Optical device, grating diffraction efficiency testing apparatus, system, method and controller

Abstract

This invention discloses an optical device, a grating diffraction efficiency testing apparatus, system, method, and controller. Probe light with different incident angles is incident on a grating through the optical device, and after diffraction by the grating, diffracted light is generated and exits from the optical device to test the diffraction efficiency of the grating. The optical path lengths of the probe light and the corresponding diffracted light at different incident angles are the same within the optical device. Therefore, since the probe light at different incident angles has the same optical path length within the optical device, it ensures that the probe light at different incident angles has the same optical loss during propagation within the optical device. Furthermore, since the diffracted light has the same optical path length within the optical device, it ensures that the diffracted light also has the same optical loss during propagation within the optical device. This reduces the influence of optical loss within the optical device and helps improve the accuracy of diffraction efficiency testing.

Description

Technical Field

[0001] This invention relates to the field of grating testing technology, and in particular to an optical device, a grating diffraction efficiency testing apparatus, system, method and controller. Background Technology

[0002] With the rapid development of optical technology, gratings, as important diffraction components, are widely used in the optical field. The diffraction efficiency of a grating determines its quality, so it is necessary to accurately test the diffraction efficiency of a grating.

[0003] In related technologies, when testing the diffraction efficiency of a grating, it is necessary to measure the probe light power P1 before the beam is incident on the prism, and the diffracted light power P2 after the beam is refracted from the prism into the air. The diffraction efficiency of the grating is calculated by the ratio of the two light powers, P2 / P1. However, when probe light with different incident angles is incident on the grating, the probe light with different incident angles has different light losses (i.e., light power losses) when propagating in the prism. Furthermore, the diffracted light formed by probe light with different incident angles has different exit angles, and the diffracted light with different exit angles also has different light losses when propagating in the prism, which greatly affects the accuracy of the grating diffraction efficiency test. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first objective of this invention is to provide an optical device in which, because the optical path length of probe light with different incident angles is the same, the probe light with different incident angles propagates with the same optical loss within the optical device. Furthermore, because the optical path length of different diffracted light is also the same within the optical device, the diffracted light also propagates with the same optical loss within the optical device, thus reducing the impact of optical loss in the optical device and improving the accuracy of diffraction efficiency testing.

[0005] The second objective of this invention is to provide a grating diffraction efficiency testing device.

[0006] The third objective of this invention is to provide a grating diffraction efficiency testing system.

[0007] The fourth objective of this invention is to propose a method for testing grating diffraction efficiency.

[0008] The fifth objective of this invention is to provide a controller.

[0009] To achieve the above objectives, a first aspect of the present invention provides an optical device in which probe light at different incident angles is incident on a grating through the optical device, and after diffraction by the grating, diffracted light is generated and emitted from the optical device to test the diffraction efficiency of the grating. In this device, the probe light at different incident angles and the corresponding diffracted light have the same optical path length.

[0010] According to the optical device of the present invention, when testing the diffraction efficiency of a grating, probe light with different incident angles is incident onto the grating through the optical device. After the probe light is diffracted by the grating, diffracted light is generated and emitted from the optical device. Since the probe light with different incident angles has the same optical path in the optical device, it is ensured that the probe light with different incident angles has the same optical loss when propagating in the optical device. Furthermore, since the diffracted light has the same optical path in the optical device, it is also ensured that the diffracted light has the same optical loss when propagating in the optical device. This reduces the influence of optical loss in the optical device and helps to improve the accuracy of diffraction efficiency testing.

[0011] According to one embodiment of the present invention, the optical device includes a first prism having a first curved surface. Probe light with different incident angles is incident on a grating through the first curved surface and diffracted by the grating to generate diffracted light that exits from the first curved surface. The curvature of each point on the surface of the first curved surface is the same and the curvature centers coincide, and the curvature centers are located on the grating.

[0012] According to one embodiment of the present invention, the first curved surface is the arcuate surface of a cylindrical prism or the arcuate surface of a spherical prism.

[0013] According to one embodiment of the present invention, the optical device further includes a grating substrate, which is located between the first prism and the grating, and the refractive index of the first prism is the same as that of the grating substrate.

[0014] According to one embodiment of the present invention, the center of curvature is located on the side surface of the grating close to the grating substrate; or, the center of curvature is located on the side surface of the grating away from the grating substrate; or, the center of curvature is located inside the grating.

[0015] According to one embodiment of the present invention, the grating is a reflective grating.

[0016] According to one embodiment of the present invention, the optical device includes a first prism and a second prism. The first prism has a first curved surface and the second prism has a second curved surface. Probe light with different incident angles is incident on a grating through the first curved surface and diffracted by the grating to generate diffracted light that exits from the second curved surface. The curvature of the surface of the first curved surface is the same at all points, and the curvature of the surface of the second curved surface is the same at all points. The curvature center of the surface of the first curved surface coincides with the curvature center of the surface of the second curved surface, and the curvature center is located on the grating.

[0017] According to one embodiment of the present invention, the first curved surface is the arc surface of a cylindrical prism or the arc surface of a spherical prism, and the second curved surface is the arc surface of a cylindrical prism or the arc surface of a spherical prism.

[0018] According to one embodiment of the present invention, the optical device further includes a grating substrate located between the grating and the second prism, wherein the refractive index of the second prism is the same as that of the grating substrate.

[0019] According to one embodiment of the present invention, the center of curvature is located on the side surface of the grating close to the grating substrate; or, the center of curvature is located on the side surface of the grating away from the grating substrate; or, the center of curvature is located inside the grating.

[0020] According to one embodiment of the present invention, the grating is a transmission grating.

[0021] According to one embodiment of the present invention, the refractive index of the grating is different from the refractive index of the grating substrate.

[0022] According to one embodiment of the present invention, the grating is a one-dimensional grating or a two-dimensional grating.

[0023] To achieve the above objectives, a second aspect of the present invention provides a grating diffraction efficiency testing device, including the optical components as described in the first aspect embodiment.

[0024] According to the grating diffraction efficiency testing apparatus of the present invention, by providing the aforementioned optical device, when testing the diffraction efficiency of a grating, probe light with different incident angles is incident onto the grating through the optical device. After the probe light is diffracted by the grating, diffracted light is generated and emitted from the optical device. Since the probe light with different incident angles has the same optical path in the optical device, it is ensured that the probe light with different incident angles has the same optical loss when propagating in the optical device. Furthermore, since the different diffracted lights have the same optical path in the optical device, it is also ensured that the different diffracted lights have the same optical loss when propagating in the optical device. This reduces the influence of optical loss in the optical device and helps to improve the accuracy of diffraction efficiency testing.

[0025] According to one embodiment of the present invention, the apparatus further includes:

[0026] An optical power meter is used to detect the power of diffracted light emitted from an optical device in order to determine the diffraction efficiency of a grating based on the power of the diffracted light and the power of the probe light.

[0027] To achieve the above objectives, a third aspect of the present invention provides a grating diffraction efficiency testing system, including the grating diffraction efficiency testing device as described in the second aspect embodiment.

[0028] According to the grating diffraction efficiency testing system of the present invention, by providing the above-mentioned grating diffraction efficiency testing device, when testing the diffraction efficiency of the grating, probe light with different incident angles is incident on the grating through an optical device. After the probe light is diffracted by the grating, diffracted light is generated and emitted from the optical device. Since the probe light with different incident angles has the same optical path in the optical device, it is ensured that the probe light with different incident angles has the same optical loss when propagating in the optical device. Furthermore, since the optical path of different diffracted light is also the same in the optical device, it is ensured that the different diffracted light also has the same optical loss when propagating in the optical device. This reduces the influence of optical loss in the optical device and helps to improve the accuracy of diffraction efficiency testing.

[0029] According to one embodiment of the present invention, the system further includes: a first rotating device and a second rotating device, wherein the grating is driven to rotate by the first rotating device and the optical power meter is driven to rotate by the second rotating device, and the optical power meter follows the rotation of the grating via the second rotating device when the grating is driven to rotate by the first rotating device.

[0030] To achieve the above objectives, a fourth aspect of the present invention provides a method for testing grating diffraction efficiency, applied to a grating diffraction efficiency testing system as described in the third aspect embodiment, the method comprising:

[0031] Detecting the power of diffracted light emitted from an optical device;

[0032] The diffraction efficiency of the grating is determined based on the power of the diffracted light and the power of the probe light.

[0033] According to the grating diffraction efficiency testing method of the present invention, the power of diffracted light emitted from the optical device is detected, and the diffraction efficiency of the grating is determined based on the power of the diffracted light and the power of the probe light. Since the probe light with different incident angles has the same optical path in the optical device, it is ensured that the probe light with different incident angles has the same optical loss when propagating in the optical device. Furthermore, since the optical path of different diffracted lights is also the same in the optical device, it is ensured that the different diffracted lights also have the same optical loss when propagating in the optical device. This reduces the influence of optical loss in the optical device and helps to improve the accuracy of diffraction efficiency testing.

[0034] According to one embodiment of the present invention, when the grating is a reflective grating, determining the diffraction efficiency of the grating based on the power of the diffracted light and the power of the probe light includes:

[0035] The ratio of the power of the diffracted light to the optical power loss rate of the first prism is obtained to obtain the first ratio.

[0036] The second ratio is obtained by multiplying the power of the probe light by the power loss rate of the first prism.

[0037] The diffraction efficiency of the grating is determined based on the first ratio and the second ratio.

[0038] According to one embodiment of the present invention, when the grating is a transmission grating, determining the diffraction efficiency of the grating based on the power of the diffracted light and the power of the probe light includes:

[0039] The ratio of the power of the diffracted light to the optical power loss rate of the second prism is obtained to obtain the third ratio;

[0040] The fourth ratio is obtained by multiplying the power of the probe light by the power loss rate of the first prism.

[0041] The diffraction efficiency of the grating is determined based on the third and fourth ratios.

[0042] According to one embodiment of the present invention, the method further includes:

[0043] The rotation angle of the second rotating device is determined based on the rotation angle of the first rotating device.

[0044] According to one embodiment of the present invention, determining the rotation angle of the second rotating device based on the rotation angle of the first rotating device includes:

[0045] The reference grating vector is determined based on the first reference light vector of the reference probe light within the grating and the second reference light vector of the reference diffracted light corresponding to the reference probe light within the grating.

[0046] When the first rotating device rotates at a preset angle, the rotation angle of the second rotating device is determined based on the preset angle, the first reference light vector, the second reference light vector, and the reference grating vector.

[0047] According to one embodiment of the present invention, determining the rotation angle of the second rotating device based on a preset angle, a first reference light vector, a second reference light vector, and a reference grating vector includes:

[0048] Based on the preset angle and the first reference light vector, determine the first light vector of the probe light after rotation;

[0049] Based on the first light vector and the reference grating vector, determine the second light vector of the diffracted light after rotation;

[0050] The rotation angle of the second rotating device is determined based on the second light vector and the second reference light vector.

[0051] According to one embodiment of the present invention, the method further includes:

[0052] Obtain the grating vector of the grating with maximum diffraction efficiency;

[0053] The quality of the grating is determined by detecting its vector characteristics.

[0054] To achieve the above objectives, a fifth aspect of the present invention provides a controller, characterized in that it includes: a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the grating diffraction efficiency testing method of the fourth aspect embodiment.

[0055] According to the controller of the present invention, the above-described grating diffraction efficiency testing method ensures that the probe light with different incident angles has the same optical path length in the optical device, thus guaranteeing that the probe light with different incident angles has the same optical loss when propagating in the optical device. Furthermore, since the optical path length of different diffracted lights is also the same in the optical device, it also guarantees that the different diffracted lights have the same optical loss when propagating in the optical device, thereby reducing the influence of optical loss in the optical device and improving the accuracy of diffraction efficiency testing.

[0056] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of a grating diffraction efficiency testing system according to an embodiment of the present invention;

[0058] Figure 2 This is a schematic diagram showing that the center of curvature of the first prism according to an embodiment of the present invention is located inside the grating;

[0059] Figure 3 This is a schematic diagram showing that the center of curvature of the first prism according to an embodiment of the present invention is located on the surface of the grating away from the first prism.

[0060] Figure 4 This is a schematic diagram showing that the center of curvature of the first prism according to an embodiment of the present invention is located on the surface of the grating near the first prism.

[0061] Figure 5 This is a schematic diagram of a first prism, a grating substrate, and a grating according to an embodiment of the present invention;

[0062] Figure 6 This is a schematic diagram of a first prism, a second prism, and a grating according to an embodiment of the present invention;

[0063] Figure 7 This is a schematic diagram of a first prism, a second prism, a grating substrate, and a grating according to an embodiment of the present invention;

[0064] Figure 8 This is a schematic diagram of a first prism and grating according to an embodiment of the present invention;

[0065] Figure 9A schematic diagram of a first prism according to an embodiment of the present invention;

[0066] Figure 10 This is a schematic diagram of a first prism and a grating substrate according to an embodiment of the present invention;

[0067] Figure 11 This is a schematic diagram of a second prism according to an embodiment of the present invention;

[0068] Figure 12 This is a schematic diagram of a second prism and a grating substrate according to an embodiment of the present invention;

[0069] Figure 13 A perspective view and a projection view of a grating diffraction efficiency testing device corresponding to a one-dimensional grating according to an embodiment of the present invention;

[0070] Figure 14 A perspective view of a grating diffraction efficiency testing device corresponding to a two-dimensional grating according to an embodiment of the present invention;

[0071] Figure 15 This is a schematic flowchart of a grating diffraction efficiency testing method according to an embodiment of the present invention;

[0072] Figure 16 This is a diagram showing the relationship between the rotation angle of the first rotating device and the rotation angle of the second rotating device according to an embodiment of the present invention.

[0073] Figure 17 (a) is a schematic diagram of the angle of the probe light and the angle of the diffracted light in the design according to an embodiment of the present invention;

[0074] Figure 17 (b) is a schematic diagram of the incident angle of the probe light and the exit angle of the diffracted light when the diffraction efficiency is maximized according to an embodiment of the present invention;

[0075] Figure 18 This is a schematic block diagram of a controller according to an embodiment of the present invention.

[0076] Figure label:

[0077] Grating diffraction efficiency testing system 100;

[0078] Grating diffraction efficiency testing device 10;

[0079] Optical device 1; Probe light 11;

[0080] First prism 2; First curved face 21;

[0081] Optical power meter 3;

[0082] Grating 4; Diffraction beam 41;

[0083] Second prism 5; Second curved face 51;

[0084] Grating substrate 6;

[0085] First rotating device 7;

[0086] Second rotating device 8;

[0087] Center of curvature P;

[0088] Controller 200;

[0089] Memory 210; Processor 220. Detailed Implementation

[0090] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0091] The optical device 1, grating diffraction efficiency testing device 10, grating diffraction efficiency testing system 100, grating diffraction efficiency testing method and controller 200 proposed in the embodiments of the present invention are described below with reference to the accompanying drawings.

[0092] like Figures 1-14 As shown, in the optical device 1 according to the first aspect embodiment of the present invention, probe light 11 with different incident angles is incident on grating 4 through optical device 1, and after being diffracted by grating 4, diffracted light 41 is generated and emitted from optical device 1 to perform diffraction efficiency test on grating 4, wherein the probe light 11 with different incident angles and the corresponding diffracted light 41 have the same optical path in optical device 1.

[0093] Specifically, the light source is used to emit probe light 11 with different incident angles to the optical device 1. It is understood that the power of the probe light 11 needs to be detected before it is incident on the grating 4. Optionally, a detection device can be set inside the light source or at the exit of the light source to detect the power of the probe light 11 before it enters the optical device 1. The specific setting method can be selected according to actual needs and is not specifically limited here.

[0094] When the probe light 11 with different incident angles is incident on the grating 4 through the optical device 1, the probe light 11 is diffracted by the grating 4 to generate diffracted light 41 which is emitted from the optical device 1. With this setup, the diffraction efficiency of the grating 4 can be tested by obtaining the power of the diffracted light 41 emitted from the optical device 1 and the power of the probe light 11 obtained in the previous step.

[0095] It should be noted that when the probe light 11 is incident on the grating 4 at different angles, the corresponding diffracted light 41 generated after the probe light 11 is diffracted by the grating 4 also has different exit angles. At the same time, when the probe light 11 and the diffracted light 41 are transmitted in the optical device 1, the probe light 11 and the diffracted light 41 will experience power attenuation. If the probe light 11 and the corresponding diffracted light 41 with different incident angles have different optical paths in the optical device 1, then the probe light 11 and the corresponding diffracted light 41 with different incident angles will experience different degrees of power attenuation when propagating in the optical device 1, which greatly reduces the accuracy of the diffraction efficiency test.

[0096] Based on this, this application ensures that the optical path length of the probe light 11 and the corresponding diffracted light 41 at different incident angles is the same in the optical device 1, so that the power loss of the probe light 11 at different incident angles when it is incident on the grating 4 through the optical device 1 is the same, and the power loss of the corresponding diffracted light 41 when it is emitted through the optical device 1 is also the same. This ensures the consistency of the power loss of the probe light 11 and the diffracted light 41 in the optical device 1, which is beneficial to improving the accuracy of diffraction efficiency testing.

[0097] According to the optical device 1 of the present invention, when performing diffraction efficiency testing on the grating 4, probe light 11 with different incident angles is incident on the grating 4 through the optical device 1. After the probe light 11 is diffracted by the grating 4, diffracted light 41 is generated and emitted from the optical device 1. Since the probe light 11 with different incident angles has the same optical path in the optical device 1, it is ensured that the probe light 11 with different incident angles has the same optical loss when propagating in the optical device 1. Furthermore, since the diffracted light 41 with different incident angles also has the same optical path in the optical device 1, it is ensured that the diffracted light 41 with different incident angles also has the same optical loss when propagating in the optical device 1. This reduces the influence of optical loss in the optical device 1 and is beneficial to improving the accuracy of diffraction efficiency testing.

[0098] In some embodiments of the present invention, such as Figure 2 As shown, the optical device 1 includes a first prism 2, which has a first curved surface 21. Probe light 11 with different incident angles is incident on the grating 4 through the first curved surface 21. After being diffracted by the grating 4, diffracted light 41 is generated and emitted from the first curved surface 21. The curvature of each point on the surface of the first curved surface 21 is the same and the curvature center P coincides. The curvature center P is located on the grating 4.

[0099] Specifically, the curvature of each point on the surface of the first curved part 21 of the first prism 2 is the same and the curvature center P coincides. That is to say, when the probe light 11 with different incident angles enters the first prism 2 through the first curved part 21, it is ensured that the probe light 11 with different incident angles is directed towards the curvature center P after entering the first prism 2. And since the curvature of each point on the first curved part 21 is the same, it is ensured that the optical path of the probe light 11 with different incident angles from the incident point of the first prism 2 to the curvature center P is the same.

[0100] Furthermore, the probe light 11, after being diffracted by the grating 4, generates diffracted light 41, which is reflected from the grating 4 to the first prism 2. Since the curvature center P of the first prism 2 is located on the grating 4, as... Figures 2-4 As shown, the diffracted light 41 generated by the grating 4 is directed from the curvature center P to the first prism 2. Since the curvature is the same at each point of the first curved surface 21, the diffracted light 41 with different exit angles has the same optical path in the first prism 2.

[0101] Therefore, by setting a first curved surface 21 with the same curvature at each point on the surface of the first prism 2 and the curvature centers P coinciding, the optical path of the probe light 11 with different incident angles in the first prism 2 is the same, and the optical path of the diffracted light 41 with different exit angles in the first prism 2 is the same. This ensures the consistency of light loss of different probe lights 11 in the first prism 2 and the consistency of light loss of different diffracted lights 41 in the first prism 2, which is beneficial to improving the accuracy of diffraction efficiency testing.

[0102] In some embodiments of the present invention, such as Figures 2-5 As shown, the first curved surface 21 is either the curved surface of a cylindrical prism or the curved surface of a spherical prism. That is, the first curved surface 21 can be constructed as the curved surface of a cylindrical prism or as the curved surface of a spherical prism. For example, the first curved surface 21 may not be a whole piece. For example, the first prism 2 can be half or a quarter of a cylindrical prism, or it can be half or a quarter of a spherical prism. This configuration ensures that the first curved surface 21 has the same curvature and the curvature centers P coincide. Both cylindrical and spherical prisms are easy to manufacture, simplifying the manufacturing difficulty of the first prism 2.

[0103] In some embodiments of the present invention, such as Figures 2-5 As shown, the optical device 1 also includes a grating substrate 6, which is located between the first prism 2 and the grating 4, and the refractive index of the first prism 2 is the same as that of the grating substrate 6.

[0104] Specifically, the optical device 1 may further include a grating substrate 6. Optionally, the grating substrate 6 is a glass matching liquid with the same refractive index as the first prism 2. The first prism 2 is bonded to the grating 4 by the glass matching liquid. The glass matching liquid eventually solidifies into the grating substrate 6 and is located between the first prism 2 and the grating 4. The grating substrate 6 has the same refractive index as the first prism 2. Figures 2-5 As shown, when the probe light 11 enters the grating substrate 6 from the first prism 2, the probe light 11 will not be refracted at the junction of the first prism 2 and the grating substrate 6, thus preventing a change in the direction of the light. This ensures the consistency of the transmission direction of the probe light 11, meaning that the direction of the probe light 11 will not change during its transmission through the first prism 2 and the grating substrate 6. Further, referring to... Figures 2-5 As shown, the diffracted light 41 enters the first prism 2 through the grating substrate 6. Since the refractive index of the first prism 2 is the same as that of the grating substrate 6, the diffracted light 41 will not be refracted at the junction of the first prism 2 and the grating substrate 6, thus preventing the change of the light direction. This ensures the consistency of the transmission direction of the diffracted light 41, that is, the direction of the diffracted light 41 will not change during the transmission process between the first prism 2 and the grating substrate 6. Therefore, it is ensured that the probe light 11 and the diffracted light 41 have the same optical path during the transmission process between the first prism 2 and the grating substrate 6.

[0105] It should be noted that the grating substrate 6 may not be placed between the first prism 2 and the grating 4. That is, if it is desired to remove the grating substrate 6 between the first prism 2 and the grating 4 during testing to eliminate the influence of the grating substrate 6 on optical power loss, a "conjugate" method can be used, such as... Figure 8 As shown, it can eliminate the need for a bonding operation of the refractive index glass matching liquid, and at this time the first prism 2 is a hemispherical curved prism.

[0106] In some embodiments of the present invention, such as Figures 2-4 As shown, the center of curvature P is located on the surface of grating 4 closest to the grating substrate 6; or, the center of curvature P is located on the surface of grating 4 furthest from the grating substrate 6; or, the center of curvature P is located inside grating 4. That is, as... Figure 2 As shown, the curvature center P can be located inside grating 4, such as... Figure 3 As shown, the center of curvature P can also be located on the surface of the grating 4 away from the grating substrate 6, such as... Figure 4 As shown, the curvature center P can also be located on the side surface of the grating 4 near the grating substrate 6, that is, it is sufficient to ensure that the curvature center P of the first prism 2 is located on the grating 4. No specific restrictions are made here. Since the thickness of the grating 4 is relatively thin, the light loss on the grating 4 can be ignored when actually calculating the light loss. With this setting, it can be approximately assumed that the light loss of the probe light 11 with different incident angles in the first prism 2 is the same, and the light loss of the corresponding diffracted light 41 in the first prism 2 is the same.

[0107] In some embodiments of the present invention, the grating 4 is a reflective grating. Specifically, as shown in the figure... Figures 2-5 As shown, a reflective grating is used to reflect the probe light 11. The first prism 2 of the optical device 1 is located on one side of the grating 4. When the light source emits probe light 11 with different incident angles towards the grating 4, the probe light 11 with different incident angles is incident on the grating 4 through the first prism 2. After the probe light 11 is incident on the grating 4, it is diffracted by the grating 4 to generate diffracted light 41, which is reflected from the grating 4 back to the first prism 2. The diffracted light 41 passes through the first prism 2 and exits. It can be understood that the optical path lengths of the probe light 11 with different incident angles and the corresponding diffracted light 41 in the first prism 2 are the same. That is to say, the power loss of the probe light 11 at different incident angles when it is incident on the grating 4 through the first prism 2 is the same, and the power loss of the corresponding diffracted light 41 when it is emitted through the first prism 2 is also the same. This ensures the consistency of the light loss of different probe lights 11 in the first prism 2, and the consistency of the light loss of different diffracted lights 41 in the first prism 2, which is beneficial to improving the accuracy of diffraction efficiency testing. At the same time, the first prism 2 is used to transmit the probe light 11 and the diffracted light 41, and ensures that the probe light 11 and the diffracted light 41 are located on the same side of the grating 4, which facilitates the diffraction efficiency testing of the grating 4.

[0108] In some embodiments of the present invention, such as Figure 6 and Figure 7 As shown, the optical device 1 includes a first prism 2 and a second prism 5. The first prism 2 has a first curved surface 21, and the second prism 5 has a second curved surface 51. Probe light 11 with different incident angles is incident on the grating 4 through the first curved surface 21. After being diffracted by the grating 4, diffracted light 41 is generated and emitted from the second curved surface 51. The curvature of each point on the surface of the first curved surface 21 is the same, and the curvature of each point on the surface of the second curved surface 51 is the same. The curvature center P of each point on the surface of the first curved surface 21 coincides with the curvature center P of each point on the surface of the second curved surface 51, and the curvature center P is located on the grating 4.

[0109] Specifically, when the probe light 11 at different incident angles enters the first prism 2 through the first curved surface 21, it is ensured that the probe light 11 at different incident angles is directed towards the curvature center P where the first curved surface 21 and the second curved surface 51 coincide. Furthermore, since the curvature is the same at all points on the surface of the first curved surface 21, the optical path length of the probe light 11 at different incident angles from its point of incidence in the first prism 2 to the curvature center P is the same. Further, after passing through the first prism 2, the probe light 11 at different incident angles is incident on the grating 4. The probe light 11 is diffracted by the grating 4 to generate diffracted light 41. Since the grating 4 is located at the curvature center P where the first curved surface 21 and the second curved surface 51 coincide, as... Figure 6As shown, the diffracted light 41 generated by the grating 4 is directed from the curvature center P to the second prism 5. Since the curvature is the same at all points of the second curved surface 51, the diffracted light 41 with different exit angles has the same optical path in the second prism 5.

[0110] Therefore, by setting up a first prism 2 and a second prism 5 respectively, the curvature of each point on the surface of the first curved part 21 of the first prism 2 is the same, and the curvature of each point on the surface of the second curved part 51 of the second prism 5 is the same. At the same time, the curvature center P of each point on the surface of the first curved part 21 coincides with the curvature center P of each point on the surface of the second curved part 51. This ensures that the optical path of the probe light 11 with different incident angles is the same in the first prism 2, and the optical path of the diffracted light 41 with different exit angles is the same in the second prism 5. This ensures the consistency of the light loss of different probe lights 11 in the first prism 2, and the consistency of the light loss of different diffracted lights 41 in the second prism 5, which is beneficial to improving the accuracy of testing the diffraction efficiency of the grating 4 using the first prism 2 and the second prism 5.

[0111] It should be noted that the curvature of the first curved surface 21 and the curvature of the second curved surface 51 can be the same or different, as long as the curvature center P at each point on the surface of the first curved surface 21 coincides with the curvature center P at each point on the surface of the second curved surface 51. No specific restrictions are imposed here.

[0112] In some embodiments of the present invention, such as Figure 6 and Figure 7 As shown, the first curved surface 21 is the curved surface of a cylindrical prism or a spherical prism, and the second curved surface 51 is the curved surface of a cylindrical prism or a spherical prism. That is, the first curved surface 21 can be constructed as the curved surface of a cylindrical prism or a spherical prism, and the second curved surface 51 can be constructed as the curved surface of a cylindrical prism or a spherical prism. For example, the first prism 2 can be half or a quarter of a cylindrical prism, or it can be half or a quarter of a spherical prism. The second prism 5 can be half or a quarter of a cylindrical prism, or it can be half or a quarter of a spherical prism. Further, as a specific example, the first prism 2 and the second prism... 5 can be set as two half-spheres with the same curvature or two half-spheres with different curvatures. It is ensured that after being installed with the grating 4, the curvature center P of the first prism 2 and the curvature center P of the second prism 5 coincide. This setting ensures that the optical path of the probe light 11 with different incident angles is the same in the first prism 2, and the optical path of the diffracted light 41 with different exit angles is the same in the second prism 5. Moreover, the first prism 2 and the second prism 5 of the cylindrical or spherical prism are easy to manufacture and simplify the manufacturing difficulty of the first prism 2 and the second prism 5.

[0113] In some embodiments of the present invention, such as Figure 7 As shown, the optical device 1 also includes a grating substrate 6, which is located between the grating 4 and the second prism 5, and the refractive index of the second prism 5 is the same as that of the grating substrate 6.

[0114] Specifically, a grating substrate 6 can be disposed between the grating 4 and the second prism 5. The grating substrate 6 is a glass matching liquid with the same refractive index as the second prism 5. The second prism 5 is bonded to the grating 4 by the glass matching liquid. The glass matching liquid eventually solidifies into the grating substrate 6 and is located between the second prism 5 and the grating 4. The grating substrate 6 has the same refractive index as the second prism 5. Figure 7 As shown, when the diffracted light 41 is emitted from the grating 4, it passes sequentially through the grating substrate 6 and the second prism 5. The refractive index of the second prism 5 is the same as that of the grating substrate 6. The diffracted light 41 will not be refracted at the junction of the second prism 5 and the grating substrate 6, thus ensuring the consistency of the transmission direction of the diffracted light 41. That is, the direction of the diffracted light 41 will not change during the transmission process between the second prism 5 and the grating substrate 6, ensuring that diffracted light 41 with different emission angles has the same optical path in the second prism 5 and the grating substrate 6.

[0115] It should be noted that, as Figure 6 As shown, the grating substrate 6 can also be omitted between the second prism 5 and the grating 4. That is, the grating substrate 6 between the second prism 5 and the grating 4 can be removed during testing to eliminate the influence of the grating substrate 6 on the loss of optical power and to save one bonding operation of the refractive index glass matching liquid.

[0116] In some embodiments of the present invention, such as Figures 2-4 As shown, the center of curvature P is located on the surface of grating 4 closest to the grating substrate 6; or, the center of curvature P is located on the surface of grating 4 furthest from the grating substrate 6; or, the center of curvature P is located inside grating 4. That is, as... Figure 2 As shown, the curvature center P can be located inside grating 4, such as... Figure 3 As shown, the center of curvature P can also be located on the surface of the grating 4 away from the grating substrate 6, such as... Figure 4 As shown, the curvature center P can also be located on the side surface of the grating 4 near the grating substrate 6, that is, it is sufficient to ensure that the curvature center P of the first prism 2 is located on the grating 4. No specific restrictions are made here. Since the thickness of the grating 4 is relatively thin, the light loss on the grating 4 can be ignored when calculating the actual light loss. With this setting, it can be ensured that the light loss of the probe light 11 with different incident angles in the first prism 2 is the same, and the light loss of the corresponding diffracted light 41 in the first prism 2 is the same.

[0117] In some embodiments of the present invention, such as Figure 6and Figure 7 As shown, grating 4 is a transmission grating. Specifically, as... Figure 6 and Figure 7 As shown, a transmission grating is used to transmit probe light 11. The first prism 2 and the second prism 5 are located on opposite sides of the grating 4. When the light source emits probe light 11 at different incident angles towards the grating 4, the probe light 11 at different incident angles is incident on the grating 4 through the first prism 2. After the probe light 11 is incident on the grating 4, it is diffracted by the grating 4 to generate diffracted light 41, which is then transmitted from the grating 4 to the second prism 5. The diffracted light 41 passes through the second prism 5 and exits. It can be understood that probe light at different incident angles... The optical path length of the probe light 11 in the first prism 2 is the same, and the optical path length of the corresponding diffracted light 41 in the second prism 5 is also the same. That is to say, the power loss of the probe light 11 at different incident angles when it is incident on the grating 4 through the first prism 2 is the same, and the power loss of the corresponding diffracted light 41 when it is emitted through the second prism 5 is also the same. This ensures the consistency of the optical loss of the probe light 11 at different incident angles in the first prism 2, and the consistency of the optical loss of the corresponding diffracted light 41 in the second prism 5, which is beneficial to improving the accuracy of diffraction efficiency testing.

[0118] In some embodiments of the present invention, such as Figure 2 and Figure 3 As shown, the refractive index of grating 4 is different from that of grating substrate 6. Specifically, the refractive index of grating substrate 6 is exactly the same as that of the first prism 2. Therefore, the probe light 11 and the corresponding diffracted light 41 at different incident angles will not be refracted at the junction of the first prism 2 and grating substrate 6. That is, the direction of the probe light 11 and the diffracted light 41 will not change during the transmission between the first prism 2 and grating substrate 6.

[0119] Furthermore, the refractive index of grating 4 can be the same as or different from that of grating substrate 6. When the refractive index of grating 4 is different from that of grating substrate 6, the probe light 11 and the corresponding diffracted light 41 at different incident angles will be refracted at the junction of grating 4 and grating substrate 6, which will cause the direction of probe light 11 and diffracted light 41 to change during transmission between grating 4 and grating substrate 6. However, since the thickness of grating 4 is relatively thin, it can be ignored. Therefore, it can be approximately considered that both probe light 41 and diffracted light 41 pass through the curvature center P. The curvature of each point on the surface of the first curved part 21 of the first prism 2 is the same. With this setting, probe light 11 at different incident angles has the same optical path when entering grating 4 from the first prism 2, and diffracted light 41 at different incident angles also has the same optical path when exiting from the first prism 2, so as not to affect the diffraction efficiency test. When the refractive index of grating 4 is the same as that of grating substrate 6, probe light 11 with different incident angles will pass through the first prism 2, grating substrate 6 and grating 4 and enter the curvature center P in a straight line without refraction. The corresponding diffracted light 41 will also exit from the curvature center P in a straight line through grating 4, grating substrate 6 and the first prism 2 without refraction. Furthermore, probe light 11 with different incident angles has the same optical path when entering grating 4 through the first prism 2 and grating substrate 6, and different diffracted light 41 also has the same optical path when exiting grating substrate 6 and the first prism 2. Therefore, it will not affect the diffraction efficiency test.

[0120] In some embodiments of the present invention, the grating 4 is a one-dimensional grating or a two-dimensional grating. Specifically, the grating 4 can be a one-dimensional grating or a two-dimensional grating. When the grating 4 is a one-dimensional grating, such as... Figure 13 As shown, the propagation trajectory of the beam is projected onto the plane where the probe light 11 and the diffracted light 41 are located, i.e., the yz plane. The curvature of the first prism 2 is the same in the yz plane, and this surface can be approximated as a semi-cylindrical surface. The center of curvature P of the surface is on the grating 4. When the probe light 11 is incident on the center of curvature P, the optical path of the probe light 11 at different incident angles is the same in the first prism 2, thereby ensuring the consistency of the light loss of the probe light 11 in the first prism 2 and reducing the influence of light loss when measuring diffraction efficiency; when the grating 4 is a two-dimensional grating, as Figure 14 As shown, the probe light 11 is in the zy plane, the diffracted light 41 is in the zx plane, and the curvature of the first prism 2 needs to be consistent at each point on the first curved surface 21 when testing the two-dimensional grating, with the curvature center P on the grating 4.

[0121] like Figure 13 and Figure 14 As shown, the grating diffraction efficiency testing apparatus 10 according to a second aspect embodiment of the present invention includes the optical device 1 as in the first aspect embodiment.

[0122] According to the embodiment of the present invention, the grating diffraction efficiency testing apparatus 10, by providing the aforementioned optical device 1, performs diffraction efficiency testing on the grating 4. Probe light 11 with different incident angles is incident onto the grating 4 via the optical device 1. After diffraction by the grating 4, the probe light 11 generates diffracted light 41 which exits from the optical device 1. Since the optical path length of the probe light 11 with different incident angles is the same in the optical device 1, it ensures that the probe light 11 with different incident angles has the same optical loss when propagating in the optical device 1. Furthermore, since the optical path length of the different diffracted lights 41 is also the same in the optical device 1, it ensures that the different diffracted lights 41 also have the same optical loss when propagating in the optical device 1. This reduces the influence of optical loss in the optical device 1 and helps improve the accuracy of the diffraction efficiency test.

[0123] In some embodiments of the present invention, such as Figure 13 and Figure 14 As shown, the device also includes an optical power meter 3, which is used to detect the power of the diffracted light 41 emitted from the optical device 1, so as to determine the diffraction efficiency of the grating 4 based on the power of the diffracted light 41 and the power of the probe light 11.

[0124] Specifically, before the probe light 11 is incident on the grating 4, its power needs to be detected. Optionally, a detection device can be installed inside the light source or at the exit of the light source to detect the power of the probe light 11 before it enters the optical device 1. The detection device can be an optical power meter 3 or other power detection devices. When the probe light 11 with different incident angles is incident on the grating 4 through the optical device 1, the probe light 11 is diffracted by the grating 4 to generate diffracted light 41 with different exit angles and exits from the optical device 1. By adjusting the position of the optical power meter 3, the power meter 3 can detect the power of the diffracted light 41 exiting from the optical device 1, thereby determining the diffraction efficiency of the grating 4 based on the detected power of the diffracted light 41 and the power of the probe light 11.

[0125] like Figure 1 As shown, the grating diffraction efficiency testing system 100 according to a third aspect embodiment of the present invention includes the grating diffraction efficiency testing device 10 as described in the second aspect embodiment.

[0126] According to the embodiment of the present invention, the grating diffraction efficiency testing system 100, by providing the above-mentioned grating diffraction efficiency testing device 10, performs diffraction efficiency testing on the grating 4. Probe light 11 with different incident angles is incident on the grating 4 through the optical device 1. After the probe light 11 is diffracted by the grating 4, diffracted light 41 is generated and emitted from the optical device 1. Since the probe light 11 with different incident angles has the same optical path in the optical device 1, it is ensured that the probe light 11 with different incident angles has the same optical loss when propagating in the optical device 1. Furthermore, since the optical path of different diffracted light 41 is also the same in the optical device 1, it is ensured that the different diffracted light 41 also has the same optical loss when propagating in the optical device 1. This reduces the influence of optical loss in the optical device 1 and is beneficial to improving the accuracy of diffraction efficiency testing.

[0127] In some embodiments of the present invention, such as Figure 1 As shown, the system also includes: a first rotating device 7 and a second rotating device 8. The grating 4 is driven to rotate by the first rotating device 7, and the optical power meter 3 is driven to rotate by the second rotating device 8. When the grating 4 is driven to rotate by the first rotating device 7, the optical power meter 3 rotates with the grating 4 via the second rotating device 8.

[0128] It should be noted that current grating diffraction efficiency testing devices 10 often rely on manual adjustment of the position of the optical power meter 3, resulting in low adjustment efficiency and poor testing accuracy. Based on this, the grating diffraction efficiency testing device 10 in this application is equipped with a first rotating device 7 and a second rotating device 8. The first rotating device 7 is used to drive the grating 4 to rotate, and the second rotating device 8 is used to drive the optical power meter 3 to rotate. It should be noted that the rotation centers of the first rotating device 7 and the second rotating device 8 are consistent. Furthermore, when the grating 4 is driven to rotate by the first rotating device 7, the optical power meter 3 follows the rotation of the grating 4 via the second rotating device 8. That is, the position of the optical power meter 3 changes with the position of the grating 4, causing the optical power meter 3 to move onto the propagation path of the diffracted light 41. According to the automatic optical power acquisition program, the automatic adjustment of the position of the optical power meter 3 and the automatic acquisition of the power of the diffracted light 41 are realized, improving the automation level of the grating 4 diffraction test, thereby improving the testing efficiency and accuracy.

[0129] Figure 15 This is a method for testing the diffraction efficiency of a grating 4 according to an embodiment of the present invention. It is applied to the grating diffraction efficiency testing system 100 as described in the third aspect embodiment, such as... Figure 15 As shown, the diffraction efficiency test method for grating 4 includes:

[0130] Step S101: Detect the power of the diffracted light 41 emitted from the optical device 1;

[0131] Step S102: Determine the diffraction efficiency of grating 4 based on the power of diffracted light 41 and the power of probe light 11.

[0132] Specifically, the grating 4 diffraction efficiency testing method is applied to a grating diffraction efficiency testing system 100. The grating diffraction efficiency testing system 100 includes a grating diffraction efficiency testing device 10, which includes an optical device 1 and an optical power meter 3. Specifically, when performing the grating 4 diffraction efficiency test, the light source emits probe light 11 with different incident angles towards the optical device 1. It should be noted that before the probe light 11 is incident on the grating 4, the power of the probe light 11 needs to be detected. In some embodiments of this application, this detection can be performed within the light source... A detection device can be installed at the light source outlet to detect the power of the probe light 11 before it enters the optical device 1. When the probe light 11 with different incident angles is incident on the grating 4 through the optical device 1, the probe light 11 is diffracted by the grating 4 to generate diffracted light 41 which is emitted from the optical device 1. By adjusting the position of the optical power meter 3, the optical power meter 3 detects the power of the diffracted light 41 emitted from the optical device 1, and the diffraction efficiency of the grating 4 is determined based on the detected power of the diffracted light 41 and the power of the probe light 11.

[0133] It should be noted that when the probe light 11 is incident on the grating 4 at different angles, the corresponding diffracted light 41 generated after the probe light 11 is diffracted by the grating 4 also has different exit angles. At the same time, when the probe light 11 and the diffracted light 41 are transmitted in the optical device 1, the probe light 11 and the diffracted light 41 will experience power attenuation. If the probe light 11 and the corresponding diffracted light 41 with different incident angles have different optical paths in the optical device 1, then the probe light 11 and the corresponding diffracted light 41 with different incident angles will experience different degrees of power attenuation when propagating in the optical device 1, which greatly reduces the accuracy of the diffraction efficiency test.

[0134] Based on this, the optical device 1 in this application ensures that the optical path of the probe light 11 and the corresponding diffracted light 41 at different incident angles is the same in the optical device 1, so that the power loss of the probe light 11 at different incident angles when it is incident on the grating 4 through the optical device 1 is the same, and the power loss of the corresponding diffracted light 41 when it is emitted through the optical device 1 is also the same. This ensures the consistency of the power loss of the probe light 11 and the power loss of the diffracted light 41 in the optical device 1, which is beneficial to improving the accuracy of diffraction efficiency testing.

[0135] According to the diffraction efficiency testing method of the grating 4 according to the embodiment of the present invention, the power of the diffracted light 41 emitted from the optical device 1 is detected, and the diffraction efficiency of the grating 4 is determined based on the power of the diffracted light 41 and the power of the probe light 11. Since the probe light 11 with different incident angles has the same optical path in the optical device 1, it is ensured that the probe light 11 with different incident angles has the same optical loss when propagating in the optical device 1. Furthermore, since the optical path of different diffracted lights 41 is also the same in the optical device 1, it is ensured that the different diffracted lights 41 also have the same optical loss when propagating in the optical device 1. This reduces the influence of optical loss in the optical device 1 and is beneficial to improving the accuracy of diffraction efficiency testing.

[0136] In some embodiments of the present invention, when the grating 4 is a reflective grating, determining the diffraction efficiency of the grating 4 based on the power of the diffracted light 41 and the power of the probe light 11 includes: obtaining the ratio of the power of the diffracted light 41 to the optical power loss rate of the first prism 2 to obtain a first ratio; obtaining the product of the power of the probe light 11 and the optical power loss rate of the first prism 2 to obtain a second ratio; and determining the diffraction efficiency of the grating 4 based on the first ratio and the second ratio.

[0137] Specifically, such as Figures 2-5 As shown, when the grating 4 is a reflective grating, the first prism 2 of the optical device 1 is located on one side of the grating 4. When the light source emits probe light 11 with different incident angles to the grating 4, the probe light 11 with different incident angles is incident on the grating 4 through the first prism 2. After the probe light 11 is incident on the grating 4, the probe light 11 is diffracted by the grating 4 to generate diffracted light 41 and is reflected from the grating 4 to the first prism 2. The diffracted light 41 passes through the first prism 2 and is emitted from the first prism 2. The optical power meter 3 is used to detect the power of the diffracted light 41 emitted from the first prism 2.

[0138] It should be noted that before obtaining the diffraction efficiency of grating 4, it is necessary to obtain the optical power loss rate of the first prism 2. Specifically, as follows: Figure 9 As shown, it is necessary to detect the optical power P5 at the interface between the air and the first prism 2 and the optical power P6 at the interface between the first prism 2 and the grating 4 in advance. The optical power loss rate of the first prism 2 can be obtained based on the optical power P5 at the interface between the air and the first prism 2 and the optical power P6 at the interface between the first prism 2 and the grating 4. The specific calculation formula is as follows:

[0139] Where, η 损1 P5 is the optical power loss rate of the first prism 2, P6 is the optical power between the air and the interface of the first prism 2, and P7 is the optical power between the interface of the first prism 2 and the grating 4.

[0140] Furthermore, the diffraction efficiency of grating 4 is the ratio of a first ratio to a second ratio. The first ratio is the ratio of the power of the diffracted light 41 to the optical power loss rate of the first prism 2, and the second ratio is the product of the power of the probe light 11 and the optical power loss rate of the first prism 2. Wherein, for example... Figure 8 As shown, assuming that the power of the diffracted light 41 is P2 and the power of the probe light 11 is P1 as measured by the optical power meter 3, the specific formula for calculating the diffraction efficiency of the grating 4 is as follows:

[0141] Where η1 is the diffraction efficiency of grating 4, η 损1 P1 is the power loss rate of the first prism 2, P2 is the power of the diffracted light 41, and P1 is the power of the probe light 11.

[0142] Therefore, the accuracy of the test is improved because the attenuation effect of the optical power of the first prism 2 is taken into account during the diffraction efficiency test of the reflective grating.

[0143] It should be noted that when the optical device 1 has a grating substrate 6, the power loss caused by the grating substrate 6 must be considered when calculating the diffraction efficiency of the grating 4. Before obtaining the diffraction efficiency of the grating 4, the power loss rate of the first prism 2 and the grating substrate 6 needs to be obtained. Specifically, as follows... Figure 10 As shown, it is necessary to detect the optical power P5' at the interface between the air and the first prism 2 and the optical power P6' at the interface between the grating substrate 6 and the grating 4 in advance. Based on the optical power P5' at the interface between the air and the first prism 2 and the optical power P6' at the interface between the grating substrate 6 and the grating 4, the optical power loss rate of the first prism 2 and the grating substrate 6 can be obtained. The specific calculation formula is as follows:

[0144] Where, η' 损1 P5' is the optical power loss rate between the first prism 2 and the grating substrate 6, P6' is the optical power between the interface between the air and the first prism 2, and P6' is the optical power between the interface between the grating substrate 6 and the grating 4.

[0145] Furthermore, the diffraction efficiency of grating 4 is the ratio of a first ratio to a second ratio. The first ratio is the ratio of the power of the diffracted light 41 to the optical power loss rate of the first prism 2 and the grating substrate 6. The second ratio is the product of the power of the probe light 11 and the optical power loss rate of the first prism 2 and the grating substrate 6. Wherein, as... Figure 5 As shown, assuming that the power of the diffracted light 41 is P2' and the power of the probe light 11 is P1' as measured by the optical power meter 3, the specific formula for calculating the diffraction efficiency of the grating 4 is as follows:

[0146] Where η1' is the diffraction efficiency of grating 4, η' 损1P1' is the power loss rate of the first prism 2 and the grating substrate 6, P2' is the power of the diffracted light 41, and P1' is the power of the probe light 11.

[0147] Therefore, when the optical device 1 has a grating substrate 6, the accuracy of the test is further improved because the attenuation effect of the first prism 2 and the grating substrate 6 on the optical power is considered in the diffraction efficiency test of the reflective grating.

[0148] In some embodiments of the present invention, when the grating 4 is a transmission grating, the diffraction efficiency of the grating 4 is determined based on the power of the diffracted light 41 and the power of the probe light 11, including: obtaining the ratio of the power of the diffracted light 41 to the optical power loss rate of the second prism 5 to obtain a third ratio; obtaining the product of the power of the probe light 11 and the optical power loss rate of the first prism 2 to obtain a fourth ratio; and determining the diffraction efficiency of the grating 4 based on the third ratio and the fourth ratio.

[0149] Specifically, such as Figure 6 and Figure 7 As shown, when the grating 4 is a transmission type grating, the first prism 2 and the second prism 5 are located on both sides of the grating 4. When the light source emits probe light 11 with different incident angles to the grating 4, the probe light 11 with different incident angles is incident on the grating 4 through the first prism 2. After the probe light 11 is incident on the grating 4, the probe light 11 is diffracted by the grating 4 to generate diffracted light 41 and is transmitted from the grating 4 to the second prism 5. The diffracted light 41 passes through the second prism 5 and is emitted from the second prism 5. The optical power meter 3 is used to detect the power of the diffracted light 41 emitted from the second prism 5.

[0150] It should be noted that before obtaining the diffraction efficiency of grating 4, it is necessary to obtain the optical power loss rate of the first prism 2 and the second prism 5. Specifically, as follows: Figure 9 and Figure 11 As shown, it is necessary to detect the optical power P5 at the interface between the air and the first prism 2, and the optical power P6 at the interface between the first prism 2 and the grating 4 in advance. It is also necessary to detect the optical power P7 at the interface between the air and the second prism 5, and the optical power P8 at the interface between the second prism 5 and the grating 4 in advance. The specific calculation formula for the optical power loss rate of the first prism 2 based on the optical power P5 at the interface between the air and the first prism 2 and the optical power P6 at the interface between the first prism 2 and the grating 4 is as follows:

[0151] Where, η 损1 P5 is the optical power loss rate of the first prism 2, P6 is the optical power between the air and the interface of the first prism 2, and P7 is the optical power between the interface of the first prism 2 and the grating 4.

[0152] The specific calculation formula for the optical power loss rate of the second prism 5, based on the optical power P7 at the interface between the air and the second prism 5 and the optical power P8 at the interface between the second prism 5 and the grating 4, is as follows:

[0153] Where, η 损2 P7 is the optical power loss rate of the second prism 5, P8 is the optical power between the air and the interface of the second prism 5, and P9 is the optical power between the interface of the second prism 5 and the grating 4.

[0154] Furthermore, the diffraction efficiency of grating 4 is the ratio of a third ratio to a fourth ratio. The third ratio is the ratio of the power of the diffracted light 41 to the optical power loss rate of the second prism 5, and the fourth ratio is the product of the power of the probe light 11 and the optical power loss rate of the first prism 2. Wherein, as... Figure 6 As shown, assuming that the power of the diffracted light 41 is P4 and the power of the probe light 11 is P3 as measured by the optical power meter 3, the specific formula for calculating the diffraction efficiency of the grating 4 is as follows:

[0155] Where η2 is the diffraction efficiency of grating 4, η 损1 η is the optical power loss rate of the first prism 2. 损2 P1 represents the optical power loss rate of the second prism 5, P4 represents the power of the diffracted light 41, and P3 represents the power of the probe light 11.

[0156] Therefore, since the attenuation effect of the optical power of the first prism 2 and the second prism 5 is considered in the diffraction efficiency test of the transmission grating, the accuracy of the test is improved.

[0157] It should be noted that when the optical device 1 has a grating substrate 6, the power loss caused by the grating substrate 6 must be considered when calculating the diffraction efficiency of the grating 4. Furthermore, as... Figure 7 As shown, when there is a grating substrate 6 between the second prism 5 and the grating 4, and no grating substrate 6 between the first prism 2 and the grating 4, as... Figure 9 As shown, it is necessary to detect the optical power P5 at the interface between the air and the first prism 2 and the optical power P6 at the interface between the first prism 2 and the grating 4 in advance. The optical power loss rate of the first prism 2 can be obtained based on the optical power P5 at the interface between the air and the first prism 2 and the optical power P6 at the interface between the first prism 2 and the grating 4. The specific calculation formula is as follows:

[0158] Where, η 损1 P5 is the optical power loss rate of the first prism 2, P6 is the optical power between the air and the interface of the first prism 2, and P7 is the optical power between the interface of the first prism 2 and the grating 4.

[0159] like Figure 12 As shown, and based on the optical power P7' at the interface between the air and the second prism 5 and the optical power P8' at the interface between the grating substrate 6 and the grating 4, the specific calculation formula for the optical power loss rate of the second prism 5 is as follows:

[0160] Where, η' 损2 P7' is the optical power loss rate between the second prism 5 and the grating substrate 6, P8' is the optical power between the interface between the air and the second prism 5, and P8' is the optical power between the interface between the grating substrate 6 and the grating 4.

[0161] Furthermore, the diffraction efficiency of grating 4 is the ratio of a third ratio to a fourth ratio. The third ratio is the ratio of the power of the diffracted light 41 to the optical power loss rate of the second prism 5 and the grating substrate 6. The fourth ratio is the product of the power of the probe light 11 and the optical power loss rate of the first prism 2. Wherein, as... Figure 6 As shown, assuming that the power of the diffracted light 41 is P4' and the power of the probe light 11 is P3 as measured by the optical power meter 3, the specific formula for calculating the diffraction efficiency of the grating 4 is as follows:

[0162] Where η'2 is the diffraction efficiency of grating 4, η' 损2 η represents the optical power loss rate of the second prism 5 and the grating substrate 6. 损1 P1 represents the optical power loss rate of the first prism 2, P4' represents the power of the diffracted light 41, and P3 represents the power of the probe light 11.

[0163] Therefore, when the optical device 1 has a grating substrate 6, the accuracy of the test is improved because the attenuation effect of the first prism 2, the second prism 5 and the grating substrate 6 on the optical power are considered in the diffraction efficiency test of the transmission grating.

[0164] In some embodiments of the present invention, the method further includes: determining the rotation angle of the second rotating device 8 based on the rotation angle of the first rotating device 7.

[0165] Specifically, current grating diffraction efficiency testing devices 10 often rely on manual adjustment of the position of the optical power meter 3, resulting in low adjustment efficiency and poor testing accuracy. Therefore, the grating diffraction efficiency testing device 10 in this application is equipped with a first rotating device 7 and a second rotating device 8. The first rotating device 7 drives the grating 4 to rotate, and the second rotating device 8 drives the optical power meter 3 to rotate. It should be noted that the rotation centers of the first rotating device 7 and the second rotating device 8 are aligned. Furthermore, when the grating 4 is driven to rotate by the first rotating device 7, the optical power meter 3 follows the rotation of the grating 4 via the second rotating device 8. That is, the rotation angle of the second rotating device 8 is determined according to the rotation angle of the first rotating device 7, causing the position of the optical power meter 3 to change with the position of the grating 4. This allows the optical power meter 3 to move onto the propagation path of the diffracted light 41. Based on the automatic optical power acquisition program, the automatic adjustment of the position of the optical power meter 3 and the automatic acquisition of the power of the diffracted light 41 are realized, improving the automation level of the grating 4 diffraction test and thus improving testing efficiency and accuracy.

[0166] In some embodiments of the present invention, determining the rotation angle of the second rotating device 8 based on the rotation angle of the first rotating device 7 includes: determining the reference grating 4 vector of the grating 4 based on the first reference light vector of the reference probe light 11 in the grating 4 and the second reference light vector of the reference diffracted light 41 corresponding to the reference probe light 11 in the grating 4; and determining the rotation angle of the second rotating device 8 based on the preset angle, the first reference light vector, the second reference light vector, and the reference grating 4 vector when the first rotating device 7 rotates by a preset angle.

[0167] Specifically, such as Figure 16 As shown, when determining the rotation angle of the second rotating device 8 based on the rotation angle of the first rotating device 7, the first reference light vector a of the reference probe light 11 within the grating 4 is obtained, and the second reference light vector b of the reference diffracted light 41 corresponding to the reference probe light 11 within the grating 4 is also obtained. The reference grating 4 vector c of the grating 4 is determined based on the first reference light vector a and the second reference light vector b. When the first rotating device 7 rotates by a preset angle α, the rotation angle of the second rotating device 8 is determined based on the preset angle α, the first reference light vector a, the second reference light vector b, and the reference grating 4 vector c.

[0168] The process of determining the rotation angle of the second rotating device 8 based on the preset angle, the first reference light vector, the second reference light vector, and the reference grating 4 vector includes: determining the first light vector of the rotated probe light 11 based on the preset angle and the first reference light vector; determining the second light vector of the rotated diffracted light 41 based on the first light vector and the reference grating 4 vector; and determining the rotation angle of the second rotating device 8 based on the second light vector and the second reference light vector.

[0169] Specifically, such as Figure 16 As shown, when the first rotating device 7 rotates counterclockwise by a preset angle α, the first reference light vector a rotates counterclockwise by a preset angle α to obtain the first light vector d of the rotated probe light 11. Based on the first light vector d and the reference grating 4 vector c, the second light vector e of the rotated diffracted light 41 can be obtained. Specifically, the reference grating 4 vector c is translated so that the first light vector d is relatively connected to the reference grating 4 vector c, and the reference grating 4 vector c is projected along the z direction onto the reference circle. The line connecting the center of the reference circle and the intersection of the reference circle and the projection of the reference grating 4 vector c along the z direction is the second light vector e. The angle between the second light vector e and the reference grating 4 vector c is the rotation angle γ that the second rotating device 8 needs to rotate.

[0170] Therefore, the optical power meter 3 can automatically move along the propagation path of the diffracted light 41 with the second rotating device 8 and perform automated acquisition, which is beneficial to improve testing efficiency and the testing accuracy is more accurate than manual adjustment testing.

[0171] In some embodiments of the present invention, the method further includes: obtaining the grating 4 vector when the diffraction efficiency is at its maximum; and detecting whether the grating 4 is qualified based on the grating 4 vector. Specifically, before performing the diffraction efficiency test, it is also necessary to detect whether the grating 4 is qualified. Specifically, by obtaining the grating 4 vector when the diffraction efficiency is at its maximum, the grating 4 is detected as qualified based on the grating 4 vector. If the grating 4 is unqualified, the diffraction efficiency test of the grating 4 is not performed; if the grating 4 is qualified, the diffraction efficiency test of the grating 4 is performed, thereby avoiding the detection of unqualified grating 4 and causing unnecessary testing waste.

[0172] Specifically, obtaining the grating 4 vector of the grating 4 when the diffraction efficiency is maximized includes: obtaining the incident angle of the probe light 11 and the exit angle of the diffracted light 41 when the diffraction efficiency is maximized; determining the vector of the probe light 11 in the grating 4 based on the incident angle of the probe light 11; determining the vector of the diffracted light 41 in the grating 4 based on the exit angle of the diffracted light 41; and determining the grating 4 vector of the grating 4 based on the vector of the probe light 11 in the grating 4 and the vector of the diffracted light 41 in the grating 4.

[0173] refer to Figure 17 As shown in (a), the incident angle θ of the probe light 11 during the design is obtained. s The exit angle θ of the diffracted light 41 r Obtain design values ​​based on vector relationships As grating 4 rotates, the reference Figure 17 As shown in (b), the incident angle θ of the probe light 11 when the diffraction efficiency is maximized is obtained. p The exit angle θ of the diffracted light 41 c Based on the vector relationship, the vector of the probe light 11 within the grating 4 can be obtained. The vector of the diffracted light 41 within the grating 4 This leads to the grating 4 vector of grating 4. This vector With design value By making comparisons, the pass rate of grating 4 can be verified.

[0174] like Figure 18 As shown, an embodiment of the present invention also provides a controller 200, including: a memory 210, a processor 220, and a program stored in the memory 210 and executable on the processor 220. When the processor 220 executes the program, it implements the above-described method for testing the diffraction efficiency of grating 4.

[0175] According to the controller 200 of the present invention, the diffraction efficiency test method of the grating 4 ensures that the probe light 11 with different incident angles has the same optical path in the optical device 1, thus ensuring that the probe light 11 with different incident angles has the same optical loss when propagating in the optical device 1. Furthermore, since the optical path of different diffracted light 41 is also the same in the optical device 1, it also ensures that the different diffracted light 41 has the same optical loss when propagating in the optical device 1, thereby reducing the influence of optical loss in the optical device 1 and improving the accuracy of diffraction efficiency test.

[0176] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable storage medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable storage medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable storage medium could be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0177] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0178] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0179] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0180] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0181] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An optical device, characterized by The optical device comprises a first prism having a first curved surface through which probe light of different incident angles is incident to a grating, and after diffraction by the grating, diffracted light is generated and emitted from the first curved surface to test the diffraction efficiency of the grating. The curvature of each point on the surface of the first curved surface is the same, and the curvature center is coincident, and the curvature center is located on the grating to ensure that the optical path of the probe light of different incident angles and the corresponding diffracted light in the optical device is the same, and the curvature center is located on the grating, including that the curvature center is located on the surface of the grating close to the probe light, or the curvature center is located on the surface of the grating away from the probe light, or the curvature center is located inside the grating.

2. The optical device of claim 1, wherein, The first curved surface is an arc surface of a cylindrical prism or an arc surface of a spherical prism.

3. The optical device of claim 1, wherein, The optical device further comprises a grating substrate selectively arranged between the first prism and the grating for refractive index matching and / or supporting effect.

4. The optical device of claim 1, wherein, The optical device further comprises a grating substrate between the first prism and the grating, and the refractive index of the first prism is the same as that of the grating substrate.

5. The optical device of claim 4, wherein, The refractive index of the grating is different from that of the grating substrate.

6. The optical device of claim 1, wherein, The grating is a reflective grating.

7. An optical device, characterized by The optical device comprises a first prism having a first curved surface and a second prism having a second curved surface, probe light of different incident angles is incident to a grating through the first curved surface, and after diffraction by the grating, diffracted light is generated and emitted from the second curved surface to test the diffraction efficiency of the grating. The curvature of each point on the surface of the first curved surface is the same, the curvature of each point on the surface of the second curved surface is the same, the curvature center of each point on the surface of the first curved surface is coincident with the curvature center of each point on the surface of the second curved surface, and the curvature center is located on the grating to ensure that the optical path of the probe light of different incident angles and the corresponding diffracted light in the optical device is the same. The curvature center is located on the grating, including that the curvature center is located on the surface of the grating close to the probe light, or the curvature center is located on the surface of the grating away from the probe light, or the curvature center is located inside the grating.

8. The optical device of claim 7, wherein, The first curved surface is an arc surface of a cylindrical prism or an arc surface of a spherical prism, and the second curved surface is an arc surface of a cylindrical prism or an arc surface of a spherical prism.

9. The optical device of claim 7, wherein, The optical device further comprises a grating substrate selectively arranged between the second prism and the grating for refractive index matching and / or supporting effect.

10. The optical device of claim 7, wherein, The optical device further comprises a grating substrate between the grating and the second prism, and the refractive index of the second prism is the same as that of the grating substrate.

11. The optical device of claim 7, wherein, The grating is a transmissive grating.

12. The optical device of claim 10, wherein, The refractive index of the grating is different from that of the grating substrate.

13. The optical device of claim 1 or 7, wherein, The grating is a one-dimensional grating or a two-dimensional grating.

14. A grating diffraction efficiency testing apparatus, characterized by, The device further comprises:

15. The apparatus of claim 14, wherein, The device further comprises: a light power meter configured to detect a power of the diffracted light emitted from the optical device, so as to determine a diffraction efficiency of the grating according to the power of the diffracted light and the power of the probe light.

16. A grating diffraction efficiency test system, characterized in that, The grating diffraction efficiency testing device according to claim 15.

17. The system of claim 16, wherein, The system further comprises a first rotating device and a second rotating device, the grating is driven to rotate by the first rotating device, the light power meter is driven to rotate by the second rotating device, and the light power meter follows the grating to rotate via the second rotating device when the grating is driven to rotate by the first rotating device.

18. A method of testing the diffraction efficiency of an optical grating, characterized by, The method is applied to the grating diffraction efficiency testing system according to claim 17, and the method comprises: detecting a power of the diffracted light emitted from the optical device; determining a diffraction efficiency of the grating according to the power of the diffracted light and the power of the probe light.

19. The method of claim 18, wherein, When the grating is a reflective grating, the determining of the diffraction efficiency of the grating according to the power of the diffracted light and the power of the probe light comprises: obtaining a ratio of the power of the diffracted light to a light power loss rate of a first prism to obtain a first ratio; obtaining a product of the power of the probe light and the light power loss rate of the first prism to obtain a second ratio; determining the diffraction efficiency of the grating according to the first ratio and the second ratio.

20. The method of claim 18, wherein, When the grating is a transmissive grating, the determining of the diffraction efficiency of the grating according to the power of the diffracted light and the power of the probe light comprises: obtaining a ratio of the power of the diffracted light to a light power loss rate of a second prism to obtain a third ratio; obtaining a product of the power of the probe light and the light power loss rate of the first prism to obtain a fourth ratio; determining the diffraction efficiency of the grating according to the third ratio and the fourth ratio.

21. The method of claim 18, wherein, The method further comprises: determining a rotation angle of the second rotating device according to a rotation angle of the first rotating device.

22. The method of claim 21, wherein, The determining of the rotation angle of the second rotating device according to the rotation angle of the first rotating device comprises: determining a reference grating vector of the grating based on a first reference light vector of a reference probe light in the grating and a second reference light vector of a reference diffracted light corresponding to the reference probe light in the grating; determining the rotation angle of the second rotating device according to the preset angle, the first reference light vector, the second reference light vector and the reference grating vector when the first rotating device rotates by a preset angle.

23. The method of claim 22, wherein, The determining of the rotation angle of the second rotating device according to the preset angle, the first reference light vector, the second reference light vector and the reference grating vector comprises: determining a first light vector of the probe light after rotation according to the preset angle and the first reference light vector; determining a second light vector of the diffracted light after rotation according to the first light vector and the reference grating vector; determining the rotation angle of the second rotating device according to the second light vector and the second reference light vector.

24. The method of claim 18, wherein, The method further comprises: obtaining a grating vector of the grating when the diffraction efficiency is maximum; determining whether the grating is qualified according to the grating vector.

25. A controller characterized by, The method comprises: A memory, a processor, and a program stored on the memory and executable on the processor, the processor implementing the method for testing the diffraction efficiency of a grating according to any one of claims 18-24 when executing the program.

Images