Partitioned coupling optical path device applied to high-speed optical module

Abstract

The utility model discloses a partition coupling optical path device applied to a high-speed optical module, which is an optical path structure of a channel of the high-speed optical module and comprises the following structures: a multimode VCSEL (Vertical Cavity Surface Emitting Laser), a first coupling lens, a second coupling lens, a multimode optical fiber and a coupling optical path. The utility model relates to the technical field of optical communication, in particular to a partition coupling optical path device applied to a high-speed optical module, which is used for carrying out annular partition independent optimization design on surface type parameters of a lens in an optical path, so that the coupling efficiency at a small emission angle is reduced, the coupling efficiency at a large emission angle is improved, and the coupling efficiency at a high emission angle is improved. According to the multi-mode VCSEL laser, the coupling efficiency difference at large and small emission angles is increased, the driving current difference at corresponding large and small emission angles is reduced, the modulation bandwidth of the multi-mode VCSEL laser is improved, and the signal stability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical communication, and in particular to a partition coupling optical path device applied to a high-speed optical module. Background Art

[0002] High-speed optical modules are key components of optical communication systems. They emit optical signals through lasers and transmit them through optical fibers. The selection of lasers is crucial to the performance of high-speed optical modules. Among them, vertical cavity surface emitting lasers (VCSELs) have the advantages of low threshold current, high conversion efficiency, and high pulse bandwidth, making them suitable optical components for high-speed optical modules.

[0003] With the rapid development of artificial intelligence technologies such as large models, large-scale applications of artificial intelligence have put forward higher and higher demands on computing power. Therefore, the high-speed data connection between artificial intelligence servers has put forward higher and higher requirements on optical modules. In particular, high-speed optical modules above 400G and 800G are quickly becoming mainstream products in the market.

[0004] In high-speed optical modules, a multi-channel parallel solution is adopted, in which each single channel emits an optical signal from a laser and transmits it through an optical fiber. Due to the high communication rate of a single channel, high requirements are placed on the performance of the laser. Existing VCSEL lasers are divided into two types: single-mode and multi-mode. Among them, multi-mode VCSEL lasers are more commonly used. The optical signal emitted by the multi-mode VCSEL laser enters the multi-mode optical fiber through the coupling optical path and is transmitted to the high-speed optical module receiving light detector at the opposite port.

[0005] In practical applications, the higher the communication rate of a high-speed optical module, the greater the modulation bandwidth of the multimode VCSEL laser in each channel, and the greater the dynamic range of modulating the multimode VCSEL laser drive current. Since the change of the multimode VCSEL laser drive current directly affects the intensity and emission angle of the multimode VCSEL laser optical signal, the increase in the dynamic range of the drive current makes the dynamic characteristics of the multimode VCSEL laser optical signal more complex, which places higher requirements on optical path coupling.

[0006] In the existing technical solutions, the coupling lenses are mostly made of the same material. In the optical path coupling process, although a certain coupling effect can be achieved, the optical path coupling effect is poor for a large range of multi-mode VCSEL lasers in high-speed optical modules.

[0007] For multi-mode VCSEL lasers, in the linear modulation range, if they are to work well under both high current and low current light intensity conditions, the current difference between high current and low current is required to be as small as possible. The smaller the difference, the larger the frequency bandwidth of amplitude modulation and the better the signal quality. In other words, the coupling efficiency is required to be high at high current and low at low current, so that the light intensity difference can be met while ensuring that the difference between high current and low current is smaller.

[0008] The prior art has a solution to adjust the photoelectric conversion component to adapt to the optical path coupling, for example: "A 4-channel external modulation electro-optical conversion component based on photoelectric hybrid integration" with publication number CN115134002B discloses an integrated design solution for photoelectric conversion components to improve the efficiency of laser current modulation. In addition, the optical path coupling is set to adapt to current modulation, for example: "Optical passive module, optical module and communication equipment" with publication number CN117538996A discloses that the mode dispersion of the VCSEL light source in the multimode optical fiber is reduced by a vortex lens group, thereby increasing the transmission distance of the VCSEL light source in the multimode optical fiber. Although this solution only records the optical passive module and does not involve the current modulation technology for the VCSEL laser, the optical path optimization of this technical solution is also conducive to optimizing the current modulation technology according to the optical path characteristics. Utility Model Content

[0009] The technical solution provided by the utility model is to set up an annular partitioned coupling optical path device to perform annular partitioning and independent optimization design on the surface parameters of the lens in the optical path, thereby reducing the coupling efficiency at small emission angles, improving the coupling efficiency at large emission angles, increasing the difference in coupling efficiency at large and small emission angles, reducing the difference in driving current at corresponding large and small emission angles, improving the modulation bandwidth of the multi-mode VCSEL laser, and increasing signal stability.

[0010] In order to solve the above technical problems, the technical solution adopted by the utility model is as follows: the utility model proposes a partitioned coupling optical path device applied to a high-speed optical module, which is an optical path structure of a channel of the high-speed optical module, including the following structures: a multi-mode VCSEL laser, a first coupling lens, a second coupling lens, a multi-mode optical fiber, and a coupling optical path; the multi-mode VCSEL laser is the light output end of the coupling optical path, and the multi-mode optical fiber is the receiving end of the coupling optical path. The first coupling lens is close to the multi-mode VCSEL laser, and converts the light emitted by the multi-mode VCSEL laser into approximately collimated parallel light, which enters the multi-mode optical fiber after passing through the second coupling lens, thereby realizing the transmission coupling of the optical signal of the multi-mode VCSEL laser to the multi-mode optical fiber.

[0011] Preferably, the central wavelength range of the multimode VCSEL laser is set to 850nm, 880nm, 910nm and 940nm, the numerical aperture of the multimode VCSEL laser is set between 0.2 and 0.3, and the oxidation aperture of the light output point of the multimode VCSEL laser is between 5μm and 10μm.

[0012] Preferably, the core diameter of the multimode optical fiber is 50 μm and the numerical aperture is set between 0.18 and 0.24.

[0013] Preferably, the numerical aperture of the multimode optical fiber is set to 0.22.

[0014] Preferably, the first coupling lens and the second coupling lens have a ring-shaped partitioned structure to achieve coupling efficiency of the multi-mode VCSEL laser under different current modulation conditions.

[0015] Preferably, the first coupling lens is divided into m annular partitions, and the corresponding radii are r11, r12, ..., r1m; similarly, the second coupling lens is divided into n annular partitions, and the corresponding radii are r21, r22, ..., r2n. The coupling efficiency of the first coupling lens and the second coupling lens can be designed independently.

[0016] Preferably, when the first coupling lens and the second coupling lens are aspheric lenses, the curvature coefficient and the quadratic Conic coefficient of the optical aspheric radius are independently designed within the range of an annular partition of the first coupling lens and the second coupling lens, and the four optical parameters form a pair of optical systems with independent coupling efficiency. Multiple pairs of annular partitions of the first coupling lens and the second coupling lens can form corresponding coupling efficiencies respectively, so that the annular partitions change continuously, thereby realizing independent regulation of the coupling efficiency of incident light at different emission angles of the multi-mode VCSEL laser.

[0017] The working principle of the partition coupling optical path device applied to the high-speed optical module is as follows:

[0018] 1. After the communication signal is modulated by the excitation circuit, an excitation current is generated to drive the multi-mode VCSEL laser to emit laser;

[0019] 2. According to the different code types of the communication signal: high-density code type signal and low-density code type signal, the output excitation current will also generate a large driving current and a small driving current, so that the multi-mode VCSEL laser emits a large emission angle incident light and a small emission angle incident light, which enter the large emission angle annular partition and the small emission angle annular partition respectively, and are coupled along the large emission angle coupling optical path and the small emission angle coupling optical path respectively;

[0020] 3. The coupling efficiency of each pair of annular partitions is designed independently, and the coupling efficiency of the multi-mode VCSEL laser incident light with a large emission angle is achieved by optimizing the design to be higher than the coupling efficiency of the incident light with a small emission angle.

[0021] Compared with the prior art, the utility model produces beneficial technical effects including: without changing the overall optical path of the existing high-speed optical module and the current driving mode of the multi-mode VCSEL laser, by setting an annular partitioned coupling optical path device, the surface parameters of the lens in the optical path are independently optimized by annular partitioning, thereby reducing the coupling efficiency at a small emission angle, improving the coupling efficiency at a large emission angle, increasing the difference in coupling efficiency at large and small emission angles, reducing the difference in driving current at corresponding large and small emission angles, improving the modulation bandwidth of the multi-mode VCSEL laser, and increasing signal stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural diagram of a partitioned coupling optical path device applied to a high-speed optical module provided by the utility model.

[0023] Among them, 100, multimode VCSEL laser, 101, first coupling lens, 102, second coupling lens, 103, multimode optical fiber, 104, coupling optical path, 105, optical center axis, 106, first coupling lens cross section, 107, excitation circuit, 108, communication signal, 109, excitation current, 201, high-density code signal, 202, low-density code signal, 203, large emission angle incident light, 204, small emission angle incident light, 205, large emission angle annular partition, 206, small emission angle annular partition, 207, large emission angle coupling optical path, 208, small emission angle coupling optical path. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and implementation methods. The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other implementation schemes, variations, improvements, equivalent schemes, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0025] like Figure 1 As shown, a structural diagram of a partitioned coupling optical path device applied to a high-speed optical module is an optical path structure of a channel of the high-speed optical module, including the following structures: a multi-mode VCSEL laser 100, a first coupling lens 101, a second coupling lens 102, a multi-mode optical fiber 103, and a coupling optical path 104.

[0026] The multi-mode VCSEL laser 100 is the light output end of the coupling optical path 104 .

[0027] Preferably, the multi-mode VCSEL laser 100 is a multi-mode VCSEL laser with a central wavelength range set to 850 nm, 880 nm, 910 nm and 940 nm.

[0028] Preferably, the numerical aperture of the multi-mode VCSEL laser 100 is set between 0.2 and 0.3.

[0029] Preferably, the oxidation aperture of the light-emitting point of the multi-mode VCSEL laser 100 is between 5 μm and 10 μm.

[0030] The multimode optical fiber 103 is the receiving end of the coupling optical path 104 .

[0031] Preferably, the core diameter of the multimode optical fiber 103 is 50 μm, and the numerical aperture is set between 0.18 and 0.24, preferably 0.22.

[0032] The first coupling lens 101 is close to the multimode VCSEL laser 100 and has the function of converting the light emitted by the multimode VCSEL laser 100 into approximately collimated parallel light, which enters the multimode optical fiber 103 after passing through the second coupling lens 102, thereby realizing the transmission coupling of the optical signal of the multimode VCSEL laser 100 to the multimode optical fiber 103.

[0033] The first coupling lens 101 and the second coupling lens 102 have an annular partition structure to achieve the coupling efficiency of the multi-mode VCSEL laser 100 under different current modulation conditions. Taking the first coupling lens cross section 106 as an example, the optical central axis 105 is taken as the center and divided into annular areas according to different radius sizes. For example, the first coupling lens 101 can be divided into a large emission angle annular partition 205 and a small emission angle annular partition 206. Similarly, the second coupling lens 102 can also perform the same annular partition setting.

[0034] The working principle of the partition coupling optical path device applied to the high-speed optical module is as follows: after the communication signal 108 is modulated by the excitation circuit 107, an excitation current 109 is generated to drive the multi-mode VCSEL laser 100 to emit laser. According to the different code types of the communication signal 108: high-density code type signal 201 and low-density code type signal 202, the output excitation current 109 will also generate a large driving current and a small driving current, so that the multi-mode VCSEL laser 100 emits a large emission angle incident light 203 and a small emission angle incident light 204, which enter the large emission angle annular partition 205 and the small emission angle annular partition 206 respectively, and are coupled along the large emission angle coupling optical path 207 and the small emission angle coupling optical path 208 respectively.

[0035] The large emission angle annular partition 205 and the small emission angle annular partition 206 are annular partitions of different radius sizes centered on the optical central axis 105 of the coupling optical path 104. Each specific radius size and the number of annular areas can be determined according to the emission angle and coupling efficiency requirements of the specific multi-mode VCSEL laser 100. This embodiment only illustrates the two annular partitions of the large emission angle annular partition 205 and the small emission angle annular partition 206.

[0036] In practical applications, a more general embodiment can divide the first coupling lens 101 into m annular partitions, and the corresponding radii are r11, r12, ..., r1m; similarly, the second coupling lens 102 can also be divided into n annular partitions, and the corresponding radii are r21, r22, ..., r2n.

[0037] When the annular partition radius of the first coupling lens 101 is small, such as within the radius r11 range, it can be considered that the area corresponding to the small emission angle coupling optical path 208 of the multi-mode VCSEL laser 100 with a small emission angle incident light 204 passes through, and this part of the light is transmitted to the second coupling lens 102, and the corresponding annular partition radius is also small, such as within the radius r21 range. Then, the radius r11 of the first coupling lens 101 to the radius r21 of the second coupling lens 102 corresponds to the optical path range of the multi-mode VCSEL laser 100 when the driving current is relatively small.

[0038] The coupling efficiency of the first coupling lens 101 and the second coupling lens 102 can be designed independently. Taking both aspheric lenses as an example, within the range of r11, the curvature coefficient of the optical aspheric radius is R11, and the quadratic Conic coefficient is C11; within the range of r21, the curvature coefficient of the optical aspheric radius is R21, and the quadratic Conic coefficient is C21; then these four optical parameters (R11, C11, R21, C21) form a pair of optical systems CE1 with independent coupling efficiency.

[0039] When the driving current of the multi-mode VCSEL laser 100 increases, the divergence angle of its divergent light will increase, and the size of the light spot at the first coupling lens 101 will be larger than the radius r11. For example, when the radius r12 is reached, there will be optical aspheric parameters R12 and C12 in the annular area between the radii r12 and r11, and there will also be optical aspheric parameters R22 and C22 corresponding to the annular partition between the radii r22 and r21 on the second coupling lens 102. These four optical parameters (R12, C12, R22, C22) can also form a pair of optical systems CE2 with independent coupling efficiency.

[0040] Since CE1 and CE2 are designed independently, the design can be optimized so that CE2 is greater than CE1, thereby achieving a higher coupling efficiency when the incident light 203 at a large emission angle of the multi-mode VCSEL laser 100 is incident than the coupling efficiency when the incident light 204 at a small emission angle.

[0041] With this design method, respective coupling efficiencies can be formed between the multiple pairs of annular partitions of the first coupling lens 101 and the second coupling lens 102. For example, r1m and r2n can form an optical system CEm with independent coupling efficiency, so that CE1, CE2, ..., CEm can change continuously, thereby realizing independent regulation of the coupling efficiency of incident light of different emission angles of the multi-mode VCSEL laser 100.

[0042] This embodiment only shows the case of two coupling lenses. However, in the case of more than two coupling lenses, the use of the annular partitioning technology described in the present invention for multi-stage coupling should be regarded as a variation of the present invention and fall within the scope of protection.

[0043] For example, the function of any coupling lens in this embodiment can be further disassembled into two coupling lenses. For example, the first coupling lens 101 close to the multi-mode VCSEL laser 100 has the function of converting the light emitted by the multi-mode VCSEL laser 100 into approximately collimated parallel light. This function can be further disassembled into two coupling lenses, which first focus the light and then convert it into parallel light.

[0044] In addition, the presence of a refraction interface and an emission interface in the coupling optical path 104 does not affect the realization of the functions of the two coupling lenses, and thus does not affect the validity of the utility model. They should be regarded as variations of the utility model and fall within the scope of protection.

[0045] In this embodiment, the letters m and n used to describe the number of annular subareas of the first coupling lens 101 and the second coupling lens 102 are both positive integers greater than or equal to 2, but do not have to be equal.

[0046] There is no specific limitation on the material of the first coupling lens 101 and the second coupling lens 102, which can be optical plastics, such as PEI material, or glass or silicon curved lens, or binary metasurface lens.

[0047] In the embodiment, the surface parameters of the annular partitions of the first coupling lens 101 and the second coupling lens 102, taking the aspheric parameters R and C as an example, do not mean that the aspheric surface can only use these two parameters, but that more orders of parameters can be used; other optical surface types, such as spiral phase surface, DOE diffraction lens or binary optical metasurface diffraction lens, can also be used. As long as the annular partitions are performed and independently coupled, and the key parameters of each annular partition are independently characterized, they should be regarded as extensions of the core of the present invention.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0049] The above description of the utility model and its implementation methods is not restrictive. The drawings show only one implementation method of the utility model, and the actual structure is not limited thereto. In short, if ordinary technicians in this field are inspired by it and design structural methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention of the utility model, they should all fall within the protection scope of the utility model.

Claims

1. A partitioned coupling optical path device applied to a high-speed optical module, characterized in that: The invention comprises the following structures: a multimode VCSEL laser, a first coupling lens, a second coupling lens, a multimode optical fiber, and a coupling optical path; the multimode VCSEL laser is the light output end of the coupling optical path, the multimode optical fiber is the receiving end of the coupling optical path, the first coupling lens is close to the multimode VCSEL laser, and converts the light emitted by the multimode VCSEL laser into approximately collimated parallel light, which enters the multimode optical fiber after passing through the second coupling lens, thereby realizing the transmission coupling of the optical signal of the multimode VCSEL laser to the multimode optical fiber.

2. According to claim 1, a partitioned coupling optical path device for a high-speed optical module is characterized in that: The central wavelength range of the multi-mode VCSEL laser is set to 850nm, 880nm, 910nm and 940nm, the numerical aperture of the multi-mode VCSEL laser is set between 0.2 and 0.3, and the oxidation aperture of the light output point of the multi-mode VCSEL laser is between 5μm and 10μm.

3. According to claim 1, a partitioned coupling optical path device for a high-speed optical module is characterized in that: The core diameter of the multimode optical fiber is 50 μm, and the numerical aperture is set between 0.18 and 0.

24.

4. According to claim 3, a partitioned coupling optical path device applied to a high-speed optical module is characterized in that: The numerical aperture of the multimode optical fiber is set to 0.

22.

5. According to claim 1, a partitioned coupling optical path device for a high-speed optical module is characterized in that: The first coupling lens and the second coupling lens have a ring-shaped partitioned structure, so as to achieve coupling efficiency of the multi-mode VCSEL laser under different current modulation conditions.

6. According to claim 1, a partitioned coupling optical path device for a high-speed optical module is characterized in that: The first coupling lens is divided into m annular partitions, and the corresponding radii are r11, r12, ..., r1m; similarly, the second coupling lens is divided into n annular partitions, and the corresponding radii are r21, r22, ..., r2n. The coupling efficiency of the first coupling lens and the second coupling lens can be designed independently.

7. The partitioned coupling optical path device for a high-speed optical module according to claim 6, characterized in that: When the first coupling lens and the second coupling lens are aspheric lenses, the curvature coefficient and the quadratic Conic coefficient of the optical aspheric radius are independently designed within the range of an annular partition of the first coupling lens and the second coupling lens, and the four optical parameters form a pair of optical systems with independent coupling efficiency. Multiple pairs of annular partitions of the first coupling lens and the second coupling lens can form respective coupling efficiencies correspondingly, so that the annular partitions change continuously, thereby realizing independent regulation of the coupling efficiency of incident light at different emission angles of the multi-mode VCSEL laser.

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