Communication and power delivery vehicle-mounted multimode optical fiber

Abstract

This invention relates to a vehicle-mounted multimode optical fiber for communication and power transmission, comprising a core layer and a cladding layer. The core layer has a parabolic refractive index profile. The core layer is characterized by a distribution index α of 2.3–2.7, a core radius R1 of 20–32 μm, and a maximum relative refractive index difference Δ at the core center. 1max The relative refractive index is 0.8%–1.4%, and the relative refractive index difference Δ1 at the core edge R1 is -0.05%–0.05%. The cladding, from the inside out, consists of a first inner cladding, a first depressed cladding, a second inner cladding, a second depressed cladding, and an outer cladding. This invention improves the bandwidth performance of multimode fiber and enhances its differential mode delay (DMD) performance by optimizing the cross-sectional structure design and the amount of multi-element doping. It also reduces the fiber's bandwidth-wavelength sensitivity, achieving both optimized optical transmission bandwidth performance and improved fiber bending insensitivity; thus realizing the integration of high-speed communication and fiber power transmission.

Description

Technical Field

[0001] This invention relates to a vehicle-mounted multimode optical fiber for communication and power transmission. This optical fiber has excellent performance in integrating high-speed communication and power transmission, and also has characteristics such as high bandwidth and strong bending resistance. It belongs to the field of automotive communication technology. Background Technology

[0002] In recent years, with the development of intelligent vehicles, the safety and driver assistance systems integrated into automotive electronic systems have deployed numerous sensors and processors within the vehicle. This necessitates higher-capacity data networks to support data exchange between these devices. In particular, for future autonomous vehicles, the sheer volume of data exchange between these sensors—including multiple LiDARs, millimeter-wave radars, high-definition cameras, and vehicle positioning systems—and the onboard computer is enormous. Traditional automotive systems, which primarily rely on copper cables for data transmission, struggle to meet the demands of high-capacity data transmission.

[0003] However, the next generation of mainstream automotive electronic networks is mainly based on Time Sensitive Network (TSN) architecture and switched Ethernet architecture, introducing time synchronization and time triggering mechanisms to provide high-capacity, low-latency in-vehicle network systems for automotive electronic systems. In this switched network, devices are interconnected through switches to achieve point-to-point data exchange.

[0004] Currently, cable switches are commonly used in automotive electronics, but the next generation of in-vehicle switches is evolving towards fiber optic switches. These fiber optic switches offer advantages over cable transmission, including greater capacity per single medium, lower power consumption, and stronger electromagnetic compatibility. This facilitates the integration of high-speed vehicle communication and power transmission, enabling a streamlined in-vehicle wiring system that improves the in-vehicle electromagnetic environment. Consequently, they are more suitable for space-constrained, high-density wiring systems like automotive electronics. In contrast, traditional copper cables occupy a large amount of space and are significantly limited by the confined space of automotive systems. Furthermore, copper cables suffer from insufficient capacity and lack power transmission capabilities, and are susceptible to the effects of bends and narrow passageways.

[0005] Driven by the evolving demands of automotive intelligent electronic systems, optical fibers require high coupling and transmission efficiencies while simultaneously enabling high-capacity data communication. Fiber optic transmission efficiencies can reach over 95%, enabling high-power laser transmission with excellent stability. Under long-term operating conditions, the temperature of fiber optic patch cord connectors should remain below 45°C, maintaining stable transmission efficiency. Existing multimode fibers only meet the requirements for low-power transmission, and in practical applications, the photoelectric power conversion efficiency in optical modules is often lower than 20%. Chinese Patent 201310435892.3 describes a large-core-diameter, bend-insensitive multimode fiber with a germanium-doped core and a graded refractive index profile. This fiber improves its bend resistance through a cladding with a refractive index dip. However, germanium doping in the core alters the material properties of the core layer, lowering the laser damage threshold, which is detrimental to medium-to-high power laser energy transmission. In this patent, the invented fiber is only suitable for power transmission below 100W. The patent does not describe the application effects of the invented fiber's bandwidth performance or its high-speed communication performance.

[0006] Chinese patent 201210221499.X describes a power transmission optical fiber for industrial control, medical and other fields. The glass portion of this optical fiber is made of low-hydroxyl high-purity quartz. A low-refractive-index coating with a specific composition ratio is coated on the surface of the quartz, thereby enabling the optical fiber to achieve a high numerical aperture, increasing the core's receiving angle, and playing a role in transmitting energy and simplifying the optical path system. This type of power transmission optical fiber can provide convenient and efficient coupling operation. However, the disadvantages are that the low-refractive-index coating is expensive, and under the same environmental conditions, the coating layer is prone to heating when transmitting higher energy, which can cause the low-refractive-index coating to soften or even burn out, leading to optical fiber failure. In addition, the optical fiber of this type of structure also has poor bending insensitivity.

[0007] Studies have shown that when the refractive index profile of a multimode fiber is constant, it often exhibits high bandwidth performance only for a specific wavelength window. When the application window of the fiber shifts to a larger or smaller wavelength, the bandwidth performance will significantly decrease. Therefore, from an application perspective, it is necessary to improve the design of multimode fibers to ensure that they are compatible with existing OM3 / OM4 multimode fibers, have low bandwidth-wavelength sensitivity to meet the application requirements of WDM technology within a certain wavelength range, and also possess excellent bending resistance and high optical transmission efficiency to adapt to the new demands of transmission technology advancements on multimode power transmission fibers.

[0008] Therefore, when designing the refractive index profile of high-bandwidth, bend-resistant multimode power transmission fibers, a method is used to add low-refractive-index regions to the fiber cladding to limit the leakage of higher-order modes and minimize signal loss. However, the introduction of a depressed cladding causes changes in the propagation constants of higher-order modes near the core edge, increasing the modal dispersion of the fiber. Furthermore, multimode power transmission fibers inevitably experience varying degrees of bending during use. When the fiber is subjected to significant bending stress for extended periods, its lifespan will inevitably be reduced, and transmission performance will deteriorate. Summary of the Invention

[0009] To facilitate the explanation of this invention, some terms are defined as follows:

[0010] Liner: A high-purity glass tube used in the preparation of mandrels;

[0011] Mandrel: A prefabricated component containing a core layer and a partial cladding layer;

[0012] Radius: The distance between the outer boundary of this layer and the center point;

[0013] Core layer: The central part of the optical fiber's cross-section, i.e., the main light-guiding area of ​​the optical fiber;

[0014] Cladding: Includes inner cladding and outer cladding. The former refers to the annular region in the cross-section of the optical fiber that is immediately adjacent to the core, while the latter refers to the annular region in the cross-section of the optical fiber that is immediately adjacent to the inner cladding.

[0015] Refractive index profile: The relationship between the refractive index of glass and its radius in an optical fiber or optical fiber preform (including the core rod), i.e., the α profile, which satisfies the following power-law function of refractive index distribution:

[0016]

[0017] Where n1 is the refractive index of the fiber axis; r is the distance from the fiber axis; a is the fiber core radius; α is the distribution index; and Δ0 is the refractive index of the core center relative to the cladding.

[0018] Relative refractive index: i.e., Δ i :

[0019]

[0020] Where, n i n is the refractive index at a distance i from the center of the fiber core; n0 is the minimum refractive index of the fiber core layer, usually the refractive index of the fiber cladding, and generally the refractive index of pure silicon dioxide.

[0021] Numerical aperture: NA = n0 * (Δ1 - Δ2) 1 / 2 =n0*(2Δ) 1 / 2 .

[0022] The contribution of fluorine (F): The difference in refractive index (ΔF) between fluorine-doped (F) quartz glass and pure quartz glass, which represents the amount of fluorine (F) doping.

[0023] Germanium (Ge) contribution: The amount of germanium (Ge) doping is expressed by the difference in refractive index (ΔGe) between germanium-doped quartz glass and pure quartz glass.

[0024] Patch cord: A fiber optic connector made from fiber optic matching connectors.

[0025] The technical problem to be solved by the present invention is to provide a vehicle-mounted multimode optical fiber for communication and power transmission, which not only has excellent performance in integrating high-speed communication and power transmission, but also has high bandwidth, strong bending resistance and stable performance.

[0026] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows:

[0027] It includes a core layer and a cladding layer. The refractive index profile of the core layer is parabolic (α-power function distribution). Its characteristics include a core layer distribution index α of 2.3–2.7, a core layer radius R1 of 20–32 μm, and a maximum relative refractive index difference Δ at the center of the core layer. 1max The relative refractive index is 0.8–1.4%, and the relative refractive index difference Δ1 at the core edge R1 is -0.05–0.05%. The cladding layers, from the inside out, are a first inner cladding, a first recessed cladding, a second inner cladding, a second recessed cladding, and an outer cladding. The single-sided width (R2–R1) of the first inner cladding is 0.2–2.0 μm, and the relative refractive index difference Δ2 of the first inner cladding is -0.08–0.02%. The single-sided width (R3–R2) of the first recessed cladding is 2.0–8.0 μm, and the relative refractive index difference Δ3 of the first recessed cladding is... The second inner cladding layer has a single-side width (R4-R3) of 3-10 μm and a relative refractive index difference Δ4 of -0.07-0.07%. The second recessed cladding layer has a single-side width (R5-R4) of 1.0-10 μm and a relative refractive index difference Δ5 of -1.2-0.4%. The outer cladding layer is a pure silica glass layer or a doped silica glass layer, with an outer cladding layer radius R6 of 60-65 μm and a relative refractive index difference Δ6 of -0.13-0.13%.

[0028] According to the above scheme, the core layer is a silicon dioxide glass layer co-doped with germanium and fluorine (Ge / F), or germanium, phosphorus, and fluorine (Ge / P / F), or germanium, boron, and fluorine (Ge / B / F). Fluorine in the core layer acts as a negative dopant, and the fluorine doping amount increases from the center of the core layer to the edge. The fluorine doping contribution Δ at the center of the core layer is... F0 The contribution of fluorine doping at the core edge is -0.12% to -0.01%, Δ.F1 The range is -0.5% to -0.1%.

[0029] According to the above scheme, the relative refractive index difference Δ2 of the first inner cladding layer is less than or equal to the minimum relative refractive index difference Δ1 at the edge of the core layer, that is, Δ2≤Δ1.

[0030] According to the above scheme, the relative refractive index difference Δ2 of the first inner cladding layer is -0.06 to -0.04%.

[0031] According to the above scheme, the first inner cladding layer is a silicon dioxide glass layer co-doped with germanium, fluorine, and phosphorus, and the radius R2 of the first inner cladding layer is ≥22μm.

[0032] According to the above scheme, the second inner cladding layer is a silicon dioxide glass layer co-doped with germanium, fluorine and phosphorus, the thickness of the second inner cladding layer on one side (R4-R3) is ≥4.5μm, and the phosphorus doping contribution ΔP of the second inner cladding layer is ≤0.10%.

[0033] According to the above scheme, the relative refractive index difference Δ4 of the second inner cladding layer decreases as the radius increases.

[0034] According to the above scheme, the relative refractive index difference Δ4 of the second inner cladding is distributed in a concave curve along the radial direction, and the relative refractive index difference at the inner edge of the second inner cladding is equal to the relative refractive index difference at the outer edge.

[0035] According to the above scheme, the radius R4 of the second inner cladding is ≥40μm, and the relative refractive index difference Δ4 of the second inner cladding is greater than or equal to the relative refractive index difference Δ2 of the first inner cladding, that is, Δ4≥Δ2.

[0036] According to the above scheme, the relative refractive index difference Δ4 of the second inner cladding layer is -0.05% to 0.06%.

[0037] According to the above scheme, the relative refractive index difference Δ5 of the second depressed cladding is less than or equal to the relative refractive index difference Δ3 of the first depressed cladding, that is, Δ3≥Δ5.

[0038] According to the above scheme, the single-sided thickness (R5-R4) of the second recessed cladding layer is greater than or equal to the single-sided thickness (R3-R2) of the first recessed cladding layer.

[0039] According to the above scheme, the ratio of the single-sided thickness of the second recessed cladding layer (R5-R4) to the single-sided thickness of the first recessed cladding layer (R3-R2) ranges from 1 to 1.5.

[0040] According to the above scheme, the outer cladding layer of the doped silica glass layer is a silica glass layer doped with one or more of the following dopants: aluminum, calcium, magnesium, titanium, zirconium, iron, cobalt, nickel, manganese, copper, lithium, sodium, potassium, boron, and chlorine. The doped silica (SiO2) glass layer contains 1 to 50 ppm of aluminum (Al), ≤60 ppm of total metal elements, and 1000 to 2000 ppm of chlorine (Cl).

[0041] According to the above scheme, the numerical aperture of the optical fiber is 0.185 to 0.215.

[0042] According to the above scheme, the DMD Inner Mask (5-18μm) and DMD Outer Mask (0-23μm) of the optical fiber are both less than or equal to 0.30ps / m; the DMD Interval Mask is less than or equal to 0.2ps / m; under preferred conditions, the DMD Inner Mask (5-18μm) and DMD Outer Mask (0-23μm) of the optical fiber are both less than or equal to 0.12ps / m, and the DMD Interval Mask is less than or equal to 0.10ps / m.

[0043] According to the above scheme, the optical fiber has a full injection bandwidth of 3500 MHz·km or more at a wavelength of 850 nm, a full injection bandwidth of 2000 MHz·km or more at a wavelength of 950 nm, and a full injection bandwidth of 500 MHz·km or more at a wavelength of 1300 nm.

[0044] Furthermore, the optical fiber has a full injection bandwidth of 6500 MHz·km or more at a wavelength of 850 nm, a full injection bandwidth of 3500 MHz·km or more at a wavelength of 950 nm, and a full injection bandwidth of 700 MHz·km or more at a wavelength of 1300 nm.

[0045] According to the above scheme, the optical fiber has an effective mode bandwidth of more than 5700 MHz·km at a wavelength of 850nm and an effective mode bandwidth of more than 2500 MHz·km at a wavelength of 953nm.

[0046] Furthermore, the optical fiber has an effective mode bandwidth of 7000 MHz·km or more at a wavelength of 850 nm and an effective mode bandwidth of 2700 MHz·km or more at a wavelength of 953 nm.

[0047] According to the above scheme, the additional bending loss caused by the optical fiber being bent twice with a bending radius of 7.5 mm at a wavelength of 850 nm is less than or equal to 0.1 dB; and the additional bending loss caused by the optical fiber being bent twice with a bending radius of 7.5 mm at a wavelength of 1300 nm is less than or equal to 0.25 dB.

[0048] According to the above scheme, the optical fiber is further processed and then prepared into a patch cord.

[0049] The fabrication process of the optical fiber of this invention is as follows: A high-purity quartz glass liner is clamped and fixed at both ends by rotating chucks on a plasma chemical vapor deposition (PCVD) lathe with a certain rotation angle. The liner is placed in a holding furnace at a certain temperature (typically 1000℃~1200℃) and passes through a high-frequency microwave resonant cavity. The process reactants required for core rod preparation are introduced into the liner in a gaseous form formed by constant temperature and pressure evaporation from one end of the lathe's rotating chuck. A certain amount of germanium is introduced into the reaction gases silicon tetrachloride (SiCl4) and O2. GeCl4, fluorine (C2F6), and phosphorus (POCl3) are doped and deposited in a multi-element doping manner via high-energy plasma excited by a high-frequency microwave resonant cavity, and finally deposited in a glassy state on the inner wall of the liner tube. According to the cross-sectional structure design requirements, the cladding and core layers of the optical fiber are deposited sequentially, and then fused into a solid core rod by a high-temperature (1800℃~2100℃) fusion lathe. After cleaning, etching, and drying, the core rod is combined with a matching ferrule to form a multimode optical fiber preform. The preform is then drawn into an optical fiber by a drawing device.

[0050] The beneficial effects of this invention are as follows: 1. By optimizing the cross-sectional structure design and the amount of multi-element doping, the bandwidth performance of multimode fiber is improved, the differential mode delay (DMD) performance of multimode fiber is enhanced, and the bandwidth-wavelength sensitivity of fiber is reduced, thus optimizing the optical transmission bandwidth performance while improving the fiber's bending insensitivity performance; 2. Through the double inner cladding and double recessed cladding design, the mutual influence between the core layer, the first inner cladding, the first recessed cladding, the second inner cladding, and the second recessed cladding, as well as refractive index distortion caused by diffusion and stress, are avoided; 3. This invention adopts a double inner cladding germanium, fluorine, and phosphorus multi-element doping method, avoiding diffusion between layers caused by differences in dopant element concentrations. The reasonable doping concentration ratio of the inner cladding optimizes the material viscosity matching of the inner cladding and the recessed cladding, improves the smoothness of fiber stress changes, and reduces stress unevenness. The fiber profile distortion caused by this invention is eliminated, thus achieving the integration of high-speed communication and fiber optic power transmission; 4. The fiber of this invention is not only compatible with existing OM3 / OM4 multimode fibers, but also supports wavelength division multiplexing technology in the wavelength range of 850nm to 980nm; 5. The fiber of this invention has high coupling efficiency and transmission efficiency, with a transmission efficiency of over 95%; fiber transmission can achieve laser power transmission in the range of 1W to 400W, and even in the low-power range, it can achieve compatibility with LED light sources; moreover, the fiber has good stability, and under long-term working conditions, the temperature of the fiber optic patch cord connector can be maintained below 45℃, and the transmission efficiency is stable; 6. The manufacturing method of this invention is simple, low-cost, highly feasible and operable, suitable for large-scale production, and applicable to vehicle-mounted optical communication networks, low-power optical energy transmission, and miniaturized optical devices. It can also adapt to the network demands of rapid data traffic growth, and is of great significance for the expansion of applications in the field of optical communication technology. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the radial cross-section structure of an optical fiber according to an embodiment of the present invention.

[0052] Figure 2 This is a schematic diagram of the refractive index profile of the first embodiment of the present invention.

[0053] Figure 3 This is a schematic diagram of the refractive index profile of the second embodiment of the present invention.

[0054] Figure 4 This is a schematic diagram of the refractive index profile of the third embodiment of the present invention.

[0055] Figure 5 This is a schematic diagram of the refractive index profile according to the fourth embodiment of the present invention.

[0056] Figure 6 This is a differential mode delay diagram for a comparative example of the present invention.

[0057] Figure 7This is a differential mode delay diagram according to an embodiment of the present invention. Detailed Implementation

[0058] Specific embodiments will be given below to further illustrate the present invention in detail.

[0059] The optical fiber comprises a core and a cladding. The refractive index profile of the core exhibits a parabolic distribution following an α-power exponential function, with a distribution exponent α ranging from 2.3 to 2.7. The core radius R1 ranges from 20 to 32 μm, and the maximum relative refractive index difference Δ at the center of the core is [missing information]. 1max The relative refractive index is 0.8–1.4%, and the relative refractive index difference Δ1 at the core edge R1 is -0.05–0.05%. The cladding layers, from the inside out, are a first inner cladding, a first recessed cladding, a second inner cladding, a second recessed cladding, and an outer cladding. The single-sided width (R2–R1) of the first inner cladding is 0.2–2.0 μm, and the relative refractive index difference Δ2 of the first inner cladding is -0.08–0.02%. The single-sided width (R3–R2) of the first recessed cladding is 2.0–8.0 μm, and the relative refractive index difference Δ3 of the first recessed cladding is... The second inner cladding layer has a single-side width (R4-R3) of 3-10 μm and a relative refractive index difference Δ4 of -0.07-0.07%. The second recessed cladding layer has a single-side width (R5-R4) of 1.0-10 μm and a relative refractive index difference Δ5 of -1.2-0.4%. The outer cladding layer is a pure silica glass layer or a doped silica glass layer, with an outer cladding layer radius R6 of 60-65 μm and a relative refractive index difference Δ6 of -0.13-0.13%.

[0060] The core layer of the optical fiber is a silica glass layer co-doped with germanium and fluorine (Ge / F), or germanium, phosphorus and fluorine (Ge / P / F), or germanium, boron and fluorine (Ge / B / F). Multi-doping can effectively reduce the bandwidth sensitivity to wavelength, enabling the optical fiber to have a high bandwidth over a wide wavelength range, thereby improving high-speed communication performance and transmission efficiency.

[0061] The first inner cladding is a silicon dioxide glass layer co-doped with germanium, phosphorus, and fluorine (Ge / P / F), and the relative refractive index difference Δ2 is less than or equal to the minimum relative refractive index difference Δ1 at the edge of the core layer. The radius of the first inner cladding is R2≥22μm, which effectively suppresses the propagation of higher-order modes in the core layer, improves bandwidth stability, and enhances the transmission performance of optical fiber communication.

[0062] The second inner cladding is a germanium, fluorine, and phosphorus co-doped silica glass layer. Its single-sided thickness (R4-R3) is ≥4.5 μm, the phosphorus doping contribution ΔP is ≤0.10%, and the radius R4 is ≥40 μm. The single-sided thickness (R5-R4) of the second recessed cladding is greater than that of the first recessed cladding (R3-R2). Specifically, the ratio of the single-sided thickness (R5-R4) of the second recessed cladding to that of the first recessed cladding (R3-R2) ranges from 1 to 1.5. This alters modal dispersion while exhibiting superior bending resistance. Compared to germanium, phosphorus has a more significant effect on improving glass viscosity. Doping the second inner cladding with phosphorus can significantly reduce its viscosity, improving its viscosity matching with the recessed cladding. The germanium, fluorine, and phosphorus co-doping design effectively improves fiber attenuation and transmission performance, better preventing light leakage under deep-channel conditions and ensuring stable and efficient power transmission.

[0063] The first and second depressed claddings with negative refractive indices can not only improve the mode dispersion of higher-order modes in the core, but also effectively enhance the fiber's resistance to bending.

[0064] According to the present invention, a set of optical fiber preforms were prepared and drawn, and a double-layer coating of multimode optical fiber was adopted, such as double-layer UV-cured acrylic resin. The structural parameters and performance parameters of the optical fiber are shown in Table 1.

[0065] Table 1: Core structure parameters and main performance parameters of optical fibers

[0066]

[0067]

[0068] Macrobending loss is measured according to the FOTP-62 (IEC-60793-1-47) method. The fiber under test is wound with a certain diameter (e.g., 10mm, 15mm, 20mm, 30mm, etc.) once, and then the loop is released. The change in optical power before and after the loop is measured, and this is used as the macrobending loss of the fiber. During the test, an encircled flux injection condition is used. The encircled flux injection condition can be obtained by the following method: a 2-meter-long section of ordinary 50-micron core diameter multimode fiber is fused to the front end of the fiber under test, and a 25mm diameter loop is wound in the middle of this fiber. When full injection light is injected into this fiber, the fiber under test is in the encircled flux injection condition.

[0069] The full injection bandwidth was measured according to the IEC60793-1-41 method, and the test was conducted under full injection conditions.

[0070] Differential mode delay (DMD) was measured according to IEC 60793-1-49. The length of the fiber under test was 1000m ± 20%. A probe single-mode fiber was connected between the fiber under test and the light source to limit the incident light mode to single-mode. The incident light pulse width was less than or equal to 100ps. The light source was incident perpendicularly to the end face of the fiber under test, and the light was scanned radially along the end face. The time difference between the fastest and slowest light pulses reaching the output end of the fiber under test was measured, which is the differential mode delay. At the same time, using these DMD data, calculations were performed to simulate a series of specified input modes to obtain the effective mode bandwidth (EMBc).

[0071] Experiments show that the high-speed communication and power transmission optical fiber manufactured according to the technical solution of this invention, namely, the integrated communication and transmission optical fiber, has good high-speed communication and laser transmission performance in wavelengths of 850nm-980nm and 1060nm. Specifically, the optical fiber has high coupling efficiency and transmission efficiency, with a transmission efficiency of over 95% and a photoelectric conversion efficiency of 20%-30%. The optical fiber can transmit laser power ranging from 1W to 400W, and even achieves compatibility with LED light sources in the low-power range. Furthermore, the optical fiber has good stability; under long-term working conditions, the temperature of the fiber optic patch cord connector can be maintained below 45℃, and the transmission efficiency is stable. The laser parameter settings and transmission test results are shown in Table 2.

[0072] Table 2: Laser parameter settings and transmission test results

[0073]

[0074]

Claims

1. A communication and power transmission vehicle-mounted multimode optical fiber, comprising a core layer and a cladding layer, wherein the refractive index profile of the core layer is parabolic, characterized in that... The core layer distribution index α is 2.3~2.7, the core layer radius R1 is 20~32μm, and the maximum relative refractive index difference Δ at the core layer center is... 1max The relative refractive index is 0.8~1.4%, and the relative refractive index difference Δ1 at the core edge R1 is -0.05~0.05%. The cladding, from the inside out, consists of a first inner cladding, a first recessed cladding, a second inner cladding, a second recessed cladding, and an outer cladding. The single-side width (R2-R1) of the first inner cladding is 0.2~2.0 μm, and the relative refractive index difference Δ2 of the first inner cladding is -0.08~0.02%. The single-side width (R3-R2) of the first recessed cladding is 2.0~8.0 μm, and the relative refractive index difference Δ3 of the first recessed cladding is -1.0~-0.24%. The single-side width (R4-R3) of the second inner cladding is 3~10 μm, and the relative refractive index difference Δ4 of the second inner cladding is -0.07~0.07%. The single-side width (R5-R4) of the second recessed cladding is 1.0~1. The outer cladding layer is a pure silica glass layer or a doped silica glass layer with a radius R6 of 60-65 μm and a relative refractive index difference Δ6 of -0.13-0.13%. The core layer is a germanium-fluorine, or germanium-phosphorus-fluorine, or germanium-boron-fluorine co-doped silica glass layer, with fluorine as a negative dopant, and the fluorine doping amount increases from the center of the core layer to the edge of the core layer. The second inner cladding layer is a germanium-fluorine-phosphorus co-doped silica glass layer, and the relative refractive index difference Δ4 of the second inner cladding layer decreases with the increase of the radius, or the relative refractive index difference Δ4 of the second inner cladding layer is distributed in a concave curve along the radial direction, and the relative refractive index difference at the inner edge of the second inner cladding layer is equal to the relative refractive index difference at the outer edge.

2. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1, characterized in that... Fluorine doping contribution Δ at the core center F0 The contribution of fluorine doping at the core edge is -0.12% to -0.01%, Δ. F1 The value is -0.5% to -0.1%.

3. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The relative refractive index difference Δ2 of the first inner cladding layer is less than or equal to the minimum relative refractive index difference Δ1 at the edge of the core layer, i.e., Δ2≤Δ1.

4. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The relative refractive index difference Δ2 of the first inner cladding layer is -0.06 to -0.04%.

5. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The first inner cladding layer is a silicon dioxide glass layer co-doped with germanium, fluorine, and phosphorus, and the radius R2 of the first inner cladding layer is ≥22μm.

6. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The thickness of the second inner cladding layer on one side (R4-R3) is ≥4.5μm, and the phosphorus doping contribution ΔP of the second inner cladding layer is ≤0.10%.

7. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The radius R4 of the second inner cladding is greater than or equal to the relative refractive index difference Δ4 of the second inner cladding, i.e., Δ4 ≥ Δ2.

8. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The relative refractive index difference Δ4 of the second inner cladding is -0.05% to 0.06%.

9. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The relative refractive index difference Δ5 of the second depressed cladding is less than or equal to the relative refractive index difference Δ3 of the first depressed cladding, i.e., Δ3 ≥ Δ5.

10. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The thickness of the second recessed cladding layer on one side (R5-R4) is greater than or equal to the thickness of the first recessed cladding layer on one side (R3-R2).

11. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 10, characterized in that... The ratio of the single-sided thickness of the second recessed cladding layer (R5-R4) to the single-sided thickness of the first recessed cladding layer (R3-R2) ranges from 1 to 1.

5.

12. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The outer cladding of the doped silica glass layer is a silica glass layer doped with one or more of the following dopants: aluminum, calcium, magnesium, titanium, zirconium, iron, cobalt, nickel, manganese, copper, lithium, sodium, potassium, boron, and chlorine. The doped silica glass layer contains 1 to 50 ppm of aluminum, ≤60 ppm of total metal elements, and 1000 to 2000 ppm of chlorine.

13. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The numerical aperture of the optical fiber is 0.185~0.

215.

14. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1, characterized in that... The DMD InnerMask (5-18μm) and DMD Outer Mask (0-23μm) of the optical fiber are both less than or equal to 0.30 ps / m; the DMD Interval Mask is less than or equal to 0.2 ps / m.

15. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The optical fiber has a wavelength of 3500 nm at 850 nm. Full injection bandwidth and above, with 2000 at a wavelength of 950nm. Full injection bandwidth and above, with 500 at a wavelength of 1300nm. Full injection bandwidth and above.

16. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The optical fiber has a wavelength of 5700 nm at 850 nm. The above effective mode bandwidth has 2500 at a wavelength of 953nm. The above are the effective mode bandwidths.

17. The communication and power transmission vehicle-mounted multimode optical fiber according to claim 1 or 2, characterized in that... The optical fiber has a bending-induced loss of less than or equal to 0.1 dB at a wavelength of 850 nm due to two turns with a bending radius of 7.5 mm; and a bending-induced loss of less than or equal to 0.25 dB at a wavelength of 1300 nm due to two turns with a bending radius of 7.5 mm.

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