A laser link optical system and a coupling method thereof

Abstract

The application relates to the technical field of optical communication, and discloses a laser link optical system, which comprises a first communication assembly, a plurality of lasers, a collimating lens and a turning prism are sequentially arranged along an optical path in the first communication assembly; a second communication assembly is oppositely arranged with the first communication assembly, and a focusing lens assembly and a plurality of detectors are sequentially arranged along the optical path in the second communication assembly; wherein the collimating lens is used for converting a plurality of beams of divergent light emitted by the plurality of lasers into a plurality of beams of parallel light, the turning prism is used for performing angle deflection on the edge parallel light, the deflected edge parallel light and the center parallel light jointly cross the assembly to enter the second communication assembly, and are received by the focusing lens assembly and respectively converge to the light-sensitive surfaces of the plurality of detectors. The application aims to reduce the passive adaptation difficulty between the two optical assemblies.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, specifically to a laser link optical system and its coupling method. Background Technology

[0002] Free-space optical communication components are widely used in short-distance, high-speed data transmission, undertaking core data exchange functions such as inter-board communication and full-duplex communication between devices. The quality and accuracy of optical path coupling transmission are key parameters for evaluating the signal transmission performance and operational status of this component.

[0003] Currently, in multi-channel optical communication, the common practice is to directly transmit and receive multiple optical signals in free space. However, in actual operation, due to the physical spatial layout of components and the characteristics of optical signal transmission across components, the receiving end of the communication module often has difficulty capturing all the transmitted beams, which can easily lead to high local optical loss, resulting in a decrease in the coupling efficiency of the overall communication link and seriously affecting the stability of multi-channel high-speed communication signals. Summary of the Invention

[0004] The purpose of this invention is to reduce the difficulty of passive adaptation between two optical components, and to propose a laser link optical system and its coupling method.

[0005] In a first aspect, embodiments of the present invention provide a laser link optical system, comprising: The first communication component has multiple lasers, collimating lenses and deflecting prisms arranged sequentially along the optical path inside the first communication component; The second communication component is arranged opposite to the first communication component, and a focusing lens assembly and multiple detectors are arranged sequentially along the optical path inside the second communication component. The collimating lens is used to convert the multiple divergent beams emitted by the multiple lasers into multiple parallel beams. The deflecting prism is used to deflect the parallel beams at the edges, so that the deflected edge parallel beams and the central parallel beams are together injected into the second communication component across the component, and are received by the focusing lens component and respectively converged to the photosensitive surfaces of the multiple detectors.

[0006] In one embodiment, the focusing lens assembly includes a mounting bracket, in which a first focusing lens and a second focusing lens are sequentially fixed along the optical path. The first focusing lens is used to perform primary focusing of the beam incident across the component, and the second focusing lens is used to perform secondary focusing and deflection of the beam after primary focusing, so as to guide it to the photosensitive surface of the corresponding detector respectively.

[0007] In one embodiment, the first focusing lens has a first light-incident surface facing the first communication component, the first light-incident surface being an aspherical or Fresnel surface.

[0008] In one embodiment, the aperture size of the first focusing lens is larger than the overall span size of the photosensitive surface array formed by the plurality of detectors, and the focal length of the second focusing lens is smaller than the focal length of the first focusing lens.

[0009] In one embodiment, the collimating lens has a central spherical region on the side facing the second communication component; The deflection prism and the collimating lens are spaced apart, and the deflection prism has a trapezoidal short side region, which is coaxially aligned with the central spherical region.

[0010] In one embodiment, the collimating lens is a short focal length lens. After the multiple diverging beams emitted by the multiple lasers are converted by the short focal length lens, the cross-sectional spot diameter of each parallel beam is smaller than a preset spot diameter threshold.

[0011] In one embodiment, a plurality of said lasers are arranged in a one-dimensional linear array to emit a central beam located in the middle and edge beams located on both sides; The number of lasers is equal to the number of detectors, and the two correspond one-to-one in spatial mapping.

[0012] Secondly, embodiments of the present invention provide a coupling method for a laser link optical system, applied to the optical system as described above, comprising: On the first communication component side, the collimating lens is placed on the light-emitting side of the plurality of lasers to obtain the first spot parameters of the beam at a first distance and the second spot parameters at a second distance; when the first spot parameters and the second spot parameters meet a preset consistency condition, the collimating lens is fixed. On the second communication component side, a collimated beam is input to the focusing lens assembly; the response current value of the collimated beam after convergence on the corresponding detector is obtained; the focusing lens assembly is moved, and when the response current value reaches the current peak value, the focusing lens assembly is fixed.

[0013] In one embodiment, the first spot parameters include a first spot diameter and a first spot position, and the second spot parameters include a second spot diameter and a second spot position; The first light spot parameters and the second light spot parameters meet a preset consistency condition, specifically: the diameter of the first light spot is equal to the diameter of the second light spot, and the deviation between the position of the first light spot and the position of the second light spot is less than a preset position deviation threshold.

[0014] In one embodiment, after fixing the collimating lens, the method further includes: The prism is attached to the light-emitting side of the collimating lens; Adjust the lateral position of the prism. When the trapezoidal short side region of the prism is coaxially aligned with the central spherical region of the collimating lens, the prism is then bonded and fixed.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: 1. The present invention employs a short focal length collimating lens in the first communication component to collimate multiple diverging beams, which effectively reduces the spot diameter of the emitted parallel light, increases the allowable range of lateral offset at the receiving end of the second communication component from the source, and shortens the optical path length, thereby realizing the miniaturization of the optical system.

[0016] 2. This invention employs a technique of using a prism to deflect parallel light at a fixed angle, so that parallel light from multiple channels is focused onto the corresponding detectors. This achieves multi-channel parallel transmission to improve communication speed while maintaining low crosstalk between channels.

[0017] 3. The present invention employs a dual-lens structure combining a first focusing lens and a second focusing lens in the second communication component. The first focusing lens achieves primary focusing with a large aperture and increases displacement alignment tolerance, while the second focusing lens achieves secondary focusing with a short focal length and increases angular tolerance. The two lenses work together to reduce the difficulty of passive adaptation between the two communication components and ensure stable signal transmission under conditions of large alignment errors and angular deviations. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall connection structure of the laser link optical system provided by the present invention; Figure 2 This is a schematic cross-sectional view of the focusing lens assembly within the second communication component provided by the present invention. Figure 3 This is a schematic diagram of the structure of the focusing lens assembly provided by the present invention, in which the first light incident surface is an aspherical surface. Figure 4 This is a schematic diagram of the structure of the focusing lens assembly provided by the present invention, in which the first light-incident surface is a Fresnel surface; Figure 5 This is a schematic diagram of the optical path simulation of the laser link optical system provided by the present invention; Figure 6 A schematic diagram of the coupling between the beam quality analyzer and the collimating lens within the first communication component provided by the present invention; Figure 7 A schematic diagram of the coupling between the fiber optic collimator and the focusing lens assembly within the second communication component provided by the present invention; Figure 8 A flowchart of a coupling method for a laser link optical system provided by the present invention.

[0019] In the diagram: 1. Laser; 2. Collimating lens; 3. Conversion prism; 4. Focusing lens assembly; 5. Detector; 6. First focusing lens; 7. Second focusing lens; 8. Mounting bracket; 9. Beam quality analyzer; 10. Fiber optic collimator. Detailed Implementation

[0020] The technical solutions of 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.

[0021] This application provides a laser link optical system. This optical system enables multi-channel high-speed optical communication between two communication components in short-distance free space. Through a three-lens optical path structure of "short focal length collimation—angular deflection—large aperture convergence—short focal length focusing" and precise beam coupling technology, it expands the lateral alignment tolerance and angular deviation tolerance between the transmitter and receiver while meeting system miniaturization constraints. This reduces the difficulty of passive adaptation between the two communication components and ensures stable transmission of multi-channel signals.

[0022] According to the first aspect of this application, Figure 1 As shown, a laser link optical system includes a first communication component and a second communication component. The first communication component contains multiple lasers 1, a collimating lens 2, and a deflecting prism 3 arranged sequentially along the optical path. The second communication component is positioned opposite to the first communication component, and its interior contains a focusing lens assembly 4 and multiple detectors 5 arranged sequentially along the optical path.

[0023] The multi-channel transmission operation process of this optical system is as follows: Figure 5As shown, the multiple diverging beams emitted from the multiple lasers 1 inside the first communication component are first converted into multiple parallel beams by the collimating lens 2. This ensures that the cross-sectional diameter of the beams no longer significantly increases with the propagation distance during subsequent free-space propagation, which is fundamental to maintaining the concentration of optical energy in short-distance transmission. Based on this, the deflecting prism 3 deflects two parallel beams located at the edge at a fixed angle, allowing the deflected edge parallel beams and the undeflected center parallel beams to enter the second communication component together across the component at a defined spatial angle. When these multi-channel beams reach the second communication component, they are uniformly received by the focusing lens assembly 4 and converged onto the photosensitive surface of their respective detectors 5, completing the conversion from optical signals to electrical signals, thereby achieving multi-channel parallel communication.

[0024] It should be noted that the designations "first communication component" and "second communication component" in this application are only used to distinguish between the transmitting and receiving sides and do not limit the transmission direction of the optical signal. In practical full-duplex communication applications, both communication components can simultaneously include lasers and detectors to achieve bidirectional communication. This application provides a detailed description using a transmission optical path in one direction as an example; the design of the optical path in the opposite direction can be implemented using the same principle.

[0025] For example, the multiple lasers 1 can be multimode VCSELs (vertical-cavity surface-emitting lasers) with operating wavelengths of 850nm, 940nm, or 1310nm. The multiple detectors 5 can be PIN photodetectors with photosensitive surface diameters of 50μm, 62.5μm, or 80μm. In one specific embodiment, there are three lasers 1 and three detectors 5, each corresponding to three independent communication channels, achieving a communication rate of over 10Gbps. Of course, in other embodiments, the number of channels can be two, four, or more, and this application does not impose any particular limitation on this.

[0026] In one embodiment of this application, such as Figure 2 As shown, the focusing lens assembly 4 includes a mounting bracket 8, within which a first focusing lens 6 and a second focusing lens 7 are sequentially fixed along the optical path. The first focusing lens 6 is used for primary focusing of the light beam incident across the assembly, and the second focusing lens 7 is used for secondary focusing and deflection of the light beam after primary focusing, guiding them to the photosensitive surfaces of their respective detectors 5.

[0027] Decomposing the focusing function of the receiver into two stages—primary focusing and secondary focusing—is the core optical design strategy for achieving high tolerance in this application. If only a single lens is used to complete the focusing process from parallel light to the photosensitive surface of the detector, this single lens needs to simultaneously meet the contradictory performance requirements of a large aperture and a short focal length. A large aperture means that the lens has a large light-gathering area, which can still capture enough light energy even when there is a lateral alignment misalignment between the transmitter and receiver, thus increasing the displacement alignment tolerance. On the other hand, a short focal length means that the focal plane position shift caused by the same incident angle deviation is smaller, thus increasing the angle deviation tolerance. However, achieving both a large aperture and a short focal length in a single lens will result in a very large aperture-to-focal-length ratio (i.e., relative aperture), causing serious aberrations such as spherical aberration and astigmatism, thus degrading the quality of the focused spot.

[0028] This application splits the focusing function onto two lenses. The first focusing lens 6 has a large-aperture primary focusing function, using a large light-passing aperture to expand the displacement alignment tolerance; the second focusing lens 7 has a short focal length secondary focusing function, using a short focal length to compress aberration shifts caused by angular deviations. The two lenses perform their respective functions, avoiding the aberration deterioration problem of a single lens while simultaneously achieving high displacement and high angular tolerances. For example, through this dual-lens combination design, the optical system of this application can expand the lateral alignment tolerance to ±0.8mm and the angular deviation tolerance to ±1.5°, while the size of the entire optical system can be controlled within a range of less than 5mm × 5mm.

[0029] It should be noted that the function of the mounting bracket 8 is to fix the first focusing lens 6 and the second focusing lens 7 into an integrated lens assembly with precise spacing and coaxial relationship, facilitating subsequent overall coupling and alignment with the detector. The mounting bracket 8 can be made of engineering plastics, metal alloys, or ceramics, etc. Figure 2 As shown, positioning steps or positioning grooves can be set inside to ensure the installation accuracy of the two lenses.

[0030] In one embodiment of this application, the first focusing lens 6 has a first light-incident surface facing the first communication component, which is an aspherical or Fresnel surface. It is understood that an aspherical design, such as... Figure 3 As shown, spherical aberration can be effectively corrected while maintaining a large aperture, ensuring good focusing even for edge-incident rays, thus fully utilizing the entire light-transmitting area of ​​the first focusing lens 6 to collect light energy. The Fresnel surface design, as... Figure 4As shown, by discretizing the continuous curved surface into multiple concentric rings, the lens thickness is reduced while maintaining the equivalent refractive focusing capability, which is particularly advantageous for system miniaturization. For example, the first incident surface can also be a freeform surface or a diffractive surface, etc. This application does not impose a unique limitation on its specific surface shape, as long as the surface shape can effectively control aberrations while receiving light through a large aperture.

[0031] In one embodiment of this application, the aperture size of the first focusing lens 6 is larger than the overall span size of the photosensitive surface array formed by the plurality of detectors 5, and the focal length of the second focusing lens 7 is smaller than the focal length of the first focusing lens 6.

[0032] The reason why the aperture of the first focusing lens 6 needs to be larger than the overall span of the photosensitive array of the detector is that when there is a lateral alignment offset between the first and second communication components, the coverage area of ​​the incident beam will shift relative to the center of the lens. If the aperture is only equal to or slightly larger than the span of the photosensitive array, under lateral offset conditions, part of the beam will exceed the effective light transmission range of the lens and be blocked, resulting in light energy loss. By designing the aperture of the first focusing lens 6 to be significantly larger than the span of the photosensitive array, sufficient light-gathering margin can be reserved for lateral offset, thereby increasing the displacement alignment tolerance. For example, when the three detectors 5 are arranged in a one-dimensional linear pattern and the overall span of the photosensitive array is 0.5 mm, the aperture of the first focusing lens 6 can be designed to be 1.5 mm, 2.0 mm, or 2.5 mm, etc.

[0033] Furthermore, the focal length of the second focusing lens 7 is shorter than that of the first focusing lens 6. The technical consideration behind this design is that when there is an angular deviation in the incident parallel light, the focal point of the beam after focusing by the lens will shift laterally relative to the ideal focal point. This lateral shift is approximately equal to the product of the focal length and the tangent of the angular deviation. Therefore, the shorter the focal length, the smaller the lateral shift of the focal point caused by the same angular deviation, and the light spot can still fall within the effective receiving area of ​​the detector's photosensitive surface. As the final stage in focusing the beam onto the detector's photosensitive surface, the short focal length design of the second focusing lens 7 effectively suppresses the impact of angular deviation on focusing accuracy, thus increasing the angular deviation tolerance. For example, the focal length of the first focusing lens 6 can be 3mm to 5mm, and the focal length of the second focusing lens 7 can be 0.5mm to 1.5mm.

[0034] In one embodiment of this application, the collimating lens 2 has a central spherical region on the side facing the second communication component; the deflecting prism 3 is spaced apart from the collimating lens 2, and the deflecting prism 3 has a trapezoidal short side region, which is coaxially aligned with the central spherical region.

[0035] like Figure 1As shown, the trapezoidal structure design of the conversion prism 3 ensures that the central region of the prism (i.e., the short side region of the trapezoid) corresponds to the central optical axis. This region does not deflect the parallel light from the central channel, allowing the central parallel light to pass through directly; as... Figure 5 As shown, the two beveled areas on both sides of the prism deflect the two edge parallel beams at preset angles, causing the three beams to propagate towards the second communication component at specific spatial angles. Aligning the short side of the trapezoid with the central spherical area of ​​the collimating lens 2 coaxially ensures that the propagation direction of the central beam is unaffected, while guaranteeing that the deflection angles of the two edge beams are symmetrical and consistent. For example, the deflection prism 3 can be integrally manufactured from optical glass or optical resin, and its deflection angle can be calculated and determined based on the laser spacing, detector spacing, and transmission distance between the two communication components; for example, the deflection angle can be 2°, 3°, or 5°.

[0036] It should be noted that the deflection prism 3 and the collimating lens 2 are spaced apart. From an assembly and adjustment perspective, the collimating lens 2 is mainly responsible for shaping the diverging beam into collimated parallel light, while the deflection prism 3 is mainly responsible for high-precision angle deflection and redirection of the edge parallel light. If the two are glued or sealed together, any fine adjustment of the pose of a single optical element during subsequent assembly will inevitably cause a corresponding shift in the optical axis of the other optical element, leading to repeated iterations and extremely low yield. The spaced arrangement allows the two to have independent spatial adjustment freedom.

[0037] In one embodiment of this application, the collimating lens 2 is a short focal length lens. After the multiple diverging beams emitted by the multiple lasers 1 are converted by the short focal length lens, the cross-sectional spot diameter of each beam of parallel light is smaller than a preset spot diameter threshold.

[0038] In the principle of optical collimation, the diameter of the parallel light beam formed after the diverging light source passes through the collimating lens is directly proportional to the focal length of the collimating lens. The shorter the focal length, the smaller the diameter of the collimated beam. A smaller beam diameter means a smaller proportion of the beam within the fixed aperture of the first focusing lens 6 at the receiving end, thus providing more space for lateral offset and increasing the system's displacement alignment tolerance. Furthermore, a short focal length means a smaller distance between the light-emitting surface of the laser 1 and the collimating lens 2, thereby shortening the optical path length at the transmitting end and facilitating the miniaturization of the entire optical system. For example, the focal length of the collimating lens 2 can be selected as 0.15mm, 0.2mm, or 0.25mm; the preset spot diameter threshold can be determined based on the aperture of the first focusing lens 6 at the receiving end and the required displacement tolerance of the system, for example, it can be set to 0.3mm, 0.4mm, or 0.5mm.

[0039] In one embodiment of this application, a plurality of lasers 1 are arranged in a one-dimensional linear array to emit a central beam located in the middle and edge beams located on both sides respectively; the number of the plurality of lasers 1 is equal to the number of the plurality of detectors 5, and the two correspond one-to-one in spatial mapping relationship.

[0040] It should be noted that "one-dimensional linear array arrangement" here refers to the arrangement of the emission points of multiple lasers 1 along the same vertical straight line, such as... Figure 1 and Figure 5 As shown. Taking a three-channel design as an example, the laser in the middle position emits a central beam, while the lasers on both sides emit edge beams. After collimation, the central beam passes directly through the trapezoidal short side region of the deflection prism 3 without deflection, while the two edge beams are deflected to their corresponding directions by the inclined surface region of the deflection prism 3. At the receiving end, the three detectors 5 are also arranged in a one-dimensional linear pattern, forming a one-to-one spatial mapping relationship with the three lasers 1. That is, the central beam emitted by the central laser converges to the detector in the central position, and the edge beams emitted by the lasers on both sides converge to the detectors on the sides. This one-to-one spatial mapping relationship is a fundamental prerequisite for ensuring that the multi-channel signals do not experience crosstalk. For example, the spacing between the lasers 1 can be 0.25mm, 0.3mm, or 0.4mm, and the spacing between the detectors 5 can be the same as the laser spacing or determined after calculation based on the deflection angle of the deflection prism.

[0041] According to the second aspect of this application, such as Figure 8 As shown, this application also provides a coupling method for a laser link optical system, applicable to the optical system described in any of the above embodiments. The core objective of this coupling method is to optimize the relative positions between the collimating lens 2 and the laser 1, and between the focusing lens assembly 4 and the detector 5, through precise spot coupling technology, so as to ensure that the optical system can achieve high-tolerance signal transmission during subsequent cross-component docking.

[0042] S110, Coupling and fixing of the collimating lens at the transmitting end.

[0043] On the first communication component side, the collimating lens 2 is placed on the light-emitting side of multiple lasers 1 to obtain the first spot parameters of the beam at a first distance and the second spot parameters at a second distance; when the first spot parameters and the second spot parameters meet the preset consistency conditions, the collimating lens 2 is fixed.

[0044] In one embodiment of this application, such as Figure 6As shown, the specific coupling operation process is as follows: A collimating lens 2 is placed on the emitting side of multiple lasers 1. The diverging light emitted from the laser 1 is converted into parallel light after passing through the collimating lens 2, and this parallel light enters the detection surface of the beam quality analyzer 9. During the test, it is necessary to first ensure that the mounting plane of the laser 1 is parallel to the detection surface of the beam quality analyzer 9 to eliminate the reference deviation of the measurement system. Then, at the first distance between the beam quality analyzer 9 and the collimating lens 2, i.e., the near-field position, the spot parameters of the central parallel light and the edge parallel light are tested to obtain the first spot parameters; then at the second distance, i.e., the far-field position, the spot parameters of the same beam are tested to obtain the second spot parameters. For example, the first distance can be 5mm, and the second distance can be 30mm. Of course, these two distance values ​​can also be adjusted according to the actual optical path design requirements. For example, the first distance can be selected as 3mm, 5mm, or 8mm, and the second distance can be selected as 20mm, 30mm, or 50mm.

[0045] The collimation quality is determined by comparing the spot parameters at two different propagation distances. The underlying principle is that when ideally collimated parallel light propagates in free space, its spot diameter and position should not change significantly with the propagation distance. If the spot diameter at the near-field position is equal to the spot diameter at the far-field position, it indicates that the beam has been accurately collimated into parallel light, and the axial distance between the collimating lens 2 and the laser 1 has been adjusted to the optimal level. If the center coordinates of the spot at the near-field position are equal to or approximately equal to the center coordinates of the spot at the far-field position, it indicates that the lateral relative position between the collimating lens 2 and the laser 1 has been adjusted to the optimal level, and the beam is not deflected along the propagation direction. Therefore, when the first and second spot parameters meet the preset consistency conditions, it can be determined that the collimating lens 2 has been properly adjusted, and at this point, the collimating lens 2 is bonded and fixed.

[0046] In one embodiment of this application, the first spot parameter includes a first spot diameter and a first spot position, and the second spot parameter includes a second spot diameter and a second spot position. The first spot parameter and the second spot parameter satisfy a preset consistency condition, specifically: the first spot diameter is equal to the second spot diameter, and the deviation between the first spot position and the second spot position is less than a preset position deviation threshold.

[0047] It should be noted that the aforementioned "equality" in engineering implementation should be understood as equality within the allowable measurement tolerance range, rather than strict mathematical equality. For example, when the first distance is 5mm, the diameter D1 and position (X1, Y1) of the first spot of the central parallel light are tested, as are the diameter D2 and position (X2, Y2) of the first spot of the edge parallel light; when the second distance is 30mm, the diameter D3 and position (X3, Y3) of the corresponding second spot are tested, as are the diameter D4 and position (X4, Y4) of the second spot of the edge parallel light. When D1=D3 and D2=D4, the axial position of the collimating lens 2 is determined to be optimal; when X1=X3 and Y1=Y3, and X2≈X4 and Y2≈Y4, the lateral position of the collimating lens 2 is determined to be optimal. The preset position deviation threshold can be set according to the alignment accuracy requirements of the system, for example, it can be 10μm, 20μm, or 50μm.

[0048] In addition to the aforementioned coupling and fixing of the collimating lens 2, the convection prism 3 also needs to be installed in place. In one embodiment of this application, after fixing the collimating lens 2, the method further includes: attaching the convection prism 3 to the light-emitting side of the collimating lens 2; adjusting the lateral position of the convection prism 3, and when the trapezoidal short side region of the convection prism 3 is coaxially aligned with the central spherical region of the collimating lens 2, the convection prism 3 is then bonded and fixed.

[0049] The installation of the deflector prism 3 is carried out after the coupling and fixing of the collimating lens 2 is completed. This sequential design is intentional because the coupling and fixing process of the collimating lens 2 requires repeated adjustments to the lens position through beam quality analysis. If the deflector prism 3 is already installed at this point, the edge beams, after deflection, will increase the complexity of beam spot parameter measurement, affecting the accuracy of collimation quality determination. Therefore, completing the independent coupling and fixing of the collimating lens 2 first, and then attaching the deflector prism 3 to the light-emitting side of the collimating lens 2 for alignment and fixing, simplifies the process and improves coupling accuracy.

[0050] S120, Coupling and fixing of the receiving end focusing lens assembly.

[0051] On the second communication component side, a collimated beam is input to the focusing lens assembly 4; the response current value of the collimated beam after convergence on the corresponding detector 5 is obtained; the focusing lens assembly 4 is moved, and when the response current value reaches the current peak value, the focusing lens assembly 4 is fixed.

[0052] In one embodiment of this application, such as Figure 7As shown, the specific coupling operation process is as follows: A collimated beam is emitted using an optical fiber collimator 10, and this collimated beam converges onto the photosensitive surface of the central position detector 5 after passing through the focusing lens assembly 4. During the test, it is necessary to first ensure that the collimated light emitted from the optical fiber collimator 10 is perpendicular to the mounting plane of the three detectors 5 to eliminate the influence of the incident angle deviation on the coupling accuracy. Then, by adjusting the three-dimensional position of the focusing lens assembly 4 (that is, the axial position along the optical axis and the lateral position perpendicular to the optical axis), the response current value output by the central position detector 5 is monitored in real time.

[0053] It is understandable that the response current value of detector 5 is directly proportional to the light power incident on its photosensitive surface. When the position of the focusing lens assembly 4 allows the collimated beam to be most precisely focused onto the center of the photosensitive surface of detector 5, the light power received on the photosensitive surface is at its maximum, and the corresponding response current value also reaches its maximum value, i.e., the peak current. Therefore, using whether the response current value reaches the peak current value as the criterion for judging the coupling quality can directly and accurately reflect whether the position of the focusing lens assembly 4 has been adjusted to the optimal level. When the response current value reaches the peak current value, the focusing lens assembly 4 is bonded and fixed to the front end of detector 5.

[0054] It should be noted that during the coupling process in step S120, the collimated beam used is an externally input standard collimated beam (e.g., provided by the fiber optic collimator 10), rather than the actual signal light from the first communication component. This is because during the coupling fixing phase, the first and second communication components have not yet completed docking, and the actual signal light cannot be used directly for coupling. Using an external standard collimated beam can simulate the incident light conditions under actual working conditions, while eliminating the influence of the alignment error of the first communication component on the coupling accuracy of the receiving end.

[0055] The specific working principle of the laser link optical system of the present invention is as follows: First, multiple lasers 1 inside the first communication component emit multiple divergent beams. These multiple divergent beams are converted into multiple parallel beams with smaller cross-sectional spot diameters by a short focal length collimating lens 2. Then, the two parallel beams at the edge are deflected at a fixed angle by a deflecting prism 3, so that the central parallel beam and the deflected edge parallel beam are emitted from the first communication component at a certain spatial angle and propagate across free space to the second communication component. Next, the multi-channel parallel beam reaches the second communication component and is initially focused by the first focusing lens 6 with a large aperture in the focusing lens assembly 4. The large aperture ensures that the beam can still be effectively captured even if there is a lateral alignment offset, increasing the displacement alignment tolerance. Finally, the primary focused beam is secondary focused by the shorter focal length second focusing lens 7, converging the beams from each channel onto the photosensitive surface of the corresponding detector 5 to complete photoelectric conversion. The short focal length design minimizes the focal plane offset caused by angular deviations, increasing the angular deviation tolerance, and also shortens the optical path length at the receiver, achieving miniaturization of the entire optical system. The entire optical system, through a three-lens optical path architecture of "short focal length collimation—angular deflection—large aperture focusing—short focal length focusing," achieves a lateral alignment tolerance of ±0.8mm and an angular deviation tolerance of ±1.5° within a compact space of less than 5mm × 5mm, effectively reducing the difficulty of passive adaptation between the two communication components.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A laser link optical system, characterized in that, include: The first communication component has multiple lasers (1), collimating lenses (2) and deflection prisms (3) arranged sequentially along the optical path inside the first communication component. The second communication component is arranged opposite to the first communication component, and a focusing lens assembly (4) and multiple detectors (5) are arranged sequentially along the optical path inside it. The collimating lens (2) is used to convert multiple divergent beams emitted by multiple lasers (1) into multiple parallel beams. The deflecting prism (3) is used to deflect the parallel beams at the edges, so that the deflected edge parallel beams and the center parallel beams are together injected into the second communication component across the component, and are received by the focusing lens component (4) and respectively converged to the photosensitive surfaces of multiple detectors (5).

2. The laser link optical system according to claim 1, characterized in that, The focusing lens assembly (4) includes a mounting bracket (8), and a first focusing lens (6) and a second focusing lens (7) are sequentially fixed along the optical path inside the mounting bracket (8). The first focusing lens (6) is used to perform primary focusing of the beam incident across the component, and the second focusing lens (7) is used to perform secondary focusing and deflection of the beam after primary focusing, so as to guide it to the photosensitive surface of the corresponding detector (5).

3. The laser link optical system according to claim 2, characterized in that, The first focusing lens (6) has a first light-incident surface facing the first communication component, and the first light-incident surface is an aspherical or Fresnel surface.

4. The laser link optical system according to claim 2, characterized in that, The aperture size of the first focusing lens (6) is larger than the overall span size of the photosensitive surface array formed by the multiple detectors (5), and the focal length of the second focusing lens (7) is smaller than the focal length of the first focusing lens (6).

5. The laser link optical system according to claim 1, characterized in that, The collimating lens (2) has a central spherical region on the side facing the second communication component; The deflection prism (3) is spaced apart from the collimating lens (2), and the deflection prism (3) has a trapezoidal short side region, which is coaxially aligned with the central spherical region.

6. The laser link optical system according to claim 1, characterized in that, The collimating lens (2) is a short focal length lens. After the multiple diverging beams emitted by the multiple lasers (1) are converted by the short focal length lens, the cross-sectional spot diameter of each beam of parallel light is smaller than the preset spot diameter threshold.

7. The laser link optical system according to any one of claims 1 to 6, characterized in that, Multiple lasers (1) are arranged in a one-dimensional linear array to emit a central beam located in the middle and edge beams located on both sides, respectively; The number of lasers (1) is equal to the number of detectors (5), and the two correspond one-to-one in spatial mapping.

8. A coupling method for a laser link optical system, applied to the optical system as described in any one of claims 1 to 7, characterized in that, include: On the first communication component side, the collimating lens (2) is placed on the light-emitting side of the plurality of lasers (1) to obtain the first spot parameter of the beam at a first distance and the second spot parameter at a second distance respectively; when the first spot parameter and the second spot parameter meet the preset consistency condition, the collimating lens (2) is fixed. On the second communication component side, a collimated beam is input to the focusing lens assembly (4); the response current value of the collimated beam after convergence on the corresponding detector (5) is obtained; the focusing lens assembly (4) is moved, and when the response current value reaches the current peak value, the focusing lens assembly (4) is fixed.

9. The coupling method of the laser link optical system according to claim 8, characterized in that, The first spot parameters include the first spot diameter and the first spot position, and the second spot parameters include the second spot diameter and the second spot position; The first light spot parameters and the second light spot parameters meet a preset consistency condition, specifically: the diameter of the first light spot is equal to the diameter of the second light spot, and the deviation between the position of the first light spot and the position of the second light spot is less than a preset position deviation threshold.

10. The coupling method of the laser link optical system according to claim 8, characterized in that, After fixing the collimating lens (2), the method further includes: The turning prism (3) is attached to the light-emitting side of the collimating lens (2); Adjust the lateral position of the prism (3) and when the trapezoidal short side region of the prism (3) is coaxially aligned with the central spherical region of the collimating lens (2), then fix the prism (3) by bonding.

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