CN205333906U - Few mode fiber - Google Patents
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- CN205333906U CN205333906U CN201620088770.0U CN201620088770U CN205333906U CN 205333906 U CN205333906 U CN 205333906U CN 201620088770 U CN201620088770 U CN 201620088770U CN 205333906 U CN205333906 U CN 205333906U
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- 239000000835 fiber Substances 0.000 title claims abstract description 116
- 230000007547 defect Effects 0.000 claims abstract description 47
- 238000001914 filtration Methods 0.000 claims abstract description 12
- 239000013307 optical fiber Substances 0.000 claims description 133
- 238000009826 distribution Methods 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 4
- 238000005452 bending Methods 0.000 abstract description 72
- 230000005540 biological transmission Effects 0.000 abstract description 8
- 230000008878 coupling Effects 0.000 abstract description 4
- 238000010168 coupling process Methods 0.000 abstract description 4
- 238000005859 coupling reaction Methods 0.000 abstract description 4
- 230000007847 structural defect Effects 0.000 abstract 4
- 239000010410 layer Substances 0.000 description 98
- 230000003287 optical effect Effects 0.000 description 11
- 238000005516 engineering process Methods 0.000 description 5
- 238000004804 winding Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 4
- 238000005253 cladding Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
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Abstract
The utility model provides a few mode fiber, this optic fibre includes: fibre core and covering, the fibre core includes: interior fibre core and encirclement the outer fibre core of interior fibre core, the covering includes: surround the adjacent core low -index layer of outer fibre core, surround little structural defect district of neighbour's core low -index layer, strain mould layer and low refracting index by the high refractive index of interval arrangement and strain the mould layer and form in little structural defect district, surround neighbour's package low -index layer in little structural defect district, surround the surrounding layer of neighbour's package low -index layer. Wherein, optic fibre is non - single mode fiber under straight waveguide state, after appropriate bending, the higher order mode of optic fibre with the close coupling takes place for the defect mould in little structural defect district, and then realizes the filtering the purpose of optic fibre higher order mode realizes single mode transmission.
Description
Technical field
This utility model relates to fiber optic communication field, more particularly, it relates to can keep low-loss transmission under small-bend radius and be capable of the less fundamental mode optical fibre of single mode operation。
Background technology
It is widely used along with the Fibre Optical Communication Technology of science and technology in daily life and work, brings huge facility for daily life and work, become the technology that people's daily life is indispensable with work。
Conventional single-mode fiber has certain bending resistance, but in life at present, Metropolitan Area Network (MAN), LAN and the technology such as fiber to the home, short haul connection are general to be applied in daily life and work, for convenient-laying or in order to reduce the space shared by optical fiber, optical fiber is accomplished by working under small-bend radius。But the G.652 optical fiber of routine, it is possible to working under minimum bending radius 30mm, but need less bending radius in Metropolitan Area Network (MAN), LAN and fiber to the home, short haul connection, G.652 optical fiber can not meet requirement。The G.657 optical fiber proposed in the world solves G.652 problem existing for optical fiber, can work under the 7.5mm even bending radius of 5mm, but bending loss is bigger G.657 optical fiber works under small-bend radius, it is difficult to realize steady in a long-term working under small-bend radius。
Therefore, how to provide a kind of and can realize single mode transport and to keep the optical fiber of low-loss transmission under small-bend radius be present stage problem demanding prompt solution。
Utility model content
For solving above-mentioned technical problem, this utility model provides a kind of less fundamental mode optical fibre, and this optical fiber can realize single mode transport and keep low-loss transmission under small-bend radius。
For achieving the above object, this utility model provides following technical scheme:
A kind of less fundamental mode optical fibre, this optical fiber includes: fibre core and covering；
Described fibre core includes: interior fibre core and the outer fibre core surrounding described interior fibre core；The refractive index of described interior fibre core is n1；The refractive index of described outer fibre core is n2；
Described covering includes: surrounding the adjacent core low-index layer of described outer fibre core, refractive index is n3；Surround the microstructural defects district of described adjacent core low-index layer；Described microstructural defects district is made up of alternately arranged high index of refraction filter mold layer and low-refraction filter mold layer；The refractive index of described high index of refraction filter mold layer is n5；The refractive index of described low-refraction filter mold layer is n6；Surrounding the adjacent bag low-index layer in described microstructural defects district, refractive index is n4；Surrounding the surrounding layer of described adjacent bag low-index layer, refractive index is n7；Wherein, the quantity of described high index of refraction filter mold layer is no less than two；
Meet between described interior fibre core and described outer fibre core: 2.0 < V < 2.65, whereinV represents normalized frequency, λ0=1310nm, a1Represent the radius of described interior fibre core；Refractive Index of Material between each layer of described optical fiber meets: n1> n2> n3, n5> n3And have n3=n4=n6, n7≥n2；
Definition is at 1550nm wavelength place, and the mean refractive index in described microstructural defects district is neAnd meet: 0.003 > n11-ne> 0, n11For fibre core LP11The effective refractive index of mould；Wherein, ne=(n5S1+n6S2)/S, S1The area sum of mold layer, S is filtered for all described highs index of refraction2The area sum of mold layer is filtered for all described low-refractions；S=S1+S2, for described microstructural defects district area sum。
Preferably, in above-mentioned optical fiber, the cutoff wavelength of described optical fiber is more than 1.625 μm。
Preferably, in above-mentioned optical fiber, described high index of refraction filter mold layer has two-layer and described low-refraction filter mold layer to have one layer。
Preferably, in above-mentioned optical fiber, described high index of refraction filter mold layer has three layers and described low-refraction filter mold layer to have two-layer。
Preferably, in above-mentioned optical fiber, the interior fibre core of described optical fiber adopts parabolic shaped structure, and described interior fibre core meets along the index distribution of described optical fiber radially r:Wherein, a1≥r≥0。
Preferably, in above-mentioned optical fiber, at 1550nm wavelength place, described optical fiber can realize effectively filtering the radius of curvature R of mouldbShould meet: | (n11-ne)-0.78dc/Rb|≤0.002；Dc=(dX+dB)/2 define dc=(dX+dB)/2, here dXFor the radius of described adjacent core low-index layer, dBRadius for described adjacent bag low-index layer。
Preferably, in above-mentioned optical fiber, described optical fiber can realize effectively filtering the radius of curvature R of mouldbShould meet: | (n11-ne)-0.78dc/Rb|≤0.001。
Preferably, in above-mentioned optical fiber, described optical fiber can realize effectively filtering the radius of curvature R of mouldbMeet 10mm >=Rb≥5mm。
Preferably, in above-mentioned optical fiber, the radial width of described outer fibre core meets: 10 μm >=a2>=3 μm and have a2> a1；Wherein, a2Represent the radial width of described outer fibre core。
Preferably, in above-mentioned optical fiber, the span of the radial width of described adjacent core low-index layer, described adjacent bag low-index layer, described high index of refraction filter mold layer and described low-refraction filter mold layer is 1 μm～5 μm。
From technique scheme it can be seen that this utility model is provided a kind of less fundamental mode optical fibre, this optical fiber includes: fibre core and covering；Described fibre core includes: interior fibre core and the outer fibre core surrounding described interior fibre core；Described covering includes: surround the adjacent core low-index layer of described outer fibre core；Surround the microstructural defects district of described adjacent core low-index layer；Mold layer is filtered by spaced high index of refraction by described microstructural defects district and low-refraction filter mold layer forms；Surround the adjacent bag low-index layer in described microstructural defects district；Surround the surrounding layer of described adjacent bag low-index layer。Wherein, described optical fiber is non-single-mode fiber under straight wave guide state, after suitable bending, and the pattern generation close coupling of the filter mold layer in the high-order mode of described optical fiber and described microstructural defects district, and then realize filtering the purpose of described optical fiber high-order mode, it is achieved single mode transport。Microstructural defects district described in described optical fiber forms defect modular group, makes Defect Modes higher with coupling of described optical fiber high-order mode, all can realize strong filter mould effect within the scope of broader wavelength and bending radius。Described microstructural defects district effective refractive index under straight wave guide state is relatively low, therefore that the impact of described optical fiber basic mode is less, it is ensured that the low bend loss transmission of described optical fiber basic mode, can keep low-loss transmission and be capable of single mode operation under small-bend radius。
Accompanying drawing explanation
In order to be illustrated more clearly that this utility model embodiment or technical scheme of the prior art, the accompanying drawing used required in embodiment or description of the prior art will be briefly described below, apparently, accompanying drawing in the following describes is only embodiment of the present utility model, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to the accompanying drawing provided。
Fig. 1 is a kind of step optical fiber equivalent refractive index scattergram under straight wave guide and bending situation；
The radial refractive index distribution figure of a kind of optical fiber that Fig. 2 (a) provides for the embodiment of the present application；
The structural representation of a kind of optical fiber that Fig. 2 (b) provides for the embodiment of the present application；
A kind of optical fiber that Fig. 3 (a) provides for the embodiment of the present application when bending, its LP11aThe mode distributions figure of mould；
A kind of optical fiber that Fig. 3 (b) provides for the embodiment of the present application when bending, its LP11bThe mode distributions figure of mould；
The bending loss of the basic mode of a kind of optical fiber that Fig. 4 (a) provides for the embodiment of the present application is with the change curve of bending radius；
The LP of a kind of optical fiber that Fig. 4 (b) provides for the embodiment of the present application11The bending loss of mould is with the change curve of bending radius；
The bending direction schematic diagram of a kind of optical fiber that Fig. 5 provides for the embodiment of the present application；
The bending loss of the basic mode of a kind of optical fiber that Fig. 6 (a) provides for the embodiment of the present application is with the change curve of optical wavelength；
The LP of a kind of optical fiber that Fig. 6 (b) provides for the embodiment of the present application11The bending loss of mould is with the change curve of optical wavelength。
Detailed description of the invention
Below in conjunction with the accompanying drawing in this utility model embodiment, the technical scheme in this utility model embodiment is clearly and completely described, it is clear that described embodiment is only a part of embodiment of this utility model, rather than whole embodiments。Based on the embodiment in this utility model, the every other embodiment that those of ordinary skill in the art obtain under not making creative work premise, broadly fall into the scope of this utility model protection。
Fig. 1 is a kind of step optical fiber equivalent refractive index scattergram under straight wave guide and bending situation。Wherein, X-axis refers to the bending axis of optical fiber, and n is refractive index。Bending loss according to optical fiber is theoretical it can be seen that when described fibre-optical bending, the structure of described optical fiber can be equivalent to a straight wave guide, and the refractive index of described optical fiber is one disturbance of generation on the basis of former Refractive Index Profile o。Namely the index distribution of the straight wave guide of equivalence is represented by:Wherein, n0((x, y) is the index distribution of straight wave guide of equivalence to n, and χ is the elasto-optical coefficient of material, and for silica fibre, χ value is-0.22, and R is the bending radius of described optical fiber for x, the cross section index distribution of optical fiber when being y) do not bend。For step index fiber, when bending, the fibre core of described optical fiber X-direction and cladding index all increase。As described in Figure 1, when bending to a certain degree, the refractive index of described covering will be greater than described fiber core refractive index, and close with described fibre core spacing, thus there is leakage loss。
With reference to Fig. 1, increase described fibre core and described clad refractive rate variance and the spacing of described cladding index region and described fibre core can be made to increase, thus reducing the bending loss of described optical fiber。But, the pattern theory according to step optical fiber, during normalized frequency V > 2.405Described optical fiber will appear from high-order mode。In order to ensure that described optical fiber is single mode transport, it is necessary to remove the high-order mode in described optical fiber。
Therefore, in order to realize a kind of single mode and low bend loss transmission, the application provides a kind of optical fiber it is achieved that the radial refractive index distribution figure of a kind of optical fiber provided for the embodiment of the present application with reference to Fig. 2 (a) and Fig. 2 (b), Fig. 2 (a)；The structural representation of a kind of optical fiber that Fig. 2 (b) provides for the embodiment of the present application。This optical fiber includes: fibre core and covering；Described fibre core includes: interior fibre core 11 and the outer fibre core 12 surrounding described interior fibre core 11；The refractive index of described interior fibre core 11 is n1；The refractive index of described outer fibre core 12 is n2；Described covering includes: surrounding the adjacent core low-index layer 13 of described outer fibre core 12, refractive index is n3；Surround the microstructural defects district of described adjacent core low-index layer 13；Described microstructural defects district is made up of alternately arranged high index of refraction filter mold layer 15 and low-refraction filter mold layer 16；The refractive index of described high index of refraction filter mold layer 15 is n5；The refractive index of described low-refraction filter mold layer 16 is n6；Surrounding the adjacent bag low-index layer 14 in described microstructural defects district, refractive index is n4；Surrounding the surrounding layer 17 of described adjacent bag low-index layer 14, refractive index is n7；Wherein, the quantity of described high index of refraction filter mold layer 15 is no less than two。Refractive Index of Material between each layer of described optical fiber meets: n1> n2> n3, n5> n3And have n3=n4=n6, n7≥n2。
Definition is at 1550nm wavelength place, and the mean refractive index in described microstructural defects district is neAnd meet: 0.003 > n11-ne> 0, n11For fibre core LP11The effective refractive index of mould；Wherein, ne=(n5S1+n6S2)/S, S1The area sum of mold layer 15, S is filtered for all described highs index of refraction2The area sum of mold layer 16 is filtered for all described low-refractions；S=S1+S2, for the area in described microstructural defects district。
High-order mode in described fibre core should have and the effective refractive index of described outer fibre core 12 refractive index close, couples thus being easier to when bending with the Defect Modes in described covering, thus, its normalized frequency parameter should be close with single-mode fiber。Meanwhile, fibre core basic mode should match with general single mode fiber。Take for this and meet between described interior fibre core 11 and described outer fibre core 12: 2.0 < V < 2.65, whereinV represents normalized frequency, λ0=1310nm, a1Represent the radius of described interior fibre core 11；Namely, when described outer fibre core 12 radial width is very wide, its structure is identical with step structure general single mode fiber。Even if the radial width of described outer fibre core 12 is less, owing to foundational model field is exponentially decayed outside described interior fibre core 11, its foundational model field also has the mould field of similar single-mode fiber。Meanwhile, described outer fibre core 12 and described interior fibre core 11 form the core structure of entirety, owing to described outer fibre core 12 area is much larger than described interior fibre core 11, become big doped core optical fiber, so that the LP formed11The effective refractive index of mould will be close with described outer fibre core 12。For this, it is desirable to the radial width a of described outer fibre core 122Radius a more than described interior fibre core 111, a2> a1。Thus the area of described outer fibre core 12 is at least more than three times of described interior fibre core 11。
Conventional telecommunications fiber is single-mode fiber, and namely its cutoff wavelength is less than its communication wavelengths。The cutoff wavelength of described optical fiber is more than 1.625 μm, and namely it is under straight wave guide state, is non-single mode transport at general communication windows such as 1.55 mum wavelengths, is a kind of less fundamental mode optical fibre。Its objective is to ensure that the described fibre core of described optical fiber and described covering have enough refractivitys so that it is basic mode has low bend loss。Its high-order mode is enable to be filtered out for this reason, it may be necessary to design suitable cladding structure, thus realizing the single mode transport of equivalence。
Described microstructural defects district can support a number of pattern, and its effective refractive index is distributed between wider index region, so that described optical fiber high-order mode is easier to couple with it。High index of refraction filter mold layer 15 described in multilamellar is adopted to form defect layer, it is possible to make the Defect Modes that each filter mold layer is formed couple, form super model group。Simultaneously, owing to the equivalent refractive index of this microstructural defects layer is described high index of refraction filter mold layer 15 and the meansigma methods of described low-refraction filter mold layer 16 refractive index, therefore, with only filtered compared with mold layer 15 forms defect layer by monolayer high index of refraction, microstructural defects layer can ensure that under the satisfactory premise of effective refractive index of Defect Modes, described high index of refraction filter mold layer 15 is bigger with the refractivity of described low-refraction filter mold layer 16, is more prone to so that making。Described high index of refraction filter mold layer 15 and described low-refraction filter mold layer 16 are alternately arranged。Wherein, described high index of refraction filter mold layer 15 is formed by 2 layers to 3 layers。
So that under corresponding bending radius, optical fiber LP11Mould couples with Defect Modes, then require effective refractive index and the optical fiber LP of Defect Modes under straight wave guide11The difference of the effective refractive index of mould is in the excursion of the refractive index in the microstructural defects district that fibre-optical bending causes。Owing to microstructural defects district area is relatively big, the effective refractive index of its Defect Modes is close with the mean refractive index in microstructural defects district。On the other hand, LP11The effective refractive index of mould is close with described outer fibre core 12。Therefore, this problem is also reduced to the optical fiber parameter that design is suitable, makes the mean refractive index in microstructural defects district and the refractive index of described outer fibre core 12 meet certain difference。Thus, bend to ask optical fiber to pass through to realize filtering the purpose of high-order mode, then the bending radius of optical fiber is had certain requirement。Namely optical fiber is in use, needs wittingly to be curved within the scope of certain bending radius, and reaches enough bending lengths。Namely it needs to be determined that be capable of effectively filtering the fiber bending radius scope R of mouldb。
The mean refractive index n in the microstructural defects district of described high index of refraction filter mold layer 15 and described low-refraction filter mold layer 16 compositioneCan approximate representation ne=(n5S1+n6S2)/S, S1The area sum of mold layer 15, S is filtered for all described highs index of refraction2The area sum of mold layer is filtered for all described low-refractions。S=S1+S2, mold layer 15 and the gross area sum of all described low-refractions filter mold layer 16 is filtered for all described highs index of refraction。
Equivalent flexural refractive index formula according to optical fiber is it can be seen that when optical fiber bends along X-axis positive direction, in X-axis positive direction, the increase amount being in the refractive index of microstructural defects district center position is 0.78dc/Rb, d herec=(dX+dB)/2, dXFor the radius of described adjacent core low-index layer, dBRadius for described adjacent bag low-index layer。Thus, it is desirable to 0.002 >=n11-ne-0.78dc/Rb>=-0.002。Namely optical fiber can realize effectively filtering the radius of curvature R of mouldbShould meet: | (n11-ne)-0.78dc/Rb|≤0.002。
For in more preferably situation, in microstructural defects district, refractive index in the bent state should with described fibre core LP11The refractive index of mould is as far as possible close, thus increasing coupling of Defect Modes and optical fiber high-order mode, also effectively suppressing the Defect Modes impact on the loss of fibre core basic mode simultaneously, thus can further require that | (n11-ne)-0.78dc/Rb|≤0.001。
As the optical fiber realizing low bend loss transmission, described optical fiber can realize effectively filtering the radius of curvature R of mouldbIdeal range be: 5mm～10mm, the bending loss to ensure the Defect Modes in microstructural defects district is sufficiently large。
The fibre core adopted and surrounding structure parameter can ensure that microstructural defects district is less on the impact of optical fiber basic mode, therefore, mode field diameter computing formula according to step optical fiber, another restrictive condition to the application optical fiber can be obtained, that is: F=8.6 μm～9.5 μm, there is F=2 (0.65+1.619V here-3/2+2.879V-6)a1。
The interior fibre core 11 of described optical fiber can adopt parabolic structure, and it meets along the index distribution of optical fiber radially r:Here a1>=r >=0。Its objective is to reduce the effective refractive index of optical fiber high-order mode, and make the mould field of its high-order mode extend to described outer fibre core 12 so that it is bending loss increases, make its refractivity with described optical fiber basic mode increase simultaneously。
A kind of optical fiber provided for the embodiment of the present application with reference to Fig. 3 (a) and Fig. 3 (b), Fig. 3 (a) when bending, its LP11aThe mode distributions figure of mould；A kind of optical fiber that Fig. 3 (b) provides for the embodiment of the present application when bending, its LP11bThe mode distributions figure of mould。When optical fiber bends, its LP11The mould difference according to its mode distributions, is divided into LP11aAnd LP11bMould, wherein LP11bMould has higher bending loss。Reason is, after fibre-optical bending, its mould field is easier to extend to covering。
The bending loss of the basic mode of a kind of optical fiber that reference Fig. 4 (a) and Fig. 4 (b), Fig. 4 (a) provide for the embodiment of the present application is with the change curve of bending radius；The LP of a kind of optical fiber that Fig. 4 (b) provides for the embodiment of the present application11The bending loss of mould is with the change curve of bending radius。When optical wavelength is 1550nm, the basic mode of optical fiber has relatively low bending loss。And two kinds of LP11The bending loss of mould differs up to an order of magnitude。For LP11bMould, its bending loss is up to more than 100dB/m, and therefore, being wound around a few circle under small-bend radius can remove。And LP11aThe bending loss of mould is relatively small。Theoretical according to fiber mode, LP11aMould and LP11bMould has reciprocity, and even bending direction is adjusted to along Y direction, then LP11aMould will have high bending loss。Therefore, to more effectively remove LP11aMould and LP11bMould, need only with small-bend radius, respectively along X-axis with Y-axis winding optical fiber is several encloses。As it is shown in figure 5, the bending direction schematic diagram of a kind of optical fiber that Fig. 5 provides for the embodiment of the present application。Namely time actually used, can pass through along orthogonal two cross section of optic fibre axis directions winding optical fiber at least two circle respectively, thus reaching to remove LP11aMould and LP11bThe purpose of mould。
The bending loss of the basic mode of a kind of optical fiber that reference Fig. 6 (a) and Fig. 6 (b), Fig. 6 (a) provide for the embodiment of the present application is with the change curve of optical wavelength；The LP of a kind of optical fiber that Fig. 6 (b) provides for the embodiment of the present application11The bending loss of mould is with the change curve of optical wavelength。When optical wavelength is more short, the bending loss of optical fiber is also more little。Thus, as long as the bending loss that optical fiber basic mode is when 1550nm wavelength meets requirement, then its bending loss when more short wavelength also can meet requirement。Equally, the LP of optical fiber11The bending loss of mould 1310nm meet require time, its bending loss when longer wavelength is bigger, it is easier to meet requirement。
Embodiment one:
The radius a of interior fibre core 111=4.1 μm, the radial width a of outer fibre core 122=6 μm。Adjacent core low-index layer 13 radial width is 3 μm, adjacent bag low-index layer 14 radial width is 3 μm, high index of refraction filter mold layer 15 radial width is 3 μm, low-refraction filter mold layer 16 radial width is 2 μm。High index of refraction filter mold layer 15 and low-refraction filter mold layer 16 respectively three layers and two-layer, and optical fiber structure is as shown in Figure 2。Interior fibre core 11, outer fibre core 12, adjacent core low-index layer 13, adjacent bag low-index layer 14, the refractive index n of high index of refraction filter mold layer 15, low-refraction filter mold layer 16 and surrounding layer 171,n2,n3,n4,n5,n6,n7Between meet: n1-n2=0.005, n2-n3=0.004, n2-n5=0.002, n3=n4=n6, n2=n7。
When optical wavelength is 1550nm, the basic mode of optical fiber and LP11The bending loss of mould is as shown in Figure 4。When the bending radius of optical fiber is 10,7.5 and 6mm, its basic mode bending loss is respectively smaller than 0.01 and 0.05,0.2dB/m。When optical wavelength is 1310nm, when the bending radius of optical fiber is 10,7.5 and 6mm, its LP11aThe bending loss of mould is respectively greater than 2,20 and 500dB/m。As it is shown in figure 5, when wavelength is shorter, the bending loss of its basic mode is also more little, and for LP11Mould, when its wavelength is longer, its bending loss is bigger。Therefore, enclose along X-direction winding optical fiber 1 with 6mm bending radius, then enclose with same bending radius winding optical fiber 1 along Y direction, LP can be made11The loss of mould increases more than 15dB, thus realizing single mode transport。Optical fiber is 9 μm in the mode field diameter of 1310nm。
Embodiment two:
The radius a of interior fibre core 111=4 μm, the radial width a of outer fibre core 122=6 μm。Adjacent core low-index layer 13 radial width is 3 μm, adjacent bag low-index layer 14 radial width is 3 μm, high index of refraction filter mold layer 15 radial width is 3 μm, low-refraction filter mold layer 16 radial width is 2 μm。High index of refraction filter mold layer 15 and low-refraction filter mold layer 16 respectively two-layer and one layer。Interior fibre core 11, outer fibre core 12, adjacent core low-index layer 13, adjacent bag low-index layer 14, the refractive index n of high index of refraction filter mold layer 15, low-refraction filter mold layer 16 and surrounding layer 171,n2,n3,n4,n5,n6,n7Between meet: n1-n2=0.005, n2-n3=0.007, n2-n5=-0.001, n3=n4=n6, n2=n7。
When optical wavelength is 1550nm, when the bending radius of optical fiber is 10,7.5 and 5mm, its basic mode bending loss is respectively smaller than 0.0019,0.015 and 0.67dB/m, and when wavelength is shorter, its bending loss is less。When optical wavelength is 1310nm, when the bending radius of optical fiber is 15,10,7.5 and 5mm, the bending loss of its LP11 mould is respectively greater than 0.6,37 and 62,191dB/m。Therefore, enclose from two mutually perpendicular directions winding optical fiber 2 respectively with 5mm bending radius, single mode transport can be realized。Optical fiber is 8.8 μm in the mode field diameter of 1310nm。
Described above to the disclosed embodiments, makes professional and technical personnel in the field be capable of or uses this utility model。The multiple amendment of these embodiments be will be apparent from for those skilled in the art, and generic principles defined herein when without departing from spirit or scope of the present utility model, can realize in other embodiments。Therefore, this utility model is not intended to be limited to the embodiments shown herein, and is to fit to the widest scope consistent with principles disclosed herein and features of novelty。
Claims (10)
1. a less fundamental mode optical fibre, it is characterised in that including: fibre core and covering；
Described fibre core includes: interior fibre core and the outer fibre core surrounding described interior fibre core；The refractive index of described interior fibre core is n1；The refractive index of described outer fibre core is n2；
Described covering includes: surrounding the adjacent core low-index layer of described outer fibre core, refractive index is n3；Surround the microstructural defects district of described adjacent core low-index layer；Described microstructural defects district is made up of alternately arranged high index of refraction filter mold layer and low-refraction filter mold layer；The refractive index of described high index of refraction filter mold layer is n5；The refractive index of described low-refraction filter mold layer is n6；Surrounding the adjacent bag low-index layer in described microstructural defects district, refractive index is n4；Surrounding the surrounding layer of described adjacent bag low-index layer, refractive index is n7；Wherein, the quantity of described high index of refraction filter mold layer is no less than two；
Meet between described interior fibre core and described outer fibre core: 2.0 < V < 2.65, whereinV represents normalized frequency, λ0=1310nm, a1Represent the radius of described interior fibre core；Refractive Index of Material between each layer of described optical fiber meets: n1> n2> n3, n5> n3And have n3=n4=n6, n7≥n2；
Definition is at 1550nm wavelength place, and the mean refractive index in described microstructural defects district is neAnd meet: 0.003 > n11-ne> 0, n11For fibre core LP11The effective refractive index of mould；Wherein, ne=(n5S1+n6S2)/S, S1The area sum of mold layer, S is filtered for all described highs index of refraction2The area sum of mold layer is filtered for all described low-refractions；S=S1+S2, for the area in described microstructural defects district。
2. less fundamental mode optical fibre according to claim 1, it is characterised in that the cutoff wavelength of described optical fiber is more than 1.625 μm。
3. less fundamental mode optical fibre according to claim 1, it is characterised in that described high index of refraction filter mold layer has two-layer and described low-refraction filter mold layer to have a layer。
4. less fundamental mode optical fibre according to claim 1, it is characterised in that described high index of refraction filter mold layer has three layers and described low-refraction filter mold layer to have two-layer。
5. less fundamental mode optical fibre according to claim 1, it is characterised in that the interior fibre core of described optical fiber adopts parabolic shaped structure, described interior fibre core meets along the index distribution of described optical fiber radially r: Wherein, a1≥r≥0。
6. less fundamental mode optical fibre according to claim 1, it is characterised in that at 1550nm wavelength place, described optical fiber can realize effectively filtering the radius of curvature R of mouldbShould meet: | (n11-ne)-0.78dc/Rb|≤0.002；Definition dc=(dX+dB)/2, here dXFor the radius of described adjacent core low-index layer, dBRadius for described adjacent bag low-index layer。
7. less fundamental mode optical fibre according to claim 6, it is characterised in that at 1550nm wavelength place, described optical fiber can realize effectively filtering the radius of curvature R of mouldbShould meet: | (n11-ne)-0.78dc/Rb|≤0.001。
8. less fundamental mode optical fibre according to claim 6, it is characterised in that described optical fiber can realize effectively filtering the radius of curvature R of mouldbMeet 10mm >=Rb≥5mm。
9. less fundamental mode optical fibre according to claim 1, it is characterised in that the radial width of described outer fibre core meets: 10 μm >=a2>=3 μm and have a2> a1；Wherein, a2Represent the radial width of described outer fibre core。
10. less fundamental mode optical fibre according to claim 1, it is characterised in that the span of the radial width of described adjacent core low-index layer, described adjacent bag low-index layer, described high index of refraction filter mold layer and described low-refraction filter mold layer is 1 μm～5 μm。
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105445853A (en) * | 2016-01-28 | 2016-03-30 | 国网江西省电力公司信息通信分公司 | Few-mode fiber |
| CN106019475A (en) * | 2016-07-28 | 2016-10-12 | 江苏大学 | Few-mode fiber device |
| CN106597603A (en) * | 2016-10-18 | 2017-04-26 | 国网江西省电力公司信息通信分公司 | Novel few-mode fiber |
| WO2023134327A1 (en) * | 2022-01-12 | 2023-07-20 | 华为技术有限公司 | Light receiving module, device and method |
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2016
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105445853A (en) * | 2016-01-28 | 2016-03-30 | 国网江西省电力公司信息通信分公司 | Few-mode fiber |
| CN105445853B (en) * | 2016-01-28 | 2018-08-28 | 国网江西省电力公司信息通信分公司 | A kind of less fundamental mode optical fibre |
| CN106019475A (en) * | 2016-07-28 | 2016-10-12 | 江苏大学 | Few-mode fiber device |
| CN106019475B (en) * | 2016-07-28 | 2019-04-02 | 江苏大学 | A kind of less fundamental mode optical fibre device |
| CN106597603A (en) * | 2016-10-18 | 2017-04-26 | 国网江西省电力公司信息通信分公司 | Novel few-mode fiber |
| CN106597603B (en) * | 2016-10-18 | 2019-12-31 | 国网江西省电力公司信息通信分公司 | Novel few-mode optical fiber |
| WO2023134327A1 (en) * | 2022-01-12 | 2023-07-20 | 华为技术有限公司 | Light receiving module, device and method |
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