Adjustable sleeve structure for optical fiber assembly

Abstract

The invention relates to the technical field of optical communication device manufacturing, and discloses an optical fiber assembly adjustable sleeve structure which comprises a lens carrier, a spherical lens is installed at the front end of the lens carrier, an adjustable sleeve is arranged in the lens carrier, a sleeve inner hole is formed in the adjustable sleeve, and a ceramic ferrule is arranged in the sleeve inner hole. A through longitudinal opening is formed in the side wall of the adjustable sleeve in the axial direction, an adjusting step is arranged at the rear end of the adjustable sleeve, and the adjusting step is of a non-circular notch structure in the outer wall of the adjustable sleeve and is clamped by an external tool so as to drive the adjustable sleeve and the ceramic ferrule to rotate relative to the spherical lens. According to the invention, the adjustable sleeve with the adjusting step is arranged, and the micro eccentricity characteristic of the ceramic ferrule is utilized, so that an active rotation compensation mechanism is provided, the coaxiality deviation caused by machining errors is compensated, and the optical path coupling efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of optical communication device manufacturing technology, specifically to an adjustable sleeve structure for optical fiber assembly. Background Technology

[0002] In the manufacturing process of optical communication modules and optical transceiver components, the optical coupling efficiency between the optical fiber and the lens (such as a spherical lens) directly determines the signal transmission quality of the device. To obtain the best coupling efficiency, the axis of the optical fiber core needs to maintain a high degree of coaxiality with the optical axis of the lens. Typically, the optical fiber is pre-installed in a ceramic ferrule, which is then installed inside the lens carrier.

[0003] Existing fiber optic assembly structures mostly employ static fixing methods, relying on the machining precision of components to ensure final coaxiality. However, in actual production, inherent machining errors exist in the concentricity of ceramic ferrules, the coaxiality of the lens carrier's inner hole, and the installation position of the spherical lens. When these components are assembled, the tolerances of each part accumulate randomly, causing the fiber core to deviate from the lens's ideal optical axis. In traditional static structures, once assembly is complete, this coaxiality deviation caused by accumulated tolerances cannot be eliminated, resulting in excessive coupling loss in some products and reducing the yield rate of finished products.

[0004] To secure ceramic ferrules, current technologies often employ adhesive filling or mechanical fastener locking. When using adhesives, the glue shrinks or expands during curing, and this volume change can easily cause misalignment of the aligned optical fibers, affecting the final coupling accuracy. Furthermore, the adhesive application and curing processes are cumbersome and have low production efficiency. If screws or other mechanical fasteners are used to tighten from the side, it can easily cause non-uniform elastic deformation of the thin-walled ceramic sleeve, affecting the cylindricity of the inner hole and consequently the splicing accuracy of the internal optical fibers.

[0005] Furthermore, in existing rotatable adjustment designs, the sleeve is typically located inside the lens carrier or housing, lacking an effective external operating interface. During assembly, it is difficult for operators or automated equipment to directly clamp and drive the sleeve for rotation adjustment from the outside, making active alignment difficult to implement. Therefore, a fiber optic assembly structure is needed that can compensate for coaxiality deviations, simplify the fixing process, and facilitate external adjustment. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an adjustable sleeve structure for optical fiber assembly, which solves the problems in existing optical fiber assembly technologies where the coaxiality deviation between the optical fiber and the lens cannot be eliminated due to the accumulation of component processing errors, and the risk of positional drift when using adhesives for fixation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an adjustable sleeve structure for optical fiber assembly, comprising a lens carrier, wherein an adjustment mechanism is provided inside the lens carrier; The adjustment mechanism includes a spherical lens mounted at the front end of the lens carrier. An adjustable sleeve is provided inside the lens carrier, with an inner hole inside the adjustable sleeve. A ceramic insert is disposed inside the inner hole of the sleeve. A through longitudinal opening is provided on the side wall of the adjustable sleeve along the axial direction. The inner wall of the adjustable sleeve and the outer wall of the ceramic insert are interference-fitted. An adjustment step is provided at the rear end of the adjustable sleeve. The adjustment step is a non-circular notch structure on the outer wall of the adjustable sleeve, which is used for external tools to clamp and drive the adjustable sleeve and the ceramic insert to rotate relative to the spherical lens.

[0008] Preferably, the lens carrier has a lens mounting hole at its front end, and the spherical lens is fixedly mounted in the lens mounting hole.

[0009] Preferably, the adjusting step includes at least one cutting plane disposed on the rear end sidewall of the adjustable sleeve, the depth of the cutting plane being less than the wall thickness of the adjustable sleeve.

[0010] Preferably, the longitudinal opening is a single slit, which extends continuously from the front end face of the adjustable sleeve to the rear end face, cutting off one side of the adjustable sleeve wall.

[0011] Preferably, the ceramic ferrule is a fiber optic short post pre-placed at the front end of the inner hole of the sleeve, and a ferrule connector is inserted into the rear end of the inner hole of the sleeve.

[0012] Preferably, after the ferrule connector is inserted into the inner hole of the sleeve, the front end face of the ferrule connector abuts against the rear end face of the ceramic ferrule.

[0013] Preferably, the lens carrier is a hollow stepped shaft structure with an internal receiving cavity, and the outer wall of the adjustable sleeve and the inner wall of the receiving cavity are in clearance fit.

[0014] Preferably, the adjustable sleeve is made of zirconium oxide ceramic; and the lens carrier is made of metal.

[0015] Preferably, it further includes a connector housing, which is fitted over the lens carrier and the ferrule connector.

[0016] Preferably, the adjustment step protrudes axially from the rear end face of the lens carrier.

[0017] This invention provides an adjustable sleeve structure for optical fiber assembly. It has the following advantages: 1. This invention provides an active rotation compensation mechanism by setting an adjustable sleeve with an adjustable step and utilizing the slight eccentricity of the ceramic ferrule itself. By clamping the adjustable step with an external tool and rotating the adjustable sleeve, the internal optical fiber can change its spatial angular position relative to the optical axis of the spherical lens, thereby compensating for coaxiality deviation caused by machining errors and improving optical path coupling efficiency.

[0018] 2. This invention utilizes the longitudinal opening to disrupt the circumferential sealing of the sleeve, giving the rigid ceramic material radial elasticity; combined with a specific 0.0015mm interference fit design, the adjustable sleeve can achieve stable clamping and self-locking of the internal ceramic ferrule solely by the static friction generated by the interference fit without the need for adhesives or fasteners, simplifying the assembly process and avoiding the risk of positional drift during the adhesive curing process.

[0019] 3. The adjustment step of this invention adopts a non-through cutting plane design, which provides a reliable force application surface for external tools and ensures the integrity of the inner hole of the sleeve at the rear end. This ensures that the external ferrule connector can obtain continuous cylindrical surface support after insertion, maintains a high-precision docking state between the ferrule connector and the internal ceramic ferrule, and prevents optical signal interruption or increased loss due to unstable support during rotation adjustment. Attached Figure Description

[0020] Figure 1 This is a perspective view of the adjustable sleeve structure for optical fiber assembly of the present invention; Figure 2 This is a schematic diagram of the structure of the spherical lens of the present invention; Figure 3 This is a cross-sectional schematic diagram of the lens carrier of the present invention; Figure 4 This is a cross-sectional schematic diagram of the adjustment mechanism of the present invention; Figure 5 This is an exploded view of the adjusting mechanism of the present invention; Figure 6 This is a schematic diagram of the adjustable sleeve of the present invention.

[0021] Among them, 1. Connector housing; 2. Lens carrier; 3. Ball lens; 4. Adjustable sleeve; 5. Molded connector; 6. Ceramic molted; 7. Inner hole of sleeve; 8. Adjustment step; 9. Longitudinal opening. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see the appendix Figure 1 Appendix Figure 4 and attached Figure 6 This invention provides an adjustable sleeve structure for optical fiber assembly, including a connector housing 1, a lens carrier 2, and an adjustment mechanism. The adjustment mechanism includes a ball lens 3, an adjustable sleeve 4, and a ceramic ferrule 6 fitted inside.

[0024] The connector housing 1 constitutes the external protective structure of the device. The connector housing 1 is fitted over the lens carrier 2 and the ferrule connector 5, serving to isolate the device from the external environment and provide a mechanical connection interface. The lens carrier 2 is the mounting base for the internal core components, and its overall structure is a hollow, stepped shaft. A positioning structure is located at the front end of the lens carrier 2, and the spherical lens 3 is mounted and fixed at the very front end of the lens carrier 2. The spherical lens 3 is used to converge or collimate optical signals, and its geometric central axis defines the theoretical optical path axis.

[0025] The lens carrier 2 has an axially formed receiving cavity inside. An adjustable sleeve 4 is coaxially disposed within this cavity. Located behind the ball lens 3, the adjustable sleeve 4 carries the optical fiber component and adjusts its position relative to the ball lens 3. A through-hole 7 is axially formed at the center of the adjustable sleeve 4. This through-hole 7 is a high-precision cylindrical hole designed to ensure the coaxiality of the internal components.

[0026] The ceramic ferrule 6 is installed at the front end of the inner hole 7 of the sleeve. In this embodiment, the ceramic ferrule 6 is a pre-installed fiber optic short post, with a section of optical fiber pre-embedded inside. The front end face of the ceramic ferrule 6 faces the spherical lens 3, maintaining a preset optical distance between them. The rear end of the inner hole 7 is used for the insertion of an external ferrule connector 5. When the ferrule connector 5 is inserted into the inner hole 7, the front end face of the ferrule connector 5 and the rear end face of the ceramic ferrule 6 physically abut against each other within the inner hole 7, thereby achieving physical connection of the optical path.

[0027] The lens carrier 2, adjustable sleeve 4, ceramic ferrule 6, and spherical lens 3 together constitute the core components of the optical path coupling. The adjustable sleeve 4 is not fixed within the lens carrier 2, but rather has a specific mating relationship to allow for subsequent adjustment operations.

[0028] Please see the appendix Figure 1 Appendix Figure 4 and attached Figure 6The adjustable sleeve 4 is a key component for achieving coaxiality adjustment. The main body of the adjustable sleeve 4 is a cylindrical structure made of zirconia ceramic. Zirconia ceramic has high hardness, wear resistance, and a stable elastic modulus, enabling it to maintain long-term dimensional stability after undergoing minute elastic deformation.

[0029] The adjustable sleeve 4 has a longitudinal opening 9 on its side wall. The longitudinal opening 9 is a single slit structure that extends along the axial direction of the adjustable sleeve 4. The longitudinal opening 9 extends continuously from the front end face to the rear end face of the adjustable sleeve 4, penetrating the entire wall thickness. This through-hole design breaks the circumferential sealing of the adjustable sleeve 4, giving it elastic expansion and contraction capabilities in the radial direction.

[0030] The presence of the longitudinal opening 9 makes the adjustable sleeve 4 an open, elastic cylindrical shell. In its natural state without external force, the inner diameter of the sleeve's inner bore 7 is designed to be slightly smaller than the outer diameter of the ferrule to be assembled.

[0031] The adjustable sleeve 4 has an adjusting step 8 at its rear end. The adjusting step 8 is formed directly on the outer wall of the adjustable sleeve 4. In this embodiment, the adjusting step 8 is a non-circular notch structure.

[0032] Specifically, the adjusting step 8 includes at least one cutting plane disposed on the circumferential surface of the rear end of the adjustable sleeve 4. This cutting plane has a certain length along the axial direction and a certain cutting depth along the radial direction. To ensure the integrity of the inner hole 7 of the sleeve, the depth of the cutting plane is less than the single-sided wall thickness of the adjustable sleeve 4. This means that the cutting operation at the adjusting step 8 does not penetrate the sleeve wall, and the inner hole 7 of the sleeve remains a complete cylindrical surface at the position corresponding to the adjusting step 8, ensuring continuous guidance and support for the internal ferrule connector 5.

[0033] The non-circular contour of the adjusting step 8 provides a point of application for the external adjusting tool. When it is necessary to rotate the adjustable sleeve 4, the external tool is used to clamp the cutting surface of the adjusting step 8 and apply rotational torque. Because the adjusting step 8 is not a smooth circular surface, the tool can reliably transmit torque, driving the adjustable sleeve 4 to rotate about its axis.

[0034] The position of the adjustment step 8 is designed with operability in mind. The adjustment step 8 protrudes axially from the rear end face of the lens carrier 2. This arrangement allows external tools to still access and operate the adjustment step 8 from the side or axially when the ferrule connector 5 is inserted.

[0035] Through the above structural design, the adjustable sleeve 4 integrates the elastic clamping function and the rotary drive interface. The longitudinal opening 9 provides the radial compliance required for clamping, while the adjusting step 8 provides the mechanical interface required for rotary adjustment. The two do not interfere with each other structurally and together realize the function of the adjustable sleeve 4.

[0036] Please see the appendix Figure 4 There is a specific mating relationship between the adjustable sleeve 4, the ceramic ferrule 6, and the ferrule connector 5. The balance between position locking and adjustment functions is achieved by controlling the dimensional tolerances.

[0037] The inner wall of the adjustable sleeve 4 and the outer wall of the ceramic ferrule 6 are designed to be interference-fitted. Specifically, in its natural state, the inner diameter of the sleeve's inner hole 7 is smaller than the outer diameter of the ceramic ferrule 6. In this embodiment, the interference amount of this interference fit is set to 0.0015 mm.

[0038] During assembly, the adjustable sleeve 4 is expanded to receive the ceramic ferrule 6, utilizing the elasticity provided by the longitudinal opening 9. Due to the interference fit, after the ceramic ferrule 6 is inserted, the elastic restoring force of the adjustable sleeve 4, attempting to return to its original shape, is converted into a radial normal force on the outer wall of the ceramic ferrule 6. This radial normal force generates static friction on the contact surface. The static friction generated by the set interference fit of 0.0015mm is sufficient to overcome the weight of the ceramic ferrule 6 and vibrations during normal use, locking the ceramic ferrule 6 in position within the inner hole 7 of the sleeve, without external intervention. When a rotational torque is applied by adjusting the step 8, as long as the tangential force transmitted by the torque is less than this maximum static friction, the adjustable sleeve 4 will drive the ceramic ferrule 6 to rotate synchronously without relative slippage between them. This design eliminates the need for additional fixing processes such as adhesive bonding or screw tightening, simplifying the assembly process.

[0039] The adjustable sleeve 4 and the lens carrier 2 are fitted with a clearance fit. The inner diameter of the internal cavity of the lens carrier 2 is slightly larger than the outer diameter of the adjustable sleeve 4. The clearance fit between the adjustable sleeve 4 and the lens carrier 2 provides an assembly gap, ensuring that the adjustable sleeve 4 has free rotation space within the cavity. During adjustment, the lens carrier 2 acts as a stationary base, and the adjustable sleeve 4 acts as a rotating component. The clearance fit prevents excessive frictional resistance between the adjustable sleeve 4 and the inner wall of the lens carrier 2 during rotation. This fit provides a smooth rotational feel during adjustment, ensuring that the adjustment process is effortless and smooth. At the same time, the inner wall of the lens carrier 2 uses the hole wall limiter to provide radial constraint and guidance for the adjustable sleeve 4, preventing excessive radial runout or offset of the adjustable sleeve 4 during adjustment and rotation.

[0040] Through a combination of internal and external fits, the following mechanical transmission chain is achieved: an external tool applies torque to the adjusting step 8, which drives the adjustable sleeve 4 to rotate smoothly relative to the lens carrier 2. The adjustable sleeve 4, through the frictional force of the internal interference fit, drives the ceramic ferrule 6 to rotate synchronously, and the ceramic ferrule 6 changes its angular position relative to the stationary spherical lens 3. The entire transmission process utilizes the internal interference fit to achieve rigid clamping transmission and the external clearance fit to reduce adjustment resistance, ensuring the sensitivity and smoothness of adjustment.

[0041] Please see the appendix Figure 2 and attached Figure 5 The optical path connection structure in this embodiment includes a two-section ferrule assembly, namely a ceramic ferrule 6 located at the front end and a ferrule connector 5 located at the rear end.

[0042] The ceramic ferrule 6, as a pre-installed component, is pressed into the front end of the adjustable sleeve 4 during the initial assembly stage. The front end face of the ceramic ferrule 6 faces the spherical lens 3. Due to manufacturing errors, the fiber core axis inside the ceramic ferrule 6 is often not perfectly aligned with the optical axis of the spherical lens 3, resulting in a slight eccentricity.

[0043] The ferrule connector 5 is the terminal joint of the external optical cable. In use, the ferrule connector 5 is inserted through the rear opening of the lens carrier 2 and then enters the inner hole 7 of the adjustable sleeve 4. The outer diameter of the ferrule connector 5 is the same as the outer diameter of the ceramic ferrule 6, and it is also subject to the elastic clamping effect of the adjustable sleeve 4.

[0044] After the ferrule connector 5 is inserted into place, its front end face makes physical contact with the rear end face of the ceramic ferrule 6. This contact is usually achieved by PC-polished end face mating to eliminate Fresnel reflection loss.

[0045] During adjustment, the ferrule connector 5 is in the inserted state. Since the ferrule connector 5 is also interference-fitted by the adjustable sleeve 4, when the adjustable sleeve 4 is rotated via the adjusting step 8, the ferrule connector 5 will rotate synchronously. This linkage mechanism is significant because it ensures that the relative position between the ferrule connector 5 and the ceramic ferrule 6 remains unchanged during adjustment, and the two rotate as a whole relative to the ball lens 3. This avoids additional mating losses caused by their relative rotation, ensuring that the adjustment operation only addresses the coaxiality deviation between the fiber optic assembly as a whole and the ball lens 3.

[0046] Furthermore, the connector housing 1, as the outermost structure, wraps around the lens carrier 2 and covers the tail area of ​​the ferrule connector 5, providing dust protection and safeguarding the delicate mating interface inside. The connector housing 1 and the lens carrier 2 are typically connected by a threaded or snap-fit ​​connection to facilitate final encapsulation after adjustment.

[0047] Working principle: First, the ceramic ferrule 6 with the pre-installed optical fiber is pressed into the adjustable sleeve 4. The elastic tension generated by the longitudinal opening 9 of the adjustable sleeve 4 and the interference fit of 0.0015mm are used to tightly clamp and fix the ceramic ferrule 6. Then, the ferrule connector 5 of the external optical cable is inserted into the rear end of the adjustable sleeve 4, so that its front end is physically in contact with the ceramic ferrule 6. At this time, due to the existence of machining tolerances, there is usually an initial random eccentricity error between the axis of the optical fiber core in the ceramic ferrule 6 and the optical axis of the front ball lens 3, which results in the optical path coupling efficiency not reaching the best.

[0048] Next, the adjustment process begins. The external adjustment tool is inserted into the protruding adjustment step 8 at the rear end of the adjustable sleeve 4, and a rotational torque is applied. The adjustable sleeve 4 is driven to rotate within the lens carrier 2, and the internal ceramic ferrule 6 and ferrule connector 5 are rotated synchronously through the interference fit friction of the inner wall. As the rotation proceeds, the spatial position of the optical fiber core within the ceramic ferrule 6 changes circumferentially, and the direction of the eccentricity vector of the actual optical axis of the optical fiber relative to the optical axis of the spherical lens 3 changes accordingly. By monitoring the optical power reading at the output end in real time, when the optical power reaches its peak value, it indicates that the position of the optical fiber core is closest to the ideal optical axis of the spherical lens 3, and the eccentricity error is compensated to the greatest extent.

[0049] After adjustment, the external adjustment tool is removed, and the adjustable sleeve 4 immediately stops rotating. It then automatically locks at the current angle due to the strong static friction generated by the interference fit, maintaining optical path alignment. Finally, the connector housing 1 is installed to complete the encapsulation. Through this rotational compensation mechanism, this invention effectively solves the coaxiality deviation problem caused by accumulated tolerances in precision optical assembly using a simple mechanical structure, achieving low-loss optical signal transmission.

Claims

1. An adjustable sleeve structure for optical fiber assembly, characterized in that, include: Lens carrier (2), wherein an adjustment mechanism is provided inside the lens carrier (2); The adjustment mechanism includes a spherical lens (3), which is installed at the front end of the lens carrier (2). An adjustable sleeve (4) is provided inside the lens carrier (2). An inner hole (7) is opened inside the adjustable sleeve (4). A ceramic insert (6) is provided inside the inner hole (7). A through longitudinal opening (9) is opened on the side wall of the adjustable sleeve (4) along the axial direction. The inner wall of the adjustable sleeve (4) and the outer wall of the ceramic insert (6) are interference fit. An adjustment step (8) is opened at the rear end of the adjustable sleeve (4). The adjustment step (8) is a non-circular notch structure on the outer wall of the adjustable sleeve (4) for external tools to clamp and drive the adjustable sleeve (4) and the ceramic insert (6) to rotate relative to the spherical lens (3).

2. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The lens carrier (2) has a lens mounting hole at its front end, and the spherical lens (3) is fixedly installed in the lens mounting hole.

3. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The adjusting step (8) includes at least one cutting plane disposed on the rear side wall of the adjustable sleeve (4), the depth of the cutting plane being less than the wall thickness of the adjustable sleeve (4).

4. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The longitudinal opening (9) is a single slit, which extends continuously from the front end face of the adjustable sleeve (4) to the rear end face, cutting off one side of the wall of the adjustable sleeve (4).

5. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The ceramic ferrule (6) is a short fiber optic post pre-placed at the front end of the inner hole (7) of the sleeve, and a ferrule connector (5) is inserted at the rear end of the inner hole (7).

6. The adjustable sleeve structure for optical fiber assembly according to claim 5, characterized in that, After the ferrule connector (5) is inserted into the inner hole (7) of the sleeve, the front end face of the ferrule connector (5) abuts against the rear end face of the ceramic ferrule (6).

7. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The lens carrier (2) is a hollow stepped shaft structure with a cavity inside. The outer wall of the adjustable sleeve (4) and the inner wall of the cavity are in clearance fit.

8. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The adjustable sleeve (4) is made of zirconium oxide ceramic; the lens carrier (2) is made of metal.

9. The adjustable sleeve structure for optical fiber assembly according to claim 5, characterized in that, It also includes a connector housing (1), which is fitted over the lens carrier (2) and the ferrule connector (5).

10. The adjustable sleeve structure for optical fiber assembly according to claim 1, characterized in that, The adjustment step (8) protrudes axially from the rear end face of the lens carrier (2).

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