Lens assembly for optical coupling and preparation method

Abstract

The invention provides a lens assembly for optical coupling and a preparation method, relates to the technical field of light-emitting communication, and can solve the problem that the coupling stability and the coupling efficiency of an optical module cannot be improved at the same time in the prior art. The lens assembly used for optical coupling comprises a base which is a transparent solid body, and the top surface of the base is provided with a containing groove extending downwards; the first lens, the isolator and the second lens are sequentially arranged in the base in the first direction, the first lens and the second lens are embedded in the two side faces, in the first direction, of the base respectively, and the containing groove is located between the first lens and the second lens; the isolator is arranged in the containing groove and tightly attached to the inner side wall of the containing groove.

Description

Technical Field

[0001] The present invention relates to the technical field of optical communication, and particularly to a lens assembly for optical coupling and a preparation method thereof. Background Art

[0002] With the continuous progress of technologies such as AI, cloud computing, big data, Internet of Things, and artificial intelligence, the demand for the rate of optical modules has gradually moved towards 200G, 400G, and even 800G and 1.6T. As a core component in an optical communication system, the performance of a high-speed optical module directly determines the speed and quality of data transmission. Silicon photonics chips use silicon-based materials to achieve the transmission and processing of optical signals, and have the advantages of high integration, low power consumption, and high-speed transmission, which can significantly improve the performance of optical communication systems. The Lens coupling technology is an important means to ensure efficient optical signal transmission. How to efficiently couple the optical signals of external light sources or lasers to silicon photonics chips has become one of the key problems to be solved.

[0003] Generally, the light emitted by a laser is coupled to the light input port of a silicon photonics chip through a Lens and an isolator. The silicon photonics chip splits the incident light into two or four parts for Mach-Zehnder Modulator (MZM) modulation, and then is coupled into a connector (Multi-fiber Push On, MPO) through a Fiber Array (FA), and then coupled to the receiving end by a PIN diode through the FA to achieve the data transmission of electrical signal - optical signal - electrical signal.

[0004] Currently, during coupling, the use of a single Lens has a low coupling efficiency, and the coupling tolerance of the Lens is small, which will increase the difficulty of coupling. In order to improve the coupling efficiency, a double Lens is used, but this will correspondingly increase the coupling time and reduce the working efficiency. In addition, during gluing, the Lens may also shift due to insufficient contact area and poor bonding, resulting in a decrease in the coupling efficiency and stability of the module. Therefore, how to simultaneously improve the coupling stability and coupling efficiency of an optical module has become an urgent problem to be solved.

[0005] In addition, there is a distance between two Lenses and an isolator in the existing coupling optical path, and it is exposed to the air, which increases the possibility of soiling the inner side of the Lens and the light passing aperture of the isolator, reduces the coupling efficiency, and even causes the phenomenon of error codes during the operation of the module. Summary of the Invention

[0006] The purpose of the present invention is to provide a lens assembly for optical coupling and a preparation method thereof to solve the problem in the prior art that the coupling stability and coupling efficiency of an optical module cannot be improved simultaneously.

[0007] In particular, an embodiment of the first aspect of the present invention provides a lens assembly for optical coupling, characterized in that it includes:

[0008] A base, the base being a transparent solid, and a receiving groove extending downward being formed on the top surface of the base;

[0009] A first lens, an isolator, and a second lens, the first lens, the isolator, and the second lens being sequentially arranged inside the base along a first direction, the first lens and the second lens being respectively embedded on two side surfaces of the base along the first direction,

[0010] wherein, the receiving groove is located between the first lens and the second lens, and the isolator is arranged inside the receiving groove and abuts against the inner side wall of the receiving groove.

[0011] Optionally, the material of the base is polyetherimide.

[0012] Optionally, the refractive index of the base is 1.6 - 1.8.

[0013] Optionally, one side surface of each of the first lens and the second lens is located inside the base,

[0014] The other side surface of each of the first lens and the second lens respectively exposes two side surfaces of the base along the first direction.

[0015] Optionally, the materials of the first lens and the second lens are selected from one of polyetherimide, polymethyl methacrylate, polycarbonate, single crystal silicon, or glass.

[0016] Optionally, the focal lengths of both the first lens and the second lens are 0.25 - 0.4 mm.

[0017] Optionally, the surface types of two side surfaces of the first lens and the second lens are spherical or aspherical.

[0018] Optionally, the distance length along the first direction between the vertical section where the center of the first lens is located and the vertical section where the center of the second lens is located is 3 - 5 mm.

[0019] Optionally, the receiving groove includes a first groove and a second groove from top to bottom, and the diameter of the first groove is larger than that of the second groove,

[0020] The isolator includes an isolator body and a magnet, the isolator body and the magnet are respectively placed in the second groove and the first groove, and the bottom surface of the magnet abuts against the top surface of the isolator body.

[0021] Optionally, the center point of the isolator body is on the straight line passing through the center point of the first lens and perpendicular to the vertical section of the first lens along the first direction.

[0022] Optionally, a ring-shaped dispensing groove is further formed on the bottom surface of the first groove.

[0023] Optionally, the first lens, the second lens and the base are integrally formed.

[0024] Optionally, the first lens is a collimating lens and the second lens is a coupling lens.

[0025] An embodiment of the second aspect of the present invention provides a preparation method for a lens assembly for optical coupling, including the following steps:

[0026] S1, integrally injection-molding to obtain an integrated lens structure based on pre-simulated optical parameters and calculated positions of the accommodating grooves,

[0027] wherein, the injection temperature is 340 - 400 °C and the injection pressure is 120 - 150 Mpa,

[0028] The integrated lens structure includes a base, a first lens and a second lens. The base is a transparent solid body. A downward-extending accommodating groove is formed on the top surface of the base. The first lens and the second lens are sequentially arranged inside the base along the first direction. The first lens and the second lens are respectively embedded on two side surfaces of the base along the first direction. The accommodating groove is located between the first lens and the second lens;

[0029] S2, placing the isolator in the accommodating groove, dispensing and curing to obtain the lens assembly for optical coupling.

[0030] Optionally, step S1 further includes:

[0031] After obtaining the integrated lens structure, it is also necessary to respectively perform mirror polishing and optical coating on the surfaces of the first lens and the second lens and the inner wall surface of the accommodating groove.

[0032] Optionally, the accommodating groove includes a first groove and a second groove from top to bottom. The caliber of the first groove is larger than that of the second groove. A ring-shaped dispensing groove is further formed on the bottom surface of the first groove;

[0033] The isolator includes an isolator body and a magnet;

[0034] Step S2 specifically includes:

[0035] Placing the isolator body into the second groove and closely attaching to the inner side wall of the second groove;

[0036] Apply glue into the glue dispensing groove. After the glue application is completed, place the magnet into the first groove. The bottom surface of the magnet abuts against the top surface of the isolator body.

[0037] Dry and cure to obtain the lens assembly for optical coupling.

[0038] The lens assembly for optical coupling in the embodiment of the present invention realizes the integrated combination of the collimating lens, the isolator, the coupling lens and the base, so that only one simulation coupling of the positions among the first lens, the isolator and the second lens on the substrate needs to be performed in advance to meet multiple subsequent uses, effectively improving the coupling stability, coupling efficiency and production efficiency.

[0039] In addition, the lens assembly for optical coupling in the embodiment of the present invention hermetically mounts the double Lens and the isolator on the base, enabling the optical path to propagate in an environment with the base (transparent solid body) as the medium, avoiding the possibility of soiling the inner side of the Lens and the light passing hole of the isolator, improving the coupling efficiency, and avoiding the phenomenon of bit error abnormality during the operation of the module.

[0040] Those skilled in the art will become more clear about the above and other objects, advantages and features of the present invention according to the following detailed description of the specific embodiments of the present invention in conjunction with the drawings. Description of the Drawings

[0041] Some specific embodiments of the present invention will be described in detail hereinafter with reference to the drawings in an exemplary but non-limiting manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0042] Figure 1 is a schematic structural diagram of a lens assembly for optical coupling according to a specific embodiment of the present invention;

[0043] Figure 2 is a schematic structural diagram of the base, the first lens and the second lens in a lens assembly for optical coupling according to a specific embodiment of the present invention;

[0044] Figure 3 is a cross-sectional view of the base, the first lens and the second lens in a lens assembly for optical coupling according to a specific embodiment of the present invention;

[0045] Figure 4 is a schematic structural diagram of the isolator in a lens assembly for optical coupling according to a specific embodiment of the present invention;

[0046] Figure 5Schematic diagram of the application of a lens assembly for optical coupling according to a specific embodiment of the present invention.

[0047] Explanation of reference numerals:

[0048] Base - 10; receiving groove - 20; first groove - 21; second groove - 22; dispensing groove - 23; isolator - 30; isolator body - 31; magnet - 32; first lens - 40; second lens - 50; PCB board - 60; laser - 70; silicon photonic chip - 80. Detailed implementation manners

[0049] In the description of this embodiment, it should be understood that the orientation or positional relationships indicated by the terms "length", "width", "height", "upper", "lower", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0050] As a specific embodiment of the present invention, as Figure 1 、 Figure 2 and Figure 3 shown, the first - aspect embodiment of the present invention provides a lens assembly for optical coupling, which may include: a base 10, a first lens 40, an isolator 30, and a second lens 50. Among them, the base 10 is a transparent solid, and a receiving groove 20 extending downward is provided on the top surface of the base 10. The first lens 40, the isolator 30, and the second lens 50 are sequentially arranged inside the base 10 along a first direction, and the first lens 40 and the second lens 50 are respectively embedded on the two side surfaces of the base 10 along the first direction. Among them, the receiving groove 20 is located between the first lens 40 and the second lens 50, and the isolator 30 is arranged inside the receiving groove 20 and closely adheres to the inner side wall of the receiving groove 20.

[0051] It should be noted that the first lens 20 is a collimating lens for collimating light; the second lens 40 is a coupling lens for converging light; the isolator 30 is arranged between the first lens 20 and the second lens 40 to isolate the reflected optical fiber and improve the return loss.

[0052] Specifically, the lens assembly for optical coupling according to the embodiment of the present invention is provided with a base 10 of a transparent solid body, and a first lens 40 (collimating lens), an isolator 30, and a second lens 50 (coupling lens) are mounted on the base 10 in a first direction (which may be the length direction of the base 10). Among them, the first lens 40 and the second lens 50 are respectively mounted on both side surfaces in the length direction of the base 10. Specifically, one side surface of each of the first lens 40 and the second lens 50 is located inside the base 10, and the other side surfaces of the first lens 40 and the second lens 50 respectively expose both side surfaces of the base 10 along the length direction. The collimated input of the light source is achieved through the first lens 40, and the coupled output of the optical path is achieved through the second lens 50. Among them, the isolator 30 is disposed in the accommodation groove 20 opened on the top surface of the base 10, and forms a dense whole with the base 10 closely attached to the inner side wall of the accommodation groove 20. It should be noted that the upper end of the accommodation groove 20 is open and the lower end is closed.

[0053] That is to say, the lens assembly for optical coupling according to the embodiment of the present invention realizes the integrated combination of the collimating lens, the isolator, the coupling lens and the base, so that only one simulation coupling of the positions among the first lens 40, the isolator 30 and the second lens 50 on the base 10 needs to be performed in advance, which can meet the subsequent multiple uses, effectively improving the coupling stability, coupling efficiency and production efficiency.

[0054] In addition, the lens assembly for optical coupling according to the embodiment of the present invention hermetically mounts the double Lens and the isolator on the base, so that the optical path propagates in an environment with the base (transparent solid body) as the medium, avoiding the possibility of soiling the inside of the Lens and the light passing holes of the isolator, improving the coupling efficiency, and avoiding the phenomenon of error code abnormality during the operation of the module.

[0055] Preferably, the material of the base 10 can be polyetherimide.

[0056] Specifically, when the above-mentioned material is selected as the base 10, it has the advantages of maintaining optical performance in a high-temperature environment (such as 180 °C), and at the same time, it can relatively shorten the optical path and reduce costs.

[0057] Preferably, the refractive index of the base 10 is 1.6 to 1.8.

[0058] Preferably, the materials of the first lens 40 and the second lens 50 are selected from one of polyetherimide, polymethyl methacrylate, polycarbonate, monocrystalline silicon or glass.

[0059] Specifically, when the foregoing materials are selected to prepare the lens, it has good stability in the infrared communication band and strong high-temperature adaptability; in addition, the larger its refractive index, the more beneficial it is to reduce the focal length and shorten the optical path length, thereby controlling the size of the entire assembly.

[0060] Preferably, the focal lengths of the first lens 40 and the second lens 50 are both 0.25 to 0.4 mm.

[0061] Specifically, it can be selected according to the actual usage scenario. For example, the focal lengths of the first lens 40 and the second lens 50 can be selected respectively based on the wavelength of the incident light.

[0062] Optionally, the surface profiles of the two sides of the first lens 40 and the second lens 50 are spherical or aspherical.

[0063] Specifically, the surface profile of the Lens can be either spherical or aspherical. According to the actual application scenario and combined with optical simulation, specific parameters such as the surface profile, radius of curvature, Conic number, and high-order term coefficients of the Lens need to be given. To ensure the high coupling efficiency of the system, the center height of the double Lens needs to be set according to the simulation results and adjusted flexibly.

[0064] As a specific embodiment of the present invention, the distance length in the first direction between the vertical section where the center of the first lens 40 is located and the vertical section where the center of the second lens 50 is located is 3 to 5 mm.

[0065] Specifically, the optical path length can be appropriately reduced or increased according to the actual situation (since the light between the two Lenses is collimated light, reducing or increasing the optical path length within a certain range has little impact on the final coupling efficiency).

[0066] As a specific embodiment of the present invention, as Figure 1 、 Figure 3 and Figure 4 shown, the accommodation groove 20 includes a first groove 21 and a second groove 22 from top to bottom, and the diameter of the first groove 21 is larger than that of the second groove 22. The isolator 30 includes an isolator body 31 and a magnet 32. The isolator body 31 and the magnet 32 are respectively placed in the second groove 22 and the first groove 21, and the bottom surface of the magnet 32 abuts against the top surface of the isolator body 31.

[0067] Specifically, the accommodation groove 20 of this embodiment is provided with a first groove 21 and a second groove 22 that are vertically connected. The diameter of the first groove 21 is larger than that of the second groove 22, so that the isolator body 31 is placed in the second groove 22, and the magnet 32 provided in the first groove 21 can play a capping role. In addition, the occupied area of the magnet 32 in this application is larger than the occupied area of the isolator body 31, so that the contact area between the isolator body 31 and the magnet 32 is maximized, ensuring that the magnetic field strength is sufficient during long-term and high and low temperature operations, thereby ensuring the isolation degree and avoiding reliability risks such as bit error and packet loss during the operation of the optical module. In addition, it can protect the (LD) laser and key components in the optical communication system from the interference of reflected light for a longer time. It should be noted that the isolator body 31 and the magnet 32 are respectively in close contact with the second groove 22 and the first groove 21.

[0068] In addition, the light passing aperture of the isolator body 31 (i.e., the isolator without a magnetic core) is usually greater than or equal to 0.7 mm and has a 7° tilt angle (for better isolation of reflected light). To enable the isolator to better isolate light and its mounting stability, in the component of the present invention, the external magnet 32 can have a length and width dimension of 2*2 mm or even a larger size, and the external magnet can be of other shapes (such as circular, etc., as long as the coverage area is large enough to stably provide a magnetic field).

[0069] Preferably, the center point of the isolator body 31 is on the straight line passing through the center point of the first lens 40 and perpendicular to the vertical section of the first lens 40 in the first direction.

[0070] Specifically, ensure that the center point of the isolator body 31 is on the straight line passing through the center point of the first lens 40 and perpendicular to the vertical section of the first lens 40 in the first direction, and is located between the first lens 40 and the second lens 50, so as to ensure the isolation degree and thus ensure the coupling efficiency.

[0071] As a specific embodiment of the present invention, as Figure 2 and Figure 3 shown, a ring-shaped glue dispensing groove 23 is further formed on the bottom surface of the first groove 21.

[0072] Specifically, the magnet 32 is placed in the first groove 21. Glue is pre-applied in the glue dispensing groove 23, and then the magnet 32 is placed in the first groove 21. After drying and curing, the magnet 32 can be fully fixed on the first groove 21.

[0073] As a specific embodiment of the present invention, the first lens 40, the second lens 50 and the base 10 are integrally formed.

[0074] That is to say, when preparing the first lens 40, the second lens 50 and the base 10 of this embodiment, after pre-simulation coupling, the first lens 40, the second lens 50 and the base 10 are integrally formed. Subsequently, only the isolator 30 needs to be installed at a predetermined position of the base 10 to be put into use, effectively improving the coupling efficiency.

[0075] The application scenarios of the lens assembly for optical coupling of the present invention will be specifically described below. Refer to Figure 5As shown in the figure, a lens assembly for optical coupling is provided on a PCB board 60. A laser 70 is provided on one side of the PCB board 60, and a silicon optical chip 80 is provided on the other side. Among them, the light-emitting position of the laser 70 and the first lens 40 and the second lens 50 on the lens assembly for optical coupling are on the same horizontal line. Among them, the laser light emitted by the laser 70 passes through the first lens 40 and is collimated by the first lens 40 to emit parallel light. The parallel light enters the second lens 50 through the isolator 30 to achieve convergence, and the converged light is coupled into the silicon optical chip 80.

[0076] In addition, considering the loss of light after passing through the silicon optical chip, the silicon optical chip may have two or more light inlet ports, so two or more outgoing lights are required for coupling. Therefore, two or more lens assemblies for optical coupling of the present invention can be combined in parallel. Among them, the positions of each part in each integrated Lens coupling structure are designed and determined according to the actual required parameters, and the overall optical path only needs to be coupled once, greatly improving the production efficiency.

[0077] It should be noted that the incident light wavelengths applicable to the lens assembly for optical coupling of the present invention are generally common optical communication wavelengths such as 850 nm, 1310 nm, and 1550 nm.

[0078] An embodiment of the second aspect of the present invention provides a preparation method for a lens assembly for optical coupling, which is applied to preparing the lens assembly for optical coupling in any embodiment of the first aspect above, and may include the following steps:

[0079] S1, an integrated lens structure is prepared by integrally injection molding based on pre-simulated optical parameters and calculated accommodation groove positions,

[0080] wherein, the injection temperature is 340-400 °C, and the injection pressure is 120-150 Mpa,

[0081] The integrated lens structure includes a base, a first lens, and a second lens. The base is a transparent solid body. A downwardly extending accommodation groove is provided on the top surface of the base. The first lens and the second lens are sequentially arranged inside the base along the first direction. The first lens and the second lens are respectively embedded on the two side surfaces of the base along the first direction. The accommodation groove is located between the first lens and the second lens;

[0082] S2, the isolator is placed in the accommodation groove and fixed by dispensing to obtain a lens assembly for optical coupling.

[0083] As a specific embodiment of the present invention, step S1 may further include:

[0084] After the integrated lens structure is prepared, the surfaces of the first lens and the second lens and the inner wall surface of the accommodation groove need to be mirror-polished and optically coated respectively.

[0085] As a specific embodiment of the present invention, the accommodating groove includes a first groove and a second groove from top to bottom. The caliber of the first groove is larger than that of the second groove, and an annular dispensing groove is further formed on the bottom surface of the first groove.

[0086] The isolator includes an isolator body and a magnet.

[0087] Step S2 may specifically include:

[0088] Place the isolator body into the second groove and closely adhere to the inner side wall of the second groove;

[0089] Dispense glue into the dispensing groove. After dispensing, place the magnet into the first groove, and the bottom surface of the magnet abuts against the top surface of the isolator body;

[0090] Dry and cure to obtain a lens assembly for optical coupling.

[0091] At this point, those skilled in the art should recognize that although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the disclosed content of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and determined to cover all these other variations or modifications.

Claims

1. A lens assembly for optical coupling, characterized in that: include: A base, the base is a transparent solid body, and a receiving groove extending downward is formed on the top surface of the base; A first lens, an isolator and a second lens, wherein the first lens, the isolator and the second lens are sequentially arranged inside the base along a first direction, and the first lens and the second lens are respectively embedded on two side surfaces of the base along the first direction. The containing groove is located between the first lens and the second lens, and the isolator is arranged inside the containing groove and closely attached to the inner wall of the containing groove.

2. The lens assembly for optical coupling according to claim 1, characterized in that: The material of the base is polyetherimide.

3. The lens assembly for optical coupling according to claim 2, characterized in that: The refractive index of the base is 1.6-1.

8.

4. The lens assembly for optical coupling according to claim 1, characterized in that: One side surface of each of the first lens and the second lens is located inside the base, The other side surfaces of the first lens and the second lens are respectively exposed to two side surfaces of the base along the first direction.

5. The lens assembly for optical coupling according to claim 4, characterized in that: The material of the first lens and the second lens is selected from one of polyetherimide, polymethyl methacrylate, polycarbonate, single crystal silicon or glass.

6. The lens assembly for optical coupling according to claim 4, characterized in that: The focal lengths of the first lens and the second lens are both 0.25-0.4 mm.

7. The lens assembly for optical coupling according to claim 4, characterized in that: The surface shapes of the two side surfaces of the first lens and the second lens are spherical or aspherical.

8. The lens assembly for optical coupling according to claim 4, characterized in that: A distance along the first direction between a vertical section where the center of the first lens is located and a vertical section where the center of the second lens is located is 3 to 5 mm.

9. The lens assembly for optical coupling according to claim 1, characterized in that: The accommodating groove includes a first groove and a second groove from top to bottom, and the diameter of the first groove is larger than the diameter of the second groove. The isolator comprises an isolator body and a magnet. The isolator body and the magnet are respectively disposed in the second groove and the first groove, and the bottom surface of the magnet abuts against the top surface of the isolator body.

10. The lens assembly for optical coupling according to claim 9, characterized in that: The center point of the isolator body is on a straight line passing through the center point of the first lens and perpendicular to a vertical cross section of the first lens along the first direction.

11. The lens assembly for optical coupling according to claim 9, characterized in that: An annular glue dispensing groove is also formed on the bottom surface of the first groove.

12. The lens assembly for optical coupling according to claim 1, characterized in that: The first lens, the second lens and the base are made in one piece.

13. The lens assembly for optical coupling according to claim 12, characterized in that: The first lens is a collimating lens, and the second lens is a coupling lens.

14. A method for preparing a lens assembly for optical coupling, characterized in that: The steps include: S1, based on the pre-simulated optical parameters and the calculated accommodating groove position, an integrated lens structure is obtained by integrated injection molding, Among them, the injection temperature is 340-400°C, and the injection pressure is 120-150Mpa. The integrated lens structure comprises a base, a first lens and a second lens, the base is a transparent solid body, the top surface of the base is provided with the accommodation groove extending downward, the first lens and the second lens are sequentially arranged inside the base along a first direction, the first lens and the second lens are respectively embedded on two side surfaces of the base along the first direction, and the accommodation groove is located between the first lens and the second lens; S2, placing the isolator in the receiving groove, dispensing glue and curing it to obtain the lens assembly for optical coupling.

15. The method for preparing a lens assembly for optical coupling according to claim 14, characterized in that: The step S1 further comprises: After the integrated lens structure is manufactured, the surfaces of the first lens and the second lens and the surface of the inner wall of the receiving groove need to be mirror-polished and optically coated respectively.

16. The method for preparing a lens assembly for optical coupling according to claim 14, characterized in that: The accommodating groove includes a first groove and a second groove from top to bottom, the diameter of the first groove is larger than the diameter of the second groove, and an annular glue dispensing groove is also formed on the bottom surface of the first groove; The isolator comprises an isolator body and a magnet; The step S2 specifically includes: Put the isolator body into the second groove and close to the inner wall of the second groove; Dispense glue into the dispensing groove, and then place the magnet into the first groove after dispensing, with the bottom surface of the magnet abutting against the top surface of the isolator body; The lens assembly for optical coupling is obtained by drying and curing.

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