Bend-insensitive vehicle-mounted multi-mode energy transfer optical fiber

Abstract

This invention relates to a bend-insensitive automotive multimode power transmission fiber, comprising a core layer and a cladding layer. The core layer has a parabolic refractive index profile, a core layer distribution index α of 2.1–2.4, a core layer radius R1 of 18–30 μm, a maximum relative refractive index difference at the core center of 0.8–1.6%, and a minimum relative refractive index difference at the core edge of -0.18–-0.06%. The cladding layer, 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 refractive index profile of the first inner cladding is a zigzag line with an increasing front and a flat back, and a single-side width (R3–R1) of 0.4–4.0 μm. This invention improves the bandwidth performance and differential mode delay (DMD) performance of the multimode fiber by optimizing the profile structure design and the amount of multi-element doping, and reduces the bandwidth-wavelength sensitivity of the fiber. It achieves both optimized optical transmission bandwidth performance and improved fiber bend insensitivity, realizing the integration of high-speed communication and fiber power transmission.

Description

Technical Field

[0001] This invention relates to a bend-insensitive automotive multimode power transmission optical fiber, which has excellent performance integrating communication and power transmission, and also has characteristics such as high bandwidth and strong bending resistance, belonging 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. This is especially true for future autonomous vehicles, which will be equipped with multiple LiDAR, millimeter-wave radars, high-definition cameras, and vehicle positioning systems. The data exchange between these sensors and the onboard computer is enormous, and traditional automotive systems, which primarily rely on copper cables for 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 should 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, ensuring 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 fiber is only suitable for power transmission below 100W. The patent does not describe the application effects of the 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 difference: 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 bend-insensitive vehicle-mounted multimode power transmission optical fiber that addresses the shortcomings of the existing technology. This optical fiber integrates high-speed communication and power transmission, and not only has the characteristics of high bandwidth and strong bending resistance, but also high transmission efficiency 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. Its characteristics include a core layer distribution index α of 2.1–2.4, a core layer radius R1 of 18–30 μm, and a maximum relative refractive index difference Δ at the center of the core layer. 1max The refractive index is 0.8–1.6%, and the minimum relative refractive index difference Δ1min at the core edge is -0.18–-0.06%. The cladding layers, from the inside out, are a first inner cladding, a first depressed cladding, a second inner cladding, a second depressed cladding, and an outer cladding. The refractive index profile of the first inner cladding is a zigzag line with an increasing front and a flat back, and the single-sided width (R3-R1) is 0.4–4.0 μm, with a relative refractive index difference of -0.24–-0.01%. The single-sided width (R4-R3) of the first depressed cladding is 2.0–8.0 μm. The refractive index difference Δ4 is ​​-1.0 to -0.22%, the single-sided width (R5-R4) of the second inner cladding is 3 to 10 μm, the relative refractive index difference Δ5 is -0.06 to 0.09%, the single-sided width (R6-R5) of the second recessed cladding is 1.0 to 10 μm, the relative refractive index difference Δ6 is -1.0 to -0.3%, and the outer cladding is a pure silica glass layer or a doped silica glass layer, the outer cladding radius R7 is 60 to 65 μm, and the relative refractive index difference Δ7 is -0.12 to 0.15%.

[0028] According to the above scheme, the first inner cladding layer is divided into a first layer and a second layer from the inside to the outside. The relative refractive index difference Δ2 of the first layer increases with the increase of the radius, while the relative refractive index difference Δ3 of the second layer is equal and flat. The relative refractive index difference at the outermost edge of the first layer is equal to the relative refractive index difference of the second layer.

[0029] According to the above scheme, the width of one side of the first inner cladding layer (R2-R1) is 0.2 to 2.0 μm, and the relative refractive index difference Δ2 is -0.24 to -0.02%. The width of one side of the second layer of the first inner cladding layer (R3-R2) is 0.2 to 2.0 μm, and the relative refractive index difference Δ3 is -0.08 to -0.01%.

[0030] According to the above scheme, the ratio of the single-side width of the first layer to the single-side width of the second layer (R2-R1) / (R3-R2) is 1 to 4, and more specifically 1.5 to 2.0.

[0031] 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 amount of fluorine doping increases from the center of the core layer to its edge. The contribution of fluorine doping at the center of the core layer is Δ. F0 The contribution of fluorine doping at the core edge is -0.12% to -0.01%, Δ. F1 The range is -0.6% to -0.1%.

[0032] According to the above scheme, the relative refractive index difference between the first inner cladding layer and the second inner cladding layer is greater than the relative refractive index difference Δ4 of the first sunken cladding layer.

[0033] According to the above scheme, the first inner cladding layer consists of two layers: a first layer of germanium and fluorine (Ge / F) co-doped silica glass layer and a second layer of germanium, fluorine, and phosphorus co-doped silica glass layer (Ge / P / F); the radius R3 of the first inner cladding layer is ≥22μm.

[0034] 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 (R5-R4) is ≥4.5μm, and the phosphorus doping contribution ΔP of the second inner cladding layer is ≤0.18%.

[0035] According to the above scheme, the relative refractive index difference Δ5 of the second inner cladding is distributed in a concave curve along the radial direction, and the relative refractive index difference of the inner edge of the second inner cladding is equal to the relative refractive index difference of the outer edge.

[0036] According to the above scheme, the radius R5 of the second inner cladding layer is ≥ 40 μm.

[0037] According to the above scheme, the relative refractive index difference Δ5 of the second inner cladding layer is greater than or equal to the relative refractive index difference Δ2 of the first inner cladding layer and the relative refractive index difference Δ3 of the second inner cladding layer, that is, Δ5≥Δ2≥Δ3.

[0038] According to the above scheme, the relative refractive index difference Δ5 of the second inner cladding is -0.02% to 0.06%.

[0039] According to the above scheme, the relative refractive index difference Δ6 of the second depressed cladding is less than the relative refractive index difference Δ4 of the first depressed cladding, that is, Δ4 > Δ6.

[0040] According to the above scheme, the single-sided thickness (R6-R5) of the second recessed cladding layer is greater than or equal to the single-sided thickness (R4-R3) of the first recessed cladding layer.

[0041] According to the above scheme, the ratio of the single-sided thickness (R6-R5) of the second depression cladding layer to the single-sided thickness (R4-R3) of the first depression cladding layer (R6-R5) / (R4-R3) is 1 to 1.5.

[0042] 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).

[0043] According to the above scheme, the numerical aperture of the optical fiber is 0.185 to 0.215.

[0044] 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.

[0045] 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.

[0046] According to the above scheme, the fiber has a full injection bandwidth of 6500MHz·km or more at a wavelength of 850nm, a full injection bandwidth of 3500MHz·km or more at a wavelength of 950nm, and a full injection bandwidth of 700MHz·km or more at a wavelength of 1300nm.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] According to the above scheme, the optical fiber is further processed and then made into a patch cord.

[0051] 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 optical fiber cross-sectional structure design requirements, the cladding and core layers 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.

[0052] 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 the fiber is reduced, thus optimizing the optical transmission bandwidth performance while improving the fiber's bending insensitivity; 2. Through the double inner cladding and double depressed cladding design, the mutual influence between the core layer, the first inner cladding, the first depressed cladding, the second inner cladding, and the second depressed cladding, as well as refractive index distortion caused by diffusion and stress, are avoided, especially reducing the distortion of the core layer; 3. This invention adopts a double inner cladding germanium, fluorine, and phosphorus multi-element doping method, avoiding diffusion caused by the concentration difference of doping elements between layers. The reasonable doping concentration ratio of the inner cladding optimizes the material viscosity matching of the inner cladding and the depressed cladding, improves the smoothness of fiber stress changes, and further reduces fiber cross-sectional distortion caused by stress unevenness. 4. The optical 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 optical fiber of this invention has high coupling efficiency and transmission efficiency, with a transmission efficiency of over 95%; the optical fiber can achieve laser power transmission from 1W to 400W, and even achieve compatibility with LED light sources in the low power range; moreover, the optical fiber has good stability, and under long-term working conditions, the temperature of the fiber optic patch cord connector can be kept 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, and can adapt to the network demand of rapid data traffic growth, which is of great significance for the expansion of applications in the field of optical communication technology. Attached Figure Description

[0053] 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.

[0054] Figure 2 This is a schematic diagram of the refractive index profile according to an embodiment of the present invention.

[0055] Figure 3 This is a differential mode delay diagram for a comparative example of the present invention.

[0056] Figure 4 This is a differential mode delay diagram according to an embodiment of the present invention. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0058] The optical fiber comprises a core and a cladding. The refractive index profile of the core is parabolic. The core distribution index α is 2.1–2.4, the core radius R1 is 18–30 μm, and the maximum relative refractive index difference Δ at the center of the core is [missing information]. 1max The refractive index is 0.8% to 1.6%, and the minimum relative refractive index difference Δ1min at the core edge is -0.18% to -0.06%. 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 refractive index profile of the first inner cladding is a zigzag line that increases at the front and flattens at the back. The first inner cladding is divided into a first layer 11 and a second layer 12 from the inside out. The relative refractive index difference Δ2 of the first layer increases with the radius, while the relative refractive index difference Δ3 of the second layer is equal and flat. The relative refractive index difference at the outermost edge of the first layer is equal to that of the second layer. The single-side width of the first inner cladding layer is (R2-R1), and the single-side width of the second inner cladding layer is (R3-R2). The width of the first recessed cladding layer (R4-R3) is 2.0–8.0 μm, and the relative refractive index difference Δ4 is ​​-1.0–-0.22%. The relative refractive index difference Δ5 of the second inner cladding layer is distributed in a concave curve along the radial direction. Furthermore, the relative refractive index difference at the inner edge of the second inner cladding layer is equal to that at the outer edge. The width of the second inner cladding layer (R5-R4) is 3–10 μm, and the relative refractive index difference Δ5 is -0.09%–0.09%. The width of the second recessed cladding layer (R6-R5) is 1.0–10 μm, and the relative refractive index difference Δ6 is -1.0–-0.3%. The outer cladding layer is a pure silica glass layer or a doped silica glass layer. The radius of the outer cladding layer R7 is 60–65 μm, and the relative refractive index difference Δ7 is -0.15–0.15%.

[0059] 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.

[0060] The first inner cladding is co-doped with germanium, phosphorus, and fluorine (Ge / P / F). The first layer (11) of the first inner cladding exhibits a gradient increasing region with germanium and fluorine co-doping, while the second layer (12) exhibits a plateau region with germanium, fluorine, and phosphorus co-doping. The relative refractive index difference between the first and second layers of the first inner cladding is greater than the relative refractive index difference Δ4 of the first depressed cladding, i.e., Δ2 > Δ4 and Δ3 > Δ4. The radius R3 of the first inner cladding is ≥ 22 μm. Specifically, the single-side width (R2-R1) of the gradient increasing region of the first inner cladding is greater than that of the second layer. The ratio of the single-side width (R3-R2) of the equivalent plateau region ranges from 1.5 to 2.0. The germanium and fluorine co-doping in the first inner cladding's layered, gradually increasing region improves the transmission performance of higher-order modes at the beginning of the core layer, effectively suppressing the propagation of higher-order modes in the core layer. This enhances bandwidth stability and attenuation performance while simultaneously improving optical fiber communication transmission performance. The second layered plateau region of the first inner cladding prevents excessive entry of higher-order modes into the depressed cladding. Simultaneously, phosphorus doping significantly reduces its viscosity, improving its viscosity matching with the depressed cladding. When phosphorus is doped in the second layered plateau region of the first inner cladding, its thickness needs to be ≥0.4 μm, and the phosphorus doping contribution ΔP is <0.12%.

[0061] When the second inner cladding is co-doped with germanium, fluorine, and phosphorus, its single-sided thickness (R5-R4) is ≥4.5μm, the phosphorus doping contribution ΔP of the second inner cladding is ≤0.18%, the radius of the second inner cladding R5 is ≥40μm, and the single-sided thickness (R6-R5) of the second depressed cladding is greater than the single-sided thickness (R4-R3) of the first depressed cladding. Specifically, the ratio of the single-sided thickness (R6-R5) of the second depressed cladding to the single-sided thickness (R4-R3) of the first depressed cladding is in the range of 1 to 1.5, which changes the modal dispersion while having better bending resistance. Compared to germanium, phosphorus has a more significant effect on improving glass viscosity. Doping phosphorus into the second inner cladding can greatly reduce the viscosity of the second inner cladding and improve its viscosity matching with the sunken cladding. The co-doping design of germanium, fluorine and phosphorus effectively improves optical fiber attenuation and transmission performance. 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, which better prevents light leakage under deep channel conditions and ensures the stability and efficiency of power transmission.

[0062] The first and second depressed claddings have negative refractive indices. In particular, when the relative refractive index difference Δ6 of the second depressed cladding is less than the relative refractive index difference Δ4 of the first depressed cladding, i.e. Δ4 > Δ6, it can not only improve the mode dispersion of higher-order modes, but also effectively improve the bending resistance of the optical fiber.

[0063] According to the above scheme, a set of optical fiber preforms were prepared and drawn into fibers. A double-layer coating of multimode optical fiber was used, such as double-layer UV-cured acrylic resin. The structural parameters and performance parameters of the optical fiber are shown in Table 1.

[0064] Table 1: Core structure parameters and main performance parameters of optical fibers

[0065]

[0066]

[0067] 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.

[0068] The full injection bandwidth was measured according to the IEC60793-1-41 method, and the test was conducted under full injection conditions.

[0069] 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).

[0070] Experiments show that the high-speed communication and power transmission optical fiber manufactured according to the technical solution of this invention, i.e., the integrated communication and transmission optical fiber, exhibits excellent high-speed communication and laser transmission performance in wavelengths of 850nm–980nm and 1060nm. Specifically, the optical fiber has high coupling and transmission efficiency, with a transmission efficiency exceeding 95% and a photoelectric conversion efficiency of 20%–30%. It 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 exhibits good stability; under long-term operating conditions, the temperature of the fiber optic patch cord connector can remain below 45℃, and the transmission efficiency remains stable. Laser parameter settings and transmission test results are shown in Table 2.

[0071] Table 2: Laser parameter settings and transmission test results

[0072]

Claims

1. A bend-insensitive automotive multimode power transmission 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 2.1~2.4, the core layer radius R1 is 18~30μm, and the maximum relative refractive index difference Δ at the core layer center is... 1max The refractive index is 0.8~1.6%, and the minimum relative refractive index difference Δ1min at the core edge is -0.18~-0.06%. 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. The refractive index profile of the first inner cladding is a zigzag line with an increasing front and a flat back, and the single-sided width (R3-R1) is 0.4~4.0μm, with a relative refractive index difference of -0.24~-0.01%. The single-sided width (R4-R3) of the first depressed cladding is 2.0~8.0μm, with a relative refractive index difference Δ4 of -1.0~-0.22%. The single-sided width (R4-R3) of the second inner cladding is... The width of the second cladding layer (R6-R5) is 3~10μm, and the relative refractive index difference Δ5 is -0.06~0.09%. The single-side width of the second cladding layer (R6-R5) is 1.0~10μm, and the relative refractive index difference Δ6 is -1.0~-0.3%. The outer cladding layer is a pure silica glass layer or a doped silica glass layer, with an outer cladding radius R7 of 60~65μm and a relative refractive index difference Δ7 of -0.12~0.15%. The core layer is a silica glass layer co-doped with germanium and fluorine, or germanium, phosphorus and fluorine, or germanium, boron and fluorine. Fluorine in the core layer acts as a negative dopant, and the amount of fluorine doping increases from the center of the core layer to the edge of the core layer.

2. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1, characterized in that... The first inner cladding is divided into a first layer and a second layer from the inside out. The relative refractive index difference Δ2 of the first layer increases with the increase of the radius, while the relative refractive index difference Δ3 of the second layer is equal and flat. The relative refractive index difference at the outermost edge of the first layer is equal to that of the second layer.

3. The bend-insensitive automotive multimode power transmission optical fiber according to claim 2, characterized in that... The width of one side of the first inner cladding layer (R2-R1) is 0.2~2.0μm, and the relative refractive index difference Δ2 is -0.24~-0.02%. The width of one side of the second layer of the first inner cladding layer (R3-R2) is 0.2~2.0μm, and the relative refractive index difference Δ3 is -0.08~-0.01%.

4. The bend-insensitive automotive multimode power transmission optical fiber according to claim 3, characterized in that... The ratio of the single-side width of the first inner cladding layer to the single-side width of the second inner cladding layer (R2-R1) / (R3-R2) is 1~4.

5. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, 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 range is -0.6% to -0.1%.

6. The bend-insensitive automotive multimode power transmission optical fiber according to claim 3, characterized in that... The relative refractive index difference between the first inner cladding layer and the second inner cladding layer is greater than the relative refractive index difference Δ4 of the first sunken cladding layer.

7. The bend-insensitive automotive multimode power transmission optical fiber according to claim 2 or 3, characterized in that... The first inner cladding layer consists of two layers: one layer is a germanium- and fluorine-doped silica glass layer, and the other layer is a germanium-, fluorine-, and phosphorus-doped silica glass layer; the radius R3 of the first inner cladding layer is ≥22μm.

8. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... 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 (R5-R4) is ≥4.5μm, and the phosphorus doping contribution ΔP of the second inner cladding layer is ≤0.18%.

9. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... The relative refractive index difference Δ5 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.

10. The bend-insensitive automotive multimode power transmission optical fiber according to claim 9, characterized in that... The radius R5 of the second inner cladding layer is ≥ 40 μm.

11. The bend-insensitive automotive multimode power transmission optical fiber according to claim 3, characterized in that... The relative refractive index difference Δ5 of the second inner cladding is greater than or equal to the relative refractive index difference Δ2 of the first inner cladding layer and the relative refractive index difference Δ3 of the second inner cladding layer, i.e., Δ5≥Δ2≥Δ3.

12. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 3, characterized in that... The relative refractive index difference Δ5 of the second inner cladding is -0.02 ~ 0.06%.

13. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... The relative refractive index difference Δ6 of the second depressed cladding is less than the relative refractive index difference Δ4 of the first depressed cladding, i.e., Δ4 > Δ6.

14. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... The thickness of the second recessed cladding layer on one side (R6-R5) is greater than or equal to the thickness of the first recessed cladding layer on one side (R4-R3).

15. The bend-insensitive automotive multimode power transmission optical fiber according to claim 14, characterized in that... The ratio of the single-sided thickness (R6-R5) of the second recessed cladding layer to the single-sided thickness (R4-R3) of the first recessed cladding layer (R6-R5) / (R4-R3) is 1~1.

5.

16. The bend-insensitive automotive multimode power transmission 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 (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).

17. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... The numerical aperture of the optical fiber is 0.185~0.

215.

18. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... The DMDInner Mask (5-18μm) and DMDOuter Mask (0-23μm) of the optical fiber are both less than or equal to 0.30 ps / m; the DMD IntervalMask is less than or equal to 0.2 ps / m.

19. The bend-insensitive automotive multimode power transmission 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.

20. The bend-insensitive automotive multimode power transmission optical fiber according to claim 1 or 2, characterized in that... The optical fiber has a wavelength of 6500 nm at 850 nm. Full injection bandwidth and above, with 3500 at a wavelength of 950nm. Full injection bandwidth and above, with 700 at a wavelength of 1300nm. Full injection bandwidth and above.

21. The bend-insensitive automotive multimode power transmission 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.

22. The bend-insensitive automotive multimode power transmission 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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