Polymer waveguide assembly, flexible polymer waveguide plate and preparation method thereof

Abstract

The invention relates to a polymer waveguide assembly, a flexible polymer waveguide plate and a preparation method thereof, the flexible polymer waveguide plate comprises a flexible substrate, a lower cladding, a core layer and a flexible upper cladding, and the core layer is located between the lower cladding and the flexible upper cladding and is prepared from a hard material; the lower cladding is located at the upper end of the flexible substrate and is made of a hard material. According to the flexible polymer waveguide plate, flexible films such as P I, PMMA and the like are used as a substrate, a conventional optical waveguide adhesive material is used as a waveguide lower cladding layer and core layer material, a flexible optical waveguide adhesive material is used as an upper cladding layer material, and the flexible optical waveguide plate is prepared by adopting an ultraviolet lithography technology, so that the problem of bending fracture of rigid waveguide adhesive can be solved, and the service life of the flexible polymer waveguide plate is prolonged. The waveguide bending performance is remarkably improved, transmission under the bending radius of 5 mm can be achieved, complex and expensive flexible polymer waveguide glue is not needed, and the preparation process difficulty and cost are remarkably reduced.

Description

Technical Field

[0001] The invention belongs to the field of optical transmission structures, and in particular relates to a polymer waveguide component, a flexible polymer waveguide plate and a preparation method thereof. Background Art

[0002] Currently, the preparation of polymer waveguides is mainly based on rigid waveguide plates, which have limited usage scenarios, insufficient flexibility and heavy weight; the preparation of existing flexible optical waveguides requires special customization of corresponding flexible optical waveguide adhesive materials, which has expensive R&D costs and complex preparation. Summary of the invention

[0003] To solve the above problems, the present invention provides a flexible polymer waveguide plate with a novel structure and a preparation method thereof, so that the flexible polymer waveguide plate can be prepared from relatively common materials by a simple method. The present invention also discloses a polymer waveguide component composed of the above flexible polymer waveguide plate.

[0004] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. A flexible polymer waveguide plate proposed in the present invention comprises a flexible substrate 1, a lower cladding layer 2, a core layer 3 and a flexible upper cladding layer 4, wherein the core layer 3 is located between the lower cladding layer 2 and the flexible upper cladding layer 4 and is made of a hard material; the lower cladding layer 2 is located at the upper end of the flexible substrate 1 and is made of a hard material.

[0005] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0006] In the aforementioned flexible polymer waveguide plate, the flexible upper cladding layer 4 is made of flexible optical path adhesive.

[0007] In the aforementioned flexible polymer waveguide plate, the flexible substrate 1 is a flexible film.

[0008] The aforementioned flexible polymer waveguide plate has a V-shaped groove 6 with a 90-degree angle processed at the waveguide channel 5 of the waveguide plate, and the groove wall of the V-shaped groove 6 has a 45-degree angle with the surface of the waveguide plate; a high-reflective film layer is evaporated on the surface of the V-shaped groove 6.

[0009] In the aforementioned flexible polymer waveguide plate, the bottom of the V-shaped groove 6 is close to the flexible substrate 1, and the groove opening is located on one side of the flexible upper cladding layer 4, and the flexible substrate 1 is made of a highly transparent material.

[0010] The purpose of the present invention and the technical problems solved by the present invention are also achieved by the following technical solutions. According to the method for preparing a flexible polymer waveguide plate proposed by the present invention, the method comprises the following steps: 1) selecting a suitable flexible film as a flexible substrate 1; 2) spin coating a low-refractive index optical waveguide adhesive on the surface of the flexible substrate 1 and curing it to form a hard lower cladding layer 2; 3) spin coating a high-refractive index optical waveguide adhesive on the upper surface of the lower cladding layer and curing it, and then sequentially performing ultraviolet exposure and development to obtain a hard core layer 3; 4) spin coating a layer of ultraviolet-curable low-refractive index flexible optical waveguide adhesive on the core layer 3 and the lower cladding layer 2 to form a flexible upper cladding layer 4, thereby obtaining a flexible polymer waveguide plate having a waveguide channel 5.

[0011] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0012] In the above-mentioned method for preparing the flexible polymer waveguide plate, the flexible optical waveguide adhesive in step 4) is a flexible optical path adhesive.

[0013] In the above-mentioned method for preparing the flexible polymer waveguide plate, the flexible substrate 1 in step 1) is made of a highly transparent flexible film; and a 90-degree V-groove is also processed at the waveguide channel 5 of the flexible polymer waveguide plate, so that the light transmitted along the waveguide channel is turned 90 degrees and then emitted from one side of the flexible substrate 1 through the V-groove.

[0014] In the above-mentioned method for preparing the flexible polymer waveguide plate, the V-shaped groove is formed by directly etching the flexible polymer waveguide plate, and a high-reflective film layer is also evaporated on the inner wall of the V-shaped groove.

[0015] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solution, the present invention can achieve considerable technical advancement and practicality, and has wide industrial utilization value, and has at least the following advantages:

[0016] The waveguide plate of the present invention adopts flexible films such as PI and PMMA as a substrate, conventional optical waveguide adhesive materials as waveguide lower cladding and core materials, and flexible optical path adhesive as upper cladding material, and adopts ultraviolet photolithography technology to make a flexible optical waveguide plate. It can not only solve the bending and fracture problems of hard waveguide adhesives, significantly improve the bending performance of the waveguide, and realize transmission under a bending radius of 5mm, but also do not require complex and expensive flexible polymer waveguide adhesives, significantly reducing the difficulty and cost of the preparation process.

[0017] The present invention uses the existing flexible optical path adhesive for bonding as the upper cladding of the waveguide plate, which not only improves the bending performance of the waveguide plate, but also provides a new material for the preparation of the flexible upper cladding of the waveguide plate, and proposes a new application of the flexible optical path adhesive.

[0018] The waveguide plate of the present invention also uses a highly transparent flexible substrate and directly utilizes a 90° V-shaped groove to evaporate a high-reflection film, thereby achieving direct 90° diversion of the light path and then direct emission from one side of the flexible substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the composition structure of the flexible polymer waveguide plate of the present invention;

[0020] Figure 2 This is a schematic diagram of the preparation process of the flexible polymer waveguide plate of the present invention;

[0021] Figure 3 A schematic diagram of the preparation process of the vertical steering structure on the flexible polymer waveguide plate of the present invention;

[0022] Figure 4 A schematic diagram of the optical path of the vertical steering structure of the flexible polymer waveguide plate of the present invention;

[0023] Figure 5 Schematic diagram of the composition of the polymer waveguide component of the present invention;

[0024] Figure 6 is a schematic diagram of the coupling structure of the polymer waveguide component of the present invention;

[0025] Figure 7 A schematic diagram of a base of the coupling structure of the present invention;

[0026] Figure 8 for Figure 7 Top view of the .

[0027]

Main component symbol description

[0028] 1: Flexible substrate

[0029] 2: Lower cladding

[0030] 3: Core layer

[0031] 4: Flexible upper cladding

[0032] 5: Waveguide channel

[0033] 51: Cantilever

[0034] 6: Vertical steering structure

[0035] 7: Coupling structure

[0036] 71: Base

[0037] 711: Coupling slot

[0038] 712: V-groove

[0039] 713: Positioning plane

[0040] 714: Guide pin hole

[0041] 72: Cover

[0042] 73: Fixed cavity

[0043] 8: Flexible polymer waveguide

[0044] 9: Switching optical fiber DETAILED DESCRIPTION

[0045] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation manner, structure, characteristics and effects of the flexible polymer waveguide plate proposed according to the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0046] See also Figure 1-4 , which is a schematic diagram of the structure of each part of the flexible polymer waveguide plate of the present invention, the flexible polymer waveguide plate includes a flexible substrate 1, the upper surface of the flexible substrate is provided with a lower cladding layer 2, the upper surface of the lower cladding layer 2 is provided with a core layer 3, and a flexible upper cladding layer 4 is formed above the core layer 3 and the lower cladding layer 2, and the flexible upper cladding layer 4 can cover the outer surface of the core layer 3 except the lower end surface. The core layer 3 and the lower cladding layer 2 are both rigid structures made of hard materials. The flexible polymer waveguide plate is a sandwich structure with flexible structures on both sides and a hard structure in the middle. As a result, the flexible polymer waveguide plate has flexibility under the action of the flexible structures on the upper and lower surfaces, and can achieve transmission under a bending radius of 5mm, which can solve the problem that the hard waveguide adhesive is easy to bend and break. In addition, in the present invention, only the substrate and the upper cladding layer adopt flexible structures, while the core layer and the lower cladding layer can be hard structures made of conventional optical waveguide adhesive materials, without the need for complex and expensive flexible polymer waveguide adhesives, which significantly reduces the difficulty and cost of the preparation process.

[0047] In an embodiment of the present invention, the flexible substrate 1 is a flexible film such as PI (polyimide) or PMMA (polymethyl methacrylate), and the upper cladding material is a flexible optical path adhesive. The existing flexible optical path adhesive is used as an adhesive, while the present invention uses the flexible optical path adhesive as the upper cladding layer 4 material. The flexible optical path adhesive provides a fully reflective mirror surface for the core layer 3 in the present invention, which not only realizes the reliable transmission of light in the core layer, but also proposes a new use of the flexible optical path adhesive.

[0048] The preparation of the flexible polymer waveguide plate of the present invention comprises the following steps:

[0049] 1) Selecting a flexible film such as PI or PMMA as the flexible substrate 1; preferably, the thickness of the flexible substrate 1 is 20-500 μm;

[0050] 2) Spin-coating a commonly used low-refractive-index optical waveguide adhesive on the upper surface of the flexible substrate 1 and curing the adhesive to form a hard lower cladding layer 2; preferably, the lower cladding layer has a thickness of 20-70 microns;

[0051] 3) Spin-coating a commonly used high-refractive-index optical waveguide adhesive on the upper surface of the lower cladding layer 2 and curing it, and then sequentially performing ultraviolet exposure and development to obtain a hard core layer 3; preferably, the core layer 3 has a thickness of 20-70 microns;

[0052] 4) A layer of UV-curable low-refractive-index flexible optical path adhesive is spin-coated on the core layer 3 and the lower cladding layer 2 to serve as the upper cladding layer 4; preferably, the upper cladding layer 4 is 20-100 microns thick.

[0053] In the present invention, the thickness of the upper cladding layer 4, the lower cladding layer 2 and the core layer 3 are precisely controlled according to the viscosity of the glue during spin coating and the spin coating conditions.

[0054] The flexible polymer waveguide plate of the present invention can also realize vertical light emission through the vertical steering structure 6 thereon. In an embodiment of the present invention, the vertical steering structure 6 is a V-groove. Based on the characteristics of the flexible polymer waveguide plate that is easy to laser etch and grayscale photolithography, the present invention directly processes a V-groove at the waveguide channel 5 on the flexible waveguide plate. The bottom of the V-groove is close to the flexible substrate side of the flexible waveguide plate, and the groove is located on the flexible upper cladding 4 side of the flexible waveguide plate. At this time, the flexible substrate 1 of the waveguide plate is made of high-transmittance material, so that the light after the V-groove is turned is emitted from one side of the flexible substrate 1. Preferably, the flexible substrate 1 uses a PMMA film, but it is not limited to this. The two side walls of the V-groove have an inclination angle of 45 degrees with the surface of the waveguide plate, and the two side walls of the V-groove are 90 degrees apart, that is, the V-groove is a 90° V-groove.

[0055] In an embodiment of the present invention, the 90° V-shaped groove is formed by directly etching on the flexible polymer waveguide plate, while in other embodiments of the present invention, the 90° V-shaped groove can also be obtained by direct cutting or other processing methods.

[0056] A high-reflection film layer is also evaporated on the inner wall of the 90° V-shaped groove to enhance the reflection intensity and achieve total reflection. The light transmitted along the waveguide plate is vertically turned after passing through the 90° V-shaped groove and emitted by the flexible substrate 1, thereby achieving vertical light emission on the waveguide plate.

[0057] See also Figure 5-8The present invention further provides a polymer waveguide component, which includes the above-mentioned flexible polymer waveguide plate 8, a vertical steering structure 6 and two coupling structures 7 for converting the waveguide end faces at both ends of the waveguide plate into optical fiber end faces, that is, the waveguide channel 5 of the flexible polymer waveguide plate 8 of the present invention is provided with a vertical steering structure 6, and the two ends of the waveguide channel 5 of the flexible polymer waveguide plate form a cantilever structure 51, the cantilever structure is located in the coupling structure 7, and the coupling end face is standardized by coupling with the switching optical fiber 9 in the coupling structure 7, thereby realizing rapid end face docking with the adapter optical fiber.

[0058] The coupling structure 7 includes a base 71 and a cover plate 72. The base 71 is provided with a coupling groove 711 extending along the extension direction of the waveguide channel 5. Both the front and rear ends of the coupling groove 711 are open, wherein the waveguide channel 5 enters the coupling groove 711 from the rear end, and the switching optical fiber 9 is located inside the front end of the coupling groove 711.

[0059] The front end of the bottom of the coupling groove 711 has an array of V-grooves 712, which are used to realize the positioning of the switching optical fiber 9 in the positioning seat 71, and each V-groove 712 is provided with a switching optical fiber 9. The rear end of the bottom of the coupling groove 711 is also provided with a positioning plane 713, which is used to support the cantilever 51 at both ends of the waveguide channel 5. At the same time, the two sides of the cantilever 51 are limited by the two side walls of the coupling groove 711, and the center line of each core layer 3 of the cantilever 51 supported and limited on the positioning plane 713 coincides with the center line of the switching optical fiber 9 in the corresponding V-groove 712, that is, in the coupling groove 711, the end face of the waveguide plate and the end face of the switching optical fiber 9 are automatically aligned, and no additional debugging is required. The end face connection of the waveguide plate and the switching optical fiber can be realized by directly filling the coupling groove 711 with optical path glue. The cover plate 72 can be buckled on the base 71 and pressed on the transfer optical fiber and the waveguide channel 5 in the coupling groove 711 of the base 71 to ensure the reliability of the end-to-end connection between the two. The setting of the coupling structure 7 of the present invention replaces the end face of the waveguide plate with the end face of the optical fiber, so that when the waveguide plate is connected with the adapter optical fiber, the waveguide plate and the adapter optical fiber can be quickly connected only through the cooperation of the coupling structure 7 and the adapter optical fiber positioning structure (such as a standard MT connector). In this connection process, there is no need to align and debug the waveguide core layer and the optical fiber, and the waveguide plate and the optical fiber can be quickly connected only through the precise positioning of the coupling structure 7 and the adapter end optical fiber positioning structure.

[0060] In the embodiment of the present invention, the cover plate 72 has a width substantially consistent with the coupling slot 711, and can enter the coupling slot 711 and fill the space after the coupling slot 711 is equipped with the optical fiber and the waveguide channel, that is, the cover plate 72 of the present invention has a certain thickness. The cover plate 72 of the present invention is connected to the groove wall of the coupling slot 711 and the waveguide plate and the optical fiber at the bottom of the groove by glue.

[0061] In the embodiment of the present invention, after the waveguide plate and the switching optical fiber 9 are passively aligned end-to-end through the coupling groove 711, they are also initially fixed by filling the optical path glue in the coupling groove 711, and the cover plate 72 coated with glue on the bottom and side walls is buckled into the coupling groove 711 from top to bottom to cover the coupling groove 711. At this time, the bottom end surface of the cover plate 72 is pressed on the waveguide plate and the switching optical fiber 9 and bonded to them, and the side walls of the cover plate are bonded to the two side walls of the coupling groove 711.

[0062] In the embodiment of the present invention, the positioning plane 713 is lower than the bottom of the V-shaped groove 712 , so that the center of the waveguide core layer 3 of the waveguide channel 5 can be aligned with the center of the transfer optical fiber 9 in the V-shaped groove 712 .

[0063] In the embodiment of the present invention, the tail of the coupling structure 7 is also provided with a fixing cavity 73 for fixing the tail sheath, and the radial dimension of the cavity is larger than the radial dimension of the coupling groove 711, so that the coupling structure 7 has a stepped hole structure with a small front and a large rear, and the stepped hole is a rectangular hole. Preferably, the fixing cavity 73 is also filled with glue for fixing the sheath.

[0064] In other embodiments of the present invention, the fixing cavity 73 directly protects and supports the waveguide plate through the glue therein, that is, in this case, the rear sheath is cancelled.

[0065] In the embodiment of the present invention, a guide pin hole 714 for matching with the guide pin on the optical fiber positioning structure at the adapter end is further provided on the front end surface of the base 71 .

[0066] The polymer waveguide component of the present invention realizes coupling with the end face of the transfer optical fiber through the coupling structure at the end of its waveguide channel, so that the waveguide end face of the waveguide plate is converted into the optical fiber end face, so that when the waveguide component is docked with the adapted optical fiber, the docking between the waveguide end face and the optical fiber end face is converted into the docking between the optical fiber end faces, and the end face docking of the optical fiber after the precise positioning of the positioning structure is a mature process in this field, and the docking between the transfer optical fiber and the adapter end optical fiber in the coupling structure of the present invention is achieved by the guiding positioning between the positioning structures where they are located, and the docking process is the plugging between the positioning structures (such as the guiding plugging between the guide pin and the guide pin hole between the coupling structure of the present application and the standard MT connector), without the need for connection through glue, and the separation after docking only needs to be achieved through the separation between the positioning structures, which can meet the needs of repeated plugging and unplugging, and there is no loss in the docked optical fiber end face during the plugging and unplugging process.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A flexible polymer waveguide plate, characterized in that: It includes a flexible substrate, a lower cladding, a core layer and a flexible upper cladding, wherein the core layer is located between the lower cladding and the flexible upper cladding and is made of a hard material; the lower cladding is located at the upper end of the flexible substrate and is made of a hard material.

2. The flexible polymer waveguide plate according to claim 1, characterized in that: The flexible upper cladding layer is made of flexible optical path adhesive.

3. The flexible polymer waveguide plate according to claim 1 or 2, characterized in that: The flexible substrate is a flexible film.

4. The flexible polymer waveguide plate according to claim 1 or 2, characterized in that: A V-shaped groove with a 90-degree angle is processed at the waveguide channel of the waveguide plate, and the groove wall of the V-shaped groove has a 45-degree angle with the surface of the waveguide plate; a high-reflective film layer is evaporated on the surface of the V-shaped groove.

5. The flexible polymer waveguide plate according to claim 4, characterized in that: The bottom of the V-shaped groove is close to the flexible substrate, the groove opening is located on one side of the flexible upper cladding layer, and the flexible substrate is made of a highly transparent material.

6. A method for preparing the flexible polymer waveguide plate according to any one of claim 1, characterized in that: The following steps are involved: 1) Selecting a suitable flexible film as a flexible substrate; 2) Spin-coating a low-refractive-index optical waveguide adhesive on the surface of the flexible substrate and curing the adhesive to form a hard lower cladding layer; 3) Spin-coating a high-refractive-index optical waveguide adhesive on the upper surface of the lower cladding layer and curing it, and then sequentially performing ultraviolet exposure and development to obtain a hard core layer; 4) A layer of ultraviolet curable low-refractive index flexible optical waveguide adhesive is spin-coated on the core layer and the lower cladding layer to form a flexible upper cladding layer, thereby obtaining a flexible polymer waveguide plate with a waveguide channel.

7. The method for preparing a flexible polymer waveguide according to claim 1, characterized in that: The flexible optical waveguide adhesive described in step 4) is a flexible optical path adhesive.

8. The method for preparing a flexible polymer waveguide plate according to claim 6 or 7, characterized in that: The flexible substrate in step 1) is a highly transparent flexible film; and a 90-degree V-groove is processed at the waveguide channel of the flexible polymer waveguide plate, through which the light transmitted along the waveguide channel is turned 90 degrees and then emitted from one side of the flexible substrate.

9. The method for preparing a flexible polymer waveguide plate according to claim 8, characterized in that: The V-shaped groove is formed by directly etching on the flexible polymer waveguide plate, and a high-reflection film layer is also evaporated on the inner wall of the V-shaped groove.

10. A polymer waveguide component, characterized in that: A flexible polymer waveguide plate comprising any one of claims 1 to 5 or a flexible polymer waveguide plate prepared by the preparation method of any one of claims 6 to 9, wherein cantilevers are formed at both ends of a waveguide channel of the flexible polymer waveguide plate, and the cantilevers are fixed in a groove in a coupling structure; the coupling structure is used to achieve end-face connection between the flexible polymer waveguide plate and an adapting optical fiber.

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