CN219997338U - Optical fiber and optical fiber communication system - Google Patents

Abstract

The present utility model provides an optical fiber and an optical fiber communication system, the optical fiber comprising at least one bare optical fiber, each bare optical fiber comprising: the fiber core, and from inside to outside cladding in proper order are at fiber core surface's first cladding, second cladding and third cladding, are doped with light attenuation material in the second cladding, and first cladding and third cladding are undoped the light attenuation material. According to the optical fiber, the light attenuation material is doped in the second cladding, the light attenuation material is not doped in the first cladding and the third cladding, so that the accelerated attenuation of a leakage mode in the optical fiber transmission can be realized, the high-quality transmission with low crosstalk and high isolation between cores can be effectively realized aiming at signals transmitted in a multi-core/core optical fiber or a single-core/core optical fiber integrated optical fiber bundle, and the larger transmission capacity per unit area of the end face of the optical fiber can be realized.

Description

Optical fiber and optical fiber communication system

Technical Field

The present utility model relates to the field of optical fiber communications technologies, and in particular, to an optical fiber and an optical fiber communication system using the same.

Background

With the advent of the big data age, continuous capacity increasing requirements are put forward on signal transmission technologies, and superposition of multiplexing technologies such as wavelength division multiplexing and time division multiplexing and coherent technologies meets the current requirements for capacity increasing of information transmission, but the multiplexing technologies and superposition gradually approach the limit for improving the transmission capacity of single-mode optical fibers.

At present, the space division multiplexing technology is a new multiplexing technology dimension with high potential. In the space division multiplexing technology, the few-mode optical fiber based on mode multiplexing is expected to realize the increase of channel capacity by several times and the reduction of unit bandwidth transmission cost, but in the transmission process, crosstalk formed by mode random coupling, decoupling and the like exists between different modes, which seriously affects the transmission quality of optical signals. Especially when a larger transmission capacity is required per unit area of the end face of the optical fiber, that is, when a larger number of cores/kernels is arranged per unit area, the crosstalk between cores/kernels is obviously deteriorated, so that the error code is serious, and the larger transmission capacity per unit area of the end face is difficult to realize.

Disclosure of Invention

In view of this, in order to solve at least one of the above drawbacks, an embodiment of the present utility model provides an optical fiber, which can realize accelerated attenuation of a leakage mode in optical fiber transmission, and can effectively realize high-quality transmission with low cross-talk (or high isolation) between cores for signals transmitted in a multi-core optical fiber or a single-core optical fiber integrated optical fiber bundle, thereby being beneficial to realizing a larger transmission capacity per unit area of an optical fiber end face.

In addition, the embodiment of the utility model also provides an optical fiber communication system comprising the optical fiber.

A first aspect of an embodiment of the present utility model provides an optical fiber comprising at least one bare fiber, each of the bare fibers comprising: the fiber core, and from inside to outside cladding in proper order at fiber core surface's first cladding, second cladding and third cladding, the doping has the light attenuation material in the second cladding, the first cladding with the undoped light attenuation material in the third cladding.

By doping the second cladding with the light attenuation material, the first cladding and the third cladding are not doped with the light attenuation material, so that the accelerated attenuation of a leakage mode in the transmission of the optical fiber can be realized, and the high-quality transmission with low crosstalk and high isolation between cores can be effectively realized for signals transmitted in the multi-core/core optical fiber or the multi-core/core optical fiber integrated optical fiber bundle, thereby being beneficial to realizing larger transmission capacity per unit area of the end face of the optical fiber.

With reference to the first aspect, in some possible embodiments, an outer diameter of the first cladding is greater than a diameter of the core and less than or equal to 10 times the core diameter.

By setting the outer diameter of the first cladding to be greater than the diameter of the fiber core and less than or equal to 10 times the diameter of the fiber core, on the one hand, attenuation of the transmitted optical signal in the fiber core can be achieved, communication light in the fiber core can be effectively restrained in the fiber core, and attenuation of a leakage mode in optical fiber transmission can be further accelerated.

With reference to the first aspect, in some possible embodiments, the light attenuating material is cobalt, vanadium or ytterbium.

Cobalt, vanadium, ytterbium and the like belong to high light attenuation materials, and the attenuation rate of a leakage mode in optical fiber transmission can be further improved by doping the materials (especially cobalt) in the second cladding layer.

With reference to the first aspect, in some possible embodiments, a doped thickness of the light attenuating material in the second cladding layer is greater than or equal to 1 μm.

By doping the second cladding layer with the light attenuation material having a thickness of 1 μm or more, the attenuation of the leakage mode in optical fiber transmission can be further accelerated by the light attenuation material having a thicker thickness.

With reference to the first aspect, in some possible embodiments, the second cladding layer includes a first surface adjacent to the first cladding layer and a second surface adjacent to the third cladding layer, and the doping concentration of the light attenuation material decreases sequentially from the second surface to the first surface along the diameter direction of the optical fiber.

By doping the second cladding layer with a lower concentration of the optical attenuation material in a portion thereof adjacent to the second cladding layer and doping the third cladding layer with a higher concentration of the optical attenuation material, loss of the transmission optical signal can be further reduced, and attenuation of the leakage mode in optical fiber transmission can be effectively accelerated. It will be appreciated that the light attenuating material may also be doped in the second cladding layer to achieve the purpose of accelerating attenuation of the leakage modes.

With reference to the first aspect, in some possible embodiments, the second cladding layer includes a first surface adjacent to the first cladding layer and a second surface adjacent to the third cladding layer, and a cross-section of the second surface is annular, D-shaped, or polygonal along an axial direction perpendicular to the core.

The second cladding layer has doping structures with different shapes, so that the accelerated attenuation of the leakage mode in the optical fiber transmission can be realized to different degrees, and especially, the abnormal doping structure can improve the attenuation rate of the leakage mode in the optical fiber transmission.

With reference to the first aspect, in some possible embodiments, a refractive index of the third cladding layer is smaller than a refractive index of the first cladding layer.

The refractive index of the third cladding is lower than that of the first cladding, and the fiber core has a high refractive index, so that the third cladding can form a low refractive index groove type structure which is greatly sunk, and even if the optical fiber is deformed by bending with a small curvature radius, the optical fiber can effectively inhibit light from leaking to the outside of the third cladding, thereby being beneficial to further reducing crosstalk and improving isolation.

With reference to the first aspect, in some possible embodiments, the number of the bare fibers is one, and a surface of the third cladding is coated with a coating layer.

By doping the attenuation material in the second cladding, attenuation of the leakage mode in optical fiber transmission can be effectively accelerated, so that high-quality transmission with low inter-core crosstalk (high isolation) is realized for signals transmitted in the single-core/core conventional optical fiber integrated optical fiber bundle.

With reference to the first aspect, in some possible embodiments, the number of the bare fibers is a plurality, and the optical fiber further includes an outer cladding covering all the bare fibers and a coating layer covering the outer cladding.

By doping the second cladding of each bare fiber with an attenuating material, attenuation of the leaky modes in fiber transmission can be effectively accelerated, thereby achieving high quality transmission with low inter-core crosstalk (high isolation) for signals transmitted in the multi-core/core fiber.

With reference to the first aspect, in some possible embodiments, the materials of the core, the first cladding, the second cladding, and the third cladding are all quartz glass, multicomponent glass, crystal, or polymer.

The mode of doping the attenuation material in the second cladding layer to accelerate attenuation of the leakage mode in optical fiber transmission is suitable for optical fibers with different matrix materials, is not particularly limited, has strong universality and is beneficial to expanding the application range of the optical fibers.

With reference to the first aspect, in some possible embodiments, the fiber core is a solid core structure or a hollow core structure.

A second aspect of the embodiments of the present utility model provides an optical fiber communication system comprising an optical fiber according to the first aspect of the embodiments of the present utility model.

By adopting the optical fiber of the first aspect of the embodiment of the utility model, the attenuation of the leakage mode in the optical fiber transmission can be effectively accelerated, the core/core crosstalk is reduced, and the isolation is improved, thereby improving the transmission quality of the optical fiber communication system and being beneficial to realizing the large transmission capacity of the optical fiber communication system.

Drawings

Fig. 1 is a schematic structural diagram of an optical fiber according to an embodiment of the present utility model.

Fig. 2 is a schematic structural diagram of an optical fiber according to another embodiment of the present utility model.

Fig. 3 is a schematic structural diagram of an optical fiber according to another embodiment of the present utility model.

Fig. 4 is a schematic structural diagram of an optical fiber according to another embodiment of the present utility model.

Fig. 5 is a schematic diagram of an optical fiber communication system according to an embodiment of the present utility model.

Description of the main reference signs

Optical fibers 100,200

Bare optical fiber 10

Fiber core 1

First cladding layer 2

Second cladding layer 3

Third cladding layer 4

Outer cladding 6

Coating layers 5,7

Inner coating layer 51

Outer coating layer 52

Fiber optic communication system 300

OLT side 310

Optical splitter 320

ONU/ONT end 330

Detailed Description

Embodiments of the present utility model will be described below with reference to the accompanying drawings in the embodiments of the present utility model.

The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used in the specification of the utility model and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include, for example, "one or more" such forms of expression, unless the context clearly indicates to the contrary.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the utility model. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

In the space division multiplexing technology, when a larger transmission capacity is required per unit area of the end face of the optical fiber, the core/core crosstalk can be obviously deteriorated, so that the error code is serious, and the larger transmission capacity per unit area of the end face is difficult to realize. At present, optical devices are generally added or optical fiber structures are changed to reduce mode crosstalk on an optical link and improve isolation, but the modes lead to complex optical fiber structures and increased optical path demodulation cost, which is not beneficial to mass production and commercial use.

In view of this, embodiments of the present utility model provide a high quality transmission optical fiber capable of achieving low crosstalk between cores, high isolation, and the optical fiber can be applied to an optical transmission system.

Referring to fig. 1, an optical fiber 100 according to an embodiment of the present utility model includes at least one bare optical fiber 10. Each bare optical fiber 10 comprises a fiber core 1, and a first cladding layer 2, a second cladding layer 3 and a third cladding layer 4 which are sequentially coated on the surface of the fiber core 1 from inside to outside, wherein a light attenuation material is doped in the second cladding layer 3, and the first cladding layer 2 and the third cladding layer 4 are not doped with the light attenuation material. And the core 1, the first cladding 2, the second cladding 3 and the third cladding 4 in the bare fiber 10 constitute an integrated multi-cladding structure.

In this embodiment of the present utility model, the optical fiber 100 may be a single-core optical fiber, that is, the number of cores 1 is one.

In some embodiments, the refractive index profile of the core 1 may be a step index profile or a graded index profile.

In some embodiments, the material of the fiber core 1 may be quartz glass, multicomponent glass, crystal or polymer, etc., specifically may be a quartz material with a high refractive index, and may also be quartz glass doped with germanium or rare earth, and the quartz fiber core may improve the communication speed and realize the high-speed communication requirement. The manner of doping the attenuation material in the second cladding layer 3 to accelerate attenuation of the leaky mode in optical fiber transmission is applicable to optical fibers of different matrix materials, is not particularly limited, has strong versatility, and is beneficial to expanding the application range of the optical fibers.

In some embodiments, the diameter of the core 1 may be designed according to the actual communication needs, for example, 8-12 μm, 12-50 μm, or 50 μm.

In some embodiments, the core 1 may be a solid core structure or a hollow core structure.

The portion of the first cladding layer 2 near the fiber core 1 may act as a part of waveguide, so that attenuation of part of communication light entering the first cladding layer 2 from the fiber core 1 can be suppressed to be very low, loss of the communication light is reduced, and transmission quality of the optical fiber 100 is improved.

In some embodiments, the material of the first cladding layer 2 may be silica glass, multicomponent glass, crystal or polymer, and may specifically be a silica material with a lower refractive index than the fiber core 1, where the silica material forms the first cladding layer 2 that extends the high-speed communication design concept of the silica optical fiber, so as to be beneficial to ensuring the high communication speed of the optical fiber 100.

In some embodiments, the outer diameter of the first cladding 2 is greater than the diameter of the core 1 and less than or equal to 10 times the diameter of the core 1. The diameter of the first cladding 2 is not limited in the embodiment of the present utility model, and may be set according to actual products. The refractive index of the first cladding 2 is generally lower than that of the core 1, and by setting the outer diameter of the first cladding 2 to be larger than the diameter of the core 1 and 10 times or less the diameter of the core 1, communication light in the core 1 can be effectively confined in the core 1, and attenuation of a leakage mode in optical fiber transmission can be further accelerated.

In some embodiments, the cross-section of the first cladding layer 2 may be circular or non-circularly symmetric.

The second cladding layer 3 is doped with an optical attenuation material, and in the optical fiber transmission process, the leakage mode is greatly attenuated in the second cladding layer 3, so that the existence of the second cladding layer 3 can effectively inhibit the leakage mode from further leaking out of the optical fiber 100, and after the multi-fiber 100 forms an optical fiber bundle, the inter-core crosstalk can be reduced, and the isolation degree is improved.

In some embodiments, the light attenuating material may be cobalt, vanadium, ytterbium, or the like. Cobalt, vanadium, ytterbium and the like belong to high light attenuation materials, and the attenuation rate of a leakage mode in optical fiber transmission can be further improved by doping the materials (especially cobalt) in the second cladding layer 3.

In some embodiments, the doping thickness of the light attenuating material in the second cladding layer 3 is greater than or equal to 1 μm. The thickness of the light attenuation material doped in the second cladding layer 3 can be set according to actual needs, and the attenuation of the leakage mode in optical fiber transmission can be further accelerated by doping the light attenuation material with the thickness of 1 μm or more in the second cladding layer 3 and making the light attenuation material thicker.

In some embodiments, the second cladding layer 3 includes a first surface 33 adjacent to the first cladding layer 2 and a second surface 34 adjacent to the third cladding layer 4, and the doping concentration of the light attenuating material decreases from the second surface 34 to the first surface 33 in the diameter direction of the optical fiber 100, that is, the doping concentration of the light attenuating material is higher in a portion of the second cladding layer 3 adjacent to the third cladding layer 4 and is lower in a portion adjacent to the first cladding layer 2. In this way, the loss of the transmission optical signal can be further reduced, and meanwhile, the attenuation of the leakage mode in the optical fiber transmission can be effectively accelerated. It will be appreciated that the light attenuating material may also be uniformly doped in the second cladding layer 3 for the purpose of accelerating the attenuation of the leakage mode.

In some embodiments, the cross-section of the second surface 34 along the axial direction perpendicular to the core 1 may be annular or shaped, i.e. when the light attenuating material is doped in the second cladding 3, annular doping may be used, or shaped doping may be used, wherein the shape may be D-shaped or polygonal (e.g. hexagonal, pentagonal, etc.). As shown in fig. 1, the cross section of the second surface 34 is annular, i.e. the second cladding layer 3 is annular doped; as shown in fig. 2, the second surface 34 of the second cladding layer 3 has a D-shaped cross section, i.e. the second cladding layer 3 is D-doped; in addition, as shown in fig. 3, the second surface 34 of the second cladding layer 3 has a hexagonal cross section, i.e. the second cladding layer 3 is hexagonally doped. The second cladding layer 3 has doping structures with different shapes, so that the accelerated attenuation of the leakage mode in the optical fiber transmission can be realized to different degrees, and especially, the abnormal doping structure can effectively improve the attenuation rate of the leakage mode in the optical fiber transmission.

In some embodiments, the material of the second cladding layer 3 may be silica glass, multicomponent glass, crystal or polymer, etc., and in particular may be a silica material with a low refractive index, which is beneficial for ensuring a high communication speed of the optical fiber 100.

The diameter of the second cladding layer 3 is not particularly limited in the embodiment of the present utility model, and may be set according to the actual product and the thickness of the light attenuation material to be doped. It will be appreciated that the thickness of the second cladding layer 3 is at least 1 μm.

Wherein the third cladding layer 4 is not doped with an optical attenuation material, which can further keep light in the fiber core 1 and further accelerate attenuation of the leakage mode in the optical fiber transmission.

In some embodiments, the refractive index of the third cladding layer 4 is lower than the first cladding layer 2, and since the refractive index of the third cladding layer 4 is lower, the refractive index profile of the optical fiber 100, if referenced to the second cladding layer 3, is: the core 1 has a trench structure in which a high refractive index portion protrudes, the first cladding 2 has a lower refractive index than the core 1, and the third cladding 4 has a low refractive index portion which is greatly depressed. In this way, even if the optical fiber 100 is deformed by bending with a small radius of curvature, the communication light is effectively prevented from leaking to the outside of the third cladding 4.

In some embodiments, the third cladding 4 may be a low refractive index quartz material, which is advantageous for ensuring a high communication speed of the optical fiber 100, while being advantageous for confining the communication light within the core 1. It will be appreciated that the third coating 4 may also be a multicomponent glass, crystal or polymer, etc.

In some embodiments, the diameter of the third coating layer 4 is not particularly limited, and may be set according to actual products.

The optical fiber 100 further comprises a coating layer 5 coated on the outer side of the third coating layer 4, and the coating layer 5 can serve as an outer sheath to protect the bare optical fiber 10, and provide excellent mechanical properties of stretch resistance and bending resistance. Specifically, the coating layer 5 may include an inner coating layer 51 and an outer coating layer 52 laminated from inside to outside, wherein the inner coating layer 51 and the outer coating layer 52 are often made of an acrylic resin or a fluoroplastic film (ETFE) material, wherein the acrylic resin may be urethane acrylate, silicone acrylate, epoxy acrylate, polyester acrylate, or the like.

The diameter of the coating layer 5 is not limited in the embodiment of the present utility model, and may be set according to actual products. Illustratively, the diameter of the coating layer 5 may be controlled between 400 μm and 2000 μm, for example 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1300 μm, 1500 μm, 1800 μm or 2000 μm, etc., without limitation.

In the optical fiber 100, the refractive index of the first cladding 2 is generally lower than that of the core 1, but the communication light is mainly transmitted in the core 1, but the portion of the first cladding 2 close to the core 1 still acts as a part of the waveguide, that is, a small amount of communication light is transmitted in the first cladding 2, and by adding the first cladding 2 of undoped light attenuation material to the side of the second cladding 3 of doped light attenuation material close to the core 1, the attenuation of the communication light can be suppressed to be low, and the loss of the communication light can be reduced. Since the leakage mode signal light is mainly generated and transmitted in a portion of the first cladding layer 2 near the second cladding layer 3, since the light attenuating material is doped in the second cladding layer 3, the leakage mode signal light can be effectively attenuated in the second cladding layer 3. In addition, by adding the third clad 4 having a lower refractive index, the optical fiber 100 can be formed with a low refractive index groove structure at the portion of the third clad 4, thereby further suppressing light leakage. Therefore, in the optical fiber 100 according to the embodiment of the present utility model, the first cladding 2 and the third cladding 4 are not doped with the light attenuating material, the second cladding 3 located between the first cladding 2 and the third cladding 4 is doped with the light attenuating material, and by matching the first cladding 2, the second cladding 3 and the third cladding 4, attenuation of a leakage mode in optical fiber transmission can be effectively accelerated, and leakage of communication light in the optical fiber 100 is suppressed, so that high quality transmission with low inter-core crosstalk (high isolation) is achieved for signals transmitted in a plurality of single-core/core conventional optical fiber integrated optical fiber bundles.

Referring to fig. 4, another optical fiber 100 is provided in the embodiment of the present utility model, and the main difference between the optical fiber 200 of the embodiment and the optical fiber 100 of the embodiment is that: the optical fiber 200 comprises a plurality of the bare optical fibers 10, the optical fiber 200 further comprises an outer cladding 6 and a coating 7, the outer cladding 6 covers all the bare optical fibers 10, and the coating 7 covers the outer cladding 6. Each bare fiber 10 has the same structure as the bare fiber 10 in the optical fiber 100 provided in the foregoing embodiment, and detailed description thereof will be omitted herein.

The primary function of the outer cladding 6 is to protect and integrate the plurality of bare fibers 10. The material of the outer cladding 6 may be quartz glass, multicomponent glass, crystal or polymer, etc., and specifically may be a quartz material having a lower refractive index than the third cladding 4.

The coating layer 7 may include an inner coating layer and an outer coating layer, and the specific material may be the same as that of the coating layer 5 in the foregoing embodiment, and will not be described in detail herein.

It will be appreciated that in other embodiments, the second cladding layer 3 in each bare fiber 10 may also be a ring-shaped doped structure or a profile doped structure, and detailed descriptions thereof will be omitted herein.

The optical fiber 200 of the embodiment of the utility model can effectively accelerate the attenuation of the leakage mode in the optical fiber transmission by doping the attenuation material in the second cladding layer 3 of each bare optical fiber 10, thereby realizing the high-quality transmission of the low-crosstalk (high isolation) between cores for the signals transmitted in the multi-core/core optical fiber.

Referring to fig. 5, an embodiment of the present utility model further provides an optical fiber communication system, where the optical fiber communication system includes the optical fiber described above. Specifically, the optical fiber communication system 300 may include an OLT side 310, an optical splitter 320, and at least one ONU/ONT side 330 connected in sequence, and the optical fiber 100 (or 200) as described above, where the optical fiber 100 (or 200) is used to optically connect the OLT side 310, the optical splitter 320, and the at least one ONU/ONT side 330. The OLT is an optical line terminal (Optical Line Termination, OLT), the ONU is an optical network unit (Optical Network Unit, ONU), and the ONT is an optical network terminal (Optical Network Termination, ONT).

By adopting the optical fiber 100 (or 200), attenuation of a leakage mode in optical fiber transmission can be effectively accelerated, core/core crosstalk is reduced, isolation is improved, transmission quality of the optical fiber communication system 300 is improved, and large transmission capacity of the optical fiber communication system 300 is facilitated.

It should be noted that the above is only a specific embodiment of the present utility model, but the scope of the present utility model is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present utility model, and the changes or substitutions are covered by the scope of the present utility model; the embodiments of the present utility model and features in the embodiments may be combined with each other without conflict. Therefore, the protection scope of the utility model is subject to the protection scope of the claims.

Claims (12)

1. An optical fiber comprising at least one bare fiber, each of said bare fibers comprising: the fiber core, and from inside to outside cladding in proper order at fiber core surface's first cladding, second cladding and third cladding, the doping has the light attenuation material in the second cladding, the first cladding with the undoped light attenuation material in the third cladding.

2. The optical fiber of claim 1, wherein the outer diameter of the first cladding is greater than the diameter of the core and less than or equal to 10 times the diameter of the core.

3. The optical fiber of claim 1, wherein the light attenuating material is cobalt, vanadium, or ytterbium.

4. The optical fiber of claim 1, wherein the doped thickness of the light attenuating material in the second cladding layer is greater than or equal to 1 μm.

5. The optical fiber of claim 4, wherein the second cladding layer comprises a first surface adjacent to the first cladding layer and a second surface adjacent to the third cladding layer, and wherein the doping concentration of the light attenuating material decreases sequentially from the second surface to the first surface along the diameter of the optical fiber.

6. The optical fiber of claim 1, wherein the second cladding comprises a first surface adjacent to the first cladding and a second surface adjacent to the third cladding, the second surface having a circular, D-shaped, or polygonal cross-section in a direction perpendicular to the axial direction of the core.

7. The optical fiber of claim 1, wherein the refractive index of the third cladding is less than the refractive index of the first cladding.

8. The optical fiber according to any one of claims 1 to 7, wherein the number of bare fibers is one, and the surface of the third cladding is coated with a coating layer.

9. The optical fiber according to any one of claims 1 to 7, wherein the number of the bare fibers is plural, the optical fiber further comprising an outer cladding covering all of the bare fibers and a coating layer covering the outer cladding.

10. The optical fiber according to any one of claims 1 to 7, wherein the material of the core, the first cladding, the second cladding, and the third cladding is quartz glass, multicomponent glass, crystal, or polymer.

11. The optical fiber according to any one of claims 1 to 7, wherein the core is a solid core structure or a hollow core structure.

12. An optical fiber communication system comprising an optical fiber according to any one of claims 1 to 11.