A fiber numerical aperture testing device and system
By employing collimation and beam splitting elements in the fiber optic testing device to process the laser beam, the problem of insufficient accuracy and stability of existing NA testers in high-power laser testing is solved, realizing high-precision and high-efficiency fiber numerical aperture measurement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- MAXPHOTONICS CORP
- Filing Date
- 2025-04-14
- Publication Date
- 2026-06-05
Smart Images
Figure CN224327882U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of optical fiber testing, specifically relating to an optical fiber numerical aperture testing device and system. Background Technology
[0002] Fiber numerical aperture, or NA for short, typically characterizes the ability of an optical fiber to receive and transmit optical signals, and is an important parameter for measuring fiber performance. Currently, common NA testers usually use attenuators to attenuate most of the laser power over a specific distance before measuring the numerical aperture of the beam using a detector. However, this testing method has significant limitations in high-power laser testing. As the power of the injected light source continues to increase, existing testing methods suffer from the following main problems:
[0003] Local saturation and nonlinear response of the detector: Since the attenuator cannot completely eliminate high-energy photons, these photons may still enter the photodetector, causing local saturation of the detector, which will cause nonlinear response of the detector and thus affect the accuracy of the test.
[0004] Damage to attenuators and beam distortion: High-power lasers can also damage the attenuators themselves. Moreover, attenuating laser power by stacking multiple attenuators can cause beam distortion, which in turn affects the measurement of the NA value.
[0005] Laser interference inside the test chamber: Existing test chamber designs lack effective partitioning, allowing laser light to easily diffuse throughout the entire chamber. When the laser energy reaches a certain threshold, it can interfere with the NA detector's testing, rendering the test results unreliable.
[0006] In summary, current NA testers on the market have significant shortcomings in high-power laser testing and cannot meet the growing demand for high-power laser applications. Utility Model Content
[0007] In view of this, the main objective of this utility model is to provide a testing device and system for high-power laser NA, so as to solve the problems of inaccurate NA value testing and low stability of the testing device caused by the use of attenuators in the prior art.
[0008] To achieve the above objectives, the technical solution of this utility model is implemented as follows:
[0009] A fiber optic numerical aperture testing device, comprising:
[0010] The fixing part is used to fix the optical fiber to be tested;
[0011] A collimating element is disposed at the light-emitting end of the optical fiber under test and is used to collimate the laser beam emitted from the optical fiber under test. The light-emitting end face of the optical fiber under test is located at the focal position of the collimating element.
[0012] A beam splitter, positioned in the light-emitting direction of the collimating element, is used to separate and guide the first power beam in the laser beam to exit along the first light-emitting path; and
[0013] A detection element is disposed on the first light output path of the beam splitter to scan the first power beam and depict a two-dimensional energy distribution diagram of the cross-section at the waist of the first power beam.
[0014] Preferably, the system further includes a beam receiver, and the beam splitter is also used to separate and guide the second power beam in the laser beam to exit along a second light exit path, the second light exit path being different from the first light exit path. The beam receiver is disposed on the second light exit path of the beam splitter and is used to receive the second power beam.
[0015] Preferably, the device further includes a light source, which is coaxially arranged with the optical fiber under test to accurately inject the light beam into the optical fiber under test.
[0016] Preferably, the light source is a pump source.
[0017] Preferably, it further includes a reflective element, which is disposed between the first power beam output end and the detection element, for reflecting the first power beam to the detection element.
[0018] Preferably, the detection element is further configured to move along a direction perpendicular to the propagation direction of the first power beam to fully scan the cross-section of the first power beam.
[0019] Preferably, the detection element is a PD photosensitive strip, which includes multiple photodiodes arranged in a linear or planar array.
[0020] Preferably, the fixing part adopts one of the following: V-groove, U-groove, rectangular groove, trapezoidal groove and elastic clamping groove.
[0021] Preferably, the collimating element is a plano-convex lens.
[0022] As another aspect of this application, a fiber optic numerical aperture testing system is also proposed, comprising a host computer and the fiber optic numerical aperture testing device described in any of the above claims, wherein the host computer and the fiber optic numerical aperture testing device are connected.
[0023] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0024] 1. By using a collimating element to collimate the laser beam, a stable spot can be measured within the Rayleigh length, ensuring the directionality and consistency of the laser beam during propagation, and providing a reliable basis for subsequent testing and analysis;
[0025] 2. The laser beam is split into a first power beam and a second power beam based on the refraction and reflection of light by a beam splitting element, while maintaining the energy distribution characteristics of the original laser beam. It does not interfere with the energy distribution of the laser beam, and no additional heat or light scattering is generated during the beam splitting process. The test accuracy is high, the test results are more accurate, and the device stability is also higher.
[0026] 3. The first power beam obtained by the beam splitter can be directly scanned by the detector to obtain the two-dimensional energy distribution map of the beam, directly acquire the energy distribution, realize dynamic measurement, and improve measurement efficiency.
[0027] The testing principle of the NA testing device in this invention is that the effective diameter D of the beam can be obtained from the two-dimensional energy distribution diagram (which can be understood as the beam diameter of the cross-section at the waist of the Gaussian beam). Since the light-emitting end face of the optical fiber is located at the focal point of the collimating element, when the focal length of the collimating element is known to be f, the 1 / 2 beam divergence angle θ = arctan(D / 2f). According to the principle of fiber optics, the numerical aperture NA of the optical fiber is n0*sinθ, where n0 is the air refractive index, which can be regarded as 1. Therefore, it can be concluded that NA = sin(arctan(D / 2f)). Thus, the numerical aperture of the optical fiber under test can be accurately calculated. Attached Figure Description
[0028] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this invention, illustrate exemplary embodiments of the present invention and, together with their description, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:
[0029] Figure 1 This is a schematic diagram of the structure of a testing device for high-power laser NA provided in an embodiment of the present invention.
[0030] In the figure, 1-fixed part, 2-collimating element, 3-splitting element, 4-detecting element, 5-light receiver, 6-reflecting element, 11-fiber under test, 31-first light output path, 32-second light output path. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0032] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.
[0033] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes that element.
[0034] This utility model provides a fiber optic numerical aperture testing device, such as... Figure 1 As shown, it includes: a fixing part 1, a collimating element 2, a beam splitting element 3, and a detection element 4;
[0035] The fixing part 1 is used to fix the optical fiber 11 to be tested;
[0036] The collimating element 2 is disposed at the light-emitting end of the optical fiber 11 under test, and is used to collimate the laser beam emitted from the optical fiber 11 under test. The light-emitting end face of the optical fiber 11 under test is located at the focal position of the collimating element 2.
[0037] The beam splitter 3 is disposed in the light output direction of the collimating element 2, and is used to separate the first power beam in the laser beam and guide it to be emitted along the first light output path 31.
[0038] The detection element 4 is disposed on the first light output path 31 of the beam splitter 3, and is used to scan the first power beam and draw a two-dimensional diagram of the energy distribution of the cross section at the waist of the first power beam.
[0039] This invention uses a collimating element 2 to collimate the laser beam, enabling the measurement of a stable and accurate spot within the Rayleigh length. This ensures the directionality and consistency of the laser beam during propagation, providing a reliable foundation for subsequent testing and analysis. Furthermore, a beam splitting element 3 divides the laser beam into a first power beam and a second power beam based on light refraction and reflection, while maintaining the original energy distribution characteristics of the laser beam. This avoids interference with the energy distribution and generates no additional heat or light scattering during beam splitting, resulting in higher testing accuracy, more accurate test results, and greater device stability. The first power beam obtained by the beam splitting element 3 can be directly scanned by the detection element 4 to obtain a two-dimensional energy distribution map of the beam, directly acquiring the energy distribution and enabling dynamic measurement, which improves measurement efficiency.
[0040] Please continue to refer to Figure 1 The optical fiber numerical aperture testing device also includes a light-receiving tube 5. The beam splitter is also used to separate and guide the second power beam in the laser beam to be emitted along the second light-emitting path 32, which is different from the first light-emitting path 31. The light-receiving tube 5 is disposed on the second light-emitting path 32 of the beam splitter 3 to receive the second power beam.
[0041] It is understood that the power of the first power beam is lower than that of the second power beam in order to facilitate reception by the detection element 4.
[0042] Optionally, the fixing part used to fix the optical fiber under test can be any one of V-groove, U-groove, rectangular groove, trapezoidal groove and elastic clamping groove.
[0043] In this embodiment, the fixing part 1 is preferably a V-groove, which can stably and accurately fix the optical fiber 11 under test, ensuring stability and accuracy during the testing process. Exemplarily, the V-groove is a groove-shaped structure with a V-shaped cross-section, used for precise positioning and fixing of the optical fiber 11 under test. Through the V-shaped cross-section of the V-groove, the optical fiber can be precisely positioned at a specific location, ensuring that the light-emitting end of the optical fiber 11 under test is located at the focal point of the collimating element 2. Furthermore, the V-groove allows for quick fixing and releasing of the optical fiber 11 under test, thereby saving testing time and improving testing efficiency.
[0044] In this embodiment, the collimating element 2 is disposed at the light-emitting end of the optical fiber 11 under test, and is used to collimate the laser beam emitted from the optical fiber 11 under test, so that the laser beam can propagate in the form of parallel light, which facilitates subsequent beam splitting and testing.
[0045] It is understood that a stable and accurate light spot can be measured within the Rayleigh length using the collimating element 2.
[0046] The collimating element 2 ensures the directionality and consistency of the laser beam during propagation, providing a reliable basis for subsequent testing and analysis.
[0047] In one embodiment, the collimating element 2 is preferably a plano-convex mirror, which can collimate the laser beam into a parallel beam, facilitating subsequent testing and analysis.
[0048] The optical fiber under test (IDT) 11 and the collimating element 2 are coaxial, and the light-emitting end face of the IDT 11 is located at the focal point of the collimating element 2. This allows the light beam from the IDT 11 to enter the collimating element 2 more accurately, thereby reducing optical signal loss and improving coupling efficiency. The coaxial configuration also helps maintain the directionality and shape of the light beam, reducing beam divergence and distortion. Furthermore, the distance required to test the NA can be determined directly using the known focal length of the collimating element 2, eliminating the need for additional distance testing, simplifying the testing process, reducing sources of error during testing, and thus improving testing accuracy and efficiency.
[0049] In this embodiment, the beam splitting element 3 is disposed on the light output path of the collimating element 2, which can split the laser beam into a first power beam and a second power beam, and make them exit along different paths, so as to facilitate different subsequent processing.
[0050] In one embodiment, the beam splitter 3 is preferably a high-transmittance, low-reflection prism to ensure that while splitting the first power beam, the transmittance of the second power beam is minimized.
[0051] In this embodiment, the detection element 4 is disposed on the first light output path 31 of the beam splitter 3. The detection element 4 scans the first power beam and plots a two-dimensional energy distribution diagram of the cross-section of the first power beam.
[0052] Furthermore, the detection element 4 can move perpendicular to the laser beam propagation direction to comprehensively scan the cross-section of the laser beam, thereby obtaining more accurate energy distribution information. As the detection element 4 moves, it collects a series of energy distribution data at different locations on the laser beam cross-section. After processing, a two-dimensional energy distribution map of the laser beam cross-section can be generated. Through the two-dimensional energy distribution map, users can intuitively understand the energy distribution of the laser beam, including key parameters such as energy peak value and energy distribution uniformity.
[0053] Optionally, the detection element 4 may be a PD photosensitive strip, a photodetector, or other components.
[0054] In this embodiment, the second power beam is received and processed by the light receiver 5.
[0055] The light-collecting tube 5 can effectively absorb and disperse the energy of the second power beam, preventing it from damaging the testing device. Preferably, the light-collecting tube 5 is equipped with a cooling system to prevent internal components from overheating under high-power laser irradiation.
[0056] Optionally, the light receiver 5 is configured as a water-cooled light receiver, with its inner wall made of a high thermal conductivity material, such as copper or aluminum, and coated with a light-absorbing coating (such as a black anodized layer or a silicon carbide coating), which is beneficial for absorbing the energy of the second power beam. The water-cooled light receiver is also designed with a continuous and closed circulating cooling water channel, which is arranged around the inner wall to supply cooling water flow. When the test device is in operation, the water-cooled light receiver carries away the heat generated by the second power beam through the circulating cooling water, thus preventing the components from overheating.
[0057] Optionally, the receiver 5 can also be configured as an air-cooled receiver.
[0058] In one embodiment, to reduce the size of the testing device, a reflective element 6 is also included. The reflective element 6 is disposed on the first light-emitting path 31 of the beam splitter 3 and is used to reflect the first power beam to the detector element 4. The reflective element 3 refracts the light path, allowing the beam to propagate along a predetermined path. The reflective element 6 is preferably a right-angle mirror. The first power beam is reflected by the right-angle mirror, and the reflection path is parallel to the second power beam. The parallelism of the two beams allows for more efficient use of space, avoids beam crossing and interference, and helps simplify the device structure, improving the compactness and integration of the device.
[0059] In this embodiment, a light source is also included for generating laser light and injecting it into the optical fiber 11 under test.
[0060] It is understood that the light source, the optical fiber under test 11, and the collimating element 2 are coaxial. The laser generated by the light source is directly injected into the optical fiber under test 11. Through the optical fiber under test 11, it can enter the collimating element 2 more accurately, thereby reducing the loss of optical signal and improving the coupling efficiency.
[0061] The testing principle of the NA testing device in this invention is that the effective diameter D of the beam can be obtained from the two-dimensional energy distribution diagram (which can be understood as the beam diameter of the cross-section at the waist of the Gaussian beam). Since the light-emitting end face of the optical fiber is located at the focal point of the collimating element, when the focal length of the collimating element is known to be f, the 1 / 2 beam divergence angle θ = arctan(D / 2f). According to the principle of fiber optics, the numerical aperture NA of the optical fiber is n0*sinθ, where n0 is the air refractive index, which can be regarded as 1. Therefore, it can be concluded that NA = sin(arctan(D / 2f)). Thus, the numerical aperture of the optical fiber under test can be accurately calculated.
[0062] As another aspect of this application, a fiber optic numerical aperture testing system is also proposed, comprising a host computer and the fiber optic numerical aperture testing device described in any of the above claims, wherein the host computer and the fiber optic numerical aperture testing device are connected to display the two-dimensional energy distribution map.
[0063] 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.
[0064] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.
Claims
1. A fiber optic numerical aperture testing device, characterized in that, include: The fixing part is used to fix the optical fiber to be tested; A collimating element is disposed at the light-emitting end of the optical fiber under test and is used to collimate the laser beam emitted from the optical fiber under test. The light-emitting end face of the optical fiber under test is located at the focal position of the collimating element. A beam splitter, positioned in the light-emitting direction of the collimating element, is used to separate and guide the first power beam in the laser beam to exit along the first light-emitting path; and A detection element is disposed on the first light output path of the beam splitter to scan the first power beam and depict a two-dimensional energy distribution diagram of the cross-section at the waist of the first power beam.
2. The optical fiber numerical aperture testing device according to claim 1, characterized in that, It also includes a light-receiving tube, and the beam splitter is further used to separate and guide the second power beam in the laser beam to be emitted along a second light-emitting path, which is different from the first light-emitting path. The light-receiving tube is disposed on the second light-emitting path of the beam splitter and is used to receive the second power beam.
3. The optical fiber numerical aperture testing device according to claim 1, characterized in that, It also includes a light source, which is coaxially arranged with the optical fiber under test to accurately inject the light beam into the optical fiber under test.
4. The optical fiber numerical aperture testing device according to claim 3, characterized in that, The light source is a pump source.
5. The optical fiber numerical aperture testing device according to claim 1, characterized in that, It also includes a reflective element, which is disposed between the first power beam output end and the detection element, for reflecting the first power beam to the detection element.
6. The optical fiber numerical aperture testing device according to claim 1, characterized in that, The detection element is also used to move along a direction perpendicular to the propagation direction of the first power beam to fully scan the cross-section of the first power beam.
7. The optical fiber numerical aperture testing device according to claim 1, characterized in that, The detection element employs a PD photosensitive strip, which comprises multiple photodiodes arranged in a linear or planar array.
8. The optical fiber numerical aperture testing device according to claim 1, characterized in that, The fixing part adopts one of the following: V-groove, U-groove, rectangular groove, trapezoidal groove and elastic clamping groove.
9. The optical fiber numerical aperture testing device according to claim 1, characterized in that, The collimating element is a plano-convex mirror.
10. A fiber optic numerical aperture testing system, characterized in that, It includes a host computer and the fiber optic numerical aperture testing device according to any one of claims 1-9, wherein the host computer and the fiber optic numerical aperture testing device are connected.