A single-fiber bidirectional lens system with a light source power monitoring function

Abstract

The application discloses a single-fiber bidirectional lens system with a light source power monitoring function, comprising a lens mechanism; the lens mechanism comprises a COB integrated lens, an MPD detector, a VCSEL laser and a PD detector; a beam splitter and a multi-mode optical fiber are assembled on the COB integrated lens, and a collimating lens, a first refracting surface, a first light-emitting focusing lens, a second light-emitting focusing lens, a total reflection surface, a second refracting surface and a third refracting surface are integrated on the COB integrated lens; the VCSEL laser is used for emitting a light beam, the MPD detector is used for monitoring the emission power of the VCSEL laser, and the PD detector is used for receiving an external optical communication signal. According to the application, the MPD detector is arranged to monitor the emission power of the VCSEL laser, when the laser has no light and the output signal is weak, the fault source can be quickly judged according to the real-time collected emission power value, and it is distinguished whether the fault is a laser fault or an optical path fault, so that it is not necessary to disassemble the system for item-by-item testing, and therefore the troubleshooting efficiency is greatly improved.

Description

Technical Field

[0001] This application relates to the field of single-fiber bidirectional optical devices, and in particular to a single-fiber bidirectional lens system with a function for monitoring the power of the emitted light source. Background Technology

[0002] Single-fiber bidirectional optical devices (BOSA) can transmit and receive optical signals on the same optical fiber and are widely used in fiber-to-the-home (FTTH), 5G fronthaul, data center interconnection and other scenarios. They can save optical fiber resources and reduce cabling costs, and are the core devices for short-distance optical communication.

[0003] Existing single-fiber bidirectional optical devices suffer from numerous and varied components, cumbersome internal installation and debugging processes, weak impact resistance, and easy wire detachment. Furthermore, existing single-fiber bidirectional optical devices lack MPD detection optical path functionality, resulting in low troubleshooting efficiency. Summary of the Invention

[0004] The main purpose of this application is to provide a single-fiber bidirectional lens system with emission light source power monitoring function, which aims to solve the problems of existing single-fiber bidirectional optical devices having a large number of different types of components, complicated internal installation and debugging process, weak impact resistance and easy wire detachment; at the same time, existing single-fiber bidirectional optical devices do not have MPD detection optical path function, resulting in low troubleshooting efficiency.

[0005] This application provides a single-fiber bidirectional lens system with emission source power monitoring function, including a lens mechanism; the lens mechanism includes a COB integrated lens, and an MPD detector, a VCSEL laser, and a PD detector, all mounted on an external mounting surface and located within the COB integrated lens; the COB integrated lens is integrally injection molded, and a beam splitter and multimode fiber are mounted on the COB integrated lens; the COB integrated lens integrates a collimating lens, a first refractive surface, a first light-emitting focusing lens, a second light-emitting focusing lens, a total reflection surface, a second refractive surface, and a third refractive surface; the VCSEL laser is used to emit a beam that is incident on the collimating lens, collimated by the collimating lens to form a parallel beam that is projected onto the total reflection surface, and after total reflection by the total reflection surface, it is projected onto the first refractive surface; the first refractive surface is used to reflect and refract the incident parallel beam. The light beam reflected by the first refractive surface is transmitted to the second refractive surface, refracted by the second refractive surface, and then projected to the third refractive surface. After being refracted by the third refractive surface, it is projected to the total internal reflection surface. After total internal reflection, it is transmitted to the MPD detector, which is used to receive the light beam and monitor the emission power of the VCSEL laser. The light beam refracted by the first refractive surface is projected to the beam splitter, transmitted through the beam splitter, and then incident on the first exit focusing lens. After being focused by the first exit focusing lens, it is coupled to the multimode fiber. The multimode fiber is used to send the returned received light beam to the first exit focusing lens. After being shaped into a collimated parallel beam by the first exit focusing lens, it is projected to the beam splitter, reflected by the beam splitter, and then incident on the second exit focusing lens. After being focused by the second exit focusing lens, it is projected to the PD detector, which is used to receive the light beam and convert the optical signal into an electrical signal to receive external optical communication signals.

[0006] Optionally, the angle between the total reflection surface and the horizontal direction is... And satisfy .

[0007] Optionally, the angle between the first refractive surface and the horizontal direction is... And satisfy .

[0008] Optionally, the angle between the third refractive surface and the horizontal direction is... And satisfy The angle between the second refracting surface and the horizontal direction is... And satisfy .

[0009] Optionally, the COB integrated lens has a mounting reference surface for mounting a beam splitter; the beam splitter is fixed to the mounting reference surface, and the angle between the mirror surface of the beam splitter and the mounting reference surface is 45°.

[0010] Optionally, the side of the beam splitter closest to the first refractive surface is... The side of the beam splitter furthest from the first refractive surface is... noodle; A transmissive coating is applied to the surface. The transmissive coating is used to transmit the light beam that has been refracted by the first refractive surface and projected onto the beam splitter. A reflective film is coated on the surface. The reflective film is used to reflect the light beam that is shaped by the first light-emitting focusing lens and projected onto the beam splitter.

[0011] Optionally, the back focal length of the first light-emitting focusing lens is The back focal length of the collimating lens is The back focal length of the second light-emitting focusing lens is Then it satisfies , .

[0012] Optionally, the collimating lens, the first light-emitting focusing lens, and the second light-emitting focusing lens are all integrally formed on the COB integrated lens.

[0013] Optionally, the collimating lens, the first light-emitting focusing lens, and the second light-emitting focusing lens are all plano-convex aspherical lenses.

[0014] Optionally, there may be one or more lens mechanisms.

[0015] Compared with the prior art, this application has the following beneficial effects: 1. By setting up a COB integrated lens, which serves as the carrier substrate, the collimating lens, the first refractive surface, the first light-emitting focusing lens, the second light-emitting focusing lens, the total reflection surface, the second refractive surface, and the third refractive surface are integrated into one unit. Only one beam splitter is needed to complete the entire optical path construction, significantly reducing the types and number of parts. After the COB integrated lens is injection molded, the relative positions of each optical structure are fixed, eliminating the need to assemble various discrete optical components step by step using limiting blocks and bolts. Therefore, this application has the advantages of simplifying the internal installation and optical path debugging process and reducing the overall size of the device.

[0016] 2. By setting a first refractive surface to achieve beam splitting from the same source, the beam is divided into two paths on the same optical surface: the refracted beam is used as the communication light for transmission and coupling to the multimode fiber, and the reflected beam is transmitted to the MPD detector to complete power acquisition. The received beam of the MPD detector and the output beam of the fiber originate from the same emitted parallel light, and their optical power has a stable splitting ratio. The MPD detector can monitor the emission power of the VCSEL laser. When the laser is not shining or the output signal is weak, the fault source can be quickly identified based on the real-time acquired emission power value, distinguishing whether the fault is a laser fault or an optical path fault. Therefore, there is no need to disassemble the system for item-by-item testing, which greatly simplifies the fault diagnosis process and improves the diagnosis efficiency.

[0017] 3. By simultaneously integrating the entire optical path structure of transmission collimation, beam splitting monitoring, fiber coupling, and downlink signal reception onto a single COB integrated lens, the transmission optical path, reception optical path, and power monitoring optical path share the same carrier substrate. The integrated molding ensures the relative positional accuracy of each optical surface and lens. During the production stage, there is no need to align the optical paths of multiple discrete optical components one by one, which greatly reduces the complexity of debugging. The integrated structure eliminates the problem of loose assembly of multiple parts, thus improving the device's shock resistance. In addition, since the COB integrated lens, MPD detector, VCSEL laser, and PD detector are all mounted on the same external mounting surface, there is no need to lay out suspended wires across the device, reducing the problem of wires easily falling off due to stress and pulling from the source. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a single-fiber bidirectional lens system with emission source power monitoring function proposed in an embodiment of this application; Figure 2 This is a schematic diagram showing the installation position of the beam splitter according to an embodiment of this application; Figure 3 This is a schematic diagram showing the back focal length of the first light-emitting focusing lens, the collimating lens, and the second light-emitting focusing lens according to an embodiment of this application; Figure 4 This is a schematic diagram showing the tilt angles of each optical surface of the COB integrated lens proposed in the embodiments of this application; Figure 5 This is a schematic diagram of the uplink optical path optical simulation proposed in the embodiments of this application; Figure 6 This is a schematic diagram of the downlink optical path optical simulation proposed in the embodiments of this application; Figure 7 This is a data diagram of the uplink optical path coupling flat region proposed in the embodiments of this application; Figure 8 This is a data diagram of the downlink optical path coupling flat region proposed in the embodiments of this application.

[0019] The reference numerals in the attached diagram are as follows: 1. COB integrated lens; 11. Collimating lens; 12. First refractive surface; 13. First light-emitting focusing lens; 14. Second light-emitting focusing lens; 15. Total internal reflection surface; 16. Second refractive surface; 17. Third refractive surface; 18. Mounting reference surface; 2. Beam splitter; 21. Transmission film; 22. Reflective film; 3. Multimode fiber; 4. MPD detector; 5. VCSEL laser; 6. PD detector. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0022] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0024] Currently, single-fiber bidirectional optical devices achieve optical signal transmission and external signal reception by setting up multiple independent optical paths. The entire optical system adopts a split assembly structure, which is assembled from a housing, filters, optical transmitter, and optical receiver. The VCSEL transmitting optical path, fiber-coupled output optical path, and PD receiving optical path are separated from each other. The internal beam splitter, transmitting collimating lens, fiber-coupled lens, receiving focusing lens, and PD detector are all individual discrete components, without an integrated lens substrate. All scattered optical components are fixed step by step by housing limiting blocks, bolts, and adhesive to complete the alignment and matching of each optical path. However, this type of single-fiber bidirectional optical device has a large variety and number of components, and the internal installation and debugging process is cumbersome. At the same time, when troubleshooting existing single-fiber bidirectional optical devices, it is necessary to disassemble the single-fiber bidirectional optical device and then check the fault item by item, so the troubleshooting efficiency is low. Therefore, the following embodiment provides a single-fiber bidirectional lens system with a power monitoring function for the transmitted light source to solve the above problems.

[0025] Example Reference Figure 1This application provides a single-fiber bidirectional lens system with emission source power monitoring function, including a lens mechanism. The lens mechanism includes a COB integrated lens 1, and an MPD detector 4, a VCSEL laser 5, and a PD detector 6, all mounted on an external mounting surface and located within the COB integrated lens 1. The COB integrated lens 1 is integrally injection molded, and a beam splitter 2 and a multimode fiber 3 are mounted on the COB integrated lens 1. The COB integrated lens 1 integrates a collimating lens 11, a first refractive surface 12, a first light-emitting focusing lens 13, a second light-emitting focusing lens 14, a total reflection surface 15, a second refractive surface 16, and a third refractive surface 17. The VCSEL laser 5 emits a beam that is incident on the collimating lens 11. After being collimated by the collimating lens 11, it forms a parallel beam that is projected onto the total reflection surface 15. After total reflection by the total reflection surface 15, it is projected onto the first refractive surface 12. The first refractive surface 12 is used to reflect and refract the incident parallel beam. The light beam is transmitted to the second refractive surface 16, refracted by the second refractive surface 16 and projected to the third refractive surface 17, refracted by the third refractive surface 17 and projected to the total reflection surface 15, and after total reflection by the total reflection surface 15, it is transmitted to the MPD detector 4. The MPD detector 4 is used to receive the light beam and monitor the emission power of the VCSEL laser 5. The light beam refracted by the first refractive surface 12 is projected to the beam splitter 2, transmitted by the beam splitter 2 and incident on the first output focusing lens 13. After being focused by the first output focusing lens 13, it is coupled to the multimode fiber 3 (for uplink optical path information transmission). The multimode fiber 3 is used to incident the returned received light beam onto the first output focusing lens 13. After being shaped into a collimated parallel beam by the first output focusing lens 13, it is projected onto the beam splitter 2, reflected by the beam splitter 2 and incident on the second output focusing lens 14. After being focused by the second output focusing lens 14, it is projected onto the PD detector 6. The PD detector 6 is used to receive the light beam and convert the optical signal into an electrical signal to receive external optical communication signals.

[0026] Reference Figure 1Specifically, the MPD detector 4, VCSEL laser 5, and PD detector 6 are all packaged on a PCB board. The COB integrated lens 1 is mounted on the PCB board and located around the MPD detector 4, VCSEL laser 5, and PD detector 6. The external mounting surface is specifically the mounting surface at the corresponding position on the PCB board. The COB integrated lens 1 has a first groove, a second groove, a third groove, and a fourth groove. The first groove is located at the bottom of the COB integrated lens 1, and the MPD detector 4, VCSEL laser 5, and PD detector 6 are all located in the first groove. The collimating lens 11 is located at the VCSE. Directly above the L laser 5, the PD detector 6 is located directly below the second light-emitting focusing lens 14; the second and third grooves are both located on the upper part of the COB integrated lens 1, the total reflection surface 15 is the inner wall of the second groove near the third groove, the first refractive surface 12 is the inner wall of the third groove near the second groove, the beam splitter 2 is located in the third groove on the side away from the first refractive surface 12, the fourth groove is located above the first groove, and the fourth groove and the first groove are completely connected, the inner wall of the fourth groove near the total reflection surface 15 is the third refractive surface 17, and the inner wall of the fourth groove near the first refractive surface 12 is the second refractive surface 16.

[0027] Specifically, the MPD detector is used to receive the light beam and convert the optical signal into an electrical signal to monitor the emission power of the VCSEL laser. When the laser is not emitting light or the output signal is weak, the source of the fault can be quickly determined based on the real-time acquired emission power value, distinguishing whether the fault is a laser fault or an optical path fault. Therefore, there is no need to disassemble the system for item-by-item testing, which greatly simplifies the fault diagnosis process and improves the diagnosis efficiency. The emission wavelength of the VCSEL laser 5 is 850nm, and the receiving wavelength of the PD detector 6 is 980nm. The surface design of the second light-emitting focusing lens 14 is adapted to the receiving surface size of the PD detector 6. The receiving surface of the PD detector 6 is inversely proportional to the transmission rate of the system. The receiving surface of the PD detector 6 is about 60μm when the transmission rate is below 10G; and about 40μm when the transmission rate is around 25G. The higher the system transmission rate, the smaller the receiving surface of the PD detector 6, the higher the requirement for the coupling spot, and the higher the requirement for the surface design of the second light-emitting focusing lens 14. Specifically, by setting up a total reflection surface to deflect the collimated parallel beam, the VCSEL laser and collimating lens are arranged on one side of the COB integrated lens, while the total reflection surface and the first refractive surface are located on the other side. This layout allows for the partitioning of optical components, flexible planning of the optical path, significantly improved space utilization, and reduced overall system volume. There is no need to add additional reflective lenses; the beam deflection is completed by relying on the optical surface integrated into the lens body, reducing the number of discrete components, simplifying assembly, and improving the coaxial stability of the optical path.

[0028] The single-fiber bidirectional lens system of this embodiment integrates a first refractive surface on a COB integrated lens, and directly samples the beam through reflection and refraction, so as to realize the power monitoring of the emitted light source without the need for additional independent beam splitting elements; in addition, it uses a beam splitter to separate beams of different wavelengths, and completes bidirectional transmission of optical signals using the same lens structure. The structure is compact, has fewer assembly steps, and is easy to mass-produce.

[0029] Furthermore, the angle between the total reflection surface 15 and the horizontal direction is... And satisfy .

[0030] Furthermore, the angle between the first refractive surface 12 and the horizontal direction is... And satisfy .

[0031] Furthermore, the angle between the third refractive surface 17 and the horizontal direction is... And satisfy The angle between the second refractive surface 16 and the horizontal direction is... And satisfy .

[0032] By setting a second and third refractive surface in conjunction with a total reflection surface to form a multi-stage optical path steering structure, the monitoring beam split from the first refractive surface is guided to the MPD detector. The above optical surfaces are integrated into the COB integrated lens body, eliminating the need for additional reflective elements and reducing the number of parts. By adjusting the propagation path of the monitoring beam through multi-stage refraction, the installation position of the MPD detector is adapted, optimizing the overall layout of the device, reducing the system size, and ensuring that the sampling beam is stably incident on the MPD detector, thus ensuring the accuracy of light source power monitoring.

[0033] Specifically, the emitted beam refracted by the first refractive surface 12 is a horizontal beam; the incident beam transmitted to the MPD detector 4 after total internal reflection by the total internal reflection surface 15 is a vertical beam; when designing the second refractive surface 16, on the one hand, the position and height of the second refractive surface 16 must ensure the integrity of its incident beam; on the other hand, the distance between the lower boundary of the second refractive surface 16 and the boundary of the second light-emitting focusing lens 14 must be greater than 0.2 mm; when designing the third refractive surface 17, on the one hand, the position and height of the third refractive surface 17 must ensure the integrity of its incident beam; on the other hand, the distance between the lower boundary of the third refractive surface 17 and the boundary of the collimating lens 11 must be greater than 0.2 mm; the angle and position design of the second refractive surface 16 and the third refractive surface 17 must ensure that there is no interference between the reflected beam of the total internal reflection surface 15 and the emitted beam of the collimating lens 11.

[0034] Furthermore, the COB integrated lens 1 is provided with a mounting reference surface 18 for mounting the beam splitter 2; the beam splitter 2 is fixed to the mounting reference surface 18, and the angle between the mirror surface of the beam splitter 2 and the mounting reference surface 18 is 45°.

[0035] Specifically, the beam splitter 2 and the mounting reference surface 18 are fixed by edge dispensing. The design of the mounting reference surface 18 and the beam splitter must take into account the interference when dispensing with the mounting reference surface 18. In order to ensure the injection molding process, the mounting reference surface 18 is provided with mounting plates with longitudinal cross sections of isosceles right triangles on the front and rear sides. The edge of the beam splitter is fixed to the two mounting plates. The beam splitter is supported and limited by the mounting plates, so that the middle area of ​​the beam splitter is completely exposed as an effective optical working surface. The top of the beam splitter and the mounting reference surface 18 are fixed by dispensing.

[0036] Reference Figure 2 Furthermore, the side of the beam splitter 2 closest to the first refractive surface 12 is... The side of the beam splitter 2 furthest from the first refractive surface 12 is... noodle; A transmissive film is coated on the surface. The transmissive film is used to transmit the light beam that is refracted by the first refractive surface 12 and projected onto the beam splitter 2. A reflective film is coated on the surface to reflect the light beam projected onto the beam splitter 2 after being shaped by the first light-emitting focusing lens 13.

[0037] By setting transmission and reflection films on both sides of the beam splitter, the selective transmission and reflection of beams of different wavelengths are achieved through the film system, distinguishing the uplink transmitted beam from the downlink received beam and ensuring that the bidirectional optical paths do not interfere with each other. The film layers are directly deposited on the surface of the beam splitter substrate, eliminating the need for additional beam splitting elements. Combined with the optical path design, the 850nm uplink beam and the 980nm downlink beam are precisely separated, reducing crosstalk, ensuring signal transmission and reception quality, and helping to maintain a high optical coupling efficiency of the system.

[0038] Specifically, the transmission film 21 allows an 850nm light beam to pass through, while the reflection film 22 reflects a 980nm light beam; the light beam incident on the reflection film is reflected and then projected onto the second light-emitting focusing lens. Surface transmittance > 99%, Surface reflectivity > 99%.

[0039] Reference Figure 3 Furthermore, the back focal length of the first light-emitting focusing lens 13 is... The back focal length of collimating lens 11 is The back focal length of the second light-emitting focusing lens 14 is Then it satisfies , .

[0040] Furthermore, the collimating lens 11, the first light-emitting focusing lens 13, and the second light-emitting focusing lens 14 are all integrally formed on the COB integrated lens 1.

[0041] Furthermore, the collimating lens 11, the first light-emitting focusing lens 13, and the second light-emitting focusing lens 14 are all plano-convex aspherical lenses.

[0042] Furthermore, there can be one or more lens mechanisms, which can be flexibly selected according to the actual application scenario. When using a single lens mechanism, the system structure is simplified and occupies little space, making it suitable for compact optical modules; when configuring multiple lens mechanisms, the multiple lens mechanisms are arranged in an array, and multiple lens mechanisms can realize parallel transmission and reception of multiple optical signals and synchronous monitoring of light source power, thereby expanding the number of channels.

[0043] Specifically, the COB integrated lens is manufactured using injection molding, with ULTEM1010 as the preferred material; the beam splitter is preferably made of K9 material; the beam splitter and COB integrated lens are bonded together using UV thermosetting adhesive; the VCSEL laser, MPD detector, PD detector, and related signal processing electronic components are all encapsulated on the PCB board; finally, the single-fiber bidirectional lens system is electrically coupled to the PCB, and fixed after successful coupling.

[0044] Specifically, this application provides the following implementation examples to address practical problems: For the 1310nm band, an 850nm VCSEL chip is used, with a light-emitting aperture of 10μm and a light source NA=0.5; the matching optical fiber NA=0.2 and a core diameter of 50μm, and the working distance of the uplink 850nm optical path L2=0.36mm, which is designed in conjunction with the VCSEL divergence angle and the 13-aperture first light-emitting focusing lens; the receiving surface size of the downlink 980nm optical path PD detector is 40μm.

[0045] In the COB integrated lens, the back focal length ratio of the first light-emitting focusing lens 13 and the collimating lens 11 is: , If it is 1.8mm, then <1.8mm; the laser and PD detector are on the same PCB board and the height difference is <50μm. In the COB integrated lens, the collimating lens 11 and the second light-emitting focusing lens 14 are on the same injection molding surface and the injection molding height difference is <100μm. Considering all the above, the back focal length of the collimating lens 11 is approximately equal to the back focal length of the second light-emitting focusing lens 14.

[0046] In the COB integrated lens, the back focal length ratio of the first light-emitting focusing lens 13 and the second light-emitting focusing lens 14 in the down-going optical path is: ,but = =0.36mm, then =0.45mm; In the downlink optical path, the multimode fiber output beam shrinks to a surface area of ​​40μm. At a certain time, A larger spot size is more conducive to spot compression; therefore >0.45mm, this example is obtained after system optimization. =0.75mm.

[0047] Reference Figure 7 and Figure 8 In this embodiment, the collimating lens, the first light-emitting focusing lens, and the second light-emitting focusing lens are all plano-convex aspherical lenses. The overall structure is biconvex with positive diopter, simple structure, and high coupling efficiency. Experiments have shown that the coupling efficiency of this system can reach more than 90%, with a coupling flat region of ±10μm in the 850nm uplink optical path and ±8μm in the 980nm downlink optical path.

[0048] Reference Figure 4 The COB integrated lens is manufactured using injection molding, with ULTEM1010 as the preferred material; its refractive index is 1.639. A normal is drawn on the total reflection surface 15, and the angle between the normal and the incident light is [value missing]. The angle between the normal and the emitted light is Calculated according to the total internal reflection condition: To achieve total internal reflection, then =90°, air refractive index =1, then 1.639 =1, where Inclination angle with total reflection surface 15 Related, = =arcsin(1 / 1.639)=39°, in order to ensure that the collimated beam achieves total internal reflection at the total reflection surface 15, then = >39°.

[0049] Furthermore, the first refracting surface 12 and the total reflection surface 15 together ensure that the refracted light beam after passing through the first refracting surface 12 is horizontally incident, and the tilt angle of the first refracting surface 12... The angle of refraction of the refracted beam with the first refraction surface 12 The relationship is The refracted rays from the first refractive surface 12 must obey the law of refraction. The incident rays from the first refractive surface 12 also interact with the rays from the total internal reflection surface. Related, and = = After optimization, the tilt angle of the total reflection surface 15° was... =48°, the tilt angle of the first refractive surface 12 The tilt angle of the second refractive surface 16 The tilt angle of the third refractive surface 17 is 131°. The angle is 77°, and the optical simulation diagram is as follows: Figure 5 and Figure 6 As shown.

[0050] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A single-fiber bidirectional lens system with emission source power monitoring function, characterized in that, The lens mechanism includes a COB integrated lens and an MPD detector, a VCSEL laser, and a PD detector, all mounted on an external mounting surface and located within the COB integrated lens. The COB integrated lens is integrally injection molded. The COB integrated lens is equipped with a beam splitter and multimode fiber. The COB integrated lens integrates a collimating lens, a first refractive surface, a first light-emitting focusing lens, a second light-emitting focusing lens, a total reflection surface, a second refractive surface, and a third refractive surface. The VCSEL laser emits a beam that is incident on a collimating lens. After being collimated by the collimating lens, the beam is formed into a parallel beam and projected onto a total reflection surface. After total reflection by the total reflection surface, the beam is projected onto a first refractive surface. The first refractive surface reflects and refracts the incident parallel beam. The beam reflected by the first refractive surface is transmitted to a second refractive surface, refracted by the second refractive surface, and projected onto a third refractive surface. After refraction by the third refractive surface, the beam is projected onto a total reflection surface, and after total reflection by the total reflection surface, it is transmitted to an MPD detector. The MPD detector receives the beam and monitors the emission power of the VCSEL laser. The beam refracted by the first refractive surface is projected onto a beam splitter, transmitted through the beam splitter, and then incident on a first exit focusing lens. After being focused by the first exit focusing lens, the beam is coupled to a multimode fiber. The multimode optical fiber is used to direct the received beam back to the first beam-emitting focusing lens. After being shaped into a collimated parallel beam by the first beam-emitting focusing lens, the beam is projected onto the beam splitter. After being reflected by the beam splitter, the beam is directed to the second beam-emitting focusing lens. After being focused by the second beam-emitting focusing lens, the beam is projected onto the PD detector. The PD detector is used to receive the beam and convert the optical signal into an electrical signal to receive external optical communication signals.

2. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The angle between the total reflection surface and the horizontal direction is And satisfy .

3. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The angle between the first refracting surface and the horizontal direction is And satisfy .

4. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The angle between the third refractive surface and the horizontal direction is And satisfy The angle between the second refracting surface and the horizontal direction is... And satisfy .

5. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The COB integrated lens has a mounting reference surface for mounting a beam splitter; the beam splitter is fixed to the mounting reference surface, and the angle between the mirror surface of the beam splitter and the mounting reference surface is 45°.

6. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The side of the beam splitter closest to the first refractive surface is The side of the beam splitter that is furthest from the first refractive surface is... noodle; The A transmissive film is coated on the surface, the transmissive film being used to transmit the light beam projected onto the beam splitter after being refracted by the first refractive surface; The A reflective film is coated on the surface, which is used to reflect the light beam projected onto the beam splitter after being shaped by the first light-emitting focusing lens.

7. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The back focal length of the first light-emitting focusing lens is The back focal length of the collimating lens is The back focal length of the second light-emitting focusing lens is Then it satisfies , .

8. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The collimating lens, the first light-emitting focusing lens, and the second light-emitting focusing lens are all integrally formed on the COB integrated lens.

9. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The collimating lens, the first light-emitting focusing lens, and the second light-emitting focusing lens are all plano-convex aspherical lenses.

10. The single-fiber bidirectional lens system with emission source power monitoring function as described in claim 1, characterized in that, The lens mechanism may be one or more.

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