New optical fiber

Abstract

The present invention provides a new type of optical fiber, which includes a coaxially arranged single-mode core, a multi-mode layer and an outer cladding from the inside to the outside, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, and the multi-mode layer surrounds the single-mode core and has an α profile distribution of refractive index; a plurality of transition layers are provided on the inside of the multi-mode layer and / or the outside of the multi-mode layer, wherein the transition layer is coaxially arranged with the single-mode core or the outer cladding, and the transition layer is in close contact with the multi-mode layer, and its refractive index is equal to the refractive index of the contact portion of the multi-mode layer. The new type of optical fiber of the present invention has both single-mode transmission and multi-mode transmission, which greatly simplifies the management of optical cables in data centers and reduces the cost of future transceiver upgrades, and the optical fiber has good low-loss characteristics by providing a transition layer. In addition, the design contains a lower doping layer or a recessed layer so that the optical fiber has better anti-bending performance.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber technology, in particular to a new type of optical fiber used in a data center. Background Art

[0002] This section is intended to provide a background or context to embodiments of the invention that are recited in the claims. No description herein is admitted to be prior art by inclusion in this section.

[0003] Single-mode fiber and multi-mode fiber are two different types of optical fibers, mainly due to the significant differences in mode and quantity. They are also used in different scenarios. In the use scenario of the data center, multi-mode fiber and single-mode fiber coexist. Compared with multi-mode fiber, single-mode fiber has obvious price advantages, but the price of single-mode transceiver is much higher than that of multi-mode transceiver. Comprehensive calculation shows that when the transmission distance is less than 100-150m, multi-mode transmission is still the most cost-effective solution.

[0004] However, as the construction volume and scale of data centers increase, the system bandwidth is high and the reach is long. Longer distance transmission in data centers still needs to rely on single-mode optical fiber. Therefore, single-mode and multi-mode optical fibers are mixed in a data center, and special processing is required during docking. If there is an optical fiber that can achieve both single-mode transmission and multi-mode transmission, it will greatly simplify optical cable management and reduce the cost of future transceiver upgrades. Summary of the invention

[0005] In view of the above, it is necessary to provide an improved new optical fiber which has both single-mode and multi-mode transmission.

[0006] The technical solution provided by the present invention is: a new type of optical fiber, which includes a coaxially arranged single-mode fiber core, a multi-mode layer and an outer cladding from the inside to the outside, wherein the single-mode fiber core is located at the center of the optical fiber and has an upper step refractive index, and the multi-mode layer surrounds the single-mode fiber core and has an α profile distribution refractive index; a plurality of transition layers are arranged on the inside of the multi-mode layer and / or on the outside of the multi-mode layer, wherein the transition layers are coaxially arranged with the single-mode fiber core or the outer cladding, and the transition layers are closely attached to the multi-mode layer, and the refractive index of the transition layers is equal to the refractive index of the contact portion of the multi-mode layer.

[0007] Further, when the transition layer is between the single-mode fiber core and the multi-mode layer, it is a first transition layer. Compared with pure silica, the relative refractive index δ0 of the first transition layer is between 0.5% and 2.0%, and the single-side width W0 of the first transition layer is between 1μm and 4μm; when the transition layer is between the multi-mode layer and the outer cladding, it is a second transition layer. Compared with pure silica, the relative refractive index δ5 of the second transition layer is between -0.4% and 0.15%, and the single-side width W5 of the second transition layer is between 1μm and 7μm.

[0008] Furthermore, the single-mode fiber core is germanium-doped silica glass, the radius r1 of which is between 3 μm and 5 μm, and the relative refractive index δ1 is higher than the relative refractive index δ0 of the first transition layer, δ1-δ0=0.25%-0.4%.

[0009] Furthermore, the relative refractive index δ2 of the multimode layer is between the relative refractive index δ0 of the first transition layer and the relative refractive index δ5 of the second transition layer, and is distributed in an α profile. The radius r2 of the multimode layer is between 15 μm and 35 μm, and α is between 1.8 and 2.5.

[0010] Furthermore, the radius r3 of the novel optical fiber is between 62 μm and 63 μm.

[0011] Furthermore, a lower doping layer with a lower step refractive index is included between the single-mode fiber core and the multimode layer, the relative refractive index δ4 of the lower doping layer is lower than the relative refractive index δ0 of the first transition layer, the single-side width W4 of the lower doping layer is between 0.5μm and 5μm, and δ4-δ0=-0.05% to -0.35%.

[0012] Furthermore, the lower doping layer comprises a coaxially arranged multi-layer structure, wherein the layer with a lower step refractive index is a main lower doping layer, and the others are auxiliary lower doping layers.

[0013] Furthermore, the lower doping layer comprises a main lower doping layer and an auxiliary lower doping layer, wherein

[0014] The single layer width of the main lower doping layer is W 04 is between 1 μm and 4 μm, and δ 04 -δ0=-0.1%~-0.35%;

[0015] The single layer width of the auxiliary lower doping layer is W 14 is between 0.5 μm and 4 μm, and δ 14 -δ0=-0.05%~-0.2%.

[0016] Furthermore, a depression layer with a lower step refractive index is included between the multimode layer and the outer cladding, the relative refractive index δ6 of the depression layer is lower than the relative refractive index δ5 of the second transition layer, the single-side width W6 of the depression layer is between 2 μm and 45 μm, the relative refractive index δ6 is between -0.05% and -0.4%, and the outer cladding is pure silica glass.

[0017] Furthermore, the depression layer comprises a coaxially arranged multi-layer structure, wherein the layer with a lower step refractive index is a main depression layer, and the others are auxiliary depression layers.

[0018] Furthermore, the depression layer includes a main depression layer and an auxiliary depression layer, wherein

[0019] The single layer width of the main depression layer is W 06 is between 2μm and 6μm, and the relative refractive index δ 06 Between -0.2% and -0.4%;

[0020] The single layer width of the auxiliary recessed layer is W 16 is between 2μm and 45μm, and the relative refractive index δ 16 It is between -0.05% and -0.2%.

[0021] Compared with the prior art, the present invention provides a new type of optical fiber, which includes a coaxially arranged single-mode core, a multi-mode layer and an outer cladding from the inside to the outside, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, and the multi-mode layer surrounds the single-mode core and has an α profile distribution refractive index; a plurality of transition layers are provided on the inside of the multi-mode layer and / or the outside of the multi-mode layer, wherein the transition layer is coaxially arranged with the single-mode core or the outer cladding, and the transition layer is in close contact with the multi-mode layer, and its refractive index is equal to the refractive index of the contact portion of the multi-mode layer. The new type of optical fiber of the present invention has both single-mode transmission and multi-mode transmission, which greatly simplifies the management of optical cables and reduces the cost of future transceiver upgrades, and the optical fiber has good low-loss characteristics by setting a transition layer. In addition, the design contains a lower doping layer or a depressed layer so that the optical fiber has better anti-bending performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0023] Figure 1 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the first embodiment of the present invention.

[0024] Figure 2 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the second embodiment of the present invention.

[0025] Figure 3 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the third embodiment of the present invention.

[0026] Figure 4 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the fourth embodiment of the present invention.

[0027] Figure 5 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the fifth embodiment of the present invention.

[0028] Figure 6 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the sixth embodiment of the present invention.

[0029] Figure 7 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the seventh embodiment of the present invention.

[0030] Figure 8 FIG. 4 is a refractive index distribution diagram of the novel optical fiber in the eighth embodiment of the present invention.

[0031] Fig. 9 for Figure 8 Schematic diagram of the cross-sectional structure of the new optical fiber shown.

[0032] Description of reference numerals:

[0033] none.

[0034] The following specific implementation manner will further illustrate the embodiments of the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0035] In order to more clearly understand the above-mentioned purposes, features and advantages of the embodiments of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0036] In the following description, many specific details are set forth to facilitate a full understanding of the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of the present invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the technical field of the embodiments of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific implementation methods and are not intended to limit the embodiments of the present invention.

[0038] The present invention provides a new type of optical fiber, which is a mixture of single-mode optical fiber and multi-mode optical fiber, and can realize single-mode transmission and multi-mode transmission, which will greatly simplify the management of optical cables and reduce the cost of future transceiver upgrades. The new type of optical fiber includes a coaxially arranged single-mode fiber core, a multi-mode layer and an outer cladding from the inside to the outside, wherein the single-mode fiber core is located at the center of the optical fiber and has an upper step refractive index, and the multi-mode layer surrounds the single-mode fiber core and has an α profile distribution refractive index; a plurality of transition layers are arranged on the inside of the multi-mode layer and / or on the outside of the multi-mode layer, wherein the transition layer is coaxially arranged with the single-mode fiber core or the outer cladding, and the transition layer is in close contact with the multi-mode layer, and its refractive index is equal to the refractive index of the contact portion of the multi-mode layer.

[0039] in,

[0040] The transition layer is between the single-mode fiber core and the multi-mode layer, and is also called the first transition layer. Compared with pure silica, the relative refractive index δ0 of the first transition layer is between 0.5% and 2.0%, and the single-side width W0 of the first transition layer is between 1 μm and 4 μm. Its relative refractive index δ0 is lower than the relative refractive index δ1 of the single-mode fiber core, and is equal to the refractive index of the contact part with the multi-mode layer (i.e., the inner side of the multi-mode layer), thereby reducing the difference. Meanwhile, during prefabrication, the viscosity of the transition layer precursor is also between the viscosity of the single-mode fiber core and the multi-mode layer, thereby realizing uniform drawing of the multi-layer sandwich structure, reducing the stress rise and large attenuation problems caused by viscosity mismatch during the drawing process, and making the new optical fiber have lower loss characteristics.

[0041] The transition layer, located between the multimode layer and the outer cladding, is also called the second transition layer. Compared with pure silica, the relative refractive index δ5 of the second transition layer is between -0.4% and 0.15%, and the single-side width W5 of the second transition layer is between 1μm and 7μm. Its relative refractive index δ5 is equal to the refractive index of the contact part of the multimode layer (i.e., the outer side of the multimode layer), which also ensures that the multimode layer has lower loss characteristics and reduces the difficulty of molding.

[0042] The single-mode fiber core is germanium-doped silica glass, with a radius r1 between 3 μm and 5 μm, and a relative refractive index δ1 higher than the relative refractive index δ0 of the first transition layer, δ1-δ0=0.25%-0.4%.

[0043] The multimode layer has a relative refractive index δ2 between the relative refractive index δ0 of the first transition layer and the relative refractive index δ5 of the second transition layer, and is distributed in an α profile. The radius r2 of the multimode layer is between 15μm and 35μm, and α is between 1.8 and 2.5.

[0044] The radius r3 of the novel optical fiber is between 62 μm and 63 μm.

[0045] The outer cladding is pure silica glass.

[0046] In a specific embodiment, a lower doping layer with a lower step refractive index is included between the single-mode fiber core and the multimode layer, the relative refractive index δ4 of the lower doping layer is lower than the relative refractive index δ0 of the first transition layer, the single-side width W4 of the lower doping layer is between 0.5 μm and 5 μm, and δ4-δ0=-0.05% to -0.35%. In a specific embodiment, the lower doping layer includes a coaxially arranged multi-layer structure, wherein the layer with a lower step refractive index is the main lower doping layer, and the others are auxiliary lower doping layers. For example, the lower doping layer includes a main lower doping layer and an auxiliary lower doping layer, wherein the single-layer width of the main lower doping layer is W 04 is between 1 μm and 4 μm, and δ 04 -δ0=-0.1%~-0.35%;The single layer width of the auxiliary lower doping layer is W 14 is between 0.5 μm and 4 μm, and δ 14 -δ0=-0.05%~-0.2%.

[0047] In a specific embodiment, a depression layer with a lower step refractive index is included between the multimode layer and the outer cladding, the relative refractive index δ6 of the depression layer is lower than the relative refractive index δ5 of the second transition layer, the single-side width W6 of the depression layer is between 2μm and 45μm, the relative refractive index δ6 is between -0.05% and -0.4%, and the outer cladding is pure silica glass. In a specific embodiment, the depression layer includes a coaxially arranged multi-layer structure, wherein the depression layer with a lower step refractive index is the main depression layer, and the others are auxiliary depression layers. For example, the depression layer includes a main depression layer and an auxiliary depression layer, wherein the single-layer width of the main depression layer is W 06 is between 2μm and 6μm, and the relative refractive index δ 06 is between -0.2% and -0.4%; the single layer width of the auxiliary depression layer is W 16 is between 2μm and 45μm, and the relative refractive index δ 16 It is between -0.05% and -0.2%.

[0048] The present invention is described in detail below with examples.

[0049] Example 1

[0050] like Figure 1As shown, the novel optical fiber includes a coaxially arranged single-mode core, a first transition layer, a multi-mode layer and an outer cladding from the inside to the outside, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, and the multi-mode layer surrounds the outer side of the transition layer and has an α profile distribution refractive index, wherein the radius r1 of the single-mode core is 4μm, and the relative refractive index δ1 is 1.25%; the first transition layer is a step refractive index, the single-side width W0 is 2μm, and the relative refractive index δ0 is 1.0%; the radius r2 of the multi-mode layer is 18μm, and α is 1.8; the outer cladding is pure silica glass, and the radius r3 of the novel optical fiber is 62μm. The main characteristics of the novel optical fiber are as follows: the mode field (@1300nm) diameter of the single-mode core is 9.8μm, and the optical fiber cutoff wavelength is 1210nm; the full injection bandwidth of the multi-mode layer is 500MHz·km at a wavelength of 850nm, and 2500MHz·km at a wavelength of 1310nm.

[0051] Example 2

[0052] like Figure 2 As shown, the novel optical fiber includes, from the inside to the outside, a coaxially arranged single-mode core, a first transition layer, a multimode layer, a second transition layer and an outer cladding, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, the multimode layer is between the first transition layer and the second transition layer, and has an α profile distribution of refractive index, wherein the radius r1 of the single-mode core is 3.8 μm, and the relative refractive index δ1 is 1.65%; the first transition layer is a step refractive index, with a single-side width W0 of 2 μm and a relative refractive index δ0 of 1.3%; the radius r2 of the multimode layer is 20.5 μm, and α is 1.97; the second transition layer is a step refractive index, with a single-side width W5 of 6 μm and a relative refractive index δ5 of -0.2%; the outer cladding is pure silica glass, and the radius r3 of the novel optical fiber is 62.5 μm. The main characteristics of the new optical fiber are as follows: the mode field diameter of the single-mode fiber core is 9.1μm, and the fiber cut-off wavelength is 1300nm; the full injection bandwidth of the multimode layer is 1300MHz·km at a wavelength of 850nm and 1300MHz·km at a wavelength of 1310nm.

[0053] Example 3

[0054] like Figure 3As shown, the novel optical fiber includes, from the inside to the outside, a coaxially arranged single-mode core, a lower doping layer, a first transition layer, a multimode layer and an outer cladding, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, the multimode layer is surrounded by the outer side of the transition layer and has an α profile distribution of refractive index, wherein the radius r1 of the single-mode core is 4 μm, and the relative refractive index δ1 is 2.1%; the single-side width W4 of the lower doping layer is 2 μm, and the relative refractive index δ4 is 1.78%; the first transition layer is a step refractive index, the single-side width W0 is 4 μm, and the relative refractive index δ0 is 1.8%; the radius r2 of the multimode layer is 30 μm, and α is 2.05; the outer cladding is pure silica glass, and the radius r3 of the novel optical fiber is 63 μm. The main characteristics of the new optical fiber are as follows: the mode field diameter of the single-mode fiber core is 8.9μm at a wavelength of 1310nm, and the fiber cutoff wavelength is 1250nm; the full injection bandwidth of the multimode layer is 4500MHz·km at a wavelength of 850nm and 600MHz·km at a wavelength of 1310nm. The macrobending loss of the new optical fiber with a bending radius of 15mm after 10 turns is 0.067dB at 850nm and 0.002dB at a wavelength of 1310nm.

[0055] Example 4

[0056] like Figure 4 As shown, the novel optical fiber includes, from the inside to the outside, a coaxially arranged single-mode core, a lower doping layer, a first transition layer, a multimode layer, a second transition layer and an outer cladding, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, the multimode layer is between the first transition layer and the second transition layer, and has an α profile distribution of refractive index, wherein the radius r1 of the single-mode core is 3.4 μm, and the relative refractive index δ1 is 1.2%; the single-side width W4 of the lower doping layer is 1 μm, and the relative refractive index δ4 is 0.7%; the first transition layer is a step refractive index, the single-side width W0 is 3 μm, and the relative refractive index δ0 is 0.8%; the radius r2 of the multimode layer is 30 μm, and α is 2.1; the second transition layer is a step refractive index, the single-side width W5 is 4 μm, and the relative refractive index δ5 is -0.2%; the outer cladding is pure silica glass, and the radius r3 of the novel optical fiber is 62.3 μm. The main characteristics of the new optical fiber are as follows: the mode field diameter of the single-mode fiber core is 8.8μm at a wavelength of 1310nm, and the cut-off wavelength is 1290nm. The full injection bandwidth of the multimode layer is 2500MHz·km at a wavelength of 850nm and 500MHz·km at a wavelength of 1310nm. The macrobending loss of the new optical fiber with a bending radius of 15mm around 10 turns is 0.067dB at 850nm, and the optical fiber attenuation at 1310nm is about 0.002dB / km.

[0057] Example 5

[0058] like Figure 5As shown, the novel optical fiber includes, from the inside to the outside, a coaxially arranged single-mode core, a first transition layer, a multi-mode layer, a second transition layer, a depressed layer and an outer cladding, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, the multi-mode layer is between the first transition layer and the second transition layer, and has a refractive index with an α profile distribution, wherein the radius r1 of the single-mode core is 5 μm, and the relative refractive index δ1 is 1.9%; the first transition layer is a step refractive index, with a single-side width W0 of 4.5 μm and a relative refractive index δ0 of 1.5%; the radius r2 of the multi-mode layer is 34.5 μm, and α is 2.2; the second transition layer is a step refractive index, with a single-side width W5 of 6 μm and a relative refractive index δ5 of 0; the single-side width W6 of the depressed layer is between 10 μm and the relative refractive index δ6 is -0.4%; the outer cladding is pure silica glass, and the radius r3 of the novel optical fiber is 63 μm. The main characteristics of the new optical fiber are as follows: the full injection bandwidth of the multimode layer is 600MHz·km at a wavelength of 850nm and 350MHz·km at a wavelength of 1310nm.

[0059] Example 6

[0060] like Figure 6 As shown, the novel optical fiber includes a coaxially arranged single-mode core, a first transition layer, a multi-mode layer, a second transition layer, a depressed layer and an outer cladding from the inside to the outside, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index, the multi-mode layer is between the first transition layer and the second transition layer and has an α profile distribution of refractive index, wherein the radius r1 of the single-mode core is 3 μm, and the relative refractive index δ1 is 1.3%; the first transition layer is a step refractive index, the single-side width W0 is 1.5 μm, and the relative refractive index δ0 is 1%; the radius r2 of the multi-mode layer is 28 μm, and α is 2.15; the second transition layer is a step refractive index, the single-side width W5 is 5.5 μm, and the relative refractive index δ5 is -0.05%; the single-side width W6 of the depressed layer is between 10 μm, and the relative refractive index δ6 is -0.35%; the outer cladding is pure silica glass, and the radius r3 of the novel optical fiber is 62.5 μm.

[0061] Example 7

[0062] like Figure 7 As shown, the novel optical fiber includes a coaxially arranged single-mode core, an auxiliary lower doping layer, a main lower doping layer, a first transition layer, a multimode layer, a second transition layer, a depressed layer and an outer cladding from the inside to the outside, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index and a refractive index with an α profile distribution, wherein the radius r1 of the single-mode core is 5 μm, and the relative refractive index δ1 is 1.9%; the single-layer width of the auxiliary lower doping layer is W 14 is 1 μm, and the relative refractive index δ 14 is 1.45%; the single layer width of the main lower doping layer is W 04is 2μm, and the relative refractive index δ 04 1.3%; the first transition layer is a step refractive index, the single-side width W0 is 4.5μm, and the relative refractive index δ0 is 1.5%; the radius r2 of the multimode layer is 35μm, and α is 2.2; the second transition layer is a step refractive index, the single-side width W5 is 6μm, and the relative refractive index δ5 is 0; the single-side width W6 of the depressed layer is between 10μm, and the relative refractive index δ6 is -0.3%; the outer cladding is pure silica glass, and the radius r3 of the new optical fiber is 62.8μm. The main characteristics of the new optical fiber are as follows: the macrobending loss with a bending radius of 15mm around 10 turns is 0.054dB at a wavelength of 850nm and 0.001dB at a wavelength of 1310nm.

[0063] Example 8

[0064] like Figure 8 As shown, the novel optical fiber includes a coaxially arranged single-mode core, a first transition layer, a multimode layer, a second transition layer, a main depressed layer, an auxiliary depressed layer and an outer cladding from the inside to the outside, wherein the single-mode core is located at the center of the optical fiber and has an upper step refractive index and a refractive index with an α profile distribution, wherein the radius r1 of the single-mode core is 5 μm, and the relative refractive index δ1 is 1.9%; the single-layer width of the auxiliary lower doping layer is W 14 is 1 μm, and the relative refractive index δ 14 is 1.45%; the single layer width of the main lower doping layer is W 04 is 2μm, and the relative refractive index δ 04 is 1.3%; the first transition layer is a step refractive index layer, with a single-side width W0 of 4.5μm and a relative refractive index δ0 of 1.5%; the radius r2 of the multimode layer is 35μm, and α is 2.2; the second transition layer is a step refractive index layer, with a single-side width W5 of 6μm and a relative refractive index δ5 of -0.05%; the single-layer width of the main depression layer is W 06 is 3μm, and the relative refractive index δ 06 is -0.35%; the single layer width of the auxiliary depression layer is W 16 is between 3μm, and the relative refractive index δ 16 The outer cladding is pure silica glass, and the radius r3 of the new optical fiber is 62.8μm. The main characteristics of the new optical fiber are as follows: the macrobending loss of 10 turns with a bending radius of 15mm is 0.048dB at 850nm and 0.001dB at 1310nm.

[0065] The above examples show that the mode field diameter of the single-mode core of the novel optical fiber of the present invention is 8.9-9.2 μm, and the optical fiber cutoff wavelength is 1250-1300 nm. The full injection bandwidth of the multimode layer is 500-4500 MHz·km at 850 nm and 400-2500 MHz·km at 1310 nm. The macrobending loss of the optical fiber with a bending radius of 15 mm around 10 turns is 0.048-0.67 dB at 850 nm and 0.001-0.02 dB at 1310 nm.

[0066] The above implementation modes are only used to illustrate the technical solutions of the embodiments of the present invention and are not intended to limit the present invention. Although the embodiments of the present invention are described in detail with reference to the above preferred implementation modes, those skilled in the art should understand that the technical solutions of the embodiments of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A new type of optical fiber, characterized by: From the inside to the outside, it includes a coaxially arranged single-mode fiber core, a multi-mode layer and an outer cladding, wherein the single-mode fiber core is located at the center of the optical fiber and has an upper step refractive index, and the multi-mode layer surrounds the single-mode fiber core and has an α profile distribution refractive index; a plurality of transition layers are arranged on the inner side of the multi-mode layer and / or on the outer side of the multi-mode layer, wherein the transition layer is coaxially arranged with the single-mode fiber core or the outer cladding, and the transition layer is closely attached to the multi-mode layer, and its refractive index is equal to the refractive index of the contact portion of the multi-mode layer; When the transition layer is between the single-mode core and the multi-mode layer, it is a first transition layer. Compared with pure silica, the relative refractive index δ0 of the first transition layer is between 0.5% and 2.0%, and the single-side width W0 of the first transition layer is between 1 μm and 4 μm. When the transition layer is between the multi-mode layer and the outer cladding, it is a second transition layer. Compared with pure silica, the relative refractive index δ5 of the second transition layer is between -0.4% and 0.15%, and the single-side width W5 of the second transition layer is between 1 μm and 7 μm. The relative refractive index δ1 of the single-mode fiber core is higher than the relative refractive index δ0 of the first transition layer, δ1-δ0=0.25%~0.4%; the relative refractive index δ2 of the multimode layer is between the relative refractive index δ0 of the first transition layer and the relative refractive index δ5 of the second transition layer, and is distributed in an α profile, where α is between 1.8 and 2.

5.

2. The novel optical fiber according to claim 1, characterized in that: The single-mode fiber core is germanium-doped silica glass, and its radius r1 is between 3 μm and 5 μm.

3. The novel optical fiber according to claim 1, characterized in that: The radius r2 of the multimode layer is between 15 μm and 35 μm.

4. The novel optical fiber according to claim 1, characterized in that: The radius r3 of the novel optical fiber is between 62 μm and 63 μm.

5. The novel optical fiber according to any one of claims 2 to 4, characterized in that: A lower doping layer with a lower step refractive index is included between the single-mode fiber core and the multimode layer, the relative refractive index δ4 of the lower doping layer is lower than the relative refractive index δ0 of the first transition layer, the single-side width W4 of the lower doping layer is between 0.5μm and 5μm, and δ4-δ0=-0.05%~-0.35%.

6. The novel optical fiber according to claim 5, characterized in that: The lower doping layer comprises a coaxially arranged multi-layer structure, wherein the layer with a lower step refractive index is a main lower doping layer, and the others are auxiliary lower doping layers.

7. The novel optical fiber according to claim 5, characterized in that: The lower doping layer includes a main lower doping layer and an auxiliary lower doping layer, wherein The single layer width of the main lower doping layer is W 04 is between 1 μm and 4 μm, and δ 04 -δ0=-0.1%~-0.35%; The single layer width of the auxiliary lower doping layer is W 14 is between 0.5 μm and 4 μm, and δ 14 -δ0=-0.05%~-0.2%.

8. The novel optical fiber according to any one of claims 2 to 4, characterized in that: A depression layer with a lower step refractive index is included between the multimode layer and the outer cladding, the relative refractive index δ6 of the depression layer is lower than the relative refractive index δ5 of the second transition layer, the single-side width W6 of the depression layer is between 2 μm and 45 μm, the relative refractive index δ6 is between -0.05% and -0.4%, and the outer cladding is pure silica glass.

9. The novel optical fiber according to claim 8, characterized in that: The depression layer comprises a coaxially arranged multi-layer structure, wherein the layer with a lower step refractive index is a main depression layer, and the others are auxiliary depression layers.

10. The novel optical fiber according to claim 8, characterized in that: The concave layer includes a main concave layer and an auxiliary concave layer, wherein The single layer width of the main depression layer is W 06 is between 2μm and 6μm, and the relative refractive index δ 06 Between -0.2% and -0.4%; The single layer width of the auxiliary recessed layer is W 16 is between 2μm and 45μm, and the relative refractive index δ 16 It is between -0.05% and -0.2%.

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