Single-mode optical fiber with a large mode field and small diameter, and micro-optical cable

Abstract

Single-mode optical fiber with a large mode field and small diameter, comprising: a core layer (1) having a diameter of 8.5-9.5 µm; an inner mantle layer (2) that surrounds an outer periphery of the core layer (1) and has a diameter of 124.3-125.7 µm; an inner coating layer (3) that surrounds the outer periphery of the inner cladding layer (2) and has a diameter of 140-150 µm; and an outer coating layer (4) that surrounds the outer periphery of the inner coating layer (3) and has a diameter of 175-185 µm.

Description

Field of invention

[0001] The present patent right relates to the field of optical fiber technology, and in particular to a single-mode optical fiber with a large mode field and small diameter and a micro-optical cable. Background of the invention

[0002] With the explosive growth of data traffic in the information society, the pressure on optical networks, which serve as the infrastructure for data transmission, has become increasingly prominent, making the increase of transmission capacity a pressing task. However, the problem of limited cable duct resources is becoming ever more critical and must be addressed by reducing the diameter of optical fibers and increasing the number of optical fibers per unit area of ​​an optical cable.Taking European countries like the Netherlands and Belgium as examples, the inner diameter of new optical fiber protective tubes has been reduced from 8 mm to 7 mm, and microcables manufactured using optical fibers with a coating diameter of 200 µm no longer meet the requirements. Optical fibers with a coating diameter of 180 µm must be adopted to further reduce the outer diameter of microcables. Therefore, optical fibers and optical cables with smaller dimensions represent a development trend in the optical communications industry.

[0003] Compared to conventional 245 µm optical fibers, 180 µm small-diameter optical fibers exhibit a 50% reduction in coating thickness, resulting in reduced protection of the bare optical fiber and increased additional attenuation caused by stress on the optical fiber during cabling, environmental and mechanical performance testing, and optical cable installation. To improve the stress resistance of optical fibers, enhancements can be made to both the glass layer and the coating layer.

[0004] Currently available 180 µm small-diameter optical fibers improve stress resistance primarily by enhancing the macrobending performance of the glass layer, thus requiring the optical fibers to exceed the standard specified in G.657.A2. However, such optical fibers are single-mode, small-mode-field fibers, and the cross-sectional design of the optical fiber glass layer differs significantly from that of conventional G.652.D optical fibers, making fusion splicing impossible (or resulting in a fusion splice loss exceeding 0.5 dB). In practical applications, problems can arise such as the inability to perform fusion splicing during installation or link attenuation that fails to meet requirements due to high fusion splice losses in the link. Brief description of the invention

[0005] The embodiment of the present patent provides a single-mode optical fiber with a large mode field and small diameter and a micro-optical cable, with the aim of solving the prior art problem that the glass layers of the small-diameter optical fibers cannot be fusion-spliced ​​with G.652.D optical fibers.

[0006] In a first aspect, the embodiment of the present patent right provides a single-mode optical fiber with a large mode field and small diameter, comprising: a core layer with a diameter of 8.5-9.5 µm; an inner mantle layer that surrounds an outer periphery of the core layer and has a diameter of 124.3-125.7 µm; an inner coating layer surrounding the outer periphery of the inner cladding layer and having a diameter of 140-150 µm; and an outer coating layer surrounding the outer periphery of the inner coating layer and having a diameter of 175-185 µm.

[0007] In some embodiments, the small-diameter single-mode optical fiber has a mode field diameter of 8.8-9.6 µm at a wavelength of 1310 nm.

[0008] In some embodiments, the small-diameter single-mode optical fiber has a mode field diameter of 9 µm at a wavelength of 1310 nm.

[0009] In some embodiments, the inner coating layer has a modulus of elasticity of 0.2–0.4 MPa, a tensile strength of ≥30 MPa, an elongation at break of ≥20%, and a Tg of ≤ -20 °C; and The outer coating layer has an elastic modulus of 700-1000 MPa, a Tg of ≤ 90 °C and a coefficient of thermal expansion of 70-130 × 10 -6 K -1 .

[0010] In some embodiments, the small-diameter single-mode optical fiber has a water permeability in the range of 20-50 g / (m²). 2 ·Day).

[0011] In some embodiments, the macrobending performance of the small-diameter single-mode optical fiber meets the following requirements: when bent into a turn with a diameter of 20 mm, the macrobending loss is ≤0.5 dB at a wavelength of 1550 nm and ≤1.5 dB at a wavelength of 1625 nm; and When bent in ten revolutions with a diameter of 30 mm, the macrobending loss is ≤0.15 dB at a wavelength of 1550 nm and ≤0.5 dB at a wavelength of 1625 nm.

[0012] In some embodiments, the small-diameter single-mode optical fiber has an additional attenuation of ≤0.03 dB / km at an operating wavelength of 1310 nm, 1383 nm, 1550 nm or 1625 nm under a temperature range of -60 °C to 85 °C.

[0013] In some embodiments, the inner coating layer and the outer coating layer of the small-diameter single-mode optical fiber have an average peel force greater than 1 N.

[0014] In a second aspect, the embodiment of the present patent provides a micro-optical cable comprising the small-diameter single-mode optical fiber according to one of the above embodiments.

[0015] In some embodiments, the micro-optical cable is provided with 96 of the small-diameter single-mode optical fibers and has an outer diameter of 4.7 mm; or The micro-optical cable is equipped with 144 small-diameter single-mode optical fibers and has an outer diameter of 5 mm.

[0016] The beneficial effects brought about by the technical solution provided in the present patent right include: The embodiment of the present patent provides a single-mode optical fiber with a large mode field and small diameter and a micro-optical cable, and the single-mode optical fiber with a large mode field and small diameter of the present patent comprises a core layer having a diameter of 8.5-9.5 µm; an inner cladding layer surrounding an outer periphery of the core layer and having a diameter of 124.3-125.7 µm; an inner coating layer surrounding the outer periphery of the inner cladding layer and having a diameter of 140-150 µm; and an outer coating layer surrounding the outer periphery of the inner coating layer and having a diameter of 175-185 µm.

[0017] Therefore, the core layer, inner cladding layer, inner coating layer, and outer coating layer of the large-mode-field, small-diameter single-mode optical fiber of the present patent patent together form a small-diameter single-mode optical fiber with a diameter of 180 µm, and the small-diameter single-mode optical fiber can be applied to micro-cable products with a smaller outer diameter. The fiber type of the small-diameter single-mode optical fiber is G.657.A1 and offers favorable macro-bending performance; additionally, the small-diameter single-mode optical fiber has a mode-field diameter of 9 µm at a wavelength of 1310 nm, which is fully compatible with a G.652.D single-mode optical fiber commonly used on the market, and exhibits unidirectional fusion splice loss between the small-diameter single-mode optical fiber and the G.652.The single-mode optical fiber is less than 0.1 dB, which is more conducive to market introduction and engineering applications. Brief description of the characters

[0018] In order to better illustrate the technical solution in the embodiments of the present patent, the figures required in the description of the embodiments are briefly introduced below, and it is obvious that the figures in the following description are part of embodiments of the present patent, and for those with ordinary expertise in the field, other figures can also be obtained on the basis of these figures without any inventive effort. Fig. Figure 1 is a cross-sectional view of an embodiment of the present intellectual property right. Reference symbol list:

[0019] 1-Core layer; 2-Inner shell layer; 3-Inner coating layer; 4-Outer coating layer. Detailed description of the embodiments

[0020] To clarify the purpose, technical solutions, and advantages of the embodiments of this patent, the technical solutions in the embodiments of this patent are described clearly and completely in conjunction with the drawings in the embodiments of this patent. Obviously, the described embodiments represent only a subset of the embodiments of this patent and not all embodiments. Based on the embodiments in this patent, all other embodiments that could be obtained by someone with ordinary expertise in the field without inventive effort shall fall within the scope of protection of this patent.

[0021] The embodiment of the present patent provides a single-mode optical fiber with a large mode field and small diameter and a micro-optical cable that can solve the prior art problem that the glass layers of small-diameter optical fibers cannot be fusion-spliced ​​with G.652.D optical fibers.

[0022] As in Fig. As shown in Figure 1, in a first aspect the embodiment of the present patent provides a single-mode optical fiber with a large mode field and small diameter, comprising: A core layer 1, which has a diameter of 8.5–9.5 µm, and preferably a diameter of 9 µm. The core layer 1 is the central section of the small-diameter single-mode optical fiber and serves as the optical transmission path.

[0023] The single-mode optical fiber with a large mode field and small diameter further comprises an inner cladding layer 2, which surrounds the outer periphery of the core layer 1. The refractive index of the inner cladding layer 2 is lower than that of the core layer 1, allowing optical energy to undergo total internal reflection in the core layer 1 and thus propagate along the optical fiber. The inner cladding layer 2 has a diameter of 124.3–125.7 µm, and preferably, its diameter is 125 µm.

[0024] The single-mode optical fiber with a large mode field and small diameter further comprises an inner coating layer 3, the inner coating layer 3 surrounds the outer periphery of the inner cladding layer 2, the inner coating layer 3 has a diameter of 140-150 µm, and the diameter of the inner coating layer 3 is further preferably 145 µm.

[0025] The single-mode optical fiber with a large mode field and small diameter further comprises an outer coating layer 4, the outer coating layer 4 surrounds the outer periphery of the inner coating layer 3, the outer coating layer 4 has a diameter of 175-185 µm, and the diameter of the outer coating layer 4 is further preferably 180 µm.

[0026] The inner coating layer 3 and the outer coating layer 4 serve as the coating layers of the small-diameter single-mode optical fiber, primarily protecting the core layer 1 from physical damage and environmental influences such as moisture and temperature variations. Additionally, the inner coating layer 3 and the outer coating layer 4 can also provide a degree of mechanical strength and prevent the multi-core optical fiber 1 from being stretched and bent during installation and use.

[0027] The small-diameter single-mode optical fiber has a mode field diameter of 8.8–9.6 µm at a wavelength of 1310 nm. Furthermore, the small-diameter single-mode optical fiber has a mode field diameter of 9 µm at a wavelength of 1310 nm.

[0028] The core layer 1, the inner cladding layer 2, the inner coating layer 3 and the outer coating layer 4 of the single-mode optical fiber with a large mode field and small diameter of the present patent right together form a single-mode optical fiber with a small diameter of 180 µm, and the single-mode optical fiber with a small diameter can be applied to micro-cable products with a smaller outer diameter.

[0029] The fiber type of the small-diameter single-mode optical fiber is G.657.A1 and offers favorable macrobending performance; additionally, the small-diameter single-mode optical fiber has a mode field diameter of 9 µm at a wavelength of 1310 nm, which is fully compatible with a G.652.D single-mode optical fiber commonly used on the market.

[0030] The diameter parameters of the G.652.D single-mode optical fiber include the core diameter, cladding diameter, and coating diameter. The core diameter of the G.652.D single-mode optical fiber is 9.2 ± 0.4 µm at a wavelength of 1310 nm and 10.4 ± 0.5 µm at a wavelength of 1550 nm, the cladding diameter is 125.0 ± 1.0 µm, and the coating diameter is 245 ± 7 µm.

[0031] The core layer 1 of the present patent has a diameter of 8.5-9.5 µm, preferably 9 µm, and the inner cladding layer 2 has a diameter of 124.3-125.7 µm, preferably 125 µm. The geometric dimensions of the core layer 1 and the inner cladding layer 2 are close to the core diameter and cladding layer diameter of the G.652.D single-mode optical fiber, thus enabling normal fusion splicing with the G.652.D single-mode optical fiber.

[0032] The small-diameter single-mode optical fiber of the present embodiment has a unidirectional fusion splice loss of less than 0.1 dB compared to the commonly used G.652.D single-mode optical fiber on the market, and a bidirectional average fusion splice loss of less than 0.05 dB compared to the G.652.D single-mode optical fiber, which is more favorable for market launch and engineering applications.

[0033] Both the inner coating layer 3 and the outer coating layer 4 are preferably made of acrylic resin. Acrylic resin not only offers excellent mechanical protection and resistance to environmental corrosion, but can also improve production efficiency through rapid ultraviolet curing, while maintaining high flexibility and transparency to support stable optical signal transmission.

[0034] The low moisture absorption property of the acrylic resin effectively prevents performance degradation, protects the core layer 1 from mechanical damage and environmental influences, while ensuring reliable operation of the core layer 1 under bending and complex conditions.

[0035] The inner coating layer 3 is preferably made of a soft acrylic resin, configured to absorb mechanical stress and reduce microbending loss; and the outer coating layer 4 is preferably made of a hard acrylic resin, configured to increase mechanical strength and abrasion resistance.

[0036] In some optional embodiments, such as in Fig. As shown in Figure 1, the first aspect of the present embodiment provides a single-mode optical fiber with a large mode field and small diameter, and the inner coating layer 3 of the small-diameter single-mode optical fiber has a modulus of elasticity of 0.2-0.4 MPa, a tensile strength of ≥ 30 MPa, an elongation at break of ≥ 20% and a Tg of ≤-20°C.

[0037] To achieve improved macrobending and microbending resistance performance, the elastic modulus of the inner coating layer 3 must be appropriately reduced. The inner coating layer 3 has an elastic modulus of 0.2–0.4 MPa, providing improved cushioning to compensate for the negative effects caused by the reduced coating thickness.

[0038] The shear stress resistance of the inner coating layer 3 must be increased, and both the adhesion to the optical fiber and the fracture toughness of the inner coating layer 3 must be improved. The fracture toughness of the inner coating layer 3 is ≥30 MPa, and the elongation at break of the inner coating layer 3 is ≥20%.

[0039] To ensure good low-temperature performance of the optical fiber, the Tg of the inner coating layer 3 must be appropriately reduced to provide better stress cushioning under low-temperature conditions. The Tg of the inner coating layer 3 is ≤-20°C.

[0040] To ensure that the optical fiber is not damaged during pulling and screening, the elastic modulus of the outer coating layer 4 is 700–1000 MPa, and the temperature constant (Tg) is ≤90°C. The coefficient of thermal expansion of the outer coating layer 4 is matched to that of the inner coating layer 3 to prevent additional stress on the optical fiber during cooling and shrinkage. The coefficient of thermal expansion of the outer coating layer 4 is 70–130 × 10⁻⁶. -6 / K.

[0041] In some optional embodiments, such as in Fig. As shown in Figure 1, the first aspect of the present embodiment provides a single-mode optical fiber with a large mode field and small diameter, and the water permeability of the small-diameter single-mode optical fiber is in the range of 2050 g / (m²). 2 ·day).

[0042] In the present embodiment, to ensure water resistance and resistance to humid-hot aging of the small-diameter single-mode optical fiber, the water permeability of the coating must be reduced after decreasing the thickness of the inner coating layer 3 and the outer coating layer 4, thereby reducing the penetration of moisture into the optical fiber. The water permeability is in the range of 20–50 g / (m²). 2 ·Day).

[0043] In some optional embodiments, such as in Fig. As shown in Figure 1, the first aspect of the present embodiment provides a single-mode optical fiber with a large mode field and small diameter. The macrobending performance of the small-diameter single-mode optical fiber meets the following requirements: when bent in one turn with a diameter of 20 mm, the macrobending loss is ≤0.5 dB at a wavelength of 1550 nm and ≤1.5 dB at a wavelength of 1625 nm; and when bent in ten turns with a diameter of 30 mm, the macrobending loss is ≤0.15 dB at a wavelength of 1550 nm and ≤0.5 dB at a wavelength of 1625 nm.

[0044] In some optional embodiments, such as in Fig.As shown in Figure 1, the first aspect of the present embodiment provides a single-mode optical fiber with a large mode field, the small-diameter single-mode optical fiber has an additional attenuation of ≤0.03 dB / km at a working wavelength of 1310 nm, 1383 nm, 1550 nm or 1625 nm under a temperature range of -60 °C to 85 °C, thereby providing the small-diameter single-mode optical fiber with excellent environmental performance.

[0045] The average peel force of the inner coating layer 3 and the outer coating layer 4 of the small diameter single-mode optical fiber is greater than 1 N, and after 30 days of water immersion or moist-hot aging tests, the average peel force of the inner coating layer 3 and the outer coating layer 4 remains greater than 1 N.

[0046] In a second aspect, the embodiment of the present patent provides a micro-optical cable comprising the small-diameter single-mode optical fiber according to one of the embodiments described above. The micro-optical cable is provided with 96 of the small-diameter single-mode optical fibers and has an outer diameter of 4.7 mm; or the micro-optical cable is provided with 144 of the small-diameter single-mode optical fibers and has an outer diameter of 5 mm. The additional attenuation after cabling is less than 0.01 dB / km. The optical cable also meets test requirements, including temperature cycles from -30°C to 70°C with additional attenuation ≤0.1 dB / km during the process; and tensile tests at 700 N with additional attenuation ≤0.1 dB / km.

[0047] The embodiment of the present patent provides a single-mode optical fiber with a large mode field and small diameter and a micro-optical cable, and the single-mode optical fiber with a large mode field and small diameter of the present patent comprises a core layer 1 having a diameter of 8.5-9.5 µm; an inner cladding layer 2 surrounding an outer periphery of the core layer 1 and having a diameter of 124.3-125.7 µm; an inner coating layer 3 surrounding the outer periphery of the inner cladding layer 2 and having a diameter of 140-150 µm; and an outer coating layer 4 surrounding the outer periphery of the inner coating layer 3 and having a diameter of 175-185 µm.

[0048] Therefore, the core layer 1, the inner cladding layer 2, the inner coating layer 3, and the outer coating layer 4 of the small-diameter, large-mode optical fiber of the present patent patent together form a small-diameter single-mode optical fiber with a diameter of 180 µm, and the small-diameter single-mode optical fiber can be applied to micro-cable products with a smaller outer diameter. The fiber type of the small-diameter single-mode optical fiber is G.657.A1 and offers favorable macrobending performance; additionally, the small-diameter single-mode optical fiber has a mode field diameter of 9 µm at a wavelength of 1310 nm, which is fully compatible with a G.652.D single-mode optical fiber commonly used on the market, and there is unidirectional fusion splice loss between the small-diameter single-mode optical fiber and the G.652.The single-mode optical fiber has a noise level of less than 0.1 dB, which is more conducive to market entry and engineering applications.

[0049] In describing this patent, it should be noted that orientations or positional relationships indicated by terms such as "above," "below," etc., are based on those shown in the drawings and are used solely for convenience and to simplify the description of this patent. These terms do not indicate or imply that the device or component in question must have a specific orientation or be designed and operated in a particular orientation. Therefore, these terms should not be construed as limiting the scope of this patent. Unless otherwise clearly specified and limited, the terms "installation," "connected," and "connection" should be understood in a broad sense.For example, it can be a fixed connection, a detachable connection, or an integral connection; furthermore, it can be a mechanical connection or an electrical connection; furthermore, it can be directly connected or indirectly connected through an intermediary, or it can be the internal communication between two components. For those with ordinary expertise in the field, the specific meanings of the aforementioned terms in the present patent application can be understood according to specific circumstances.

[0050] It should be noted that relational terms such as "first" and "second" serve only to distinguish one entity or operation from another entity or operation of the present intellectual property right and do not necessarily require or imply any actual relationship or sequence between such entities or operations. Furthermore, the terms "include," "comprise," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a set of elements includes not only those elements but also those not expressly listed, or further includes elements inherent in the process, method, article, or device. Unless there are further limitations, the phrase "comprising a set of elements" includes...“The defined element does not imply the existence of other identical elements in the process, procedure, article or apparatus comprising the elements.”

[0051] The above-mentioned are merely embodiments of the present patent right, such that those with expertise in the field can understand or implement the present patent right. To those with expertise in the field, various modifications to these embodiments will be obvious, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present patent right. Therefore, the present patent right will not be limited to the embodiments shown in this document, but will be subject to the broadest scope consistent with the principles and novel features applied herein.

Claims

[1] Single-mode optical fiber with a large mode field and small diameter, comprising: a core layer (1) having a diameter of 8.5-9.5 µm; an inner mantle layer (2) that surrounds an outer periphery of the core layer (1) and has a diameter of 124.3-125.7 µm; an inner coating layer (3) that surrounds the outer periphery of the inner cladding layer (2) and has a diameter of 140-150 µm; and an outer coating layer (4) that surrounds the outer periphery of the inner coating layer (3) and has a diameter of 175-185 µm. [2] Single-mode optical fiber with a large mode field and small diameter according to claim 1, wherein the single-mode optical fiber with a small diameter has a mode field diameter of 8.8-9.6 µm at a wavelength of 1310 nm. [3] Single-mode optical fiber with a large mode field and small diameter according to claim 1 or 2, wherein the single-mode optical fiber with a small diameter has a mode field diameter of 9 µm at a wavelength of 1310 nm. [4] Single-mode optical fiber with large mode field and small diameter according to claim 1, wherein the inner coating layer (3) has a modulus of elasticity of 0.2-0.4 MPa, a tensile strength of ≥ 30 MPa, an elongation at break of ≥ 20% and a Tg of ≤ -20 °C; and the outer coating layer (4) has a modulus of elasticity of 700-1000 MPa, a Tg of ≤ 90 °C and a coefficient of thermal expansion of 70-130 × 10 -6 K -1 has. [5] Single-mode optical fiber with a large mode field and small diameter according to claim 1, wherein the single-mode optical fiber with small diameter has a water permeability in the range of 20-50 g / (m²). 2 ·Day) has. [6] Single-mode optical fiber with large mode field and small diameter according to claim 1, wherein The macrobending performance of the small-diameter single-mode optical fiber meets the following requirements: when bent into a turn with a diameter of 20 mm, the macrobending loss is ≤0.5 dB at a wavelength of 1550 nm and ≤1.5 dB at a wavelength of 1625 nm; and When bent in ten revolutions with a diameter of 30 mm, the macrobending loss is ≤0.15 dB at a wavelength of 1550 nm and ≤0.5 dB at a wavelength of 1625 nm. [7] Single-mode optical fiber with a large mode field and small diameter according to claim 1, wherein the single-mode optical fiber with small diameter has an additional attenuation of ≤0.03 dB / km at a working wavelength of 1310 nm, 1383 nm, 1550 nm or 1625 nm in a temperature range of -60 °C to 85 °C. [8] Single-mode optical fiber with a large mode field and small diameter according to claim 1, wherein the inner coating layer (3) and the outer coating layer (4) of the single-mode optical fiber with small diameter have an average pull-off force greater than 1 N. [9] Micro-optical cable, wherein the micro-optical cable comprises the small-diameter single-mode optical fiber according to any one of claims 1 to 8. [10] Micro-optical cable according to claim 9, wherein the micro-optical cable is equipped with 96 small-diameter single-mode optical fibers and has an outer diameter of 4.7 mm; or The micro-optical cable is equipped with 144 small-diameter single-mode optical fibers and has an outer diameter of 5 mm.

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