Spectral measurement beam combining device

Abstract

The invention relates to the technical field of spectral measurement, in particular to a spectral measurement beam combining device which comprises an input optical cable, a light gathering unit and an output optical cable which are sequentially arranged in the light path propagation direction. The N input optical cables are connected with the N lasers in a one-to-one correspondence manner; emergent ends of the N input optical cables are arranged in parallel so as to transmit laser emitted by the N lasers to the condensation unit in parallel; the light condensing unit converges N beams of parallel laser on an incident light path into one beam of light on an emergent light path; the output optical cable transmits a beam of light converged by the light condensing unit to the spectrograph; n is an integer greater than or equal to 1. According to the invention, the N laser beams emitted by the N lasers can be converged into one beam of light and then transmitted to the spectrograph, so that the N lasers share one spectrograph to carry out spectral measurement, the number of required spectrographs can be reduced, and the equipment purchase and maintenance cost is saved.

Description

Technical Field

[0001] This invention relates to the field of spectral measurement technology, and specifically to a spectral measurement beam combining device. Background Technology

[0002] In the process of mass-producing lasers, it is necessary to control the consistency of the batch of lasers.

[0003] In existing technologies, spectrometers are used to measure the spectra of lasers. For example, N spectrometers are used to measure the spectra of N (N≥1) lasers from the same batch, or one spectrometer is placed in each laboratory / workshop, and the spectrometer is moved to the corresponding workstation when the spectra of lasers at different workstations need to be measured.

[0004] To ensure the consistency of the laser output spectrum, the spectrum of each laser needs to be tested individually, and then the spectra of multiple lasers produced in the same batch are compared together through data fitting to evaluate the consistency differences.

[0005] If multiple spectrometers are used to perform spectral measurements one-to-one with the laser, the entire process requires multiple spectrometers, which will lead to a sharp increase in equipment procurement and maintenance costs.

[0006] Placing a spectrometer in every laboratory / workshop would increase the time required for spectral measurements and make data processing more difficult. Summary of the Invention

[0007] In view of this, the present invention provides a spectral measurement beam combining device that enables multiple lasers to share a single spectrometer for spectral measurement, thereby saving equipment procurement and maintenance costs and reducing spectral measurement time.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A beam combining device for spectral measurement is disclosed, which is used to focus the laser beams emitted by N lasers into a single beam before transmitting it to a spectrometer. The beam combining device includes an input optical cable, a focusing unit, and an output optical cable arranged sequentially along the optical path propagation direction. The input optical cables have N inputs, each connected to one of the N lasers. The exit ends of the N input optical cables are arranged parallel to each other to transmit the laser beams emitted by the N lasers to the focusing unit in parallel. The focusing unit focuses the N parallel laser beams on the incident optical path into a single beam on the exit optical path. The output optical cable transmits the beam focused by the focusing unit to the spectrometer. The beam combining device also includes a collimating lens disposed on the incident or exit optical path of the focusing unit. The collimating lens adjusts the laser beam incident on or emitted from the focusing unit into a collimated beam. N is an integer ≥ 1.

[0009] In some alternative implementations, the focusing unit is a concave reflector or a convex lens.

[0010] In some optional embodiments, when the focusing unit is a concave reflector, the laser incident on the focusing unit has an angle θ between it and the vertical plane of the main optical axis of the focusing unit, where the angle θ = 30° to 60°.

[0011] In some optional implementations, the output ends of the N input optical cables are arranged in an array to arrange the N laser beams directed toward the focusing unit; the effective light-receiving area diameter of the focusing unit is ≥ the diameter of the circumscribed circle corresponding to the N laser beams after the array is arranged; the effective light-receiving area of ​​the focusing unit is the projection of the light-passing aperture of the focusing unit perpendicular to the laser incident direction.

[0012] In some optional embodiments, there are N collimating lenses, each of which is configured to correspond one-to-one with either the N laser beams incident on or emitted from the focusing unit.

[0013] In some alternative implementations, the collimating lens is a plano-convex lens.

[0014] In some alternative embodiments, the diameter of the plano-convex lens is greater than or equal to the diameter of the collimated laser spot after collimation by the plano-convex lens.

[0015] In some optional embodiments, when the collimating lens is disposed on the incident light path of the focusing unit, N collimating lens arrays are arranged, and the diameter of the circumscribed circle corresponding to the N collimating lens arrays is less than or equal to the diameter of the effective light-receiving area of ​​the focusing unit; the effective light-receiving area of ​​the focusing unit is the projection of the light-transmitting aperture of the focusing unit perpendicular to the laser incident direction.

[0016] In some optional embodiments, the beam combining device further includes an optical stop disposed between the output end of the input optical cable and the focusing unit, wherein N optical stops are provided and are disposed one-to-one with the output ends of the N input optical cables.

[0017] In some optional embodiments, when the collimating lens is disposed on the incident light path of the focusing unit, the aperture is disposed between the collimating lens and the focusing unit; the maximum aperture of the aperture is greater than or equal to the diameter of the collimated laser spot after collimation by the collimating lens.

[0018] In summary, compared with existing technologies, this invention has the following advantages and beneficial effects: This invention can converge N laser beams emitted by N lasers into a single beam before transmitting it to a spectrometer, enabling N lasers to share a single spectrometer for spectral measurement. This reduces the number of spectrometers required, saving on equipment procurement and maintenance costs. Furthermore, this invention allows for the placement of only one spectrometer in a laboratory / workshop, enabling spectral measurements of lasers from different workstations within the same batch without moving the spectrometer. It also allows for simultaneous spectral measurements of N lasers, and only requires a single measurement to quickly and intuitively assess the consistency differences among the N lasers in the batch, significantly reducing spectral measurement time. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention during spectral measurement.

[0020] Figure 2 This is a cross-sectional structural diagram of the light-concentrating unit in this invention when it is a concave reflector.

[0021] Figure 3 This is a cross-sectional view of the collimating lens in this invention when it is a plano-convex lens.

[0022] Figure 4 This is a schematic diagram of the structure of the nine laser spots arranged in a 3×3 array in this invention.

[0023] The definitions of the reference numerals in the attached figures are as follows: 1. Laser, 2. Input optical fiber cable, 3. Input optical fiber connector, 4. Collimating lens, 5. Aperture, 6. Focusing unit, 7. Output optical fiber connector, 8. Output optical fiber cable, 9. Spectrometer. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0025] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0026] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, while "above," "below," "within," etc. are understood to include the stated number. If terms such as "first," "second," etc., are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0027] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0028] This invention introduces a spectral measurement beam combining device for converging N laser beams emitted by N lasers 1 into a single beam and transmitting it to a spectrometer 9, where N is an integer ≥1.

[0029] like Figure 1 As shown, the beam combining device includes an input optical cable 2, a focusing unit 6, an output optical cable 8, and a collimating lens 4.

[0030] The input optical cable 2, the focusing unit 6, and the output optical cable 8 are arranged sequentially along the optical path propagation direction.

[0031] The input optical cables 2 are provided with N cables and are connected one-to-one with the N lasers 1. The output ends of the N input optical cables 2 are arranged in parallel to transmit the N laser beams emitted by the N lasers 1 to the focusing unit 6 in parallel.

[0032] The focusing unit 6 focuses N parallel laser beams on the incident light path into a single beam on the outgoing light path.

[0033] The output optical cable 8 transmits a beam of light focused by the focusing unit 6 to the spectrometer 9.

[0034] The collimating lens 4 is disposed in the incident or outgoing light path of the focusing unit 6. The collimating lens 4 adjusts the laser incident on or emitted from the focusing unit 6 into a collimated beam.

[0035] Optionally, the focusing unit 6 and the collimating lens 4 can be encapsulated in a housing, on the walls of which are installed an input fiber optic connector 3 and an output fiber optic connector 7 to connect to the input optical cable 2 and the output optical cable 8, respectively.

[0036] For example, if the input optical cable 2 and the output optical cable 8 can be FC fiber optic patch cords, then the input fiber optic connector 3 and the output fiber optic connector 7 can be FC flanges.

[0037] The input ends of the N input optical cables 2 are respectively connected to the N lasers 1, and the output ends of the N input optical cables 2 are respectively connected to the N input optical fiber connectors 3 on the housing. Furthermore, the output directions of the N input optical cables 2 are parallel to each other and face the focusing unit 6, so that the N input optical cables 2 can direct the N laser beams emitted by the N lasers 1 to the focusing unit 6 in parallel.

[0038] The focusing unit 6 can converge N parallel incident laser beams into a single beam at the focal point of the output optical path. The input end of the output optical cable 8, connected via the output fiber optic connector 7 on the housing, is positioned precisely at the focal point of the output optical path of the focusing unit 6, ensuring that the beam focused by the focusing unit 6 enters the output optical cable 8. The output end of the output optical cable 8 is connected to the spectrometer 9, transmitting the converged light to the spectrometer 9 for spectral measurement.

[0039] When performing spectral measurements on the consistency of N lasers 1 in the same batch, the present invention generates N laser beams simultaneously by having N lasers 1 operate at the same time. The N laser beams are transmitted through the input optical cable 2 and directed in parallel towards the focusing unit 6. The focusing unit 6 focuses the N incident laser beams into a single beam and transmits this beam to the spectrometer 9 through the output optical cable 8, thereby achieving simultaneous measurement of the laser spectra of N lasers 1. The laser spectra of all lasers 1 are displayed simultaneously on the spectrometer 9, enabling rapid and intuitive discovery and evaluation of consistency differences in the batch of lasers 1.

[0040] The evaluation method can adopt the following steps: S1: The laser linewidth of a standard laser is tested using this invention, or the laser linewidth of one of the lasers 1 in the batch is tested (for example, one of the lasers 1 in the batch can be in working state to generate laser, while the other lasers 1 are in non-working state and do not generate laser). The measured linewidth is recorded as A.

[0041] S2: The linewidth of N lasers 1 in this batch is tested using this invention (even if all lasers 1 are working simultaneously to generate lasers), and the measured linewidth is recorded as B.

[0042] S3: Calculate the linewidth difference BA and compare it with the standard coefficient K. If BA ≤ K, the consistency of the N lasers in this batch is considered good; if BA > K, the consistency of the N lasers in this batch is considered poor. K is a value selected based on the circumstances.

[0043] This invention can focus N laser beams emitted by N lasers 1 into a single beam and transmit it to a spectrometer 9, enabling N lasers 1 to share a single spectrometer 9 for spectral measurement. This reduces the number of spectrometers 9 required and saves on equipment procurement and maintenance costs.

[0044] This invention also enables the placement of only one spectrometer 9 in a laboratory / workshop, and allows for the spectral measurement of lasers 1 in different workstations of the same batch without moving the spectrometer 9. It also enables the simultaneous spectral measurement of N lasers 1, and allows for a quick and intuitive assessment of the consistency differences among the N lasers 1 in the batch with just one measurement by the spectrometer 9, which can significantly reduce the spectral measurement time.

[0045] As mentioned above, the collimating lens 4 in this invention can be disposed in the incident light path or the outgoing light path of the focusing unit 6.

[0046] As an optional implementation, the collimating lens 4 can be a large collimating lens that covers the entire incident light path or the entire outgoing light path of the focusing unit 6.

[0047] As another optional implementation, the collimating lens 4 can also be provided in N forms, with each of the N collimating lenses 4 corresponding to one of the N laser beams incident on the focusing unit 6 or the N laser beams emitted from the focusing unit 6.

[0048] The function of collimating lens 4 is to collimate the laser beam; therefore, collimating lens 4 can be a plano-convex lens.

[0049] Here, we will take the example of setting N plano-convex lenses in the incident light path of the focusing unit 6 to illustrate its size design.

[0050] The following principle can be adopted for the size design of plano-convex lenses: the diameter of the plano-convex lens is greater than or equal to the diameter of the collimated laser spot after collimation by the plano-convex lens.

[0051] Assume that the numerical aperture NA of the laser emitted by laser 1 is 0.22 when it is emitted after being transmitted through the input optical cable 2.

[0052] like Figure 3 As shown, assuming the image-side focal length f' of the plano-convex lens is 30 mm, the diameter of the collimated laser spot after collimation by the plano-convex lens is D0≈NA×f'=0.22×30 mm=6.6 mm. Therefore, the diameter Φ1 of the plano-convex lens ≥ 6.6 mm is sufficient.

[0053] As an optional implementation method, such as Figure 3 As shown, the main dimensional parameters of the plano-convex lens are as follows: diameter Φ1=10 mm, radius of curvature R1=13.8 mm, center thickness Tc1=2.3 mm, edge thickness Te1=1.4 mm, image-side focal length f'=30 mm, and back intercept fb=28.5 mm.

[0054] The focusing unit 6 can be a convex lens, or preferably a concave mirror. Since concave mirrors produce reflective imaging, they do not exhibit chromatic aberration, a unique advantage unmatched by any other lens imaging method.

[0055] Here, we will explain the size design of the focusing unit 6 by taking it as an example, where the focusing unit 6 is a concave reflector and a large plano-convex lens is provided in the incident light path of the focusing unit 6.

[0056] like Figure 1 As shown, the collimated laser incident on the focusing unit 6 has an angle θ between it and the plane perpendicular to the principal optical axis of the focusing unit 6, where the angle θ = 30° to 60°. In this case, the effective light-receiving area diameter D2 of the concave mirror should be the projection of the aperture Φ3 of the concave mirror onto the direction perpendicular to the laser incident direction, i.e., D2 = Φ3 × sinθ.

[0057] The size of the effective light-collecting area of ​​the concave reflector needs to be designed to ensure that all N parallel collimated laser beams are incident within the effective light-collecting area of ​​the concave reflector. In other words, the diameter of the effective light-collecting area of ​​the focusing unit 6 needs to be greater than or equal to the diameter of the circumscribed circle corresponding to the N laser beams arranged in the array. Therefore, the size of the effective light-collecting area of ​​the concave reflector determines the number of lasers 1 that can be detected.

[0058] As an optional implementation, the output ends of the N input optical cables 2 are arranged in an array to arrange the N laser beams directed toward the focusing unit 6, such as a triangular array, a circular array, or preferably a square array, to reduce space occupation.

[0059] like Figure 4 As shown, this example illustrates the arrangement of nine input optical cables 2 at their output ends in a 3×3 square array. Assuming the diameter of the collimated laser spot after collimation by the plano-convex lens is D0 = 6.6 mm, and the spacing between adjacent spots is L = 10 mm, then the side length of the square spot region corresponding to the nine-spot square array is H = D0 + 2L = 6.6 mm + 2 × 10 mm = 26.6 mm. The diameter of the circumcircle of the square corresponding to the nine-spot square array is... ≈1.414×26.6 mm=37.6124 mm.

[0060] To ensure that all nine laser beams can be directed onto the concave mirror, the effective light-receiving area diameter D2 of the concave mirror needs to be ≥ ≈1.414×26.6 mm=37.6124 mm.

[0061] Assuming the angle θ between the laser incident on the concave mirror and the plane perpendicular to the principal optical axis of the concave mirror is 45°, then the aperture diameter of the concave mirror Φ3 = D2 / sinθ = 37.6124 mm ÷ sin45° ≈ 53.2 mm. Therefore, the diameter Φ2 of the concave mirror must be greater than or equal to the aperture diameter Φ3 = 53.2 mm.

[0062] If nine plano-convex lenses are placed in the incident light path of the focusing unit 6, these nine plano-convex lenses are also arranged in a 3×3 square array. Assuming the diameter of the plano-convex lens Φ1 = 10 mm and the spacing between adjacent plano-convex lenses is L = 10 mm, then the side length H of the square light spot region corresponding to the square array of nine plano-convex lenses is H = 3Φ1 = 3 × 10 mm = 30 mm, and the diameter of the circumcircle of the square corresponding to the square array of nine plano-convex lenses is... ≈1.414×30 mm=42.42 mm.

[0063] To ensure that all nine laser beams collimated by the plano-convex lens can be projected onto the concave mirror, the effective light-receiving area diameter D2 of the concave mirror needs to be ≥ ≈1.414×30 mm=42.42 mm.

[0064] Assuming the collimated laser incident on the concave mirror makes an angle θ = 45° between it and the plane perpendicular to the principal axis of the concave mirror, then the aperture diameter of the concave mirror Φ3 = D2 / sinθ = 42.42 mm ÷ sin45° ≈ 60 mm. Therefore, the diameter of the concave mirror Φ2 ≥ aperture diameter Φ3 = 60 mm.

[0065] As an optional implementation method, such as Figure 2 As shown, the main dimensional parameters of the concave mirror are as follows: diameter Φ2 = 76.2 mm, radius of curvature R2 = 304.8 mm, center thickness Tc2 = 6.1 mm, edge thickness Te2 = 6.35 mm, focal length f = 152.4 mm, and aperture Φ3 ≥ 0.9Φ2. The reflecting surface of the concave mirror is coated with a reflective film with a reflectivity > 95%.

[0066] As an optional implementation method, such as Figure 1 As shown, the present invention may further include N apertures 5 disposed between the output end of the input optical cable 2 and the focusing unit 6, with each of the N apertures 5 corresponding to one of the output ends of the N input optical cables 2. Each aperture 5 controls whether a laser beam can enter the focusing unit 6.

[0067] The advantage of this configuration is that the opening and closing of the aperture 5 allows selection of which laser beams generated by laser 1 can enter the spectrometer 9 for spectral measurement. For example, if only the laser beam generated by a specific laser 1 needs to be measured, the aperture 5 corresponding to that laser beam is opened, while the other apertures 5 are closed, and the spectrometer 9 only measures the spectrum of the laser beam generated by that specific laser 1. If spectral measurements are to be performed on the laser beams generated by all laser 1s, all apertures 5 can be opened. Therefore, the configuration of the aperture 5 greatly improves the flexibility of this invention, allowing for targeted measurements as needed.

[0068] If the collimating lens 4 is placed in the incident light path of the focusing unit 6, the aperture 5 can be placed in the incident light path or the outgoing light path of the collimating lens 4.

[0069] When the aperture 5 is placed in the output light path of the collimating lens 4, that is, when the aperture 5 is placed between the collimating lens 4 and the focusing unit 6, the size design of the aperture 5 can adopt the following principle: the maximum light-passing aperture of the aperture 5 is greater than or equal to the diameter of the collimated laser spot after collimation by the collimating lens 4, and less than or equal to the diameter of the collimating lens 4, so as to ensure that the laser after collimation by the collimating lens 4 can be fully projected onto the focusing unit 6.

[0070] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, various improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A spectroscopic measurement beam combining apparatus, characterized by: The beam combining device is used for converging the laser beams emitted by the N laser devices (1) into one laser beam and then transmitting the laser beam to the optical spectrometer (9); The beam combining device comprises an input optical cable (2), a light converging unit (6) and an output optical cable (8) arranged in sequence along the propagation direction of the optical path; The input optical cable (2) is provided with N input optical cables (2) corresponding to the N laser devices (1) respectively; the exit ends of the N input optical cables (2) are arranged in parallel to transmit the laser beams emitted by the N laser devices (1) to the light converging unit (6) in parallel; The light converging unit (6) converges the N parallel laser beams on the incident optical path into one laser beam on the exit optical path; The output optical cable (8) transmits the laser beam converged by the light converging unit (6) to the optical spectrometer (9); The beam combining device further comprises a collimating lens (4) arranged on the incident optical path or the exit optical path of the light converging unit (6); the collimating lens (4) adjusts the laser beams incident on the light converging unit (6) or the laser beams emitted from the light converging unit (6) into collimated beams; N is an integer greater than or equal to 1.

2. A spectroscopic measurement beam combining device as claimed in claim 1, characterized in that: The light converging unit (6) is a concave mirror or a convex lens.

3. A spectroscopic measurement beam combining device as claimed in claim 2, characterized in that: When the light converging unit (6) is a concave mirror, the laser beams incident on the light converging unit (6) have an included angle θ with the vertical plane of the main optical axis of the light converging unit (6), and the included angle θ is 30°-60°.

4. A spectroscopic measurement beam combining device as claimed in any one of claims 1-3, characterized in that: The exit ends of the N input optical cables (2) are arranged in an array to make the N laser beams incident on the light converging unit (6) arranged in an array; The effective light receiving area of the light converging unit (6) has a diameter greater than the diameter of the circumscribed circle corresponding to the N laser beams arranged in an array; The effective light receiving area of the light converging unit (6) is the projection of the light passing aperture of the light converging unit (6) in the direction perpendicular to the incident direction of the laser beams.

5. A spectroscopic measurement beam combining device as claimed in claim 1, characterized in that: The collimating lens (4) is provided with N collimating lenses (4) corresponding to the N laser beams incident on the light converging unit (6) or the N laser beams emitted from the light converging unit (6) respectively.

6. A spectroscopic measurement beam combining device as claimed in claim 5, characterized in that: The collimating lens (4) is a plano-convex lens.

7. A spectroscopic measurement beam combining device as claimed in claim 6, characterized in that: The diameter of the plano-convex lens is greater than the diameter of the collimated laser beam spot after collimation by the plano-convex lens.

8. A spectroscopic measurement beam combining device as claimed in any one of claims 5-7, characterized in that: When the collimating lens (4) is arranged on the incident optical path of the light converging unit (6), the N collimating lenses (4) are arranged in an array, and the diameter of the circumscribed circle corresponding to the array of the N collimating lenses (4) is less than the diameter of the effective light receiving area of the light converging unit (6). The effective light receiving area of the light converging unit (6) is the projection of the light passing aperture of the light converging unit (6) in the direction perpendicular to the incident direction of the laser beams.

9. A spectroscopic measurement beam combining device as claimed in claim 1, characterized in that: The beam combining device further comprises a light barrier (5) arranged between the exit ends of the input optical cables (2) and the light converging unit (6); the light barrier (5) is provided with N light barriers (5) corresponding to the exit ends of the N input optical cables (2) respectively.

10. A spectroscopic measurement beam combining device as claimed in claim 9, characterized in that: When the collimating lens (4) is arranged on the incident optical path of the light converging unit (6), the light barrier (5) is arranged between the collimating lens (4) and the light converging unit (6). The maximum light passing aperture of the light barrier (5) is greater than the diameter of the collimated laser beam spot after collimation by the collimating lens (4).

Images