of Invention
The invention aims to provide a time domain-frequency domain converter for ultrafast process detection, which has the advantages of greatly improving the detection speed of pulse frequency domain information to be detected and realizing the real-time measurement of non-repetitive signals in the ultrafast process.
The technical scheme adopted by the invention is that the time domain-frequency domain converter for the ultrafast process detection comprises a first layer and a second layer;
the first layer comprises a single-mode semiconductor laser and an optical flat plate, the single-mode semiconductor laser is connected with a first space collimator arranged on the optical flat plate through a first optical fiber connector, a second space collimator connected with the first space collimator through a space optical path is also arranged on the optical flat plate, a shutter is arranged between the first space collimator and the second space collimator and connected with a shutter controller, the shutter controller is connected with a shutter switch, the single-mode semiconductor laser is connected with a light source switch,
the second layer comprises a signal source to be detected, one end of the signal source to be detected is connected with the second space collimator through the second optical fiber connector, the other end of the signal source to be detected is connected with the three-port beam splitter through the third optical fiber connector, and the three-port beam splitter is connected with the first output port, the second output port and the third output port.
The invention is also characterized in that:
the first output port is connected with a spectrometer to directly detect the spectrogram of the signal to be detected, the second output port is connected with an oscilloscope to directly detect the time domain sequence of the signal to be detected, and the third output port is connected with the oscilloscope through a dispersion compensation optical fiber to detect the real-time frequency domain sequence of the signal to be detected.
The beam splitting proportion of the light beams output by the first output port and the second output port is 25%, and the beam splitting proportion of the light beam output by the third output port is 50%.
The first space collimator is connected with the first optical fiber connector through a single-mode optical fiber.
The optical flat plate is 13-16cm long and 9-11cm wide, and a plurality of screw mounting hole positions are arranged on the surface.
The voltage of the shutter controller is 12V, the shutter controller is driven by a rechargeable battery, and the shutter opening and closing speed is 1ms-5ms each time.
The working wave band of the single-mode semiconductor laser is 960-990nm, and the output power is 0-550mW.
The type of the dispersion compensation fiber is NDCF-G.652C, and the length of the dispersion compensation fiber is 1km-5km.
The working wavelength band of the three-port beam splitter is 1520-1580nm.
The beneficial effects of the invention are:
(1) The time domain-frequency domain converter has high resolution of 0.18nm, high detection speed of 0.05ns, and can detect the instantaneous spectrum in the ultrafast process;
(2) The time domain-frequency domain converter is insensitive to the environment, has strong anti-interference capability and is simple to maintain;
(3) The time domain-frequency domain converter has simple structure and low cost;
(4) The size range of the portable system of the time domain-frequency domain converter is 300 multiplied by 250 multiplied by 200 to 350 multiplied by 300 multiplied by 250mm 3 ；
(5) The time domain-frequency domain converter of the invention uses devices which are all universal devices, can be commercialized and has low cost;
(6) The optical path part of the time domain-frequency domain converter adopts devices based on optical fibers except the space collimator, so that the system is easy to adjust and has good stability.
Drawings
FIG. 1 is a top view of a first layer of a time-to-frequency domain converter of the present invention;
FIG. 2 is a top view of a second layer of the time-domain to frequency-domain converter of the present invention;
FIG. 3 is a side view of the time-to-frequency domain converter of the present invention;
FIG. 4 is a control panel of the time-to-frequency domain converter of the present invention;
FIG. 5 is an average spectrum measured with a spectrometer with a center wavelength of 1556nm;
FIG. 6 is a real-time spectrogram measured with an oscilloscope with a center wavelength of 1556nm;
fig. 7 is a pulse sequence measured using an oscilloscope.
In the figure, 1, a shutter, 2, a first space collimator, 3, a second space collimator, 4, an optical flat plate, 5, a single-mode optical fiber, 6, a first optical fiber connector, 7, a single-mode semiconductor laser, 8, a shutter controller, 9, a light source switch, 10, a shutter switch, 11, a second optical fiber connector, 12, a signal source to be tested, 13, a third optical fiber connector, 14, a three-port beam splitter, 15, a dispersion compensation optical fiber, 16, a first output port, 17, a second output port, 18, a third output port, and 19, a liquid crystal display screen.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The invention relates to a time domain-frequency domain converter for ultrafast process detection, which comprises a first layer and a second layer as shown in figures 1-4; the first layer comprises a single-mode semiconductor laser 7 and an optical flat plate 4, the single-mode semiconductor laser 7 is connected with a first space collimator 2 through a first optical fiber connector 6, a section of space light is received by a second space collimator 3 and is input to a signal source 12 to be tested of the second layer as a pumping source, the first space collimator 2 and the second space collimator 3 are both fixed on a screw hole of the optical flat plate 4, a shutter 1 is arranged between the first space collimator 2 and the second space collimator 3, the first space collimator 2 is connected with the first optical fiber connector 6 through a single-mode optical fiber 5, the shutter 1 is connected with a shutter controller 8, the shutter controller 8 is connected with a shutter switch 10, the single-mode semiconductor laser 7 is connected with a light source switch 9, the second layer comprises the signal source 12 to be tested, one end of the signal source 12 to be tested is connected with the second space collimator 3 through a second optical fiber connector 11, the other end is connected with a three-port beam splitter 14 through a third optical fiber connector 13, the three-port beam splitter 14 is connected with a first output port 16, a second output port 17 and a third output port 18, a liquid crystal display 19 displays the output power of the single-mode semiconductor laser 7, the three-port beam splitter 14 divides the output laser of the signal source 12 to be detected into a light beam a, a light beam b and a light beam c, the beam splitting ratios of the light beam a and the light beam b are 25%, the light beam a and the light beam b are respectively output through the first output port 16 and the second output port 17, the first output port 16 is connected with a spectrometer to detect the average spectrum of a signal to be detected, the second output port 17 is connected with an oscilloscope to detect the time domain sequence of the signal to be detected, the beam splitting ratio of the light beam c is 50%, the light beam c is firstly input to a section of dispersion compensation optical fiber 15, the signal to be detected is stretched under the influence of group velocity dispersion, meanwhile, different wavelengths in the spectrum are separated in time due to different propagation velocities, the time domain waveform obtained after stretching has a specific corresponding relation with the spectrum thereof, so that the frequency domain information of the optical pulse is mapped onto the time domain, the signal to be detected passing through the dispersion compensation optical fiber 15 is output from the third output port 18, and the signal is received by the high-speed photoelectric detector and input into an oscilloscope to detect the real-time frequency domain sequence of the signal to be detected;
preferably, the optical flat plate 4 is 13-16cm long and 9-11cm wide, and the surface is provided with a plurality of screw mounting hole positions;
preferably, the voltage of the shutter controller 8 is 12V, the shutter controller is driven by a rechargeable battery, and the speed of the shutter switch 10 is 1ms-5ms each time;
preferably, the working wave band of the single-mode semiconductor laser 7 is 960-990nm, and the output power is 0-550mW;
preferably, the type of the dispersion compensation fiber 15 is NDCF-G.652C, and the length is 1km-5km;
preferably, the operating wavelength band of the three-port beam splitter 14 is 1520-1580nm;
preferably, the spectral characteristics of the output pulses are monitored using a spectrum analyzer (YOKOGAWA-6370B), and the time and frequency sequences of the output pulses are measured with a photodetector with a bandwidth of 25GHz using a real-time oscilloscope with a sampling rate of 20G;
preferably, the shutter 1 is a high-speed electrically controlled shutter;
preferably, a 980nm laser source is used as a pump light source of a signal source to be measured.
The invention relates to a time domain-frequency domain converter for ultrafast process detection, which has the working principle as follows: when an optical pulse propagates in a dispersive medium, the optical pulse is stretched under the influence of group velocity dispersion, different wavelengths in a pulse spectrum are separated in time due to different propagation velocities, and a time domain waveform obtained after stretching has a specific corresponding relation with the spectrum of the time domain waveform, so that the frequency domain information of the optical pulse is mapped to a time domain. Then a high-speed photodetector is used to receive the signal and a high-speed analog-to-digital converter is used to sample, thereby realizing a detection rate far higher than that of a traditional spectrometer. Meanwhile, the dispersion compensation optical fiber serving as a dispersion medium can also serve as an increasing medium for optical amplification, and frequency domain detection with higher sensitivity can be realized by amplifying optical pulses in the dispersion compensation optical fiber.
Examples
When the pumping power is 90-120mW and the shutter is in the open state, the signal source to be measured outputs ultrashort pulses, fig. 5 is an average spectrogram of a signal to be measured by a spectrometer, the center wavelength of the output pulses of the signal source to be measured is 1556nm, the full width at half maximum of the spectrum is about 9nm, fig. 6 is a real-time spectrogram of the signal to be measured after the signal to be measured passes through a dispersion compensation optical fiber, the center wavelength of the signal pulses is 1556nm, the full width at half maximum of the spectrum is about 9nm, the result is consistent with that of the spectrogram of fig. 5, fig. 7 is an oscilloscope sequence measured after the signal to be measured passes through the dispersion compensation optical fiber, wherein the period of the signal pulses is about 100ns, and the corresponding resonant cavity length is 20.5m.
The time domain-frequency domain converter system provided by the invention has the advantages of high detection speed, high resolution, simple structure and low cost, and is strong in anti-interference capability and simple to maintain. The system is a portable system with the size range of 300 × 250 × 200-350 × 300 × 250mm 3 Most of system devices adopt devices based on optical fibers, so that the system is easy to adjust and has good stability.
Claims (8)
1. A time-domain-to-frequency-domain converter for ultrafast process detection, comprising a first layer and a second layer;
the first layer comprises a single-mode semiconductor laser (7) and an optical flat plate (4), the single-mode semiconductor laser (7) is connected with a first space collimator (2) arranged on the optical flat plate (4) through a first optical fiber connector (6), a second space collimator (3) connected with the first space collimator (2) through a space optical path is further arranged on the optical flat plate (4), a shutter (1) is arranged between the first space collimator (2) and the second space collimator (3), the shutter (1) is connected with a shutter controller (8), the shutter controller (8) is connected with a shutter switch (10), the single-mode semiconductor laser (7) is connected with a light source switch (9),
the second layer comprises a signal source to be tested (12), one end of the signal source to be tested (12) is connected with the second space collimator (3) through a second optical fiber connector (11), the other end of the signal source to be tested is connected with a three-port beam splitter (14) through a third optical fiber connector (13), and the three-port beam splitter (14) is connected with a first output port (16), a second output port (17) and a third output port (18);
the first output port (16) is connected with a spectrograph for directly detecting a spectrogram of a signal to be detected, the second output port (17) is connected with an oscilloscope for directly detecting a time domain sequence of the signal to be detected, and the third output port (18) is connected with the oscilloscope for detecting a real-time frequency domain sequence of the signal to be detected through a dispersion compensation optical fiber (15).
2. A time-to-frequency domain converter for ultrafast process detection as claimed in claim 1, wherein the first output port (16) and the second output port (17) output beams having a splitting ratio of 25% and the third output port (18) output beams having a splitting ratio of 50%.
3. A time-to-frequency domain converter for ultrafast process detection according to claim 1, wherein said first spatial collimator (2) is connected to said first fiber connector (6) by a single mode fiber (5).
4. The time-domain-to-frequency-domain converter for ultrafast process detection as claimed in claim 1, wherein said optical plate (4) is 13-16cm long and 9-11cm wide, and has a plurality of screw mounting holes on its surface.
5. Time-domain-to-frequency-domain converter for ultrafast process detection according to claim 1, wherein said shutter controller (8) has a voltage of 12V, is driven by a rechargeable battery, and said shutter switch (10) has a speed of 1ms to 5ms each.
6. The time-frequency domain converter for ultrafast process detection of claim 1, wherein said single-mode semiconductor laser (7) has an operating band of 960-990nm and an output power of 0-550mW.
7. The time-frequency domain converter for ultrafast process detection of claim 1, wherein said dispersion compensating fiber (15) is NDCF-g.652c type and has a length of 1km to 5km.
8. A time-to-frequency domain converter for ultrafast process detection according to claim 1, wherein said three-port beam splitter (14) has an operating wavelength band of 1520-1580nm.
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| US20100141829A1 (en) * | 2008-11-18 | 2010-06-10 | The Regents Of The University Of California | Apparatus and method for optically amplified imaging |
| CN110243477A (en) * | 2019-07-12 | 2019-09-17 | 重庆大学 | A kind of spectrographic pulse laser polarization analyzer complete in real time |
| US20190356103A1 (en) * | 2017-01-05 | 2019-11-21 | Ipg Photonics Corporation | Optical frequency comb generator with carrier envelope offset frequency detection |
| CN210243001U (en) * | 2019-05-29 | 2020-04-03 | 中国科学院西安光学精密机械研究所 | High-resolution real-time ultrashort pulse time-frequency domain measuring device |
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| JP4471572B2 (en) * | 2003-01-31 | 2010-06-02 | 独立行政法人科学技術振興機構 | Optical transmission method |
| WO2018170824A1 (en) * | 2017-03-23 | 2018-09-27 | The University Of Hong Kong | Real-time optical spectro-temporal analyzer and method |
| CN110207837B (en) * | 2019-05-29 | 2024-04-05 | 中国科学院西安光学精密机械研究所 | High-resolution real-time ultrashort pulse time-frequency domain measuring device and method |
| CN110186557A (en) * | 2019-06-05 | 2019-08-30 | 国网江苏省电力有限公司检修分公司 | A kind of Reactor Fault diagnostic method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100141829A1 (en) * | 2008-11-18 | 2010-06-10 | The Regents Of The University Of California | Apparatus and method for optically amplified imaging |
| US20190356103A1 (en) * | 2017-01-05 | 2019-11-21 | Ipg Photonics Corporation | Optical frequency comb generator with carrier envelope offset frequency detection |
| CN210243001U (en) * | 2019-05-29 | 2020-04-03 | 中国科学院西安光学精密机械研究所 | High-resolution real-time ultrashort pulse time-frequency domain measuring device |
| CN110243477A (en) * | 2019-07-12 | 2019-09-17 | 重庆大学 | A kind of spectrographic pulse laser polarization analyzer complete in real time |
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