CN211668646U

CN211668646U - System for measuring laser wavelength in real time

Info

Publication number: CN211668646U
Application number: CN202020131821.XU
Authority: CN
Inventors: 郭瑞民; 董贺伟; 李东
Original assignee: National Institute of Metrology
Current assignee: National Institute of Metrology
Priority date: 2020-01-20
Filing date: 2020-01-20
Publication date: 2020-10-13
Anticipated expiration: 2030-01-20

Abstract

The application provides a system for measuring laser wavelength in real time, relates to the technical field of laser measurement, and aims to provide a system for simply and accurately measuring the wavelength of a laser in real time. The method comprises the following steps: the photoelectric detector comprises a light splitting structure (1), a parallel flat plate (2), a first photoelectric detector group (3), a second photoelectric detector group (4), a first amplifying circuit (5), a second amplifying circuit (6) and a data acquisition device (7). A plurality of beams of incident light are arranged through the light splitting structure (1), the plurality of beams of incident light form a plurality of groups of data after passing through the parallel flat plate (2), the data acquisition device (7) processes the plurality of groups of data to obtain the ratio of the light intensity of a plurality of reflected lights to the light intensity of the transmitted light, and the wavelength of the emergent laser is determined by combining the current temperature of the laser.

Description

System for measuring laser wavelength in real time

Technical Field

The application relates to the technical field of laser measurement, in particular to a system for measuring laser wavelength in real time.

Background

The laser has wide application in the fields of optical communication, gaseous sample detection, medical instrument manufacturing, intelligent transportation and the like. In the above laser applications, a laser wavelength measuring operation is required. For example, when detecting the structure of gas atoms, molecules, and many other substances in a cavity using a compact CRDS (cavity ring-down spectroscopy), it is necessary to determine the wavelength of laser light incident on the CRDS.

Conventional spectrum or wavemeter measurements can incur significant time and equipment cost. In addition, in the existing laser wavelength measuring technology, the wavelength needs to be obtained by determining the interference level or the variation of the interference level, or the laser wavelength is calculated by measuring the throughput of the interference rings and the variation of the resonant cavity length.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, embodiments of the present application provide a system for measuring laser wavelength in real time, aiming to simply and accurately measure the wavelength of laser light generated by a laser in real time.

The embodiment of the application provides a system for measuring laser wavelength in real time, include: the device comprises a light splitting structure, a parallel flat plate, a first photoelectric detector group, a second photoelectric detector group, a first amplifying circuit, a second amplifying circuit and a data acquisition device;

the data acquisition device is connected with the laser through the laser controller and is used for reading the temperature of the laser;

the light splitting structure is connected with the laser and is used for splitting emergent laser generated by the laser into a plurality of incident lights and enabling the plurality of incident lights to be incident on the parallel flat plate at different target angles;

the first photoelectric detector group and the second photoelectric detector group are respectively used for collecting first light intensity of a plurality of reflected light convergence points and second light intensity of a plurality of transmitted light convergence points; the reflected light collection point and the transmitted light collection point are collection points of a plurality of reflected lights or a plurality of transmitted lights obtained after one incident light in the plurality of incident lights passes through the parallel flat plate;

the first photoelectric detector group and the second photoelectric detector group respectively convert the collected multiple first light intensities and multiple second light intensities into multiple first current signals and multiple second current signals;

the first amplifying circuit and the second amplifying circuit convert the plurality of first current signals and the plurality of second current signals into a plurality of first voltage signals and a plurality of second voltage signals, respectively;

the data acquisition device calculates to obtain a ratio set of the first voltage signals and the second voltage signals, and calculates to obtain a wavelength value set of the emergent laser according to the ratio set;

the data acquisition device obtains a wavelength interval of the emergent laser according to a corresponding relation between a prestored reference wavelength and the temperature of the laser;

and the data acquisition device determines the wavelength of the emergent laser in the wavelength value set according to the wavelength interval.

Optionally, the data acquisition device comprises a computer and a data acquisition card;

the laser is connected with the computer through the laser controller;

the computer adjusts and reads the temperature of the laser through the laser controller;

the computer obtains the measured reference wavelength of the laser emitted at different temperatures and the corresponding relation between the reference wavelength and the temperature of the laser;

the computer stores a correspondence of the reference wavelength to the temperature of the laser.

Optionally, the laser is connected to a fabry-perot interferometer, a mach-zehnder interferometer, or a michelson interferometer;

measuring the reference wavelength of the emergent laser of the laser at different temperatures by using the Fabry-Perot interferometer, the Mach-Zehnder interferometer or the Michelson interferometer;

the computer stores reference wavelengths corresponding to different temperatures.

Optionally, the light splitting structure comprises a spatial light coupler, a planar mirror group, a first 1/2 wave plate, a second 1/2 wave plate, a first PBS prism and a second PBS prism;

the spatial light coupler couples the emergent laser light into spatial light, and the spatial light is made to enter a first light splitting assembly formed by the first 1/2 wave plate and the first PBS prism;

the first light splitting assembly splits the space light into first incident light and parallel light, and the parallel light is incident to a second light splitting assembly formed by the second 1/2 wave plate and the second PBS prism;

the second light splitting component splits the parallel light into second incident light and third incident light;

the plane mirror group is used for adjusting the light paths of the first incident light, the second incident light and the third incident light, enabling the first incident light to enter the parallel flat plate at a first target angle, enabling the second incident light to enter the parallel flat plate at a second target angle and enabling the third incident light to enter the parallel flat plate at a third target angle;

the phase difference of any two of the first target angle, the second target angle and the third target angle with respect to a measurement curve is 120 degrees.

Optionally, the first set of photodetectors comprises a first photodetector, a second photodetector, and a third photodetector; the second photodetector group comprises a fourth photodetector, a fifth photodetector and a sixth photodetector;

the first photoelectric detector and the fourth photoelectric detector are respectively used for collecting the light intensity of a first reflected light convergence point and the light intensity of a first transmitted light convergence point; the first incident light enters the parallel flat plate at a first target angle, and is continuously transmitted and reflected by the parallel flat plate to obtain a plurality of first reflected light beams and a plurality of first transmitted light beams;

the second photoelectric detector and the fifth photoelectric detector are respectively used for collecting the light intensity of a second reflected light convergence point and the light intensity of a second transmitted light convergence point; the second incident light enters the parallel flat plate at a second target angle, and is continuously transmitted and reflected by the parallel flat plate to obtain a plurality of second reflected light beams and a plurality of second transmitted light beams;

the third photoelectric detector and the sixth photoelectric detector are respectively used for collecting the light intensity of a third reflected light convergence point and the light intensity of a third transmitted light convergence point; and the third incident light enters the parallel flat plate at a third target angle, and is continuously transmitted and reflected by the parallel flat plate to obtain a plurality of third reflected light beams and a plurality of third transmitted light beams.

Optionally, the system further comprises three first convex lenses and three second convex lenses;

the three first convex lenses are arranged in the incident light area of the parallel flat plate and are used for converging a plurality of first reflected light beams, or converging a plurality of second reflected light beams, or converging a plurality of third reflected light beams;

the three second convex lenses are arranged in the emergent light area of the parallel flat plate and used for converging a plurality of first transmission lights, or converging a plurality of second transmission lights, or converging a plurality of third transmission lights.

Optionally, the first amplifying circuit and the second amplifying circuit each include a signal amplifying circuit and a filter circuit;

the signal amplification circuit is connected with the first photoelectric detector group or the second photoelectric detector group and is used for converting the first current signal into a first voltage signal or converting the second current signal into a second voltage signal;

the signal amplification circuit amplifies the first voltage signal or the second voltage signal and then transmits the amplified first voltage signal or the amplified second voltage signal to the filter circuit;

the filter circuit is connected with the data acquisition card and sends the first voltage signal or the second voltage signal after noise filtration to the data acquisition card.

Optionally, the signal amplifying circuit is a pre-T type amplifying network;

the preposed T-shaped amplifying network comprises an amplifier, a capacitor and a plurality of resistors;

the filter circuit is an instrument amplifier consisting of a plurality of amplifiers;

the amplification factor of the instrument amplifier is a preset amplification factor.

Optionally, the data acquisition card acquires the plurality of first voltage signals and the plurality of second voltage signals N times;

the data acquisition card sends the acquired first voltage signals acquired for multiple N times and the acquired second voltage signals acquired for multiple N times to the computer;

the computer averages the first voltage signals acquired for N times and the second voltage signals acquired for N times to obtain the average values of the first voltage signals and the second voltage signals;

the computer calculates the ratio of the average value of the first voltage signals to the average value of the second voltage signals;

the computer obtains a value subset of the wavelength of the emergent laser according to the ratio of any one of the average values of the first voltage signals to any one of the average values of the second voltage signals;

and the computer combines the plurality of value sub-sets to obtain a value set of the wavelength of the emergent laser.

Optionally, the computer reads the current temperature of the laser according to the laser controller;

the computer obtains a wavelength interval of the emergent laser according to the corresponding relation between the current temperature of the laser and the temperature of the reference wavelength and the laser;

the computer judges whether an element in a ratio set of the first voltage signals and the second voltage signals is in an extreme value position or not at the current temperature;

if the ratio set does not have the element at the extreme value position, calculating to obtain a wavelength value set of the emergent laser according to all the elements in the ratio set;

if the elements at the extreme position exist in the ratio set, calculating to obtain a wavelength value set of the emergent laser according to other elements except the elements at the extreme position in the ratio set;

The system for measuring the laser wavelength in real time provided by the embodiment of the application is based on the parallel flat plate interference principle, and after the outgoing laser passes through the same parallel flat plate, the light intensity of the obtained reflected light and the light intensity of the transmitted light are collected by the photoelectric detector, the ratio of the light intensity of the reflected light to the light intensity of the transmitted light is obtained through calculation, and the wavelength of the outgoing laser of the current laser is obtained by combining the temperature of the current laser. The wavelength measurement adopts the ratio of the light intensity of reflected light to the light intensity of transmitted light, is irrelevant to the intensity of laser, can measure the wavelength of emergent laser at any time when the laser is excited by a laser, is not influenced by the stability of the laser, and realizes the real-time monitoring of the laser wavelength.

In addition, the system for measuring the laser wavelength in real time provided by the embodiment of the application can be used for simultaneously acquiring multiple groups of data aiming at the same emergent laser, so that the accuracy of laser wavelength measurement is improved.

Drawings

FIG. 1 is a schematic view of incident light passing through a parallel plate in an embodiment of the present application;

FIG. 2 is a graph of a simulation of a function of the ratio of reflected light intensity to transmitted light intensity for an embodiment of the present application;

FIG. 3 is a schematic diagram of a system for measuring laser wavelength in real time according to an embodiment of the present application;

FIG. 4 is a graph of the temperature of a laser and the reference wavelength of the laser in an embodiment of the present application;

FIG. 5 is a graph of the ratio of reflected light to incident light versus wavelength measured in an embodiment of the present application;

fig. 6 is a schematic diagram of a first amplification circuit and a second amplification circuit according to an embodiment of the present application.

Reference numerals: 1. a light splitting structure; 11. a spatial light coupler; 12. a planar lens group; 13. a first 1/2 wave plate; 14. a second 1/2 wave plate; 15. a first PBS prism; 16. a second PBS prism; 2. parallel plates; 21. a first convex lens; 22. a second convex lens; 3. a first set of photodetectors; 31. a first photodetector; 32. a second photodetector; 33. a third photodetector; 4. a second set of photodetectors; 41. a fourth photodetector; 42. a fifth photodetector; 43. a sixth photodetector; 5. a first amplifying circuit; 51. a signal amplification circuit; 52. a filter circuit; 6. a second amplifying circuit; 7. a data acquisition device; 71. a data acquisition card; 72. a computer; 8. a laser controller.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is described in further detail with reference to the accompanying drawings and the detailed description.

The method for measuring the laser wavelength by determining the interference level or the interference level variation of the existing laser wavelength measuring device can measure the laser wavelength only when the laser wavelength is stable, and inevitably generates errors when determining the interference level or the interference level variation and needs to repeatedly measure for many times. Meanwhile, the whole device is large in size and inconvenient to carry.

The wavelength of light is determined by measuring the ratio of the light intensity of reflected light of an incident light domain of the parallel flat plate to the light intensity of transmitted light of a transmitted light domain by utilizing the principle of multi-beam interference of the parallel flat plate.

Referring to fig. 1, fig. 1 is a schematic diagram of incident light passing through a parallel plate in an embodiment of the present application.

A convex lens L is placed in the incident light region of the parallel plate, and a convex lens L' is placed in the transmission light region.

When a beam of laser light of a light source omega enters a parallel flat plate, the laser light continuously transmits and reflects in the parallel flat plate, a plurality of beams of reflected light and a plurality of beams of transmitted light are emitted from two sides of the flat plate, and the plurality of beams of reflected light and the plurality of beams of transmitted light are focused on one point P and one point P 'respectively by utilizing a convex lens L and a convex lens L'. The light intensity of the reflected light at point P is:

the light intensity of the transmitted light at P' is:

wherein, I^(r)Is the intensity of reflected light, I⁽ⁱ⁾Is the intensity of incident light, I^(t)F is a constant relating to the reflectance of the parallel plate, and is the relationship between the wavelength of the incident laser light entering the parallel plate and the refraction angle of the laser light after it is incident on the parallel plate.

In the above formula, λ is the wavelength of the incident laser, h is the thickness of the parallel plate, and θ₂For incident laser light at theta₁The angle of refraction within the parallel plates after incidence on the parallel plates, ρ, is the square of the reflectivity.

The ratio R of the reflected light intensity of the point P to the transmitted light intensity of the point P' can be obtained:

as can be seen from the above equation and FIG. 2, FIG. 2 is a simulation graph of the ratio function of the reflected light intensity and the transmitted light intensity of the embodiment of the present application. The dashed, solid and dotted lines in fig. 2 represent three sinusoidal curves, i.e. three incident lights with different phases entering the same parallel plate, resulting in simulated curves of the ratio of the reflected light to the transmitted light intensity with respect to the above formula. As can be seen from fig. 2, the phase difference does not affect the actual content of the amplitude, the period, etc. of the curves, and one of the curves is shifted to obtain the other two curves. The different R is related to the reflectivity of the parallel flat plate, the thickness of the parallel flat plate, the incident angle of incident laser entering the parallel flat plate and the incident laser wavelength, under the condition that the parallel flat plate is determined, the thickness and the reflectivity of the parallel flat plate are known, after any beam of incident light enters the parallel flat plate at a certain incident angle, the relation between the ratio of the light intensity of the obtained reflected light to the light intensity of the obtained transmitted light and the reciprocal of the wavelength of the reflected light to the reciprocal of the wavelength is in a sine function, so that the light intensities of the reflected light and the transmitted light can be respectively collected in the incident light domain and the transmitted light domain of the parallel flat plate, and the wavelength of.

The point P and the point P 'on the two sides of the parallel flat plate are convergent points of a plurality of reflected lights or a plurality of transmitted lights, the light intensity signals of the point P and the point P' can be directly and accurately collected by using the photoelectric detector, and the laser wavelength is calculated in a mode of determining the interference level or the interference level variable quantity without stabilizing the laser wavelength, so that the real-time monitoring on the laser wavelength is realized; meanwhile, errors caused by determination of the interference level or the interference level variable quantity are avoided.

Furthermore, the laser to be measured is divided into a plurality of incident lasers which are incident to the parallel flat plate at different incident angles, a plurality of convex lenses L are arranged in the incident light domain of the parallel flat plate, a plurality of convex lenses L 'are arranged in the transmission light domain, each convex lens L is used for converging a plurality of reflected lights obtained after the same incident laser passes through the parallel flat plate, each convex lens L' is used for converging a plurality of transmitted lights obtained after the same incident laser passes through the parallel flat plate, the ratio of the light intensity of the plurality of reflected lights to the light intensity of the transmitted light is obtained by one-time measurement, and the accuracy of laser wavelength measurement and calculation is further guaranteed.

The system further comprises three first convex lenses 21 and three second convex lenses 22;

the three first convex lenses 21 are arranged in the incident light area of the parallel flat plate 2, and the first convex lenses 21 are used for converging a plurality of first reflected light, a plurality of second reflected light or a plurality of third reflected light;

the three second convex lenses 22 are arranged in the emergent light area of the parallel flat plate 2, and the second convex lenses 22 are used for converging a plurality of first transmission lights, or converging a plurality of second transmission lights, or converging a plurality of third transmission lights.

Illustratively, the light splitting structure 1 may be used to split the laser light into three incident lights, and the three incident lights are made incident on the parallel flat plate 2 at different angles. Three convex lenses are respectively arranged on two sides of the parallel flat plate 2, so that three reflected light convergence points of incident light and three transmitted light convergence points of the incident light can be obtained, and then the light intensity of each reflected light convergence point and each transmitted light convergence point is collected by six photoelectric detectors.

The first convex lens 21 is a convex lens L which is arranged in the incident light field of the parallel flat plate 2 and is used for converging the reflected light of the parallel flat plate 2; the second convex lens 22 is a convex lens L' which is arranged in the transmission light field of the parallel flat plate 2 and is used for converging the transmission light of the parallel flat plate 2; the three first convex lenses 21 and the three second convex lenses 22 may be identical.

In order to divide the laser to be measured into a plurality of beams of incident laser, the embodiment of the application is further provided with a light splitting structure 1. The light splitting structure 1 is used for converting laser to be measured into a preset number of spatial incident lights, and enabling a plurality of spatial incident lights to enter the parallel flat plate 2 at different incident angles.

As can be seen from the above examples, a plurality of photodetectors may be provided to collect the light intensity of each of the reflected light collection points and the transmitted light collection points. Specifically, the first photodetector group 3 may be set for the purpose of collecting the light intensity of the reflected light converging point, and the second photodetector group 4 may be set for the purpose of collecting the light intensity of the transmitted light converging point.

After the photoelectric detector converts the light intensity signal into an electric signal, the weak electric signal is input into an amplifying circuit for amplification and is input into a data acquisition device 7, and data is processed to obtain the ratio of the light intensity of the reflected light to the light intensity of the transmitted light.

According to the above analysis, the system for measuring laser wavelength in real time provided by the embodiment of the present application mainly includes: the device comprises a light splitting structure 1, a parallel flat plate 2, a first photoelectric detector group 3, a second photoelectric detector group 4, a first amplifying circuit 5, a second amplifying circuit 6 and a data acquisition device 7;

referring to fig. 3, fig. 3 is a schematic diagram of a system for measuring laser wavelength in real time according to an embodiment of the present application.

In fig. 3, a straight line is a circuit control line, a dotted line is an optical fiber, the optical fiber (dotted line) connects the spatial light coupler and the laser, and a dotted line is an optical path of spatial light formed by coupling outgoing laser light.

The data acquisition device 7 is connected with a laser through a laser controller 8 so as to read the temperature of the laser;

specifically, the data acquisition device 7 is composed of a data acquisition card 71 and a computer 72.

The data acquisition device 7 comprises a computer 72 and a data acquisition card 71;

the laser is connected with the computer 72 through a laser controller 8;

the laser controller 8 can adjust and read the current and temperature of the laser, when the wavelength of the laser emitted from the laser is measured by using the system for measuring the laser wavelength in real time, the laser controller 8 correspondingly displays the real-time temperature and current of the laser, and the computer 72 is connected with the laser controller 8 to obtain the temperature when the laser emits the emitted laser.

In another embodiment of the present application, a computer 72 connects the laser controller 8 and a gauge that measures a reference wavelength of the laser light excited by the laser.

The computer 72 adjusts and reads the temperature of the laser through the laser controller 8; the temperature of the laser read by the computer is incremented by a preset step. The preset step length is set during the debugging and the building of a system for measuring the laser wavelength in real time, and the temperature change range of the laser is set at the same time.

The computer 72 obtains the measured reference wavelength of the laser emitted at different temperatures;

the computer 72 generates a correspondence of the reference wavelength to the temperature of the laser.

Because the laser excited by the laser is related to the current and the temperature of the laser, the laser wavelength can be adjusted by changing the temperature and the current of the laser through the photoelectric controller, so that the corresponding temperatures of the laser at different wavelengths can be obtained. Firstly, the temperature range of laser excited by the laser and the step length of the temperature increased in the set temperature range are set through the computer, the temperature of the laser is controlled through the laser controller 8, the temperature of the laser is gradually increased in the temperature range according to the preset step length, and when the laser is positioned at each temperature node, the laser wavelength of the current temperature node is roughly measured through the measuring instrument.

Illustratively, when a system component for measuring laser wavelength in real time and debugging are carried out, the preset temperature range is set to be 21-40 degrees, the laser current is 100mA, and then 0.1 degree is used as a preset step length for temperature increase. When the system component for measuring the laser wavelength in real time and debugging, the corresponding relation between the reference wavelength and the temperature of the laser can be calibrated through a standard wavelength meter or a commercial wavelength meter, and the corresponding relation between the calibrated reference wavelength and the temperature of the laser is stored in a computer to be calculated. Fig. 4 is a graph showing the correspondence between the reference wavelength of the laser and the temperature of the laser in the embodiment of the present application.

In actual measurement, the laser controller LDC501 is used to adjust and read the temperature of the laser, and the wavelength of the laser beam emitted therefrom is measured when the temperature of the laser is 21.1 degrees, 21.2 degrees, … … 39.9.9 degrees, and 40 degrees in this order. Then, the corresponding relationship between the reference wavelength and the temperature of the laser is stored by the computer 72, the wavelength of the laser excited by the laser at the current temperature and current is roughly estimated as the reference wavelength, and the variation interval of the reference wavelength acceptable is used as the wavelength interval.

For example, when the temperature of the laser is 26.4 degrees and the reference wavelength of the laser is 1573.5nm, [1573.5 +. DELTA., 1573.5-. DELTA ] is defined as the wavelength region. Where Δ is an acceptable variation parameter of the reference wavelength determined according to the actual situation. If Δ is 3nm, the wavelength interval is [1576.5, 1570.5 ]. In the subsequent actual measurement, after a wavelength set is calculated from the intensities of the reflected light and the transmitted light, the wavelength in the wavelength interval [1576.5, 1570.5] is taken as the wavelength of the emitted laser light.

In general, a fabry-perot interferometer, a mach-zehnder interferometer, or a michelson interferometer may be used as a means for calibrating the reference wavelength, and another wavelength meter may be used to roughly measure the reference wavelength of the laser light.

The laser is connected with a Fabry-Perot interferometer, a Mach-Zehnder interferometer or a Michelson interferometer;

Or, the wavelength of the laser emitted from the laser may be calibrated by a commercial wavelength meter, a relation graph of the laser temperature and the wavelength of the emitted laser may be established, and the relation graph may be stored in the computer 72. In the wavelength and actual measurement, on the basis of obtaining the rough wavelength of the emergent laser by contrasting a relation curve graph of the temperature of the laser and the wavelength of the emergent laser, the actual temperature of the laser and voltage data acquired by an acquisition card and obtained by the light intensity of the emergent laser are read, and the accurate wavelength of the emergent laser can be obtained.

With continued reference to fig. 3, the light splitting structure 1 is connected to a laser through an optical fiber, converts the outgoing laser light generated by the laser into spatial light, and splits the spatial light into a plurality of incident light beams.

The DFB laser is adopted in the embodiment of the application, the wavelength range is 1573-1575.2nm, and the optical isolator is placed at the light outlet of the laser to place the light reflected back in the light path to damage the laser.

The light splitting structure 1 is connected with the laser and is used for splitting emergent laser generated by the laser into a plurality of incident lights and enabling the plurality of incident lights to be incident on the parallel flat plate 2 at different target angles;

following the foregoing example, the laser light is split into three incident lights propagating in space by the light splitting structure 1.

The light splitting structure 1 comprises a spatial light coupler 11, a plane mirror group 12, a first 1/2 wave plate 13, a second 1/2 wave plate 14, a first PBS prism 15 and a second PBS prism 16;

the spatial light coupler 11 is connected to an optical fiber for transmitting the outgoing laser light, and couples the outgoing laser light into spatial light.

The spatial light coupler 11 couples the emitted laser light into spatial light, and the spatial light is made to enter a first light splitting assembly composed of the first 1/2 wave plate 13 and the first PBS prism 15;

the first 1/2 wave plate 13 and the first PBS prism 15 constitute a first light splitting assembly, the second 1/2 wave plate 14 and the second PBS prism 16 constitute a second light splitting assembly, and the spatial light coupled by the spatial light coupler 11 is divided into three incident lights with the same wavelength by combining the first light splitting assembly and the second light splitting assembly.

The first light splitting assembly splits the space light into a first incident light and a parallel light, and the parallel light is incident to a second light splitting assembly formed by the second 1/2 wave plate 14 and the second PBS prism 16;

the plane mirror group 12 is configured to adjust optical paths of the first incident light, the second incident light, and the third incident light, and make the first incident light enter the parallel plate at a first target angle, make the second incident light enter the parallel plate at a second target angle, and make the third incident light enter the parallel plate at a third target angle;

The plane mirror group 12 includes four plane mirrors, changes the propagation light paths of the first incident light, the second incident light, and the third incident light by reflection, and adjusts the phase difference between the three incident lights by the plane mirror group 12.

The phase difference between any two of the first target angle, the second target angle and the third target angle can be 90 degrees, 80 degrees and the like, and the sum of the phase differences among the first target angle, the second target angle and the third target angle is larger than 120 degrees, at this moment, after at least two beams of incident light in the first incident light, the second incident light and the third incident light pass through the parallel flat plate 2, the ratio of the obtained reflected light to the transmitted light is an effective ratio.

Preferably, it is optimal that the sum of the phase differences between the first target angle, the second target angle and the third target angle is one period of the sine function.

With continued reference to fig. 1 and 3, the first photodetector group 3 and the second photodetector group 4 are respectively configured to collect a first light intensity of the plurality of reflected light converging points and a second light intensity of the plurality of transmitted light converging points; wherein, the reflected light collection point and the transmitted light collection point are the collection points of a plurality of reflected lights or a plurality of transmitted lights obtained after one incident light in the plurality of incident lights passes through the parallel flat plate 2;

the first photoelectric detector group 3 and the second photoelectric detector group 4 respectively convert the collected multiple first light intensities and multiple second light intensities into multiple first current signals and multiple second current signals;

as can be seen from fig. 1 and the principle of multi-beam interference of parallel plates, a beam of incident light enters a parallel plate 2 and emits a plurality of reflected lights and a plurality of transmitted lights at two sides of the parallel plate 2, convex lenses are arranged at two sides of the parallel plate 2 to converge the emitted plurality of reflected lights and the plurality of transmitted lights, a point P where the plurality of reflected lights converge is a reflected light convergence point, and a point P' where the plurality of transmitted lights converge is a transmitted light convergence point; when a plurality of incident lights enter the parallel flat plate 2, a plurality of convex lenses are correspondingly arranged on two sides of the parallel flat plate 2 so as to converge a plurality of reflected lights and a plurality of incident lights from each incident light.

Following the above example, the outgoing laser beam passes through the light splitting structure 1 to obtain three incident light beams, three indium gallium arsenic photodetectors are arranged in the first photodetector group 3 to perform measurement corresponding to the three incident light beams, and three indium gallium arsenic photodetectors are arranged in the second photodetector group 4 to perform measurement.

The first group of photodetectors 3 comprises a first photodetector 31, a second photodetector 32 and a third photodetector 33; the second photodetector group 4 comprises a fourth photodetector 41, a fifth photodetector 42 and a sixth photodetector 43;

the first photodetector 31 and the fourth photodetector 41 are respectively used for collecting the light intensity of a first reflected light convergence point and the light intensity of a first transmitted light convergence point; the first incident light enters the parallel flat plate 2 at a first target angle, and is continuously transmitted and reflected by the parallel flat plate 2 to obtain a plurality of first reflected lights and a plurality of first transmitted lights;

the second photodetector 32 and the fifth photodetector 42 are respectively used for collecting the light intensity of a second reflected light convergence point and the light intensity of a second transmitted light convergence point; the second incident light enters the parallel flat plate 2 at a second target angle, and is continuously transmitted and reflected by the parallel flat plate 2 to obtain a plurality of second reflected lights and a plurality of second transmitted lights;

the third photodetector 33 and the sixth photodetector 43 are respectively used for collecting the light intensity of a third reflected light convergence point and the light intensity of a third transmitted light convergence point; the third incident light enters the parallel flat plate 2 at a third target angle, and is continuously transmitted and reflected by the parallel flat plate 2 to obtain a plurality of third reflected light beams and a plurality of third transmitted light beams.

The first photodetector 31, the second photodetector 32 and the third photodetector 33 are used for collecting the light intensity of the three reflected light convergence points; the fourth photodetector 41, the fifth photodetector 42 and the sixth photodetector 43 are used for collecting the light intensity of three converging points of the transmitted light.

For a convergent point of a plurality of first reflected lights obtained by the first incident light passing through the parallel flat plate and a convergent point of a plurality of first transmitted lights obtained by the first incident light passing through the parallel flat plate, the light intensities of the convergent point of the first reflected light and the convergent point of the first transmitted light are respectively collected by the corresponding first photoelectric detector 31 and the fourth photoelectric detector 41, and then the light intensity signals are input into the data processing device to obtain the ratio of the light intensity of the reflected light to the light intensity of the transmitted light of the first incident light.

Simultaneously using the corresponding second photodetector 32 and fifth photodetector 42 to respectively collectThe light intensity of the convergence point of the second reflected light and the light intensity of the convergence point of the second transmitted light are respectively collected by the corresponding third photodetector 33 and the corresponding fifth photodetector 43, the light intensity of the convergence point of the third reflected light and the light intensity of the convergence point of the third transmitted light are collected, the light intensity of the reflected light and the light intensity of the transmitted light of the first incident light are collected, the light intensity of the reflected light and the light intensity of the transmitted light of the second incident light are collected, the light intensity of the reflected light and the light intensity of the transmitted light of the third incident light can be collected simultaneously, and the first incident light, the second incident light and the third incident light are based on the emergent laser generated by the same laser, namely based on the same emergent laser generated by the same laser: ratio R of reflected light intensity to transmitted light intensity of first incident light₁The ratio R of the reflected light intensity to the transmitted light intensity of the second incident light₂And the ratio R of the reflected light intensity to the transmitted light intensity of the third incident light₃。

From the foregoing analysis, R can be known₁、R₂、R₃Three groups of data are related to the reflectivity of the parallel flat plate, the thickness of the parallel flat plate, the incident angle of incident laser entering the parallel flat plate and the incident laser wavelength, the first incident light, the second incident light and the third incident light are incident into the same parallel flat plate, and the reflectivity and the thickness of the parallel flat plate are the same; the first incident light, the second incident light and the third incident light are obtained by splitting the same emergent laser beam generated by the same laser, and the wavelengths are the same, so that R is₁、R₂、R₃The three sets of measurement data obtained simultaneously in the embodiment of the present application only have differences among the first target angle, the second target angle, and the third target angle due to differences among the first incident light, the second incident light, and the third incident light, so that a phase difference exists between any two target angles among the first target angle, the second target angle, and the third target angle, and the sum of the phase differences is greater than 120 degrees.

Following the foregoing example, the phase difference existing between any two of the first target angle, the second target angle, and the third target angle is set to 120 degrees.

The first amplifying circuit and the second amplifying circuit respectively convert the first current signal and the second current signals into a plurality of first voltage signals and a plurality of second voltage signals;

the first photoelectric detector group 3 and the second photoelectric detector 4 convert the collected light intensity signals into current signals, then respectively input the current signals into the first amplifying circuit and the second amplifying circuit, the current signals are converted and amplified by the first amplifying circuit and the second amplifying circuit to obtain voltage signals, the voltage signals are input into the data acquisition device, and the data acquisition device obtains R based on the obtained voltage signals₁，R₂、R₃。

Referring to fig. 5, fig. 5 is a graph of the ratio of reflected light to incident light versus wavelength measured in an embodiment of the present application.

In the actual measurement process, the measurement curve is found to be obviously distorted at the position close to the curve measurement extreme point, in order to improve the measurement accuracy, the non-extreme region of the curve is used for wavelength calculation, based on the arrangement of the embodiment, the phase difference of three detection signals is 120 degrees, one period is uniformly divided into three parts, when any detection signal is in the extreme region, the other two detection signals are in the linear region, the two detection signals are used for calculating to obtain the wavelength and calculating the average value, and the detection accuracy is further improved.

The data acquisition device 7 calculates a ratio set of the plurality of first voltage signals and the plurality of second voltage signals, and calculates a wavelength value set of the emergent laser according to the ratio set;

the data acquisition device 7 obtains a wavelength interval of the emergent laser according to a corresponding relation between a pre-stored reference wavelength and the temperature of the laser emission device;

and the data acquisition device 7 determines the wavelength of the emergent laser in the wavelength value set according to the wavelength interval.

The wavelength value set refers to all values of the wavelength of the emergent laser, which are calculated according to the ratio of the light intensity of the reflected light to the light intensity of the transmitted light.

The data acquisition device 7 roughly calculates the laser wavelength according to the corresponding relation between the prestored reference wavelength and the temperature of the laser; and according to the roughly calculated wavelength of the emergent laser, the wavelength of the emergent laser is accurately determined according to the ratio of the multiple groups of reflected light to the transmission light.

Illustratively, the computer reads through the laser controller 8 that the current of the laser is 100mA, the temperature is t1, and the rough wavelength is 1573.8nm at the temperature of t1(30 ℃) corresponding to fig. 4. It can be seen that when the current is 100mA, the temperature is t1, the wavelength interval of the wavelength of the emitted laser light is [1573.8nm +. DELTA.,. 1573.8 nm-. DELTA. ], and when the wavelength of the laser light is calculated based on the ratio R1 of the first reflected light to the first transmitted light, the ratio R2 of the second reflected light to the second transmitted light, and the ratio R3 of the third reflected light to the third transmitted light, the value corresponding to the wavelength interval of [1573.8nm +. DELTA.,. 1573.8 nm-. DELTA. ]shouldbe selected.

Reading the multi-channel detector voltage signals, calculating that R1 is 0.606293, R2 is 0.486152, and R3 is 0.095013. Corresponding to fig. 5, R1, R2 were in the linear range of the curve, R3 were not in the linear range, and the value of R3 was omitted from the three measurements. According to the roughly estimated wavelength and formula

Respectively calculate to obtain lambda₁1573.88932nm, lambda₂At 1573.90010nm, determine λ₁And λ₂The average value of (A) was 1573.89471nm, which was the wavelength of the finally emitted laser beam.

It will be appreciated that R in fig. 5 is due to the nature of the sine function₂0.486152, and therefore, the wavelength of the emitted laser light needs to be accurately determined by combining with the roughly estimated wavelength 1573.8 nm.

In another embodiment of the present application, the computer 72 in the data acquisition device 7 will determine the currently measured ratio R according to the read temperature of the laser, and combine fig. 4 and 5₁，R₂、R₃Whether the corresponding wavelength is at the extreme value or not is judged, because three incident lights enterThe phase of each pair of pairs striking the parallel plates is 120 degrees, so that R is the temperature at which the temperature is determined₁，R₂、R₃At least two specific values correspond to the wavelength in the linear region, and the value of the final wavelength is more accurate by taking the value of the linear region as an average value.

The computer 72 reads the current temperature of the laser according to the laser controller 8;

the computer 72 obtains the wavelength interval of the emergent laser according to the corresponding relationship between the current temperature of the laser and the temperature of the reference wavelength and the laser;

the computer 72 determines whether an element in a ratio set of the first voltage signals and the second voltage signals is at an extreme position at the current temperature;

The extreme position generally refers to the position of a peak or trough and the position near the peak or trough in the ratio of reflected light to incident light versus wavelength plot.

In an example, in the embodiment of the present application, the light splitting structure 1 is used to split the outgoing laser into three different incident lights, so as to obtain ratios of reflected light and transmitted light after passing through the parallel flat plate, and if the ratio of the first reflected light and the first transmitted light is located at an extreme position, the wavelength of the outgoing laser is calculated by using the ratio of the second reflected light and the second transmitted light, and the ratio of the third reflected light and the third transmitted light. If the ratio of the reflected light and the transmitted light of the first incident light, the second incident light and the third incident light after passing through the parallel flat plate does not have a value at an extreme value position, the wavelength of the emergent laser is calculated by adopting the ratio of the first reflected light and the first transmitted light, the ratio of the second reflected light and the second transmitted light and the ratio of the third reflected light and the third transmitted light.

If R is₁，R₂、R₃At temperature t₀With elements at extreme values, e.g. R₁The value of (A) is 0.74, the corresponding point of the wavelength value is just at the position of the peak of the ratio-wavelength curve of the reflected light and the incident light, and R is taken at the moment₂And R₃In the ratio-wavelength curve of the reflected light and the incident light, the corresponding wavelength is taken as the final wavelength value. And the value of the wavelength at the extreme value position is eliminated, so that the accuracy of laser wavelength measurement is improved.

Referring to fig. 6, fig. 6 is a schematic diagram of a first amplification circuit and a second amplification circuit according to an embodiment of the present application.

Is the light collected by a photodiode and converted into a current signal I₀，V₀Is a voltage signal amplified by the circuit board;

the first amplifying circuit 5 and the second amplifying circuit 6 each include a signal amplifying circuit 51 and a filter circuit 52;

the first amplifying circuit 5 and the second amplifying circuit 6 adopt the same design, the first amplifying circuit is connected with the first photoelectric detector group 3 and the data acquisition card 71, the second amplifying circuit 6 is connected with the second photoelectric detector group 4 and the data acquisition card 71, the reflected light intensity signals and the transmitted light intensity signals collected by the first photoelectric detector group 3 and the second photoelectric detector group 4 are processed in the same way respectively, the current signals are converted into voltage signals, the voltage signals are amplified by the same times, and the amplified voltage signals are used for filtering circuit board noise and the like.

The signal amplification circuit 51 is connected to the first photodetector group or the second photodetector group, and is configured to convert the first current signal into a first voltage signal or convert the second current signal into a second voltage signal;

the signal amplifying circuit 51 amplifies the first voltage signal or the second voltage signal and transmits the amplified first voltage signal or the amplified second voltage signal to the filter circuit 52; the signal amplifying circuit 51 is a front-mounted T-shaped amplifying network; the preposed T-shaped amplifying network comprises an amplifier, a capacitor and a plurality of resistors;

the values of the resistors in fig. 6 are an embodiment for implementing the functions of the first amplifying circuit and the second amplifying circuit, and the specific values of the resistors are not to be construed as limiting the present application.

ADA4817 in fig. 6 is an embodiment of an amplifier in the first amplifying circuit and the second amplifying circuit according to the embodiment of the present disclosure.

The ADA4817 and high-precision resistor form the prepositive T-shaped amplification network to amplify the input micro current, the T-shaped network adopts the resistor with smaller resistance value to realize larger amplification factor, the temperature drift error generated by the resistor with large resistance value is reduced, meanwhile, the two ends of the feedback resistor are connected with a capacitor with 10pF in parallel to filter high-frequency noise, the signal-to-noise ratio of the amplified signal is improved, and the amplification factor of the T-shaped operational amplification circuit is 500 in the application.

The filter circuit 52 is connected to the data acquisition card, and sends the first voltage signal or the second voltage signal with noise filtered to the data acquisition card. The filter circuit 52 is an instrumentation amplifier composed of a plurality of amplifiers; the amplification factor of the instrument amplifier is a preset amplification factor.

The three ADA4817 form an instrumentation amplifier with a preset amplification factor of 1, and when the amplification factor of the formed instrumentation amplifier is 1, the instrumentation amplifier has the function of filtering magazine waves on signals. The accuracy and the stability of the amplifying circuit are improved. The ADA4817 has wide bandwidth and low noise characteristics, and has good conditioning effect on signals collected by the photoelectric detector.

In another embodiment of the present application, the data acquisition card 71 in the data acquisition device 7 may perform 100 times of acquisition on the converted voltage signal input to the first amplification circuit or the second amplification circuit by each photodetector, and calculate an average value of the voltage signals after 100 times of acquisition as the detection signal of the intensity of the reflected light and the intensity of the transmitted light of the outgoing laser at the temperature.

The data acquisition card 71 acquires the plurality of first voltage signals and the plurality of second voltage signals N times;

the data acquisition card 71 sends the acquired first voltage signals acquired for a plurality of N times and the acquired second voltage signals acquired for a plurality of N times to the computer 72;

the computer 72 averages the plurality of first voltage signals acquired for N times and the plurality of second voltage signals acquired for N times to obtain an average value of the plurality of first voltage signals and an average value of the plurality of second voltage signals;

the computer 72 calculates a ratio of an average value of the plurality of first voltage signals to an average value of the plurality of second voltage signals;

to explain the above embodiments of the present application, the data acquisition device 7 respectively acquires the light intensity of the first reflected light convergence point, the light intensity of the second reflected light convergence point, and the light intensity of the third reflected light convergence point, which are acquired by the first photodetector, the second photodetector, and the third photodetector, 100 times; and respectively collecting the light intensity of the first transmission light convergence point, the light intensity of the second transmission light convergence point and the light intensity of the third transmission light convergence point which are collected by the fourth photoelectric detector, the fifth photoelectric detector and the sixth photoelectric detector for 100 times.

Respectively averaging the light intensity of the collected 100 times of first reflected light convergence points, averaging the light intensity of the collected 100 times of second reflected light convergence points, and averaging the light intensity of the collected 100 times of third reflected light convergence points; and similarly, the average value of the light intensity of the first transmission light convergence point, the light intensity of the second transmission light convergence point and the light intensity of the third transmission light convergence point is obtained.

Then calculating R according to the average value of the light intensity of the first reflected light convergence point and the average value of the light intensity of the first transmitted light convergence point₁。R₁The method is obtained according to a large amount of light intensity data in the measurement of one laser wavelength, and random errors caused by single measurement are avoided.

The computer 72 obtains a value subset of the wavelength of the emitted laser according to a ratio of any one of the average values of the first voltage signals to any one of the average values of the second voltage signals;

the computer 72 combines the plurality of value subsets to obtain a value set of the wavelength of the emitted laser.

Based on this application embodiment utilizes beam splitting structure 1 to divide into three bundles of incident lights with emergent laser, by the ratio of the light intensity of first reverberation convergent point and the light intensity of first transmitted light convergent point, the wavelength value of the emergent laser that arrives of calculation is the value subset. Similarly, the calculated wavelength value of the emitted laser is also a value subset according to the ratio of the light intensity of the second reflected light convergence point to the light intensity of the second transmitted light convergence point to the ratio of the light intensity of the third reflected light convergence point to the light intensity of the third transmitted light convergence point. And combining the value sub-sets obtained by the three beams of incident light to obtain a wavelength value set of the emergent laser.

In the above example, the computer 72 calculates that R1 is 0.606293, R2 is 0.486152, and R3 is 0.095013 according to the voltage signals collected by the multi-channel detector and read by the data acquisition card 71. Corresponding to fig. 5, R1, R2 were in the linear range of the curve, R3 were not in the linear range, and the value of R3 was omitted from the three measurements. According to the roughly estimated wavelength and formula

Wherein λ₁Possible values of (A) and (B)₂Possible values are subsets of values. Merging of lambda₁And λ₂Obtaining a value set in a wavelength range [1573.8nm + △,1573.8nm- △ ] obtained according to rough estimation]Determining to take lambda from the value set₁＝1573.88932nm，λ₂The average value of 1573.89471nm was calculated as 1573.90010nm, and the wavelength of the finally emitted laser beam was determined.

Referring to FIG. 5, λ₁The subset of (a) may be [1573.88932nm,1573.20211nm,1573.43512nm,1574.74213nm …]。

The system for measuring the laser wavelength in real time has the advantages of simple structure and component parts: light splitting structure 1, parallel flat board 2, first photoelectric detector group 3, second photoelectric detector group 4, first amplifier circuit 5, second amplifier circuit 6 and data acquisition device 7 are small and exquisite, and the relation of connection is simple, portable.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, or article that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, or article.

The system for measuring the laser wavelength in real time provided by the present application is introduced in detail above, and a specific example is applied in the present application to explain the principle and the implementation of the present application, and the description of the above embodiment is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A system for measuring laser wavelength in real time, comprising: the device comprises a light splitting structure (1), a parallel flat plate (2), a first photoelectric detector group (3), a second photoelectric detector group (4), a first amplifying circuit (5), a second amplifying circuit (6) and a data acquisition device (7);

the data acquisition device (7) is connected with a laser through a laser controller (8) and is used for reading the temperature of the laser;

the light splitting structure (1) is connected with the laser and is used for splitting emergent laser generated by the laser into a plurality of incident lights and enabling the incident lights to be incident on the parallel flat plate (2) at different target angles;

the first photoelectric detector group (3) and the second photoelectric detector group (4) are respectively used for collecting first light intensity of a plurality of reflected light convergence points and second light intensity of a plurality of transmitted light convergence points; wherein the reflected light collection point and the transmitted light collection point are collection points of a plurality of reflected lights or a plurality of transmitted lights obtained after one incident light in the plurality of incident lights passes through the parallel flat plate (2);

the first photoelectric detector group (3) and the second photoelectric detector group (4) are respectively used for converting the collected multiple first light intensities and multiple second light intensities into multiple first current signals and multiple second current signals;

the first amplifying circuit (5) and the second amplifying circuit (6) are respectively connected with the first photoelectric detector group (3) and the second photoelectric detector group (4) and are used for converting a plurality of first current signals and a plurality of second current signals into a plurality of first voltage signals and a plurality of second voltage signals;

the data acquisition device (7) is connected with the first amplification circuit (5) and the second amplification circuit (6) and is used for calculating a ratio set of the plurality of first voltage signals and the plurality of second voltage signals and calculating a wavelength value set of the emergent laser according to the ratio set;

the data acquisition device (7) is used for obtaining a wavelength interval of the emergent laser according to a corresponding relation between a pre-stored reference wavelength and the temperature of the laser;

the data acquisition device (7) is used for determining the wavelength of the emergent laser in the wavelength value set according to the wavelength interval.

2. The system for real-time measurement of laser wavelength according to claim 1, characterized in that the data acquisition device (7) comprises a computer (72) and a data acquisition card (71);

the laser is connected with the computer (72) through the laser controller (8);

the computer (72) is used for adjusting and reading the temperature of the laser through the laser controller (8);

the computer (72) is used for obtaining the measured reference wavelength of the laser emitted when the laser is at different temperatures and the corresponding relation between the reference wavelength and the temperature of the laser;

the computer (72) is configured to store a correspondence of the reference wavelength to the temperature of the laser.

3. The system for measuring laser wavelength in real time according to claim 2,

the laser is used for measuring the reference wavelength of the emergent laser of the laser at different temperatures through the Fabry-Perot interferometer, the Mach-Zehnder interferometer or the Michelson interferometer;

the computer (72) is used for storing the reference wavelengths corresponding to different temperatures.

4. The system for measuring laser wavelength in real time according to claim 1,

the light splitting structure (1) comprises a spatial light coupler (11), a plane mirror group (12), a first 1/2 wave plate (13), a second 1/2 wave plate (14), a first PBS prism (15) and a second PBS prism (16);

the spatial light coupler (11) is connected with the laser through an optical fiber and is used for coupling the emergent laser into spatial light, so that the spatial light is incident to a first light splitting assembly consisting of the first 1/2 wave plate (13) and the first PBS prism (15);

the first light splitting component is positioned on one side of the spatial light coupler (11) for emitting the spatial light, and is used for splitting the spatial light into first incident light and parallel light, and enabling the parallel light to be incident to a second light splitting component formed by the second 1/2 wave plate (14) and the second PBS prism (16);

the second light splitting component is positioned in the area where the parallel light is emitted by the first light splitting component and is used for splitting the parallel light into second incident light and third incident light;

the plane mirror group (12) is used for adjusting the optical paths of the first incident light, the second incident light and the third incident light, and enabling the first incident light to enter the parallel flat plate (2) at a first target angle, the second incident light to enter the parallel flat plate (2) at a second target angle and the third incident light to enter the parallel flat plate (2) at a third target angle;

the phase difference with respect to the measurement curve of any two of the first target angle, the second target angle, and the third target angle is 120 degrees.

5. The system for real-time measurement of laser wavelength according to claim 4, characterized in that the first set of photodetectors (3) comprises a first photodetector (31), a second photodetector (32) and a third photodetector (33); the second photodetector group (4) comprises a fourth photodetector (41), a fifth photodetector (42) and a sixth photodetector (43);

the first photoelectric detector (31) and the fourth photoelectric detector (41) are respectively used for collecting the light intensity of a first reflected light convergence point and the light intensity of a first transmitted light convergence point; the first incident light enters the parallel flat plate (2) at a first target angle, and is continuously transmitted and reflected by the parallel flat plate (2) to obtain a plurality of first reflected light beams and a plurality of first transmitted light beams;

the second photoelectric detector (32) and the fifth photoelectric detector (42) are respectively used for collecting the light intensity of a second reflected light convergence point and the light intensity of a second transmitted light convergence point; the second incident light enters the parallel flat plate (2) at a second target angle, and is continuously transmitted and reflected by the parallel flat plate (2) to obtain a plurality of second reflected light beams and a plurality of second transmitted light beams;

the third photoelectric detector (33) and the sixth photoelectric detector (43) are respectively used for collecting the light intensity of a third reflected light convergence point and the light intensity of a third transmitted light convergence point; and the third incident light enters the parallel flat plate (2) at a third target angle, and is continuously transmitted and reflected by the parallel flat plate (2) to obtain a plurality of third reflected light beams and a plurality of third transmitted light beams.

6. The system for real-time measurement of laser wavelength according to claim 5, characterized in that the system further comprises three first convex lenses (21) and three second convex lenses (22);

three first convex lenses (21) are arranged in the incident light area of the parallel flat plate (2), and the first convex lenses (21) are used for converging a plurality of first reflected light, or converging a plurality of second reflected light, or converging a plurality of third reflected light;

the three second convex lenses (22) are arranged in the emergent light area of the parallel flat plate (2), and the second convex lenses (22) are used for converging a plurality of first transmission lights, or converging a plurality of second transmission lights, or converging a plurality of third transmission lights.

7. The system for real-time measurement of laser wavelength according to claim 2, characterized in that the first amplification circuit (5) and the second amplification circuit (6) each comprise a signal amplification circuit (51) and a filter circuit (52);

the signal amplification circuit (51) is connected with the first photoelectric detector group (3) or the second photoelectric detector group (4) and is used for converting the first current signal into a first voltage signal or converting the second current signal into a second voltage signal;

the signal amplification circuit (51) is used for amplifying the first voltage signal or the second voltage signal and transmitting the amplified first voltage signal or the amplified second voltage signal to the filter circuit (52);

the filter circuit (52) is connected with the data acquisition card (71) and is used for sending the first voltage signal or the second voltage signal after noise filtering to the data acquisition card (71).

8. The system for real-time measurement of laser wavelength according to claim 7, wherein the signal amplification circuit (51) is a pre-T type amplification network;

the filter circuit (52) is an instrumentation amplifier composed of a plurality of amplifiers;

9. The system for measuring laser wavelength in real time as claimed in claim 7, wherein said data acquisition card (71) is connected to said computer (72) for acquiring a plurality of said first voltage signals and a plurality of said second voltage signals N times;

the data acquisition card (71) is used for sending the acquired first voltage signals acquired for multiple N times and the acquired second voltage signals acquired for multiple N times to the computer (72);

the computer (72) is used for averaging the first voltage signals acquired for a plurality of N times and the second voltage signals acquired for a plurality of N times to obtain an average value of the first voltage signals and an average value of the second voltage signals;

the computer (72) is used for calculating the ratio of the average value of the first voltage signals to the average value of the second voltage signals;

the computer (72) is configured to obtain a value subset of the wavelength of the emitted laser light according to a ratio of any one of the average values of the first voltage signals to any one of the average values of the second voltage signals;

and the computer (72) is used for combining the plurality of value sub-sets to obtain a value set of the wavelength of the emergent laser.

10. The system for real-time measurement of laser wavelength according to claim 2, characterized by the computer (72) for reading the current temperature of the laser according to the laser controller (8);

the computer (72) is used for obtaining the wavelength interval according to the corresponding relation between the current temperature of the laser and the temperature of the reference wavelength and the laser;

the computer (72) is configured to determine whether an element in a ratio set of the first voltage signals and the second voltage signals is at an extreme position at the current temperature;

if the ratio set does not have the element at the extreme position, the computer (72) is used for calculating to obtain a wavelength value set of the emergent laser according to all the elements in the ratio set;

if the ratio set contains the element at the extreme position, the computer (72) is used for calculating to obtain a wavelength value set of the emergent laser according to other elements except the element at the extreme position in the ratio set;