Testing system and testing method for diffractive optical waveguide

Abstract

The embodiment of the invention provides a diffractive optical waveguide test system and test method. The diffractive optical waveguide comprises a light coupling-in area, and the test system comprises a movable carrying platform which is used for carrying the diffractive optical waveguide; the first sliding rail is arranged on the outer side of the movable carrying table in a surrounding mode, a light source assembly is arranged on the first sliding rail, and the light source assembly is used for projecting first light rays to the light ray coupling-in area; the second sliding rail is arranged on the outer side of the first sliding rail in a surrounding mode, a light ray analysis component is arranged on the second sliding rail, the light ray analysis component is movably arranged on the first sliding rail, and the light ray analysis component is used for receiving second light rays and determining energy of the second light rays; and determining the light energy loss proportion of the diffraction optical waveguide according to the energy of the second light, wherein the second light is the light coupled out by the light coupling-in area.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of diffraction optical waveguides, and more specifically, relate to a testing system and a testing method for diffraction optical waveguides. Background Art

[0002] In the field of diffraction waveguides, grating efficiency is a particularly important parameter, which directly affects the final optical efficiency of the waveguide. There are many factors that affect grating efficiency, such as grating type, grating structure, etc. Regarding hardware conditions such as grating type and grating structure, the diffraction efficiency of the grating can be improved by changing the grating type or optimizing the grating structure, thereby ultimately improving the optical efficiency of the diffraction waveguide. However, no matter how the grating type is changed or the optical parameters are optimized, there will always be a phenomenon that will directly affect the diffraction efficiency of the grating for the diffraction waveguide, namely back-coupling.

[0003] The incident light enters the coupling grating (IG), enters the waveguide after diffraction by the grating and is transmitted by total reflection in the waveguide. When the totally reflected light passes through the coupling grating, part of the light will continue to be totally reflected and transmitted in the optical waveguide, while the other part of the light will be diffracted here and coupled out of the waveguide, causing energy loss. This phenomenon is called back-coupling.

[0004] Currently there is no device or apparatus for detecting the energy lost due to the back-coupling phenomenon. Summary of the invention

[0005] The purpose of this application is to provide a new technical solution for a test system and a test method of a diffraction optical waveguide.

[0006] In a first aspect, the present application provides a test system for a diffractive optical waveguide. The diffractive optical waveguide includes a light coupling-in region, and the test system includes:

[0007] A movable stage, the movable stage being used to carry the diffractive optical waveguide;

[0008] A first slide rail, the first slide rail is arranged around the outer side of the movable platform, a light source assembly is arranged on the first slide rail, and the light source assembly is used to project a first light to the light coupling-in area;

[0009] A second slide rail, wherein the second slide rail is arranged on the outer side of the first slide rail, and a light analyzing component is arranged on the second slide rail, and the light analyzing component can be movably arranged on the second slide rail, and the light analyzing component is used to receive a second light, determine the energy of the second light, and determine the light energy loss ratio of the diffraction light waveguide according to the energy of the second light, wherein the second light is the light coupled out of the light coupling-in area.

[0010] Optionally, the light source assembly includes a light source body, and the light source body is movably disposed on the first slide rail.

[0011] Optionally, the light source assembly further includes a polarization element, and the light source body and the polarization element are detachably connected.

[0012] Optionally, the first slide rail has a hollow area, and the light analysis component is opposite to the hollow area.

[0013] Optionally, the second slide rail is movably arranged on the outer side of the first slide rail;

[0014] The second slide rail has a first end and a second end, and the first end and the second end are both provided with an electric slide rail so that the second slide rail moves along the electric slide rail.

[0015] Optionally, the first slide rail is a dome structure, and the light source assembly is located on the inner surface of the dome structure.

[0016] Optionally, the second slide rail is a dome structure, and the light analysis component is located on the inner surface of the dome structure.

[0017] Optionally, the light analysis component is a spectrum analyzer or an optical power meter.

[0018] In a second aspect, a test method for a diffractive optical waveguide is provided. The diffractive optical waveguide includes a light coupling-in region, and the test system includes:

[0019] By projecting a first light into the light coupling region;

[0020] A second light is obtained, the energy of the second light is determined, and the light energy loss ratio of the diffraction light waveguide is determined according to the energy of the second light, wherein the second light is the light coupled out of the light coupling-in area.

[0021] Optionally, before projecting the first light to the light coupling-in area, the method further comprises:

[0022] A first light beam is acquired, and energy of the first light beam is determined.

[0023] The beneficial effects of this application are:

[0024] According to an embodiment of the present application, a test system for a diffraction optical waveguide is provided, wherein the energy of a second light coupled out from a light coupling-in region is obtained through a first slide rail, a second slide rail, and a light analysis component, and the light energy loss ratio of the diffraction optical waveguide is determined according to the energy of the second light. The quality of the diffraction optical waveguide can be determined according to the light energy loss ratio, or the grating structure of the diffraction optical waveguide can be optimized according to the light energy loss ratio, so as to gradually reduce the light energy loss ratio and improve the final optical efficiency of the diffraction optical waveguide.

[0025] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0027] Figure 1 The figure shows a back-coupling schematic diagram.

[0028] Figure 2 Shown is a schematic structural diagram of a diffraction optical waveguide testing system provided in an embodiment of the present application.

[0029] Figure 3 Shown is a top view schematic diagram of the first slide rail provided in an embodiment of the present application.

[0030] Figure 4 Shown is a flow chart of a method for testing a diffraction optical waveguide provided in an embodiment of the present application.

[0031] Description of reference numerals:

[0032] 1. Diffractive optical waveguide; 10. Light incoupling region; 11. Light outcoupling region; 12. First light; 13. Second light;

[0033] 2. Movable platform;

[0034] 3. First slide rail; 31. Hollow area;

[0035] 4. Light source assembly; 41. Light source body; 42. Polarization element;

[0036] 5. Second slide rail;

[0037] 6. Light analysis components;

[0038] 7. Electric slide rail. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0040] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0041] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0042] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0043] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0044] The following describes in detail the test system and test method of the diffractive optical waveguide provided in the embodiments of the present application in conjunction with the accompanying drawings.

[0045] The AR optical display system consists of a micro display screen and an optical element assembly. Common optical elements include prisms, free-form surfaces, diffraction optical waveguides 1, etc. Among these optical elements, the diffraction optical waveguide 1 includes a transmission diffraction optical waveguide 1 and a reflection diffraction optical waveguide 1, wherein the test system of the diffraction optical waveguide 1 provided in the embodiment of the present application can be applied to the transmission diffraction optical waveguide 1 and the reflection diffraction optical waveguide 1.

[0046] The diffraction optical waveguide 1 includes an optical waveguide body, a light coupling-in region 10 and a light coupling-out region 11, wherein the light coupling-in region 10 and the light coupling-out region 11 are located on the optical waveguide body, wherein the incident light enters the diffraction optical waveguide 1 from the light coupling-in region 10, and after being transmitted by the diffraction optical waveguide 1, the light is emitted from the light coupling-out region 11.

[0047] The back-coupling phenomenon can directly affect the diffraction efficiency of the grating. Based on this, the quality of the diffraction light waveguide 1 can be detected by testing the light energy loss ratio of the second light 13 and the first light 12 of the diffraction light waveguide 1.

[0048] Currently, there is no concise test system and test method for detecting the energy loss caused by the back-coupling phenomenon in the diffractive optical waveguide 1. In order to solve the above problem, the embodiment of the present disclosure proposes a test system and test method for the diffractive optical waveguide 1.

[0049] Hereinafter, various embodiments and examples according to the present disclosure are described with reference to the drawings.

[0050] <System Embodiment>

[0051] See also Figure 1 and Figure 2 As shown, the embodiment of the present disclosure provides a test system for a diffraction optical waveguide 1. The system is used to detect the proportion of light energy loss caused by the back-coupling phenomenon in the diffraction optical waveguide 1. The test system for the diffraction optical waveguide 1 provided in the embodiment of the present application can be applied to a transmission type diffraction optical waveguide 1 and a reflection type diffraction optical waveguide 1.

[0052] like Figure 1-Figure 3 As shown, the testing system of the diffractive optical waveguide 1 includes: a movable stage 2, a first slide rail 3 and a second slide rail 5.

[0053] The movable stage 2 is used to carry the diffractive optical waveguide 1 .

[0054] The first slide rail 3 is disposed around the outer side of the movable platform 2 . A light source assembly 4 is disposed on the first slide rail 3 . The light source assembly 4 is used to project a first light 12 to the light coupling-in area 10 .

[0055] The second slide rail 5 is arranged around the outside of the first slide rail 3, and a light analyzing component 6 is arranged on the second slide rail 5, and the light analyzing component 6 can be movably arranged on the second slide rail 5, and the light analyzing component 6 is used to receive the second light 13, determine the energy of the second light 13, and determine the light energy loss ratio of the diffraction light waveguide 1 according to the energy of the second light 13. The second light 13 is the light coupled out of the light coupling-in area 10.

[0056] In the embodiment of the present application, the test system of the diffractive optical waveguide 1 includes a movable stage 2, on which the diffractive optical waveguide 1 is placed. The stage is movable, for example, the stage can be moved arbitrarily in a horizontal plane. Since the stage is movable, the light energy loss caused by the grating back-coupling phenomenon at different positions of the light coupling region 10 can be tested.

[0057] The test system of the diffractive optical waveguide 1 includes a first slide rail 3, which is disposed outside the movable stage 2. For example, no matter where the stage moves to, the first slide rail 3 is disposed outside the movable stage 2. When the diffractive optical waveguide 1 is disposed on the stage, the first slide rail 3 is also disposed outside the diffractive optical waveguide 1.

[0058] A light source assembly 4 is disposed on the first slide rail 3, and the light source assembly 4 emits a first light ray 12, and projects the first light ray 12 to the light coupling-in area 10. In one example, the light source assembly 4 identifies the energy of the emitted first light ray 12, so that the user does not need to obtain the energy of the first light ray 12 separately. Or in another example, the light source assembly 4 emits the first light ray 12, and the energy of the first light ray 12 is analyzed by an optical power meter, an energy meter, a thermal imager, or a spectrometer. For example, the energy of the first light ray 12 is Q. The energy acquisition of the first light ray 12 is well known to those skilled in the art, and will not be described in detail in the embodiments of the present application.

[0059] The test system of the diffraction optical waveguide 1 includes a second slide rail 5, which is arranged around the outside of the first slide rail 3. A light analysis component 6 is arranged on the second slide rail 5, through which the energy emitted from the light coupling region 10 can be received in real time, the energy of the second light 13 (diffracted light) can be detected in real time, and the light energy loss ratio of the diffraction optical waveguide 1 can be determined according to the energy of the second light 13.

[0060] Specifically, the light analyzing component 6 is slidably disposed on the second slide rail 5, and the light analyzing component 6 can slide along the second slide rail 5 to cooperate with the light source assembly 4 to receive the light coupled out from the light coupling-in area 10 from different angles. For example, the light analyzing component 6 receives the second light 13 in real time and determines the energy of the second light 13, wherein the energy of the second light 13 is the sum of the energies of multiple second light rays 13. For example, after moving the light analyzing component 6, the back-coupling (second light 13) energies measured are q1, q2, q3...qi, respectively, and the energy of the second light 13 is ∑qi.

[0061] In addition, the light analyzing component 6 can also determine the light energy loss ratio of the diffraction light waveguide 1 according to the energy of the second light 13. For example, the light analyzing component 6 is internally integrated with a data processing module, and the light analyzing component 6 obtains the light energy loss ratio of the diffraction light waveguide 1 according to the energy Q of the first light 12 and the energy ∑qi of the second light 13. For example, the light energy loss ratio is η=∑qi / Q.

[0062] In an embodiment of the present application, a test system for a diffractive optical waveguide 1 is provided, wherein the energy of a second light 13 coupled out from a light coupling-in region 10 is obtained through a first slide rail 3, a second slide rail 5, and a light analyzing component 6, and the light energy loss ratio of the diffractive optical waveguide 1 is determined according to the energy of the second light 13. The quality of the diffractive optical waveguide 1 can be determined according to the light energy loss ratio, or the grating structure of the diffractive optical waveguide 1 can be optimized according to the light energy loss ratio, so as to gradually reduce the light energy loss ratio and improve the final optical efficiency of the diffractive optical waveguide 1.

[0063] At present, in the field of diffraction optical waveguide 1, technicians improve the diffraction efficiency of diffraction optical waveguide 1 by changing the grating type or grating structure, etc. However, they ignore the influence of the light energy loss ratio on the diffraction efficiency of diffraction optical waveguide 1. The present application provides a test system for diffraction optical waveguide 1, which can determine the energy of the second light 13 and the light energy loss ratio of the diffraction optical waveguide 1, so that the grating structure of the diffraction optical waveguide 1 is optimized according to the parameters of the energy of the second light 13 and the light energy loss ratio of the diffraction optical waveguide 1, so as to achieve the purpose of improving the optical efficiency of the diffraction optical waveguide 1.

[0064] In an optional embodiment, the light analyzing component 6 is used to receive the second light 13 and determine the energy of the second light 13. The test system of the diffractive optical waveguide 1 also includes a detection module, and the light analyzing component 6 can transmit the energy of the second light 13 to the detection module, and the light energy loss ratio of the diffractive optical waveguide 1 is calculated by the detection module. Of course, it is still preferred that the light analyzing component 6 can determine the energy of the second light 13 according to the received second light 13, and at the same time determine the light energy loss ratio of the diffractive optical waveguide 1 according to the energy of the second light 13, so that the structure of the test system of the diffractive optical waveguide 1 can be light and compact, and convenient for users to use.

[0065] In an optional embodiment, the light source may be a single wavelength light source or a wide-band, broad-spectrum light source.

[0066] In one embodiment, referring to Figure 2 The light source assembly 4 includes a light source body 41 , and the light source body 41 can be movably disposed on the first slide rail 3 .

[0067] Specifically, the light source assembly 4 can be slidably disposed on the first slide rail 3, for example, the light source assembly 4 can slide along the first slide rail 3, so that the first light 12 emitted by the light source assembly 4 can be incident on the light coupling region 10 at different incident angles. In this way, the test system of the diffraction optical waveguide 1 can detect: when the first light 12 is incident on the light coupling region 10 at different incident angles, the different light energy loss proportions of the diffraction optical waveguide 1, the incident angle of the first light 12 and the light energy loss proportion correspond one to one, and according to the one-to-one correspondence between the incident angle of the first light 12 and the light energy loss proportion, the best incident angle of the first light 12 is determined, so as to achieve the purpose of low light energy loss of the diffraction optical waveguide 1 and high optical efficiency of the diffraction optical waveguide 1.

[0068] In an optional embodiment, a plurality of light source assemblies 4 are disposed on the first slide rail 3 , and the first light 12 projected by each light source assembly 4 enters the light coupling-in area 10 at a different incident angle.

[0069] In one embodiment, referring to Figure 2The light source assembly 4 further includes a polarizing element 42, and the light source body 41 and the polarizing element 42 are detachably connected.

[0070] Specifically, the light source assembly 4 further includes a polarization element 42 , which is used to change the polarization state of the light emitted from the light source body 41 , so that the first light 12 is incident on the light coupling region 10 in a different polarization state.

[0071] For example, according to actual needs, the type of the polarization element 42 is changed, and the first light 12 is incident on the light coupling region 10 in different polarization states.

[0072] In one embodiment, the first slide rail 3 has a hollow area 31 , and the light analysis component 6 is opposite to the hollow area 31 .

[0073] Specifically, the second slide rail 5 is arranged outside the first slide rail 3, and the second slide rail 5 is provided with a light analyzing component 6, which is used to receive the second light 13. This embodiment defines that the structure of the first slide rail 3 includes a hollow area 31, and the light analyzing component 6 is opposite to the hollow area 31, ensuring that the light analyzing component 6 can smoothly receive the energy of the second light 13 coupled out of the light coupling-in area 10 due to the back-coupling phenomenon.

[0074] In one embodiment, referring to Figure 2 The second slide rail 5 is movably arranged and surrounded by the outer side of the first slide rail 3.

[0075] The second slide rail 5 has a first end and a second end, and the first end and the second end are both provided with an electric slide rail 7 so that the second slide rail 5 moves along the electric slide rail 7 .

[0076] Specifically, both ends of the second slide rail 5 are installed on the electric slide rail 7, which can move the second slide rail 5 left and right in the horizontal direction. By controlling the electric slide rail 7, the position of the light analysis component 6 receiving the second light 13 can be further controlled, thereby receiving all the second light rays 13 (such as light rays A, B, and C in the figure) into the light analysis component 6, and calculating the total energy of the second light rays 13.

[0077] In one embodiment, referring to Figure 2 The first slide rail 3 is a dome structure, and the light source assembly 4 is located on the inner surface of the dome structure.

[0078] Specifically, the first slide rail 3 is a dome structure, and the first slide rail 3 of the dome structure can be better surrounded on the outside of the movable stage 2. For example, the dome structure is surrounded on the outside of the movable stage 2 in a semi-enclosed manner. In this way, the diffraction light waveguide 1 is arranged on the movable stage 2, and the second light 13 coupled out from the light coupling-out region 11 of the diffraction light waveguide 1 can all be transmitted to the light analysis component 6 through the first slide rail 3, so as to ensure that the light analysis component 6 receives all the second light 13.

[0079] The light source assembly 4 is mounted on the inner surface of the dome structure, so that the first light 12 emitted by the light source assembly 4 can be directly projected onto the light coupling-in area 10 .

[0080] In one embodiment, referring to Figure 2 The second slide rail 5 is a dome structure, and the light analysis component 6 is located on the inner surface of the dome structure.

[0081] Specifically, the second slide rail 5 is a dome structure, and the second slide rail 5 of the dome structure can be better surrounded on the outside of the first slide rail 3. For example, the dome structure is surrounded on the outside of the first slide rail 3 in a semi-enclosed manner. In this way, the light analysis component 6 arranged on the second slide rail 5 can receive the second light 13 in real time to ensure that the light analysis component 6 receives all the second light 13.

[0082] In one embodiment, the light analyzing component 6 is a spectrum analyzer or an optical power meter.

[0083] For example, the light analyzing component 6 includes but is not limited to a spectrum analyzer and an optical power meter. The light analyzing component 6 is a component with light receiving and data processing capabilities, capable of receiving the second light 13, obtaining the energy of the second light 13, and determining the light energy loss ratio of the diffraction optical waveguide 1 according to the energy of the first light 12 and the energy of the second light 13.

[0084] <Method Example>

[0085] See also Figure 4 , a method for testing a diffractive optical waveguide 1 is provided. The diffractive optical waveguide 1 comprises a light coupling-in region 10, and the method comprises the following steps:

[0086] S101: Projecting a first light 12 to the light coupling-in area 10;

[0087] S102 : Acquire a second light 13 , determine the energy of the second light 13 , and determine the light energy loss ratio of the diffractive optical waveguide 1 according to the energy of the second light 13 , wherein the second light 13 is the light coupled out of the light coupling-in area 10 .

[0088] In an embodiment of the present application, a test method for a diffractive optical waveguide 1 is provided, and the light energy loss ratio of the diffractive optical waveguide 1 is determined according to the energy of the second light 13 and the energy of the first light 12. The quality of the diffractive optical waveguide 1 can be determined according to the light energy loss ratio, or the grating structure of the diffractive optical waveguide 1 can be optimized according to the light energy loss ratio, so as to gradually reduce the light energy loss ratio and improve the final optical efficiency of the diffractive optical waveguide 1.

[0089] At present, in the field of diffraction optical waveguide 1, technicians improve the diffraction efficiency of diffraction optical waveguide 1 by changing the grating type or grating structure, etc. However, they ignore the influence of the light energy loss ratio on the diffraction efficiency of diffraction optical waveguide 1. The present application provides a test method for diffraction optical waveguide 1, which can determine the energy of the second light 13 and the light energy loss ratio of the diffraction optical waveguide 1, so that the grating structure of the diffraction optical waveguide 1 is optimized according to the parameters of the energy of the second light 13 and the light energy loss ratio of the diffraction optical waveguide 1, so as to achieve the purpose of improving the optical efficiency of the diffraction optical waveguide 1.

[0090] In one embodiment, before projecting the first light 12 to the light coupling-in area 10, the method further comprises:

[0091] A first light 12 is acquired, and energy of the first light 12 is determined.

[0092] In one example, the light source assembly 4 emits the first light 12 , and the energy of the first light 12 is analyzed by an optical power meter, an energy meter, a thermal imager, or a spectrometer.

[0093] Or in another example, the light source assembly 4 identifies the energy of the first light 12 emitted by it, so that the user does not need to obtain the energy of the first light 12 separately.

[0094] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0095] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A diffraction optical waveguide testing system, characterized in that: The diffractive optical waveguide comprises a light coupling-in region (10), and the testing system comprises: A movable carrier (2), the movable carrier (2) being used to carry the diffraction optical waveguide; a first slide rail (3), the first slide rail (3) being arranged around the outer side of the movable carrier (2), a light source assembly (4) being arranged on the first slide rail (3), the light source assembly (4) being used for projecting a first light (12) onto the light coupling-in area (10); A second slide rail (5), the second slide rail (5) is arranged on the outer side of the first slide rail (3), a light analysis component (6) is arranged on the second slide rail (5), the light analysis component (6) is movably arranged on the second slide rail (5), the light analysis component (6) is used to receive a second light (13), determine the energy of the second light (13), and determine the light energy loss ratio of the diffraction light waveguide according to the energy of the second light (13), wherein the second light (13) is the light coupled out of the light coupling-in area (10).

2. The diffraction optical waveguide testing system according to claim 1, characterized in that: The light source assembly (4) comprises a light source body (41), and the light source body (41) is movably arranged on the first slide rail (3).

3. The diffraction optical waveguide testing system according to claim 2, characterized in that: The light source assembly (4) further comprises a polarizing element (42), and the light source body (41) and the polarizing element (42) are detachably connected.

4. The diffraction optical waveguide testing system according to claim 1, characterized in that: The first slide rail (3) has a hollow area (31), and the light analysis component (6) is opposite to the hollow area (31).

5. The diffraction optical waveguide testing system according to claim 1, characterized in that: The second slide rail (5) is movably arranged and is arranged around the outer side of the first slide rail (3); The second slide rail (5) has a first end and a second end, and the first end and the second end are both provided with an electric slide rail (7) so that the second slide rail (5) moves along the electric slide rail (7).

6. The diffraction optical waveguide testing system according to claim 1, characterized in that: The first slide rail (3) is a dome structure, and the light source assembly (4) is located on the inner surface of the dome structure.

7. The diffraction optical waveguide testing system according to claim 1, characterized in that: The second slide rail (5) is a dome structure, and the light analysis component (6) is located on the inner surface of the dome structure.

8. The diffraction optical waveguide testing system according to claim 1, characterized in that: The light analysis component (6) is a spectrum analyzer or an optical power meter.

9. A method for testing a diffractive optical waveguide, characterized in that: The diffractive optical waveguide comprises a light coupling-in region (10), and the method comprises: By projecting a first light (12) into the light coupling-in region (10); A second light (13) is obtained, the energy of the second light (13) is determined, and the light energy loss ratio of the diffraction light waveguide is determined according to the energy of the second light (13), wherein the second light (13) is the light coupled out of the light coupling-in area (10).

10. The testing method according to claim 9, characterized in that: Before projecting the first light (12) to the light coupling-in area (10), the method further comprises: A first light beam (12) is acquired, and the energy of the first light beam (12) is determined.

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