CN111665519A - Large field depth full optical fiber laser Doppler velocimeter - Google Patents
Large field depth full optical fiber laser Doppler velocimeter Download PDFInfo
- Publication number
- CN111665519A CN111665519A CN202010530213.0A CN202010530213A CN111665519A CN 111665519 A CN111665519 A CN 111665519A CN 202010530213 A CN202010530213 A CN 202010530213A CN 111665519 A CN111665519 A CN 111665519A
- Authority
- CN
- China
- Prior art keywords
- optical fiber
- laser
- optical
- fiber
- doppler velocimeter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013307 optical fiber Substances 0.000 title claims description 105
- 239000000835 fiber Substances 0.000 claims abstract description 65
- 230000003287 optical effect Effects 0.000 claims abstract description 60
- 238000012545 processing Methods 0.000 claims abstract description 23
- 230000033001 locomotion Effects 0.000 claims abstract description 21
- 238000012544 monitoring process Methods 0.000 claims abstract description 16
- 238000005259 measurement Methods 0.000 claims description 21
- 230000035559 beat frequency Effects 0.000 claims description 11
- 230000008878 coupling Effects 0.000 claims description 7
- 238000010168 coupling process Methods 0.000 claims description 7
- 238000005859 coupling reaction Methods 0.000 claims description 7
- 230000010287 polarization Effects 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 description 14
- 238000004891 communication Methods 0.000 description 6
- 230000003321 amplification Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000003199 nucleic acid amplification method Methods 0.000 description 4
- 238000005070 sampling Methods 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/50—Systems of measurement based on relative movement of target
- G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The invention provides a large depth of field all-fiber laser Doppler velocimeter, which solves the problems that the existing laser Doppler velocimeter has small depth of field and cannot continuously measure the speed of a large-stroke moving object. The large-field-depth all-fiber laser Doppler velocimeter comprises a seed light source, an optical isolator, a first fiber beam splitter, a second fiber beam splitter, a seed light monitoring detector, a laser amplifier, a fiber circulator, a fiber online attenuator, an optical antenna, a fiber beam combiner, a balanced photoelectric detector, a data acquisition card and a signal processing system. In the large-depth-of-field all-fiber laser Doppler velocimeter disclosed by the invention, in the movement range of the object to be measured, which is as long as 30 meters, interference signals obtained by the fiber laser Doppler velocimeter are always in a stable state, and the movement speed of the object under the condition of large stroke can be continuously measured.
Description
Technical Field
The invention relates to the field of photoelectric transient test, in particular to the field of laser Doppler velocity and acceleration measurement, and particularly relates to a large-depth-of-field all-fiber laser Doppler velocimeter.
Background
The laser Doppler velocity measurement technology is a high-precision non-contact velocity measurement technology based on the optical Doppler effect, has the advantages of non-contact, electromagnetic interference resistance and the like, and is widely applied to various occasions. When the speed of a measured object is measured, particularly when a high-speed moving object is measured, the situation that the moving stroke of the measured object is long may exist, the conventional speed measuring means can only measure the moving speed in a short stroke, and the speed or acceleration change situation of the measured object in the whole moving process cannot be completely reflected; if the field depth range of the speed measuring instrument can be enlarged, the continuous speed and the acceleration change condition in the whole movement stroke of the measured object can be obtained at one time, the experimental device can help experimenters to accurately analyze the movement process of the measured object, and the experimental effect is improved.
In order to measure the movement speed with a large stroke, the laser Doppler velocimeter is required to have a larger measurement depth of field, the measurement depth of field of the velocimeter is ensured to cover the whole movement stroke of the measured object, and stable interference signals can be received in the whole movement stroke of the measured object.
A principle structure of a common fiber laser doppler velocimeter is shown in fig. 1, wherein laser emitted by a laser is divided into two paths, one path is used as reference light, and the other path is used as signal light; the signal light is transmitted spatially after passing through the optical fiber circulator and the optical antenna, reflected after being irradiated on the surface of the measured object, and reenters the optical antenna; because of the movement of the object to be measured, the signal light re-entering the optical antenna has Doppler frequency shift, and will beat frequency with the reference light at the optical fiber coupler to form interference signal, and the interference light signal is received by the photoelectric detector and processed and analyzed by the signal processing system, so that the movement speed of the object to be measured can be obtained. However, the conventional fiber laser doppler velocimeter is limited by the coupling loss of the optical antenna and the laser power, and generally has a small depth of field, which cannot satisfy the continuous velocity measurement of a large stroke of a measured object.
Disclosure of Invention
The invention aims to solve the problems that the existing laser Doppler velocimeter has small depth of field and cannot continuously measure the speed of a large-stroke moving object, and provides a large-depth-of-field all-fiber laser Doppler velocimeter which realizes the large-stroke continuous speed measurement of the measured object.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a large depth of field all-fiber laser Doppler velocimeter comprises a seed light source, an optical isolator, a first fiber beam splitter, a second fiber beam splitter, a seed light monitoring detector, a laser amplifier, a fiber circulator, a fiber online attenuator, an optical antenna, a fiber beam combiner, a balanced photoelectric detector, a data acquisition card and a signal processing system, wherein the optical antenna is a large depth of field optical antenna; the line width of continuous laser emitted by the seed light source is less than 100kHz, the seed light source is connected with a first optical fiber beam splitter through an optical isolator, and the first optical fiber beam splitter divides the laser into two beams of laser with different powers; one output port of the first optical fiber beam splitter is connected with the seed optical monitoring detector and used for monitoring the working state of the seed light source, and the other output port of the first optical fiber beam splitter is connected with the input port of the second optical fiber beam splitter; two output ports of the second optical fiber beam splitter are respectively connected with the laser amplifier and the optical fiber online attenuator, a light path connected with the laser amplifier is a measuring light path, and a light path connected with the optical fiber online attenuator is a reference light path; the optical fiber online attenuator can control the laser power of the reference light path to keep consistent with the laser power of the measurement light path; the output port of the laser amplifier is connected with the port a of the optical fiber circulator, the port b of the optical fiber circulator is connected with the optical antenna, a laser signal transmitted in the optical fiber is output by the optical antenna to become space light, the space light is emitted to the surface of an object to be measured, the laser signal reflected by the surface of the object to be measured is transmitted again by the optical antenna, enters the port b of the optical fiber circulator along the original propagation path and is transmitted to the port c of the optical fiber circulator; two input ports of the optical fiber beam combiner are respectively connected with an output port of the optical fiber online attenuator and a port c of the optical fiber circulator, and laser signals in the reference light path and the measurement light path generate beat frequency interference in the optical fiber beam combiner to form interference light signals; two output ports of the optical fiber beam combiner are respectively connected with two input ports of the balanced photoelectric detector to convert the interference optical signals into current signals; the output port of the balanced photoelectric detector is connected with the input port of the data acquisition card, and the current signal is converted into a digital signal; the data acquisition card inputs the acquired digital signals into the signal processing system to obtain the movement velocity distribution of the object to be measured.
Furthermore, the data acquisition card is connected with the general control computer through a trigger delay device, and the trigger delay device is used for controlling the data acquisition card to start to acquire data.
Furthermore, the trigger time delay device and the seed light source are connected with a general control computer through an RS232 signal line or an RS485 signal line; the signal processing system is respectively connected with the data acquisition card and the general control computer through a PCIE bus; the balance photoelectric detector is connected with the data acquisition card and the seed optical monitoring detector is connected with the general control computer through shielded signal lines, and other devices are connected through single-mode optical fibers or polarization-maintaining optical fibers.
Furthermore, the output power of the seed light source is more than 10mW, the laser line width after the amplification of the laser amplifier is less than 200kHz, the laser output energy is more than 1W, and the memory of the data acquisition card is more than 4 GB.
Further, the coupling ratio of the first optical fiber beam splitter and the second optical fiber beam splitter is set to be within the range of 99: 1-90: 10.
Further, the return loss of the optical fiber circulator is more than 50 dB.
Further, the coupling ratio of the optical fiber combiner is set to be 50: 50.
Further, the signal processing system is an FPGA, a DSP or an ARM.
Compared with the prior art, the invention has the following beneficial effects:
in the large-depth-of-field all-fiber laser Doppler velocimeter disclosed by the invention, in the movement range of the object to be measured, which is as long as 30 meters, interference signals obtained by the fiber laser Doppler velocimeter are always in a stable state, and the movement speed of the object under the condition of large stroke can be continuously measured.
Drawings
FIG. 1 is a schematic structure diagram of a conventional fiber laser Doppler velocimeter;
fig. 2 is a schematic diagram of the large depth-of-field all-fiber laser doppler velocimeter of the present invention.
Reference numerals: 1-a seed light source, 2-an optical isolator, 3-a first optical fiber beam splitter, 4-a second optical fiber beam splitter, 5-a laser amplifier, 6-an optical fiber circulator, 7-an optical antenna, 8-an optical fiber online attenuator, 9-an optical fiber beam combiner, 10-a balanced photoelectric detector, 11-a data acquisition card, 12-a seed light monitoring detector, 13-a trigger delay device, 14-a signal processing system, 15-a general control computer, 16-a single-mode optical fiber or a polarization maintaining optical fiber, 17-a shielding signal line, 18-a PCIE bus, and 19-an RS232 signal line or an RS485 signal line.
Detailed Description
The invention is described in further detail below with reference to the figures and specific embodiments.
The invention provides a large depth of field all-fiber laser Doppler velocimeter, which is characterized in that in the motion range of a measured object up to 30 meters, interference signals obtained by the fiber laser Doppler velocimeter are always in a stable state, and the motion speed of the object can be continuously measured under the condition of large travel.
As shown in fig. 2, the large depth of field all-fiber laser doppler velocimeter of the present invention includes a seed light source 1, an optical isolator 2, a first fiber splitter 3, a second fiber splitter 4, a seed light monitoring detector 12, a laser amplifier 5, a fiber circulator 6, an optical fiber online attenuator 8, an optical antenna 7, a fiber combiner 9, a balanced photodetector 10, a trigger delay device 13, a data acquisition card 11, a signal processing system 14, and a general control computer 15, and the working principle and the connection relationship of each component of the large depth of field all-fiber laser doppler velocimeter are as follows:
firstly, a seed light source 1 emits a beam of continuous laser with the line width less than 100 kHz;
the output end of the seed light source 1 is connected with the input end of the optical isolator 2, and the optical isolator 2 is used for preventing light in the optical fiber from reversely transmitting and entering the seed light source 1;
the output end of the optical isolator 2 is connected with a first optical fiber beam splitter 3, and the first optical fiber beam splitter 3 divides the laser into two beams of laser with different powers;
one output port of the first optical fiber beam splitter 3 is connected with a seed light monitoring detector 12, and the detector is used for monitoring the working state of the seed light source 1 and checking whether the seed light source 1 emits light normally; the other output port of the first optical fiber beam splitter 3 is connected with the input port of the second optical fiber beam splitter 4;
two output ports of the second optical fiber beam splitter 4 are respectively connected with the laser amplifier 5 and the optical fiber online attenuator 8, the optical path connected with the laser amplifier 5 is called a measurement optical path, and the optical path connected with the optical fiber online attenuator 8 is called a reference optical path; the optical fiber online attenuator 8 can control the laser power of the reference light path to keep consistent with the laser power of the measurement light path;
the output port of the laser amplifier 5 is connected with the port a of the optical fiber circulator 6, and the port b of the optical fiber circulator 6 is connected with the optical antenna 7; the laser signal transmitted in the optical fiber is output by the optical antenna 7 to become space light which is directly emitted to the surface of the object to be measured;
the laser signal reflected by the surface of the measured object reenters the optical fiber for transmission through the optical antenna 7, enters the port b of the optical fiber circulator 6 along the original propagation path, and is transmitted to the port c of the optical fiber circulator 6;
two input ports of the optical fiber combiner 9 are respectively connected with an output port of the optical fiber online attenuator 8 and a port c of the optical fiber circulator 6, therefore, laser signals in the reference light path and the measurement light path undergo beat frequency interference in the optical fiber combiner 9 to form interference light signals, and the laser signals in the reference light path and the measurement light path are respectively expressed as:
wherein, ω is1And ω2Respectively representing the laser frequencies of the reference and measurement paths,
and
respectively representing the laser phases of the reference optical path and the measurement optical path, the interfered interference optical signal can be represented as:
⑨ the two output ports of the optical fiber combiner 9 are connected with the two input ports of the balanced photodetector 10 respectively to convert the interference light signal into current signal, and only the equation (2) is the square law effect of the balanced photodetector 10
One term can be responded to by the balanced photodetector 10, and the remaining terms are filtered out by the balanced photodetector 10 in the form of dc noise, so that the current signal of the output of the balanced photodetector 10 can be expressed as:
wherein η denotes the photoelectric conversion efficiency of the balanced photodetector 10, E1Denotes the amplitude of the reference light, t denotes time, E2Represents the amplitude of the signal light;
the output port of the charge right photodetector 10 is connected to the input port of a data acquisition card 11, converts the current signal into a digital signal,
wherein λ represents the output laser wavelength of the laser doppler velocimeter.
The velocimeter of the invention adopts the seed light source 1 with narrower line width and the laser amplifier 5 with smaller laser line width broadening, so the coherence length corresponding to the laser signal output by the optical antenna 7 is longer (usually more than 1km), and the effective beat frequency can be realized within the detection range of 30 meters, thereby the velocimeter of the invention can realize the continuous speed measurement of large stroke.
The internal memory of the velocimeter data acquisition card 11 is large, generally more than 4GB, the arrangement enables the data transmission rate to be fast, and the caching and the unloading of the acquired data can be fast realized, so that the long-time continuous acquisition of beat frequency interference signals can be realized, and the velocimeter can realize the continuous speed measurement of a large stroke.
The optical antenna 7 of the velocimeter adopts a unique optical design structure, particularly adopts a large depth-of-field optical antenna with application publication number CN 110716064A, adopts a convergent structure for the whole optical path of the optical antenna 7, and arranges the beam waist position of laser at the farthest moving end of a measured object, namely 30 meters; therefore, when the object to be measured moves from near to far, the loss caused by the increase of the laser transmission distance is gradually increased, and the loss caused by the reduction of the receiving efficiency of the optical antenna 7 is gradually reduced, so that the echo signals received by the optical antenna 7 are basically consistent within the detection range of 30 meters, and continuous measurement with a large stroke can be realized.
In the large-depth-of-field all-fiber laser Doppler velocimeter, the line width of the laser output by the seed light source 1 is narrow, the coherence length is longer, and the laser signals can be ensured to interfere in a detection range of 30 meters; the output power of the seed light source 1 is usually more than 10mW, the line width is less than 100kHz, the laser line width is less than 200kHz after the amplification of the laser amplifier 5, and the laser output energy is more than 1W.
In the large-depth-of-field all-fiber laser Doppler velocimeter, the balance detector can filter low-frequency direct current noise below 1Hz caused by fiber vibration or environmental change, effectively reduce noise interference and improve the signal-to-noise ratio; meanwhile, the balance detector has an amplification effect of 3dB on the alternating current signal, and the echo signal received by the laser Doppler velocimeter belongs to the alternating current signal, so that the echo signal can be amplified by the balance detector, and the strength of the received signal can be improved by the balance detector.
In the large-depth-of-field all-fiber laser Doppler velocimeter, the coupling ratio of the first fiber beam splitter 3 and the second fiber beam splitter 4 is usually set to be in the range of 99:1 to 90: 10; the return loss of the fiber optic circulator 6 should typically be > 50 dB; the coupling ratio of the optical combiner 9 is typically set to 50: 50.
In the large-depth-of-field all-fiber laser Doppler velocimeter, the trigger delay device 13 and the seed light source 1 are specifically connected with a general control computer 15 through an RS232 signal line or an RS485 signal line 19. The RS232 signal line and the RS485 signal line have high communication stability, and the phenomenon of communication interruption or communication packet loss is not easy to occur; and 2, the RS232 signal line and the RS485 signal line belong to serial port communication, the communication protocol is simple, the development difficulty and the cost are relatively low, and the equipment cost and the development period can be effectively reduced.
In the large depth of field all-fiber laser doppler velocimeter of the present invention, the signal processing system 14 is connected with the data acquisition card 11 and the general control computer 15 through the PCIE bus 18 respectively. The laser Doppler velocimeter can continuously acquire laser signals at a high sampling rate for a long time, so that the data volume obtained by the data acquisition card 11 is extremely large, the data transmission rate of the PICE bus is extremely high, and all data in the memory of the data acquisition card 11 can be transferred to an upper computer for processing in a short time, so that the data processing speed of the laser Doppler velocimeter designed by the invention can be effectively improved; meanwhile, the data acquisition card 11 for data transmission by the PCIE bus 18 can directly install the PICE interface in the PCIE slot of the upper computer, so that the overall size of the equipment can be saved, the system integration level is improved, in addition, when the data transmission is carried out by the PCIE bus 18, the transmission link is short, the signal amplitude attenuation and noise increase caused in the transmission process of signals through cables can be effectively reduced, and the signal quality is improved.
In the large-depth-of-field all-fiber laser Doppler velocimeter, the balanced photoelectric detector 10 and the data acquisition card 11, and the seed light monitoring detector 12 and the general control computer 15 are connected through the shielding signal line 17, and the shielding signal line 17 can effectively isolate electromagnetic interference in the environment, thereby ensuring that the amplitude of signals is not attenuated and the noise is not increased in the transmission process of signals at all levels, and effectively improving the signal-to-noise ratio of final signals.
In the large depth of field all-fiber laser Doppler velocimeter of the invention, other devices are connected through a single mode fiber or a polarization maintaining fiber 16. Compared with the multimode fiber, the transmission loss of the laser signal in the single-mode fiber or the polarization maintaining fiber 16 is lower, so that the amplitude of the signal reaching the detector is larger, and the receiving of the detector is facilitated; meanwhile, the single-mode fiber or the polarization maintaining fiber 16 can ensure that the frequency and the mode of the laser transmitted inside the fiber are unchanged, so that the beat frequency interference can normally occur on the laser signals at the two input ports of the fiber combiner 9, while when the multimode fiber is adopted, the beat frequency interference cannot normally occur due to the change of the frequency and the mode of the laser transmitted inside the fiber, or the signal frequency shifts after the beat frequency interference occurs, which causes measurement errors.
The large-field-depth all-fiber laser Doppler velocimeter of the invention is applied to wind tunnel experiments.
Firstly, fixing an optical antenna 7 at an observation window of a wind tunnel;
secondly, a main power supply of the equipment is turned on to supply power to the seed light source 1, the laser amplifier 5, the balanced photoelectric detector 10, the seed light monitoring detector 12, the trigger delay device 13, the data acquisition card 11, the signal processing system 14 and the main control computer 15, control software is turned on, the communication function among the equipment is started, and the main control computer 15 can monitor the working states of other equipment in real time;
inputting laser power to the seed light source 1 and the laser amplifier 5, inputting sampling time, sampling time before triggering and sampling time after triggering to the data acquisition card 11, and inputting delay time after triggering to the triggering delay device 13 in the control software, then clicking a 'start working' button in the control software, wherein the system is in a waiting state, and the equipment starts working after the wind tunnel gives a triggering signal;
fourthly, after the object to be measured starts to move, a sensor in the wind tunnel gives out a trigger signal, and the trigger delay device 13 controls the data acquisition card 11 to start to acquire data after receiving the trigger signal; at the moment, laser emitted by the seed light source 1 is divided into two beams after passing through the optical isolator 2 and the first optical fiber beam splitter 3, and one beam enters the seed light monitoring detector 12 through the single-mode optical fiber and is used for monitoring the working state of the seed light source 1; the other beam enters a second optical fiber beam splitter 4 through the single-mode optical fiber;
at the second optical fiber beam splitter 4, laser is continuously split into two beams, one beam enters a laser amplifier 5 through a single mode optical fiber for amplification, the other beam enters an optical fiber on-line attenuator 8 through the single mode optical fiber, and enters an optical fiber beam combiner 9 through the single mode optical fiber;
the laser amplified by the laser amplifier 5 enters the optical fiber circulator 6 through the single-mode optical fiber and enters the optical antenna 7 through the single-mode optical fiber, and a laser signal is converted into space transmission from the transmission in the optical fiber and is emitted to the surface of the object to be measured;
seventhly, the laser emitted to the surface of the measured object is reflected, received by the optical antenna 7 and continuously converted into optical fiber transmission from space transmission; the single mode fiber enters the fiber circulator 6 and then enters the fiber combiner 9;
due to the movement of the object to be measured, the laser signals received by the optical antenna 7 have Doppler frequency shift, so that the laser signals of the two input ports of the optical fiber beam combiner 9 generate beat frequency phenomena and carry the movement information of the object to be measured;
ninthly, enabling beat frequency signals to enter the balance photoelectric detector 10 through the single-mode optical fiber from two output ports of the optical fiber combiner 9, and after the balance photoelectric detector 10 completes photoelectric conversion, acquiring output current signals by the data acquisition card 11 through the shielding signal line 17 and converting the output current signals into digital signals;
after the acquisition of the data acquisition card 11 at the time of the vehicle (R), transmitting the digital signal to a signal processing system 14 through a PCIE bus 18 for processing, and acquiring the movement velocity distribution of the object to be measured;
Claims (8)
1. The utility model provides a big depth of field full fiber laser doppler velocimeter which characterized in that: the device comprises a seed light source (1), an optical isolator (2), a first optical fiber beam splitter (3), a second optical fiber beam splitter (4), a seed light monitoring detector (12), a laser amplifier (5), an optical fiber circulator (6), an optical fiber online attenuator (8), an optical antenna (7), an optical fiber beam combiner (9), a balanced photoelectric detector (10), a data acquisition card (11) and a signal processing system (14), wherein the optical antenna (7) is a large depth-of-field optical antenna;
the line width of continuous laser emitted by the seed light source (1) is less than 100kHz, the seed light source (1) is connected with a first optical fiber beam splitter (3) through an optical isolator (2), and the first optical fiber beam splitter (3) divides the laser into two beams of laser with unequal power; one output port of the first optical fiber beam splitter (3) is connected with the seed optical monitoring detector (12) to monitor the working state of the seed light source (1), and the other output port is connected with the input port of the second optical fiber beam splitter (4);
two output ports of the second optical fiber beam splitter (4) are respectively connected with the laser amplifier (5) and the optical fiber online attenuator (8), a light path connected with the laser amplifier (5) is a measuring light path, and a light path connected with the optical fiber online attenuator (8) is a reference light path; the optical fiber online attenuator (8) is used for controlling the laser power of the reference light path to keep consistent with the laser power of the measurement light path;
the output port of the laser amplifier (5) is connected with the port a of the optical fiber circulator (6), the port b of the optical fiber circulator (6) is connected with the optical antenna (7), a laser signal transmitted in the optical fiber is output by the optical antenna (7) to become space light, the space light is emitted to the surface of a measured object, the laser signal reflected by the surface of the measured object is transmitted again by the optical antenna (7), enters the port b of the optical fiber circulator (6) along the original propagation path and is transmitted to the port c of the optical fiber circulator (6);
two input ports of the optical fiber beam combiner (9) are respectively connected with an output port of the optical fiber online attenuator (8) and a port c of the optical fiber circulator (6), and laser signals in a reference light path and a measurement light path generate beat frequency interference in the optical fiber beam combiner (9) to form interference light signals;
two output ports of the optical fiber beam combiner (9) are respectively connected with two input ports of the balanced photoelectric detector (10) to convert interference optical signals into current signals;
the output port of the balanced photoelectric detector (10) is connected with the input port of a data acquisition card (11) to convert the current signal into a digital signal; the data acquisition card (11) inputs the acquired digital signals into the signal processing system (14) to obtain the motion velocity distribution of the object to be measured.
2. The large depth-of-field all-fiber laser doppler velocimeter of claim 1, wherein: the data acquisition card (11) is connected with the general control computer (15) through a trigger delay device (13), and the trigger delay device (13) is used for controlling the data acquisition card (11) to start to acquire data.
3. The large depth-of-field all-fiber laser doppler velocimeter of claim 2, wherein: the trigger time delay device (13) and the seed light source (1) are connected with a general control computer (15) through an RS232 signal line or an RS485 signal line (19); the signal processing system (14) is respectively connected with the data acquisition card (11) and the general control computer (15) through a PCIE bus (18); the balance photoelectric detector (10) is connected with the data acquisition card (11), the seed optical monitoring detector (12) is connected with the general control computer (15) through a shielding signal line (17), and other devices are connected through a single-mode optical fiber or a polarization maintaining optical fiber (16).
4. The large depth-of-field all-fiber laser doppler velocimeter of claim 1, 2 or 3, wherein: the output power of the seed light source (1) is more than 10mW, the laser line width is less than 200kHz after the seed light source is amplified by the laser amplifier (5), the laser output energy is more than 1W, and the internal memory of the data acquisition card (11) is more than 4 GB.
5. The large depth-of-field all-fiber laser doppler velocimeter of claim 4, wherein: the coupling ratio of the first optical fiber beam splitter (3) to the second optical fiber beam splitter (4) is set to be 99: 1-90: 10.
6. The large depth-of-field all-fiber laser doppler velocimeter of claim 5, wherein: the return loss of the optical fiber circulator (6) is more than 50 dB.
7. The large depth-of-field all-fiber laser doppler velocimeter of claim 6, wherein: the coupling ratio of the optical fiber combiner (9) is set to be 50: 50.
8. The large depth-of-field all-fiber laser doppler velocimeter of claim 7, wherein: the signal processing system (14) is an FPGA, a DSP or an ARM.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010530213.0A CN111665519A (en) | 2020-06-11 | 2020-06-11 | Large field depth full optical fiber laser Doppler velocimeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010530213.0A CN111665519A (en) | 2020-06-11 | 2020-06-11 | Large field depth full optical fiber laser Doppler velocimeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111665519A true CN111665519A (en) | 2020-09-15 |
Family
ID=72386575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010530213.0A Pending CN111665519A (en) | 2020-06-11 | 2020-06-11 | Large field depth full optical fiber laser Doppler velocimeter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111665519A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116298382A (en) * | 2023-05-17 | 2023-06-23 | 山东省科学院海洋仪器仪表研究所 | All-fiber photon counting coherent Doppler ocean flow field velocity measurement system |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5272513A (en) * | 1991-12-06 | 1993-12-21 | Optical Air Data Systems, L.P. | Laser doppler velocimeter |
| US5835199A (en) * | 1996-05-17 | 1998-11-10 | Coherent Technologies | Fiber-based ladar transceiver for range/doppler imaging with frequency comb generator |
| CN102419442A (en) * | 2011-09-06 | 2012-04-18 | 中国工程物理研究院流体物理研究所 | Double source laser interference velocity measurement system |
| CN205374743U (en) * | 2015-09-22 | 2016-07-06 | 中国科学院上海技术物理研究所 | Relevant homodyne doppler of optics quadrature demodulation laser radar system that tests speed |
| CN107783144A (en) * | 2017-10-30 | 2018-03-09 | 南京牧镭激光科技有限公司 | Windfinding laser radar apparatus |
| CN108802756A (en) * | 2018-08-09 | 2018-11-13 | 常州信息职业技术学院 | A kind of full optical fiber laser Doppler range rate measuring system based on acousto-optic null coupler |
| CN109116371A (en) * | 2018-07-23 | 2019-01-01 | 中国科学院半导体研究所 | Doppler speed radar based on two-wavelength semiconductor laser |
| CN110261644A (en) * | 2018-07-27 | 2019-09-20 | 成都信息工程大学 | A kind of airborne measuring wind speed laser radar system |
| CN110716064A (en) * | 2019-10-12 | 2020-01-21 | 中国科学院西安光学精密机械研究所 | Large depth-of-field optical antenna device applied to optical fiber Doppler velocimeter |
-
2020
- 2020-06-11 CN CN202010530213.0A patent/CN111665519A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5272513A (en) * | 1991-12-06 | 1993-12-21 | Optical Air Data Systems, L.P. | Laser doppler velocimeter |
| US5835199A (en) * | 1996-05-17 | 1998-11-10 | Coherent Technologies | Fiber-based ladar transceiver for range/doppler imaging with frequency comb generator |
| CN102419442A (en) * | 2011-09-06 | 2012-04-18 | 中国工程物理研究院流体物理研究所 | Double source laser interference velocity measurement system |
| CN205374743U (en) * | 2015-09-22 | 2016-07-06 | 中国科学院上海技术物理研究所 | Relevant homodyne doppler of optics quadrature demodulation laser radar system that tests speed |
| CN107783144A (en) * | 2017-10-30 | 2018-03-09 | 南京牧镭激光科技有限公司 | Windfinding laser radar apparatus |
| CN109116371A (en) * | 2018-07-23 | 2019-01-01 | 中国科学院半导体研究所 | Doppler speed radar based on two-wavelength semiconductor laser |
| CN110261644A (en) * | 2018-07-27 | 2019-09-20 | 成都信息工程大学 | A kind of airborne measuring wind speed laser radar system |
| CN108802756A (en) * | 2018-08-09 | 2018-11-13 | 常州信息职业技术学院 | A kind of full optical fiber laser Doppler range rate measuring system based on acousto-optic null coupler |
| CN110716064A (en) * | 2019-10-12 | 2020-01-21 | 中国科学院西安光学精密机械研究所 | Large depth-of-field optical antenna device applied to optical fiber Doppler velocimeter |
Non-Patent Citations (3)
| Title |
|---|
| 王希涛等: "高精度1.55μm全光纤激光相干测速实验及数据分析", 《激光与光电子学进展》 * |
| 白蕊霞等: "激光多普勒测速雷达技术研究现状", 《激光与红外》 * |
| 陈震等: "全光纤相干多普勒连续激光风速仪研究", 《量子电子学报》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116298382A (en) * | 2023-05-17 | 2023-06-23 | 山东省科学院海洋仪器仪表研究所 | All-fiber photon counting coherent Doppler ocean flow field velocity measurement system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106940444B (en) | Coherent Doppler wind-observation laser radar based on microwave differential gain | |
| CN101634571B (en) | Optical pulse raster distributed fiber sensing device | |
| CN101893475B (en) | A kind of distributed optical fiber vibration sensing system based on fiber delay line | |
| CN108534686B (en) | Zero-drift-free heterodyne laser Doppler measurement optical fiber light path and measurement method | |
| CN104236697A (en) | Distributed optical fiber vibration detection method and system based on wavelength division multiplexing | |
| CN110501062B (en) | Distributed optical fiber sound sensing and positioning system | |
| CN103017887A (en) | Optical fiber vibration sensing system and detection method thereof | |
| CN103984184A (en) | Light pulse compression reflecting device | |
| CN103487133B (en) | Method and device for improving signal-to-noise ratio of laser micro-vibration sensing system | |
| CN104199044A (en) | Dual-mode superspeed moving object movement speed measurement device and method | |
| CN111007526B (en) | System and method for suppressing optical noise of continuous wave all-fiber coherent Doppler laser speed measurement radar | |
| CN104296783A (en) | Sensor detecting method and device for enhanced coherent optical time domain reflection | |
| CN102401691B (en) | All-fibre laser Doppler three-dimensional vibration meter | |
| CN103900623A (en) | Optical time domain reflectometer based on double acoustic-optical modulators and common-mode rejection method of optical time domain reflectometer | |
| CN109120337A (en) | A kind of few mould time-domain reflectomer | |
| CN112923959B (en) | System for improving sensing distance of phase-sensitive optical time domain reflectometer | |
| CN212030564U (en) | Light source frequency shift calibration auxiliary channel structure and optical fiber vibration measuring device | |
| CN205120239U (en) | Vibration detection device based on optical frequency domain reflectometer | |
| CN101581586B (en) | Distributed optical fiber sagnac positioning sensor inhibiting dead zone of sensor | |
| CN111665519A (en) | Large field depth full optical fiber laser Doppler velocimeter | |
| CN107064539A (en) | A kind of big visual field photon Doppler speed measuring device and method | |
| CN102419442B (en) | Double source laser interference velocity measurement system | |
| CN203443662U (en) | Device for improving signal-to-noise ratio of laser micro-vibration sensing system | |
| CN104180832A (en) | Distributed orthogonal vector disturbance sensing system based on four-core optical fiber | |
| CN110635841B (en) | Method and device for improving echo signal of chaotic optical time domain reflectometer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200915 |