Guided anti-rotation tunable fiber collimator

Abstract

This utility model discloses a guide-type anti-rotation adjustable-focus fiber optic collimator, belonging to the field of fiber optic collimator technology, aiming to solve the problem in existing technologies where the rotation of the adjusting cap causes the lens assembly to rotate, thus leading to laser deflection. The coupler includes a collimator body, a fiber optic inlet, an adjusting cap, an adjusting spring, a lens holder, a top ring, and a lens assembly. Its innovation lies in the axial guide portion between the top ring and the collimator body, composed of an axial protrusion and an axial groove, ensuring that the top ring slides only axially, limiting radial movement and circumferential rotation. Through this design, the adjusting cap will not cause the lens assembly to rotate when turned, thereby ensuring that the laser is always output along the central axis of symmetry, significantly improving the alignment accuracy and stability of the fiber optic collimator, effectively enhancing the efficiency and quality of optical signal transmission, and is suitable for fields with high precision requirements such as optical communication and laser processing.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic collimator technology, and more specifically to a guide-type anti-rotation adjustable focus fiber optic collimator. Background Technology

[0002] A fiber optic collimator is a device used to couple laser light from free space into an optical fiber, or to output laser light from an optical fiber as an adjustable collimated beam for transmission to the outside.

[0003] A free-space fiber collimator is an optical device used to construct a spatial optical path, converting a diverging beam emitted from an optical fiber into a parallel beam. It is widely used in optical communication, laser processing, laser measurement, and optical laboratories. In these applications, the performance of the fiber collimator directly affects the efficiency and accuracy of optical signal transmission. Typically, based on the fiber's NA (nanoscale range), core mode field diameter, and the wavelength of the transmitted light, different focal length lenses are selected to output collimated light of the desired spot size. Collimated light refers to laser spot size that remains approximately constant over long distances; this is the most widespread application. In addition, users can adjust the distance between the lens and the fiber core to achieve laser beam contraction and expansion, placing the beam waist at different distances to fulfill specific optical requirements.

[0004] Fiber optic collimators operate based on the refraction of optical lenses. By adjusting the position and angle of the lenses, the divergence angle or collimation state of the emitted beam can be changed to meet the needs of different applications. Their main performance indicators include the collimation (divergence angle) of the emitted beam, insertion loss, and optical alignment accuracy. These indicators directly affect the quality of optical signal transmission. In high-precision applications, fiber optic collimators with low insertion loss and high collimation are particularly needed to ensure signal integrity and accuracy.

[0005] Fiber optic collimators are crucial components connecting optical fibers to other optical elements, such as lasers and detectors. Their primary task is to introduce optical signals from external systems into the fiber. During this process, the fiber optic collimator needs excellent alignment capabilities and low-loss transmission characteristics. Therefore, the fiber optic collimator requires adjustable focal length, as the divergence characteristics of laser light input in free space are unknown; thus, adjusting the coupler's focal length is necessary to improve coupling efficiency. Coupling efficiency and alignment accuracy are important indicators for evaluating the performance of fiber optic collimators. High-quality couplers ensure minimal light loss while guaranteeing signal stability and interference resistance. Modern fiber optic collimators continuously innovate in material selection, processing technology, and structural design to adapt to the increasingly complex demands of optical communication applications. Since fiber optic collimators and optical fiber collimators each play a key role in the optical system, their performance directly affects the efficiency and reliability of the entire optical path system. Especially in optical communication, accurate collimation and efficient coupling are fundamental to achieving high-quality signal transmission.

[0006] However, a common problem arises when using collimators with adjustable knobs: when the adjustment cap is rotated, the lens (lens group) usually rotates along with it, causing the output laser to deviate from its central axis of symmetry. This results in a non-ideal deflection of the output laser during use. Currently available collimators with adjustable knobs have not resolved this issue. Utility Model Content

[0007] In view of this, the present invention provides a guide-type anti-rotation adjustable focus fiber collimator, which aims to solve the above-mentioned technical problems.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A guide-type anti-rotation adjustable focus fiber collimator includes: a collimator body, one end of which has a fiber optic inlet, and the other end of which is threadedly connected to an adjustment cap. The inner cavity of the collimator body is provided with an adjustment spring, a lens holder, and a top ring that abut against each other in sequence from the fiber optic inlet toward the adjustment cap. The lens holder contains a lens assembly, and the position of the lens assembly can be adjusted by turning the adjustment cap.

[0010] The outer wall of the top ring has an axial guide portion between the mating surfaces of the outer and inner walls of the collimator body. The axial guide portion consists of an axial protrusion and an axial groove forming an axial sliding mating structure, so that when the adjusting cap pushes the top ring to move, the top ring can only slide along the axial direction of the collimator body and is restricted from radial movement and circumferential rotation.

[0011] Through the above technical solution, this utility model effectively solves the problem in the prior art where the rotation of the adjustment cap causes the lens assembly to rotate, leading to laser offset. This design utilizes an axial sliding fit structure composed of an axial convex strip and an axial groove to ensure that the top ring can only slide along the axial direction of the collimator body, while restricting its radial movement and circumferential rotation. This ensures that the lens assembly maintains a stable position when adjusting the focal length, avoiding optical path offset caused by rotation, significantly improving the alignment accuracy and stability of the fiber optic collimator, and thus enhancing the efficiency and quality of optical signal transmission.

[0012] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the axial guide portion includes the axial protrusion provided on the outer wall of the top ring, and the axial groove provided on the inner wall of the collimator body and slidably connected to the axial protrusion.

[0013] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the axial guide portion includes the axial protrusion provided on the inner sidewall of the collimator body, and the axial groove provided on the outer sidewall of the top ring and slidably connected to the axial protrusion.

[0014] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, both the axial protrusion and the axial groove are cuboid structures.

[0015] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the axial guide portion formed by the combination of the axial protrusion and the axial groove is provided in multiple sets circumferentially between the mating surfaces of the top ring and the collimator body.

[0016] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the lens assembly includes a lens and a stress balancing kit that presses the lens against the inside of the lens holder.

[0017] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the inner wall of the lens holder has a stepped surface, and the two side edges of the lens abut against the stepped surface and the stress balancing kit respectively; the stress balancing kit includes a metal pressure ring threadedly tightened at the end of the lens holder, and an elastic element is provided between the metal pressure ring and the lens.

[0018] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the elastic element includes a rubber ring and / or a transition spring.

[0019] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the elastic element includes the rubber ring padding the edge of the lens, and the transition spring is pressed between the rubber ring and the metal pressure ring.

[0020] Preferably, in the above-mentioned guide-type anti-rotation adjustable focus fiber collimator, the diameter of the lens is smaller than the diameter of the stepped surface.

[0021] As can be seen from the above technical solution, compared with the prior art, this utility model discloses a guide-type anti-rotation adjustable focus fiber collimator. Through innovative structures such as the guide-type anti-rotation design and stress balancing kit, it effectively solves the problem of laser offset caused by lens assembly rotation when adjusting the focus in existing fiber collimators, while improving the stability of the device under temperature changes and stress. The axial guide restricts the radial and circumferential movement of the top ring, ensuring stable axial movement of the lens assembly, significantly improving alignment accuracy and optical signal transmission quality. In addition, the stress balancing kit, through the combination of rubber rings and transition springs, alleviates stress deformation between components of different materials, further enhancing the performance stability of the coupler in complex environments, and comprehensively improving the reliability and practicality of the fiber collimator. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 The attached figure is a cross-sectional view of an existing fiber optic collimator;

[0024] Figure 2 The attached diagram is an exploded view of an existing fiber optic collimator.

[0025] Figure 3 The attached figure is a cross-sectional view of the structure of the guide-type anti-rotation adjustable focus fiber collimator provided by this utility model.

[0026] Figure 4 The attached figure is a structural anatomical view of the fiber optic collimator of Embodiment 1 provided by this utility model;

[0027] Figure 5 The attached figure is an exploded view of the fiber optic collimator of Embodiment 3 provided by this utility model;

[0028] Figure 6 The attached figure is a schematic diagram of the lens assembly of Embodiment 4 provided by this utility model;

[0029] Figure 7 The attached figure is a test schematic diagram of Embodiment 2 provided by this utility model;

[0030] Figure 8 The attached figure is a test schematic diagram of Embodiment 5 provided by this utility model.

[0031] in:

[0032] 1-Collider body;

[0033] 11-Fiber optic access point;

[0034] 2-Adjusting cap;

[0035] 3-Adjusting spring;

[0036] 4-Lens holder;

[0037] 41-Step surface;

[0038] 5-Top ring;

[0039] 6-Lens assembly;

[0040] 61-Lens; 62-Stress balancing kit; 621-Metal pressure ring; 622-Elastic element; 6221-Rubber ring; 6222-Transition spring;

[0041] 7-Axial guide section;

[0042] 71 - Axial protrusion; 72 - Axial groove. Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0044] The structure of a traditional fiber optic collimator is as follows: Figure 1 and Figure 2 As shown, it includes: a collimator body 1, one end of which has an optical fiber inlet 11, and the other end of which is threadedly connected to an adjustment cap 2. The inner cavity of the collimator body 1 is provided with an adjustment spring 3, a lens support 4 and a top ring 5 that abut against each other in sequence from the optical fiber inlet 11 toward the adjustment cap 2. The lens support 4 is provided with a lens assembly 6. The position of the lens assembly 6 can be adjusted by turning the adjustment cap 2.

[0045] When adjusting the focus, two significant problems are often encountered: First, there is obvious resistance and friction during the rotation process, which not only affects the user experience, but also causes the long-term stability of the device to decrease due to the stress generated by friction; Second, due to the imbalance or inaccuracy of the rotating structure, there will be slight left and right disturbances during the adjustment process, which will cause the output beam to deflect and negatively affect the accurate transmission of the light signal.

[0046] like Figure 1 As shown, when adjusting the front and rear focal lengths by rotating the adjusting cap 2, the lens assembly 6 undergoes undesirable rotation. When the adjusting cap 2 rotates, friction exists between it and the top ring 5, causing the top ring 5 to rotate with the adjusting cap 2. Friction also exists between the top ring 5 and the lens support 4, ultimately causing the lens assembly 6 to rotate as well. This is undesirable, affecting the alignment stability of the collimator. Ideally, after light exits the fiber, the collimated laser should exit through the fiber optic inlet 11, the lens assembly 6, and the central axis of other components. However, considering that the components are not necessarily perfectly centrosymmetric in principle, and that there will be some gaps in the tracks, this rotation will cause undesirable optical path off-axis, resulting in changes in the emitted and incident laser beams.

[0047] Example 1:

[0048] See appendix Figure 3 To address the aforementioned issues, this embodiment designs the top ring 5. This utility model embodiment discloses a guide-type anti-rotation adjustable focus fiber collimator. The mating surface between the outer wall of the top ring 5 and the inner wall of the collimator body 1 has an axial guide portion 7. The axial guide portion 7 consists of an axial protrusion 71 and an axial groove 72 forming an axial sliding mating structure, so that when the adjusting cap 2 pushes the top ring 5 to move, the top ring 5 can only slide along the axial direction of the collimator body 1, and is restricted from radial movement and circumferential rotation.

[0049] By adding an anti-rotation structure to the axial guide, it is ensured that when the external adjusting cap 2 is rotated, the adjusting cap 2 will push the top ring 5 to move back and forth, but the top ring 5 will not rotate during the back and forth movement, and will not affect the rotation of the lens part.

[0050] In this embodiment, the axial guide portion 7 includes an axial protrusion 71 disposed on the outer side wall of the top ring 5, and an axial groove 72 disposed on the inner side wall of the collimator body 1 and slidably connected to the axial protrusion 71.

[0051] In other embodiments, the positions of the axial protrusion 71 and the axial groove 72 can be interchanged. For example, the axial guide portion 7 includes an axial protrusion 71 provided on the inner side wall of the collimator body 1, and an axial groove 72 provided on the outer side wall of the top ring 5 and slidably connected to the axial protrusion 71.

[0052] In this embodiment, both the axial protrusion 71 and the axial groove 72 are cuboid structures. However, the shape is not actually limited to rectangles; any shape that matches during assembly is acceptable.

[0053] In traditional fiber optic collimators, uneven force transmission during focus adjustment via the rotating adjustment cap 2 causes the lens assembly 6 to deviate from its intended central axis of symmetry. Specifically, the adjustment cap 2 is threaded to the collimator body 1, requiring a necessary gap. This allows the adjustment cap 2 to deviate from the central axis of symmetry when rotated. Similarly, a necessary gap is required between the top ring 5 and the lens holder 4 and the collimator body 1; otherwise, they cannot slide. Therefore, any collimator with adjustable focus will inevitably have the potential for the emitted light to deviate from the collimated optical axis.

[0054] In other commercially available products, the contact surfaces of the adjusting cap 2 pushing the top ring 5 and the top ring pushing the lens holder 4 are both smooth planes. In actual operation, when rotating the adjusting cap 2 to move the top ring 5 and lens holder 4 back and forth, both contact surfaces are in full-surface contact, resulting in sliding friction. Considering the flatness and precision of the machined surfaces, when the two contact surfaces undergo both rotation and forward / backward movement, even the slightest unevenness in particle size will immediately generate non-uniform forces, leading to rotational deviation. Furthermore, considering the nature of the thread and the clearance space, there will always be non-centrally symmetrical left-right components of force during the pushing process. Therefore, the force transmitted by the adjusting cap 2 will change the orientation of the top ring 5, which will further be transmitted to the lens holder 4, causing the lens assembly 6 to deviate from its central axis of symmetry. This problem will also cause the laser emission to deviate from the desired central axis of symmetry, which is undesirable during use.

[0055] Therefore, when the structure of this embodiment is used, the uneven force caused by rotation can be avoided, and the rotation of the lens support 4, lens assembly 6, etc. relative to the collimator body 1 can be avoided.

[0056] Example 2:

[0057] This embodiment is based on Embodiment 1, with specific parameter limitations and experiments:

[0058] In this embodiment, an aspherical lens with a focal length of 11mm was selected as the collimating lens and placed in the lens holder 4. Single-mode PC fiber was selected as the optical fiber to transmit a continuous laser at 650nm.

[0059] A protruding axial ridge 71 is designed on the top ring 5, such as... Figure 4As shown, the axial protrusion 71 has a length of 6mm and a width of 1mm, and is a cuboid structure. At the same time, an axial groove 72 is constructed inside the adjusting cap 2, and its size is adapted to the axial protrusion 71.

[0060] Next, the performance of the collimator was tested. During the testing process, the collimators before and after the improvement were selected as comparative references. The specific test optical path is as follows: Figure 7 As shown, the laser is first transmitted through an optical fiber. After the fiber is inserted into the collimator, the focal length is adjusted to produce a long-distance collimated beam. The change of the laser spot with length is shown in Table 1 below:

[0061] Table 1

[0062] Spot size / μm 1517*1513 1467*1472 1508*1504 1692*1697 1852*1849

[0063] The beam waist diameter is 1460μm.

[0064] This basically proves that the light spot is collimated at this time.

[0065] The collimator is then fixed in place, and the laser transmission path is determined. A beam spot display screen is placed on a plane perpendicular to the laser beam, displaying the beam spot's position using a two-dimensional coordinate system. Alternatively, a beam quality analyzer can be used; such optoelectronic devices can directly convert the optical signal into the beam spot position, eliminating the need for manual reading. At this point, the distance between the collimator and the beam spot display screen is controlled at 2 meters.

[0066] Next, rotate adjustment cap 2 to adjust the focal length back and forth. The focal length adjustment range is controlled within ±0.25mm. Position 0 represents the optimal collimation point, where the collimated light divergence angle is the smallest, and the light spot on the observation screen is the smallest. Record the center position of the light spot every half turn of the adjustment cap, starting from -0.25mm to +0.25mm, and then continuing from +0.25mm back to -0.25mm, recording the light spot trajectory of one round trip.

[0067] (1) During adjustment, the optimized collimator exhibited a maximum offset of 39 μm in the x-direction (vertical direction of the radial direction), corresponding to 0.0195 mrad, and a maximum offset of 160 μm in the y-direction (lateral direction of the radial direction), corresponding to 0.08 mrad. Furthermore, no significant jump occurred during switching between the two directions, as shown in Table 2.

[0068] Table 2

[0069] coordinates / μm (-10,158) (38,101) (0,0) (39,-83) (-34,10) (15,-65) (-5,112) (10,160) (-32,119)

[0070] (2) Before optimization, the collimator exhibited a maximum offset of 2537 μm in the x-direction (corresponding to 1.26 mrad) and a maximum offset of 1568 μm in the y-direction (corresponding to 0.78 mrad) during adjustment. Furthermore, there were significant jumps during the switching between the two directions, as shown in Table 3.

[0071] Table 3

[0072] coordinates / μm (-595,1008) (354,987) (0,0) (-735,-113) (419,1386) (-1698,-69) (-2537,-653) (-1484,-1568) (-756,-994)

[0073] The above-mentioned indicators are superior to similar products from other manufacturers and traditional collimators that have not been optimized. Therefore, with the addition of this optimized collimator, there will be no significant left-right shift caused by rotation during focus adjustment.

[0074] Example 3:

[0075] See appendix Figure 5 The difference between this embodiment and embodiment 1 is that the axial guide portion 7, which is formed by the combination of axial protrusion 71 and axial groove 72, is provided with multiple sets in the circumferential direction between the mating surfaces of the top ring 5 and the collimator body 1.

[0076] In this embodiment, four sets of axial guide parts 7 are provided, which are evenly distributed, formed by the combination of axial protrusions 71 and axial grooves 72.

[0077] Example 4:

[0078] In addition to the stress unevenness caused by rotation, laser collimators also experience unevenness due to temperature changes and the coefficient of thermal expansion. Metals and glass have different coefficients of thermal expansion. If a metal ring is directly pressed against the glass, stress deformation can easily occur under drastic temperature changes, leading to unwanted wavefront distortion and optical path deflection. Since the lens holder and top ring are usually made of metal, while the lens itself is made of glass, typically only the lens material differs within the entire collimator. Therefore, special strain treatment is required at the lens contact points.

[0079] See appendix Figure 6 The lens assembly 6 includes a lens 61 and a stress balancing kit 62 that presses the lens 61 against the inside of the lens holder 4.

[0080] To further optimize the above technical solution, the inner wall of the lens holder 4 has a stepped surface 41, and the two sides of the lens 61 abut against the stepped surface 41 and the stress balancing kit 62 respectively; the stress balancing kit 62 includes a metal pressure ring 621 threadedly tightened at the end of the lens holder 4, and an elastic element 622 is provided between the metal pressure ring 621 and the lens 61.

[0081] To further optimize the above technical solution, the elastic element 622 includes a rubber ring 6221 and / or a transition spring 6222.

[0082] To further optimize the above technical solution, the diameter of lens 61 is smaller than the diameter of step surface 41, leaving a buffer area for radial deformation. This approach can alleviate deformation and stress problems caused by large temperature changes, thus maintaining a high-quality laser output even under temperature variations.

[0083] In this embodiment, the elastic element 622 includes a rubber ring 6221 placed on the edge of the lens 61, and a transition spring 6222 is pressed between the rubber ring 6221 and the metal pressure ring 621.

[0084] By placing a rubber ring 6221 and a transition spring 6222 between the lens 61 and the metal pressure ring 621, two components made of different materials are connected by the elastic rubber ring 6221 and the transition spring 6222. After adding this stress-balancing structure, the lens 61 and the lens holder 4 only directly contact the stepped surface 41 of the lens holder 4 in the axial direction, while the other side is pressed by the rubber ring 6221, the transition spring 6222, and the metal pressure ring 621, which is a non-rigid connection and can reduce the impact of deformation.

[0085] It should be noted that this embodiment is not limited to the space between lens 61 and lens support 4. In addition, if there is stress contact between components made of two different materials and a degree of freedom of movement is required, stress optimization can be achieved by using the structure of transition spring 6222 and rubber ring 6221.

[0086] In addition, the structure for optimizing intermediate stress is not limited to a spring and a rubber ring; it can also be two rubber rings and a spring, or a suitable rubber ring structure.

[0087] Example 5:

[0088] This embodiment tests the collimator's stability with respect to temperature and stress. For example... Figure 8 As shown, the fiber-coupled optical path was first constructed with a light source wavelength of 780nm, and both the collimating and coupling lenses had a focal length of 11mm. The fiber optic connector was a PC connector. Next, the temperature of the collimator for the emitted laser was continuously increased from 25 degrees Celsius to 35 degrees Celsius. Then, the heating device was turned off, and the system was allowed to cool naturally. The relationship between the fiber coupling efficiency and temperature during the temperature increase and subsequent decrease was recorded. The data is shown in Table 4.

[0089] Table 4

[0090] Coupling efficiency 80.45％ 81.64％ 82.04％ 82.50％ 81.43％ 81.71％ 82.40％ 82.52％ 81.63％ 82.15％ 81.71％ Temperature drop / °C 35 34 33 32 31 30 29 28 27 26 25 Coupling efficiency 81.71％ 82.10％ 81.87％ 80.83％ 81.17％ 82.01％ 82.05％ 81.43％ 81.50％ 81.66％ 80.19％

[0091] Based on the test results above, it can be found that the stability can be further improved after using the stress balancing kit 62.

[0092] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0093] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A guide-type anti-rotation adjustable focus fiber collimator, comprising: A collimator body (1) has an optical fiber inlet (11) at one end and an adjusting cap (2) threaded to the other end. The inner cavity of the collimator body (1) contains an adjusting spring (3), a lens holder (4), and a top ring (5) arranged sequentially from the optical fiber inlet (11) towards the adjusting cap (2). A lens assembly (6) is housed within the lens holder (4). The position of the lens assembly (6) can be adjusted by turning the adjusting cap (2). The collimator body (1) is characterized by: The outer side wall of the top ring (5) and the inner side wall of the collimator body (1) have an axial guide portion (7). The axial guide portion (7) is composed of an axial protrusion (71) and an axial groove (72) forming an axial sliding fit structure, so that when the adjusting cap (2) pushes the top ring (5) to move, the top ring (5) can only slide along the axial direction of the collimator body (1) and is restricted from radial movement and circumferential rotation.

2. The guide-type anti-rotation adjustable focus fiber collimator according to claim 1, characterized in that, The axial guide portion (7) includes the axial protrusion (71) provided on the outer side wall of the top ring (5) and the axial groove (72) provided on the inner side wall of the collimator body (1) and slidably connected to the axial protrusion (71).

3. The guide-type anti-rotation adjustable focus fiber collimator according to claim 1, characterized in that, The axial guide portion (7) includes the axial protrusion (71) disposed on the inner side wall of the collimator body (1) and the axial groove (72) opened on the outer side wall of the top ring (5) and slidably connected to the axial protrusion (71).

4. A guide-type anti-rotation adjustable focus fiber collimator according to any one of claims 1-3, characterized in that, Both the axial protrusion (71) and the axial groove (72) are cuboid structures.

5. A guide-type anti-rotation adjustable focus fiber collimator according to any one of claims 1-3, characterized in that, The axial guide portion (7) formed by the combination of the axial protrusion (71) and the axial groove (72) is provided in multiple sets circumferentially between the mating surfaces of the top ring (5) and the collimator body (1).

6. A guide-type anti-rotation adjustable focus fiber collimator according to claim 1, characterized in that, The lens assembly (6) includes a lens (61) and a stress balancing kit (62) that presses the lens (61) against the inside of the lens holder (4).

7. A guide-type anti-rotation adjustable focus fiber collimator according to claim 6, characterized in that, The inner wall of the lens holder (4) has a stepped surface (41), and the two sides of the lens (61) abut against the stepped surface (41) and the stress balancing kit (62) respectively; the stress balancing kit (62) includes a metal pressure ring (621) threadedly tightened at the end of the lens holder (4), and an elastic element (622) is provided between the metal pressure ring (621) and the lens (61).

8. A guide-type anti-rotation adjustable focus fiber collimator according to claim 7, characterized in that, The elastic element (622) includes a rubber ring (6221) and / or a transition spring (6222).

9. A guide-type anti-rotation adjustable focus fiber collimator according to claim 8, characterized in that, The elastic element (622) includes a rubber ring (6221) placed on the edge of the lens (61), and the transition spring (6222) is pressed between the rubber ring (6221) and the metal pressure ring (621).

10. A guide-type anti-rotation adjustable focus fiber collimator according to claim 7, characterized in that, The diameter of the lens (61) is smaller than the diameter of the stepped surface (41).

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