Optical fiber light-receiving coupling device

Abstract

The application relates to a fiber light-receiving coupling device in the field of optical communication, which comprises a flange, a check ring, a lens, a fiber assembly, a pressing sleeve and a protective tail sleeve; the front end inner diameter size of the flange corresponds to the lens and the check ring, the rear end inner diameter size of the flange corresponds to a fiber ferrule, sectional glue injection holes are arranged at both ends of the flange, and the sectional glue injection holes are used for fixing the radial positions of the lens and the fiber ferrule; the check ring is installed outside the lens, an outer ring of the check ring is provided with a glue injection groove and is used for fixing the axial position of the lens; the lens and the fiber assembly are fixed by using optical glue; the pressing sleeve is used for fixing an outer sheath of an optical cable; and the protective tail sleeve is used for protecting the connection between the tail part of the lens and the optical cable.

Description

Technical Field

[0001] This application relates to the technical field of spatial light and optical fiber coupling, and in particular to an optical fiber receiving coupling device. Background Technology

[0002] In the field of spatial light and fiber optic coupling, the mode field diameter and numerical aperture of optical fibers are much smaller than those of lenses. The coupling performance and reliability of fiber optic receiving coupling devices determine the transmission performance of communication systems.

[0003] Fiber optic optical coupling devices typically employ single lenses or lens systems to match spatial light with the optical fiber. Considering the difficulty of assembling and adjusting lens systems, as well as transmission losses caused by optical components, single lenses are generally preferred. To achieve optimal coupling, two approaches are taken: firstly, simplifying the optical path structure through optical design to match the input laser with the single lens and fiber core diameter parameters; secondly, designing the coupling device with reasonable limits to avoid human error during assembly and adjustment. Fiber optic optical coupling devices that balance high coupling efficiency, simple assembly structure, and high reliability are increasingly favored.

[0004] Currently, most optical receiving coupling devices using single-lens-fiber coupling employ direct adhesive bonding, fixing the lens and fiber entirely with adhesive. This method requires a large amount of adhesive for fixation, which can easily leave adhesive residue on the lens surface during assembly and adjustment. Lens displacement may occur during adhesive curing, and stress may be generated on the lens under wide temperature range operating conditions. Under harsh mechanical conditions, the adhesive is prone to detachment, and the adhesive is susceptible to aging and failure, resulting in the long-term reliability of the optical receiving coupling device being compromised. Summary of the Invention

[0005] This application provides an optical fiber receiving and coupling device, the purpose of which is to reduce the difficulty of processing and assembly and improve the reliability of the device.

[0006] Firstly, a fiber optic optical receiving coupling device is provided, comprising a flange, a retaining ring, a lens, and a fiber optic assembly; wherein...

[0007] The flange has a hollow structure, and the lens and the optical fiber assembly are housed in the cavity of the flange. The lens is disposed at the first end of the flange, and the optical fiber assembly is disposed at the second end of the flange.

[0008] The flange has a step on its inner wall near the first end, and the retaining ring presses the lens against the step.

[0009] The flange has a first injection hole on its side wall near the first end. The first injection hole is opposite to the injection ring groove on the outer periphery of the retaining ring. Adhesive injected through the first injection hole fills the injection ring groove to fix the retaining ring and the lens.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the optical fiber assembly includes an optical fiber ferrule, and the sidewall of the flange is further provided with a plurality of glue injection holes, the plurality of glue injection holes corresponding one-to-one with a plurality of positions of the optical fiber ferrule.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the sidewall of the flange is provided with a second injection hole, a third injection hole and a fourth injection hole, the second injection hole corresponds to the front part of the optical fiber ferrule, the third injection hole corresponds to the middle part of the optical fiber ferrule, and the fourth injection hole corresponds to the tail of the optical fiber ferrule. The outer diameter of the middle part is larger than the outer diameter of the front part and larger than the outer diameter of the tail.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the injection sequence of the third injection hole is earlier than the injection sequence of the second injection hole, and the injection sequence of the fourth injection hole is earlier than the injection sequence of the second injection hole.

[0013] In conjunction with the first aspect, in some implementations of the first aspect, an adhesive is used to fill the space between the front portion of the optical fiber ferrule and the inner wall of the flange.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, the gap between the front part of the fiber optic ferrule and the inner wall of the flange is smaller than the gap between the tail of the fiber optic ferrule and the inner wall of the flange.

[0015] In conjunction with the first aspect, in some implementations of the first aspect, the projection of the side of the third glue injection hole near the lens onto the fiber optic ferrule is located at the front, and the projection of the side of the third glue injection hole away from the lens onto the fiber optic ferrule is located at the middle.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, a chamfer is provided at the step.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, the device further includes a pressure sleeve and a protective tail sleeve. The optical fiber assembly includes an inner optical fiber sheath, an outer optical fiber sheath, an optical fiber ferrule, and an internal optical fiber. The pressure sleeve presses the outer optical fiber sheath to the flange tail. One end of the protective tail sleeve has a groove for cooperating with the pressure sleeve during installation.

[0018] In conjunction with the first aspect, in some implementations of the first aspect, the outer sheath of the optical fiber is an insulating braided mesh.

[0019] Secondly, a method for assembling an optical fiber receiving and coupling device is provided, applicable to the optical fiber receiving and coupling device as described in the second implementation of the first aspect above, comprising:

[0020] Place the flange with the side for mounting the lens facing upwards;

[0021] Apply adhesive around the outside of the lens and place it on the stepped part of the flange;

[0022] Apply adhesive around the outside of the retaining ring and place it inside the flange, in front of the lens;

[0023] Press the retaining ring to make the retaining ring, lens and flange fit together and pre-curing is performed;

[0024] Inject adhesive into the first injection hole of the flange and the injection ring groove of the retaining ring and allow it to cure;

[0025] Lay the flange with the first glue injection hole facing upwards, inject laser into the lens, apply adhesive around the outside of the fiber optic ferrule of the fiber optic assembly and insert it into the flange, adjust the axial position of the fiber optic ferrule in the inner hole of the flange, and monitor the optical performance of the assembly online until the performance is optimal.

[0026] Inject adhesive into the third injection hole of the flange in one go. Stop injecting adhesive when the third injection hole is completely filled by visual inspection. Inject adhesive into the second injection hole of the flange in one go. Stop injecting adhesive when the second injection hole is completely filled by visual inspection. Allow the adhesive to pre-cure.

[0027] Inject adhesive into the fourth injection hole of the flange. Stop injecting when overflow of adhesive is observed at the tail of the fiber optic ferrule or the fourth injection hole, and allow it to cure.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The present invention uses a retaining ring and flange structure to fix the lens and optical fiber. The structure is simple and compact. The combination of mechanical limiting and glue fixing effectively reduces the complexity of product assembly and adjustment and improves the reliability of optical fiber receiving coupling device.

[0030] (2) The present invention adopts a flange structure with multiple injection holes to realize the segmented fixing of the retaining ring and the fiber optic ferrule. The ceramic ferrule and the metal tail are both fixed to the inner cavity of the flange by adhesive. The amount of adhesive injected is limited by the size of the injection hole. The injection state can be observed during the manufacturing process. It does not involve the mixing of multiple types of adhesives such as UV adhesive and epoxy adhesive. The process is simple and reliable.

[0031] (3) The flange inside the present invention is chamfered to protect the lens and fiber optic assembly from damage and to provide radial constraint for the lens and fiber optic assembly, ensuring that the lens and fiber optic axis are aligned. The axial position of the fiber optic assembly inside the flange can be finely adjusted during manufacturing, leaving adjustment margin for defocus design.

[0032] (4) The optical fiber assembly and the flange of the present invention adopt a crimping method, and the outer sheath of the optical fiber is crimped to the tail of the optical fiber ferrule by using a crimping sleeve, thereby improving the tensile strength of the optical fiber receiving coupling device. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the optical fiber receiving and coupling device of the present invention.

[0034] Figure 2 This is a schematic diagram of the optical fiber assembly structure of the present invention.

[0035] Figure 3 This is a schematic diagram of the crimping structure of the pressure sleeve, optical fiber outer sheath, and flange of the present invention.

[0036] Figure 4 This is a cross-sectional schematic diagram of the crimping of the pressure sleeve and the outer sheath of the optical fiber according to the present invention. Detailed Implementation

[0037] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 1 The diagram shows the structure of the optical fiber receiving and coupling device.

[0039] The optical fiber receiving and coupling device may include a flange 1, a retaining ring 2, a lens 3, an optical fiber assembly 4, a pressure sleeve 5, and a protective tail sleeve 6.

[0040] Flange 1 is a hollow structure. The retaining ring 2, lens 3, and fiber optic assembly 4 can be housed within the cavity of flange 1. The pressure sleeve 5 and protective tail sleeve 6 can be positioned on the outside of flange 1. The first end of flange 1 is used to mount lens 3. Fiber optic assembly 4 can be inserted into flange 1 from the second end. Flange 1 provides mechanical restraint for lens 3 and fiber optic assembly 4.

[0041] Flange 1 has a step on its inner wall near the first end, the inner diameter of which matches the outer diameter of lens 3. Lens 3 can abut against the step to define its axial position within flange 1. Lens 3 can be fixed within flange 1 by a retaining ring 2 and a colloid. Figure 1 As shown in the enlarged view, the step on the inner side of flange 1 is chamfered to prevent damage to the lens and fiber optic assembly.

[0042] A glue injection hole 12 is provided at the first end of the flange 1. The glue injection hole is a groove formed on the side wall of the flange 1, located axially on the side of the step away from the fiber optic assembly 4. When the retaining ring 2 is installed in the flange groove of the flange 1 and abuts against the lens 3, the glue injection ring groove on the outer side wall of the retaining ring 2 can be positioned opposite to the glue injection hole. Glue is injected through the glue injection hole, allowing the adhesive 11 to fill the glue injection hole and the glue pit on the retaining ring 2, thus fixing the retaining ring 2 to the flange 1 and thereby fixing the position of the lens 3 in the flange 1. Alternatively, glue can also be filled between the retaining ring 2 and the lens 3.

[0043] The side wall of flange 1 is also provided with injection holes 13, 14, and 15. Injection holes 13, 14, and 15 correspond to the front, middle, and tail sections of the fiber optic ferrule 9, respectively. The outer diameter of the middle section of the fiber optic ferrule 9 can be larger than the outer diameter of the front section and the outer diameter of the tail section. Adhesive 11 is injected through injection holes 13, 14, and 15 to fix the axial position of the fiber optic assembly 4 in sections.

[0044] It should be noted that the amount of adhesive applied near the fiber end face should not be excessive to avoid contaminating the fiber end face. For example... Figure 1 As shown, there can be a certain gap between the inner wall of the flange 1 and the front part of the fiber optic ferrule 9, and a certain amount of adhesive 11 can be stored in this gap. The size of this gap should be as appropriate as possible, so as to provide a margin for the assembly of the fiber optic assembly 4 and to allow the adhesive 11 to be distributed around the fiber optic ferrule 9 without flowing to the fiber end face.

[0045] The side of the injection hole 14 closest to the lens 3 can be projected onto the front of the fiber optic ferrule 9, while the side of the injection hole 14 furthest from the lens 3 can be projected onto the middle of the fiber optic ferrule 9. Therefore, the adhesive 11 injected through the injection hole 14 can fill the space between the flange 1 and the end face of the middle of the fiber optic ferrule 9, improving the bonding stability of the fiber optic ferrule 9.

[0046] The gap between flange 1 and the tail of fiber optic ferrule 9 can be relatively large, which can increase the amount of adhesive filling in local areas, increase the bonding stability of fiber optic ferrule 9, and prevent excessive filling of adhesive.

[0047] In this embodiment, the adhesive 11 can be a material with a coefficient of thermal expansion similar to that of the optical fiber and lens. The optical fiber receiving coupling device can use only a single type of adhesive, without involving the use of multiple types.

[0048] like Figure 2 The diagram shows the structure of the optical fiber assembly 4. The optical fiber assembly 4 may include an inner optical fiber sheath 7, an outer optical fiber sheath 8, an optical fiber ferrule 9, and an internal optical fiber 10. The optical fiber 10 passes through the optical fiber ferrule 9 and is firmly bonded to the inner optical fiber sheath 7. The outer optical fiber sheath 8 has a certain length allowance for crimping after assembly with the flange 1. After the optical fiber assembly 4 is inserted into the flange 1, the crimping sleeve 5 can crimp the outer optical fiber sheath 8 to the tail of the flange 1. The protective tail sleeve 6 has a groove that matches the crimping sleeve 5 for installation. The crimping point between the outer optical fiber sheath 8 and the flange 1 is protected by a soft protective tail sleeve 6.

[0049] like Figure 3The diagram shows the assembly structure of the crimp sleeve 5, the fiber optic outer sheath 8, and the flange 1. The crimp sleeve 5 presses the fiber optic outer sheath 8 to the tail of the flange 1, giving the fiber optic receiving coupling device a certain tensile strength. The fiber optic outer sheath 8 can be a braided mesh, and the material of the fiber optic outer sheath 8 itself can have a certain tensile strength. In addition, due to the uneven nature of the fiber optic outer sheath 8, the resistance to detachment after crimping can be increased, thereby improving the tensile strength of the fiber optic receiving coupling device.

[0050] like Figure 4 The diagram shows a cross-sectional view of the crimping of the ferrule 5 and the outer sheath 8 of the optical fiber. Taking hexagonal crimping as an example, the force F exerted by the ferrule on the outer sheath of the optical fiber is... L The equivalent force F is the force F exerted on the outer sheath of the optical fiber by the six crimping surfaces after crimping. T The sum of, i.e., F L =6μF T μ is the coefficient of friction, which is the force F exerted on the outer sheath of the optical fiber by a single crimping surface. T By multiplying the shear strength of the material by the cross-sectional area of ​​a single press-fit surface, a relationship can be established between the tensile strength and the material of the press-fit sleeve and the dimensions of the press-fit surface. The outer diameter D of the flange tail press-fit position, the outer diameter d of the press-fit sleeve component, and the thickness t of the press-fit sleeve component must satisfy... And allowance is provided for the assembly of the fiber optic outer sheath.

[0051] The specific assembly steps of the fiber optic receiving and coupling device are as follows:

[0052] (1) Place the flange 1 vertically upward on the side where the lens is installed to facilitate the installation of the lens 3 and the retaining ring 2.

[0053] (2) Apply adhesive 11 around the outside of lens 3 and place it on the step of the flange.

[0054] (3) Apply adhesive 11 around the outside of the retaining ring 2 and place it inside the flange and in front of the lens.

[0055] (4) Press the retaining ring gently so that the retaining ring, lens and flange fit directly without warping, and perform pre-curing.

[0056] (5) Inject adhesive 11 into the injection hole 12 at the front end of flange 1 and the injection groove of the retaining ring and cure it.

[0057] (6) Place the glue injection hole 12 of the above flange 1 upward and inject laser into the lens. Apply adhesive 11 around the outside of the tail of the fiber optic ferrule 9 of the fiber optic assembly 4 and insert it into the flange 1. Fine-tune the axial position of the fiber optic ferrule 9 in the inner hole of the flange and monitor the optical performance of the assembly online until the performance is optimal.

[0058] (7) Inject adhesive 11 into the injection hole 14 (middle injection hole) above flange 1 in one go. Stop injecting adhesive when the injection hole is filled by visual inspection. Inject adhesive 11 into the injection hole 13 (left injection hole) above flange in one go. Stop injecting adhesive when the injection hole is filled by visual inspection. Do not add more adhesive. Pre-curing is then carried out.

[0059] It should be noted that, since the glue injection hole 13 is close to the fiber end face, the amount of glue should not be too much. If, after glue injection hole 14 is filled, glue 11 overflows into glue injection hole 13, the amount of glue injected into the left hole should be appropriately reduced.

[0060] (8) Inject adhesive 11 into the glue injection hole 15 (right glue injection hole) above the flange. Stop injecting when overflow of glue is observed at the end of the fiber optic ferrule or the glue injection hole 14, and allow it to cure.

[0061] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims of the present invention.

Claims

1. An optical fiber receiving and coupling device, characterized in that, Includes flange (1), retaining ring (2), lens (3), and fiber optic assembly (4); among which, The flange (1) is a hollow structure. The lens (3) and the optical fiber assembly (4) are housed in the cavity of the flange (1). The lens (3) is disposed at the first end of the flange (1), and the optical fiber assembly (4) is disposed at the second end of the flange (1). The flange (1) has a step on its inner wall near the first end, and the retaining ring (2) presses the lens (3) against the step; The flange (1) has a first injection hole (12) on its side wall near the first end. The first injection hole (12) is opposite to the injection ring groove on the outer periphery of the retaining ring (2). The adhesive (11) injected through the first injection hole (12) fills the injection ring groove to fix the retaining ring (2) and the lens (3). The side wall of the flange (1) is provided with a second glue injection hole (13), a third glue injection hole (14) and a fourth glue injection hole (15). The second glue injection hole (13) corresponds to the front part of the optical fiber ferrule (9), the third glue injection hole (14) corresponds to the middle part of the optical fiber ferrule (9), and the fourth glue injection hole (15) corresponds to the tail of the optical fiber ferrule (9). The outer diameter of the middle part is larger than the outer diameter of the front part and larger than the outer diameter of the tail. The gap between the front part of the fiber optic ferrule (9) and the inner wall of the flange (1) is smaller than the gap between the tail of the fiber optic ferrule (9) and the inner wall of the flange (1); The injection sequence of the third injection hole (14) is earlier than that of the second injection hole (13), and the injection sequence of the fourth injection hole (15) is earlier than that of the second injection hole (13).

2. The apparatus according to claim 1, characterized in that, The optical fiber assembly (4) includes an optical fiber ferrule (9), and the side wall of the flange (1) is also provided with a plurality of glue injection holes, which correspond one-to-one with a plurality of positions of the optical fiber ferrule (9).

3. The apparatus according to claim 1, characterized in that, The front part of the optical fiber ferrule (9) and the inner wall of the flange (1) are filled with adhesive (11).

4. The apparatus according to claim 1, characterized in that, The projection of the third glue injection hole (14) near the lens (3) onto the fiber optic ferrule (9) is located at the front, while the projection of the third glue injection hole (14) away from the lens (3) onto the fiber optic ferrule (9) is located at the middle.

5. The apparatus according to claim 1, characterized in that, The steps are chamfered.

6. The apparatus according to claim 1, characterized in that, The device also includes a pressure sleeve (5) and a protective tail sleeve (6). The optical fiber assembly (4) includes an inner optical fiber sheath (7), an outer optical fiber sheath (8), an optical fiber ferrule (9), and an internal optical fiber (10). The pressure sleeve (5) presses the outer optical fiber sheath (8) to the tail of the flange (1). One end of the protective tail sleeve (6) has a groove and is installed in conjunction with the pressure sleeve (5).

7. The apparatus according to claim 6, characterized in that, The outer sheath of the optical fiber (8) is an insulating braided mesh.

8. An assembly method for an optical fiber receiving and coupling device, characterized in that, The optical fiber receiving and coupling device as described in claim 3 includes: Place the flange (1) vertically upward on the side where the lens (3) is mounted; Apply adhesive (11) around the outside of the lens (3) and place it on the step of the flange (1); Apply adhesive (11) around the outside of the retaining ring (2) and place it inside the flange (1) and in front of the lens (3); Press the retaining ring (2) to make the retaining ring (2), lens (3) fit with the flange (1) for pre-curing; Inject adhesive (11) into the first injection hole (12) of the flange (1) and the injection ring groove of the retaining ring (2) and cure it; Place the first glue injection hole (12) of the flange (1) upwards and inject laser into the lens (3). Apply adhesive (11) around the outside of the fiber optic ferrule (9) of the fiber optic assembly and insert it into the flange (1). Adjust the axial position of the fiber optic ferrule (9) in the inner hole of the flange (1) and monitor the optical performance of the assembly online until the performance is optimal. Inject adhesive (11) into the third injection hole (14) of flange (1) in one go. Stop injecting adhesive when the adhesive (11) fills the third injection hole (14) by visual inspection. Inject adhesive (11) into the second injection hole (13) of flange (1) in one go. Stop injecting adhesive when the adhesive (11) fills the second injection hole (13) by visual inspection. Pre-curing is then carried out. Inject adhesive (11) into the fourth injection hole (15) of the flange (1). Stop injecting when overflow is observed at the tail of the fiber optic ferrule (9) or the fourth injection hole (145) and allow it to cure.

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