CN101055330A - Optical fiber - Google Patents
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- CN101055330A CN101055330A CN 200710107321 CN200710107321A CN101055330A CN 101055330 A CN101055330 A CN 101055330A CN 200710107321 CN200710107321 CN 200710107321 CN 200710107321 A CN200710107321 A CN 200710107321A CN 101055330 A CN101055330 A CN 101055330A
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 184
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- 238000000576 coating method Methods 0.000 claims description 114
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Abstract
An optical fiber includes: a core at a center; a first cladding layer; a second cladding layer; and a third cladding layer. A maximum refractive index of the core is greater than any of maximum refractive indices of the first cladding layer, the second cladding layer, and the third cladding layer, and the maximum refractive index of the second cladding layer is smaller than any of the maximum refractive indices of the first and the third cladding layer. Additionally, a ratio of a<SUB>2</SUB>/a<SUB>1 </SUB>is not less than about 2.5 and not more than about 4.5, where a 1 represents the radius of the core, and a 2 represents the radius of an outer periphery of the first cladding layer, and a relative refractive index difference of the core with respect to a maximum refractive index of the third cladding layer is not less than 0.20% and not more than 0.70%.
Description
The application be that April 12, application number in 2004 are 2004800089414 the applying date, denomination of invention divides an application for the patent application of " optical fiber ".
Technical field
The present invention relates to have the optical fiber of excellent flexural property.
The application is willing to that to the spy who applied on April 11st, 2003 spy of application on July 18th, 2003-107760 number 1 is willing to 2003-199270 number and the spy of application on January 27th, 2004 is willing to advocate right of priority 2004-18514 number, and has quoted their content at this.
Background technology
In No. 2618400, Japan's patent gazette, disclose and a kind ofly on the circumference of central core, be provided with coating, and on this coating, be provided with the optical fiber of the refractive-index trench of low-refraction.For the optical fiber of aforementioned formation, can expect to reduce the effect of chromatic dispersion gradient and minimizing bending loses etc., yet for producing this effect, when the core radius is made as a
1, the inner edge radius of refractive-index trench is made as a
2The time, need make a
2/ a
1Value be in 1.5～3.5 these scopes.
For a long time, be to enlarge the transmission capacity of main line and long range systems, adopted the exploitation of the transfer system of WDM (Wave Length Division Multiplexing) and optical fiber in the ascendant always.For WDM transmission optical fiber, require to have the non-linear effect of inhibition and this characteristic of decentralised control.In recent years, at several hundred kilometers left and right sides spans such as subway from system, the optical fiber that having of having proposed reduced chromatic dispersion gradient and almost not based on the optical fiber of the loss increment of OH etc.
Yet, considering under the occasion of office and family's introducing optical fiber (FTTH:Fiber To The Home), require to have and these transmission different characteristics of optical fiber.That is, when buildings and premises laid optical fiber, may need to implement bending diameter was 30mm Φ and this minimum bending of 20mm Φ.During the unnecessary length of this external gathering, even reel with small-bend radius, also do not produce the loss increment, this point is very important.That is, can bear the crooked this point of minor diameter is a very important characteristic towards the optical fiber of FTTH.In addition, have and to be laid in the good connectivity of the optical fiber (mostly being 1.3 common mu m range single-mode fibers) between base station and buildings and the dwelling house also very important.In addition, this purposes is required low cost.
As the optical fiber of distribution in office and family, generally in the past adopt 1.3 common mu m ranges with single-mode fiber and multimode optical fiber.
Yet the bending diameter lower limit of these optical fiber generally only allows and reaches about 60mm Φ, when laying, is necessary that carefulness is careful bending diameter and surpasses permissible range.
Develop a kind of optical fiber recently, it is in meeting the scope G.652 that the international standard of 1.3 mu m ranges with single-mode fiber (hereinafter to be referred as SMF) is ITU-T (International TelecommunicationUnion-Telecom Standardization), reduce MFD (mode field diameter), can will allow that bending diameter is decreased to 30mm Φ thus.
Yet to reaching the distribution optical fiber in the family in building, hope can have littler bending diameter.Before this, although it is said that little bending diameter optical fiber emerges, exist with traditional fiber to be connected loss excessive, and problem such as manufacturing cost is high.
Among the technical research report OFT2002-81 of electronic information communication association, inquired into a kind of scheme that in premises and buildings, adopts photonic crystal optical fiber in the distribution.Photonic crystal optical fiber is near a kind of optical fiber that is provided with the emptying aperture structure center of optical fiber, although can expect to have the not available characteristic of optical fiber of traditional structure, its present situation is still to be inferior to traditional optical fiber aspect manufacturing.
To traditional cable optical fiber, also wish to have stronger resistance to bend(ing).Such as, if the optical fiber that employing can be carried out littler bending in the laying in connecting the packaging body of each cable then can improve and connects and draw efficiency of operation in, and can reduce the volume of packaging body.In this external wiring operation, with at the state that is communicated by the part outside the operation optical fiber, carry out operation sometimes.Same under this occasion, if adopt optical fiber, then in operation, can be not the circuit (live wire) of communicating by letter not be impacted because of accident contact etc. with less bending loses.
Summary of the invention
The present invention is in view of the above mentioned facts, and its purpose is, provides a kind of bending loses less, and is good with the connectivity of optical fiber with common transmission, and can the low-cost optical fiber of making.
For solving aforementioned problems, optical fiber provided by the present invention has: the core that is disposed at the center; Be disposed at first coating on the circumference of aforementioned core; Be disposed at second coating on the circumference of aforementioned first coating; Be disposed at the 3rd coating on the circumference of aforementioned second coating, wherein, the largest refractive index of aforementioned core, greater than any one of each largest refractive index of aforementioned first～the 3rd coating, the largest refractive index of aforementioned second coating, less than aforementioned first and any one of each largest refractive index of the 3rd coating, and be made as a when radius with aforementioned core
1, the outer rim radius of aforementioned first coating is made as a
2The time, a
2/ a
1Value be between 2.5 to 4.5, when with the refractive index of aforementioned the 3rd coating during as benchmark, the specific refractivity difference of aforementioned core is between 0.20 to 0.70%.
The cutoff wavelength of optical fiber of the present invention is preferably 1260nm and following.
The refractive index volume V of aforementioned second coating that following formula (1) is expressed is preferably 25% μ m
2And more than.
The refractive index volume V of this second coating is preferably 50% μ m
2And more than.
In the following formula (1),
R: radius,
Δ n (r): radius is the specific refractivity of r poor (benchmark is the largest refractive index of the 3rd coating),
a
2: the outer rim radius of first coating,
a
3: the outer rim radius of second coating.
In the optical fiber of the present invention, when with the largest refractive index of the 3rd coating during as benchmark, the specific refractivity difference of first coating is preferably between-0.10% to 0.05%.
According to the present invention, can obtain a kind of following optical fiber: in the time will making the bending loses added value that has under the wavelength 1550nm that is produced when the identical single peak type optical fiber of the single peak type index distribution that is not provided with second coating and cutoff wavelength twines ten circles on diameter is the mandrel of 20mm be made as 1, with the bending loses ratio of recently expressing of the bending loses added value of same mensuration be 0.4 and below.
According to the present invention, can realize a kind of following optical fiber: in the time will making the bending loses added value that has under the wavelength 1550nm that is produced when the identical single peak type optical fiber of the single peak type index distribution that is not provided with second coating and cutoff wavelength twines ten circles on diameter is the mandrel of 15mm be made as 1, with the bending loses ratio of recently expressing of the bending loses added value of same mensuration be 0.55 and below.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle 0.05dB and following.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1650nm is every circle 0.05dB and following.
The mode field diameter that can obtain in addition under a kind of wavelength 1550nm is 8.3 μ m and above optical fiber thereof.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 15mm, the bending loses value under the wavelength 1550nm is every circle 0.05dB and following.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 15mm, the bending loses value under the wavelength 1650nm is every circle 0.05dB and following.
The mode field diameter that can obtain in addition under a kind of wavelength 1550nm is 7.8 μ m and above optical fiber thereof.
According to the present invention, can realize a kind of following optical fiber: when will having the identical mode field diameter (MFD) of single peak type optical fiber under 1550nm of the single peak type index distribution that is not provided with second coating and cutoff wavelength when value is made as 1, the ratio of the same MFD value of measuring be 0.98 and more than.
According to the present invention, can realize that the mode field diameter under a kind of wavelength 1310nm is 7.3 μ m and above optical fiber thereof.
According to the present invention, can realize that the mode field diameter under a kind of wavelength 1310nm is 6.8 μ m and above optical fiber thereof.
Can obtain a kind ofly when reeling by bending diameter 10mm in addition, the bending loses value under the wavelength 1550nm is every circle 0.05dB and following optical fiber thereof.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 10mm, the bending loses value under the wavelength 1650nm is every circle 0.05dB and following.
According to the present invention, can realize that the mode field diameter under a kind of wavelength 1550nm is 7.3 μ m and above optical fiber thereof.
The mode field diameter that can obtain in addition under a kind of wavelength 1310nm is 6.3 μ m and above optical fiber thereof.
According to the present invention, can realize a kind of following optical fiber: the mode field diameter under the wavelength 1310nm be 7.9 μ m and more than, when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle 1dB and following.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle 0.5dB and following.
According to the present invention, can realize that the mode field diameter under a kind of wavelength 1550nm is 7.3 μ m and above optical fiber thereof.
The mode field diameter that can obtain in addition under a kind of wavelength 1310nm is 6.3 μ m and above optical fiber thereof.
According to the present invention, can realize a kind of following optical fiber: the mode field diameter under the wavelength 1310nm be 7.9 μ m and more than, when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle 1dB and following.
According to the present invention, can realize a kind of following optical fiber: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle 0.5dB and following.
Can obtain a kind of zero-dispersion wavelength in addition and be in optical fiber between the 1300nm to 1324nm.
According to the present invention, can be with low cost, it is less to obtain a kind of bending loses, with the connectivity good optical fiber of common transmission with optical fiber.
Description of drawings
Fig. 1 is the curve map of the index distribution in a kind of embodiment of expression optical fiber of the present invention.
Fig. 2 is the curve map of the relation of the position of second coating in the expression test example 1 and MFD.
Fig. 3 is the curve map of the relation of the position of second coating in the expression test example 1 and bending loses.
Fig. 4 is the curve map of index distribution among the embodiment that represents the present invention relates to.
Fig. 5 is the curve map of index distribution among the embodiment that represents the present invention relates to.
Fig. 6 is the curve map of index distribution among the embodiment that represents the present invention relates to.
Fig. 7 is the curve map of index distribution among the embodiment that represents the present invention relates to.
Embodiment
Following with reference to accompanying drawing, the preferred embodiments of the present invention are described.But the invention is not restricted to following each embodiment, such as the combination that also can between the inscape of these embodiment, suit.
Below the present invention is described in detail.Fig. 1 is the curve map of the index distribution in a kind of embodiment of expression optical fiber of the present invention.
At the center of the optical fiber of present embodiment, being provided with radius is a
1, largest refractive index is n
1Core 1.On the circumference of core 1, being provided with the outer rim radius is a
2, largest refractive index is n
2 First coating 2, on the circumference of this first coating 2, being provided with the outer rim radius is a
3, largest refractive index is n
3Second coating 3.On the circumference of this second coating 3, be provided with the outermost layer that becomes optical fiber, and the outer rim radius is a
4, largest refractive index is n
4The 3rd coating 4.
In this manual, so-called largest refractive index means that the outer rim radius of working as certain layer is made as a
n, the outer rim radius of the la m of this layer is made as a
N-1The time, a
N-1With a
nBetween largest refractive index.Here, n is the integer more than 1, and a
0=0 (μ m).In scalariform index distribution shown in Figure 1, at a
N-1To a
nBetween, it is stable that refractive index keeps, and this refractive index becomes largest refractive index.Yet, shown in Fig. 4～7, in seeking each layer, under the occasion of index distribution, adopt largest refractive index as described later with the preceding method definition.
In optical fiber of the present invention, the largest refractive index n of core 1
1, greater than each largest refractive index n of first～the 3rd coating 2,3,4
2, n
3, n
4Any one, the largest refractive index n of aforementioned second coating 3
3, less than each largest refractive index n of the first and the 3rd coating 2,4
2, n
4Any one.
The index distribution of optical fiber forms by adding adulterants such as germanium and fluorine.In the processing of VAD that is adopted in the optical fiber manufacturing (Vapor-phase Axial Deposition) and CVD (Chemical VaporDeposition), diffusion that is subjected to adulterant etc. influences the index distribution that the interface of each layer also can occur bluring.
In the optical fiber shown in Figure 1, the refractive index of first coating 2 is at almost stable radially, and index distribution almost is complete scalariform.The index distribution of optical fiber of the present invention needn't necessarily be complete scalariform, is not in refractive index under the occasion of scalariform, by adopting each layer footpath value by the following formula definition, can obtain effect of the present invention equally with the scalariform occasion.At first, with the radius a of core 1
1Be defined as: the maximal value Δ that reduces to the specific refractivity difference in the core 1 from the specific refractivity difference
11/10 position to center till distance.In addition, with each outer rim radius a of first coating 2, second coating 3
2, a
3Be defined as: reach the distance till position to the center of extreme value from differential value d Δ (the r)/dr (r represents radius) of the radial distribution Δ (r) of specific refractivity difference.
Utilize the radius that in this way defines, can be regarded as out scalariform index distribution (the following component level that also claims converts) with equivalent characteristic.In the present invention, be not scalariform,, then can obtain the desired effect of the present invention yet if the index distribution of being calculated by this component level can satisfy the regulation index of refraction relationship that the present invention relates to even actual refractive index distributes.In the embodiment of this instructions, the specific refractivity that integrating representation carries out the equivalent scalariform profile that component level converts by aforementioned sequence is poor.
In this manual, the specific refractivity difference Δ of each layer
i(unit: %), with the largest refractive index n of the 3rd coating 4
4Be benchmark, represent with following formula (2).
(in the formula, i is 1～3 integer, n
iIt is the largest refractive index of aforementioned each layer.)
As shown in Figure 1, under the occasion that core is made up of one deck, if increase the specific refractivity difference Δ of core 1
1, then can further reduce bending loses, but MFD will be tending towards reducing.In addition, Δ
1After reducing, can obtain bigger MFD, but bending loses will worsen.The invention is characterized in, by second coating 3 is set, even to the MFD of single peak type same degree, also can obtain the good optical fiber of flexural property.In the present invention, although Δ
1Value be not particularly limited, if but with Δ
1If to 0.20～0.70% this scope, preferably establish to 0.25～0.65% this scope, then can obtain connection performance and the good optical fiber of flexural property with Conventional SMF.
The specific refractivity difference Δ of first coating 2
2Be 0.05% and below, be preferably 0.00% and below.And be preferably-0.10% and more than.
Δ
2After the increase, cutoff wavelength just increases, and can not realize the cutoff wavelength that 1260nm is following.And if the specific refractivity difference Δ of first coating 2
2Too small, then the mould field sealing process based on first coating 2 will strengthen, and be favourable for reducing bending loses, thereby but to improve connectivity then be disadvantageous for enlarging MFD.Therefore, be preferably in the scope that can realize desirable cutoff wavelength, good bending loses and desirable MFD simultaneously Δ is set
2Generally speaking, with Δ
2After being made as more than-0.10%, just can obtain desirable effect.
The specific refractivity difference Δ of second coating 3
3As described later, stipulate its scope of design by refractive index volume V.
Outer rim external diameter (a of the 3rd coating 4
42 times) be the external diameter of optical fiber, be generally 125 μ m.In recent years, external diameter is that small light parts about 80 μ m have been realized commercialization with product.Although in the present invention, also the external diameter of employing and the same scope of ordinary optic fibre is not limited to aforementioned range.
Although can be by the radius a of core 1
1, control cutoff wavelength, but so, after further shortening cutoff wavelength, bending loses is tending towards just increasing.Therefore, in conjunction with the specific refractivity difference Δ of core 1
1, and, suitably select the radius a of core 1 according to desired MFD, cutoff wavelength and bending loses
1
Ratio (a of the outer rim radius of first coating 2 and the radius of core 1
2/ a
1), represent the position of second coating 3.In the present invention, this value be 2.5 and more than, be preferably 3.0 and more than.By at a
2/ a
1The position that is in the aforementioned range of value second coating 3 is set, shown in Fig. 2～3 of hereinafter describing in detail, the variation of mode field diameter (Mode Field Diameter also claims MFD in this manual) can be suppressed to lowlyer, and can improve the bending loses characteristic.
Even a
2/ a
1Excessive, also can expect the reduction effect of bending loses.Yet, a
2/ a
1After the increase, because of Δ
2Variation and the variation of the optical characteristics, the especially cutoff wavelength that take place can become significantly, thereby manufacturing is worsened.In addition, a
2/ a
1After the increase, just can reduce, be difficult to carry out single mode and transmit because of being provided with the effect that second coating 3 brings.Therefore, a
2/ a
1Be 4.5 and below.
The outer rim radius a of second coating 3
3Same with specific refractivity difference Δ, stipulate by refractive index volume V described later.
Wide range of wavelengths band communication till optical fiber can be used for from the 1300nm scope to the 1600nm scope.In the ITU-T standard, G.652 the optical fiber that the 1300nm scope is used be defined as.The lower limit wavelength of 1300nm scope generally is envisioned for 1260nm, in normal term G.652,1260nm and following cutoff wavelength thereof is also stipulated.For this interior single mode till realizing from the 1300nm scope to the 1600nm scope transmits, optical fiber of the present invention is wished to have 1260nm and following cutoff wavelength thereof too on a large scale.This optical characteristics of cutoff wavelength and MFD and bending loses has trade-off relation, and sets index distribution according to desirable characteristic.
It is found that bending loses ratio and a
2/ a
1Value and the value of aforementioned V correlationship is arranged.Particularly, after V increased, bending loses was tending towards reducing than just, and the relation of V and bending loses is by a
2/ a
1The position of the promptly low rate of curving layer of value decide.In the present invention, for realizing better bending loses characteristic, be preferably 25% μ m by the refractive index volume (V) of second coating of following formula (1) expression
2And more than, as be 50% μ m
2And it is above then better.Considering that aforementioned V value is preferably 110% μ m under the occasion that 1260nm and above single mode thereof transmit
2And below.
According to the present invention,, can effectively reduce loss based on bending by being provided with second coating.
Such as, shown in table 1～4 of hereinafter describing in detail, for optical fiber be at diameter the bending loses added value that produced when twining ten circles on the mandrel of 20mm (20mm Φ, below also abbreviate 20 Φ as) (measure wavelength 1550nm, below same.), when the aforementioned bending loses added value in will constituting the single peak type optical fiber that obtains identical cutoff wavelength by the single peak type index distribution that is not provided with second coating 3 is made as 1, under wavelength 1550nm, can make the ratio of the bending loses increase of the optical fiber that the present invention relates to (in this manual, be called the bending loses ratio.) be reduced to 0.4 and below, preferably can be reduced to 0.15 and below.
According to the present invention, can obtain based on the littler optical fiber of the loss of bending.Particularly, under wavelength 1550nm, can make the aforementioned bending loses ratio that is produced when on diameter is the mandrel of 15mm (15mm Φ, below also abbreviate 15 Φ as), twining ten circles be reduced to 0.55 and below, preferably can be reduced to 0.25 and below.
According to optical fiber of the present invention, when reeling, can make the bending loses value under the wavelength 1550nm be reduced to every circle 0.05dB and following by bending diameter 20mm.Here, can calculate the bending loses value of every circle by working as the bending loses value that produced when on the mandrel of specified diameter, reeling ten circles divided by 10.
In addition, also can when reeling, make the bending loses value under the wavelength 1650nm be reduced to every circle 0.05dB and following by bending diameter 20mm.
According to the present invention, can realize a kind of can so the loss based on bending be suppressed to lower, and optical fiber with big mode field diameter.Particularly, the mode field diameter that can obtain under a kind of wavelength 1550nm is 8.3 μ m and above optical fiber thereof.
According to optical fiber of the present invention, can when reeling, make the bending loses value under the wavelength 1550nm be reduced to every circle 0.05dB and following by bending diameter 15mm.
In addition, also can when reeling, make the bending loses value under the wavelength 1650nm be reduced to every circle 0.05dB and following by bending diameter 15mm.
According to the present invention, can realize so the loss based on bending being suppressed to lower, and optical fiber with big mode field diameter.Particularly, can obtain that mode field diameter is 7.8 μ m and above optical fiber thereof under a kind of wavelength 1550nm.
According to the present invention, can realize a kind of can so the loss based on bending be suppressed to lower, and optical fiber with big mode field diameter.Particularly, the mode field diameter that can obtain under a kind of wavelength 1310nm is 7.3 μ m and above optical fiber thereof.
Particularly, can obtain that mode field diameter is 6.8 μ m and above optical fiber thereof under a kind of wavelength 1310nm.
Can when reeling, make the bending loses value under the wavelength 1550nm be reduced to every circle 0.05dB and following by bending diameter 10mm.
According to optical fiber of the present invention, can when reeling, make the bending loses value under the wavelength 1650nm be reduced to every circle 0.05dB and following by bending diameter 10mm.
According to the present invention, can realize a kind of can so the loss based on bending be suppressed to lower, and optical fiber with big mode field diameter.Particularly, the mode field diameter that can obtain under a kind of wavelength 1550nm is 7.3 μ m and above optical fiber thereof.
Particularly, can obtain that mode field diameter is 6.3 μ m and above optical fiber thereof under a kind of wavelength 1310nm.
According to the present invention, can the mode field diameter under the wavelength 1310nm be 7.9 μ m and more than, and when reeling, make the bending loses value under the wavelength 1550nm be reduced to every circle 1dB and following by bending diameter 20mm.
According to the present invention, can obtain a kind of zero-dispersion wavelength and be the optical fiber between the 1300nm to 1324nm.
Here, so-called wavelength 1550nm scope is a kind ofly together to be widely used in the wavelength coverage of communicating by letter with wavelength 1310nm scope, and in these wavelength coverages, it is important transmitting loss and less this characteristic of bending loses thereof.Especially in purposes such as premises wiring, in song and the optical fiber to place, the corner connecting box draw in, might implement to come small bendings such as bending or coiling with minor diameter in the corner.Therefore, the flexural property under the little bending diameter such as bending diameter 20mm and bending diameter 15mm is important.In addition,, it is envisaged for a kind of 1650nm and following wavelength coverage thereof to line supervision, even thereby under 1650nm, also have less bending loses, this point just becomes a key property.
Be provided with the optical fiber of the present invention of second coating 3, have the reduction that can suppress MFD, and compare the feature that can reduce bending loses greatly with single peak type.Particularly, when the MFD of optical fiber of the present invention under wavelength 1550nm is made as M1, and will constitute obtain same cutoff wavelength with the single peak type index distribution that is not provided with second coating 3 single peak type optical fiber when the MFD under the 1550nm is made as M2, the value of M1/M2 can reach 0.98 and more than.
In addition, optical fiber of the present invention is realized aforementioned various feature by second coating 3 is set.Such as, the non-zero dispersion of developing for WDM communication shifts optical fiber (NZ-DSF:Non-ZeroDispersion Shifted Fiber) needs complicated core refraction distribution, optical fiber of the present invention is owing to need not to change the core index distribution and just can improve characteristic, thereby have can be with the original strong point of making of lower one-tenth.
(embodiment)
Following with reference to specific embodiment, effect of the present invention is described.
Following test examples and " cutoff wavelength " among embodiment value, utilization is based on ITU-TG.650.Definitions and test methods for linear, and the method for deterministic attributes ofsingle-mode fiber and cable is measured.In following test examples and embodiment, express unless have especially, otherwise so-called cutoff wavelength just means the 2m fiber cutoff.
(test example 1)
The specific refractivity difference Δ of core 1
1: 0.52%,
The specific refractivity difference Δ of first coating 2
2: 0%,
The specific refractivity difference Δ of second coating 3
3:-0.20%,
Ratio (a of the thickness of second coating 3 and core radius
3-a
2)/a
1=3.0
Optical fiber external diameter: 125 μ m
Cutoff wavelength: be designed to 1250nm, produce optical fiber with this.
Sought a
2/ a
1The variation of value MFD when changing and the variation of bending loses.The mensuration wavelength of MFD and bending loses is 1550nm.
Loss increment when the mensuration of bending loses, the optical fiber by making specified length are reeled ten circles on diameter is the mandrel of 20mm is assessed.That is, if will be made as at the power of the light of the optical fiber outgoing before reeling on the mandrel P1 (unit: dBm), the power of the emergent light when reeling be made as P2 (unit: dBm), then with P1-P2 (dB) as bending loses.Its result as shown in Figures 2 and 3.
Dotted line among the figure, expression constitutes MFD and the bending loses value that obtains the single peak type optical fiber of same cutoff wavelength with the single peak type index distribution that is not provided with second coating 3 respectively.
Can find out that from the result of Fig. 3 by second coating 3 is set, compare with single peak type optical fiber, flexural property can be greatly improved.Can find out in addition, along with a
2/ a
1The increase of value, bending loses just is tending towards increasing gradually.
Can find out from the result of Fig. 2, at a
2/ a
1Value less than in 3.0 the zone, compare with single peak type, MFD sharply reduces.For remaining to lessly, be necessary to suppress the reduction of MFD with the loss that is connected that as ITU-T G652 standard is the bigger optical fiber of MFD.As make a
2/ a
1Be in 2.5 and more than, then for single peak type, can guarantee the MFD more than 98%, can keep the connection performance that does not go wrong.
Can find out from aforementioned result, by making a
2/ a
1Value be in 2.5 times and more than, be preferably 3.0 times and more than, can realize bigger MFD and less bending loses.
(test example 2)
Set each parameter shown in the following tabulation 1, thereby make optical fiber, and utilize known method respectively, measured cutoff wavelength, the long-pending (A of effective core section
Eff), MFD, wavelength dispersion, chromatic dispersion gradient and zero-dispersion wavelength.
Utilize G.650.1 Definitions and test methods for linear of ITU-T, deterministic attributes of single-mode fiber and cable, 5.3.1 the Transmitted Power Technique of middle record has carried out the mensuration of cutoff wavelength.Usually, in Transmitted Power Technique, the power loss when as much adopts basis to make the optical fiber minor diameter crooked is measured the method (bending method) of cutoff wavelength.Yet for the optical fiber of this trial-production, the bending loses of higher modes is also bigger, and aforementioned bending method is difficult to carry out correct ending and measures.Therefore, utilizing the power when seeing through from multimode optical fiber is the method (multimode reference entry) that benchmark is assessed, and measures.
For the bending loses characteristic, use with the same method of afore-mentioned test example 1 and measured bending loses.Measuring wavelength is 1550nm and 1650nm.Axle diameter is these three kinds of 20mm, 15mm, 10mm.Under the less occasion of the bending loses of being measured, suitably increase number of bends (number of crimp), after having obtained can to guarantee to measure the bending loses of precision, be converted into the bending loses of reeling for per ten times.In addition, in the form, also record loss increment (bending loses recruitment, the unit: dB/m) of constituent parts length in the lump.If will be made as Px such as the bending loses (aforementioned P1-P2 (dB)) of on 20mm Φ mandrel, having reeled ten times the time, just then the loss increment Py of unit length is represented by following formula.
Px (unit: dB/m)=Py/ (π * 0.02 * 10)
In addition, refractive index volume (V) is calculated by following formula (1).
Sample No.1,5,9,12,21,28,35,38 is the single peak type optical fiber that does not have second coating 3.
The bending loses ratio of sample No.2～4 is when bending loses ten times time that sample No.1 is reeled is made as 1, the reel ratio of the bending loses value ten times time of sample No.2～4.Equally, the bending loses ratio of sample No.6～8, be to be the value of benchmark with sample No.5, sample No.10,11 bending loses ratio, be to be the value of benchmark with sample No.9, the bending loses ratio of sample No.13～20, be to be the value of benchmark with sample No.12, the bending loses ratio of sample No.22～27 is to be the value of benchmark with sample No.21, the bending loses ratio of sample No.29～34, be to be the value of benchmark with sample No.28, sample No.36,37 bending loses ratio is to be the value of benchmark with sample No.35, sample No.39,40 bending loses ratio is to be the value of benchmark with sample No.38.
In addition, sample No.16,18,24～27,32 V value are bigger, can not reduce cutoff wavelength with benchmark sample same degree ground.Therefore, to these samples, do not put down in writing the bending loses ratio sometimes.In addition, under sample No.35,38 part condition determination, bending loses can not be assessed excessive.Therefore, in sample No.36,37,39,40 the part, do not put down in writing the bending loses ratio sometimes.Table 2～4 expression measurement results.
Table 1
| Sample No. | Δ 1 [％] | Δ 2 [％] | Δ 3[％] | a 1 [μm] | a 2[μm] | a 3[μm] | a 2/a 1 | a 3/a 1 | V [％μm 2] | 2a 2/MFD at1550nm |
| 1 | 0.65 | 0.00 | - | 3.04 | 9.12 | - | 3.0 | - | - | - |
| 2 | 0.65 | 0.00 | -0.30 | 3.01 | 7.83 | 12.05 | 2.6 | 4.0 | 25 | 2.1 |
| 3 | 0.65 | 0.00 | -0.30 | 2.99 | 8.97 | 13.46 | 3.0 | 4.5 | 30 | 2.4 |
| 4 | 0.65 | 0.00 | -0.40 | 2.99 | 8.98 | 13.48 | 3.0 | 4.5 | 40 | 2.4 |
| 5 | 0.60 | 0.00 | - | 3.18 | 9.53 | - | 3.0 | - | - | - |
| 6 | 0.60 | 0.00 | -0.30 | 3.13 | 8.14 | 13.16 | 2.6 | 4.2 | 32 | 2.1 |
| 7 | 0.60 | 0.00 | -0.30 | 3.12 | 9.35 | 14.03 | 3.0 | 4.5 | 33 | 2.4 |
| 8 | 0.60 | 0.00 | -0.40 | 3.12 | 9.35 | 14.03 | 3.0 | 4.5 | 44 | 2.4 |
| 9 | 0.58 | 0.00 | - | 4.85 | 14.55 | - | 3.0 | - | - | - |
| 10 | 0.58 | -0.05 | -0.30 | 3.32 | 9.97 | 14.95 | 3.0 | 4.5 | 37 | 2.6 |
| 11 | 0.58 | -0.10 | -0.30 | 3.44 | 10.31 | 15.47 | 3.0 | 4.5 | 40 | 2.7 |
| 12 | 0.52 | 0.00 | - | 3.43 | 10.30 | - | 3.0 | - | - | - |
| 13 | 0.52 | 0.00 | -0.20 | 3.35 | 10.04 | 15.40 | 3.0 | 4.6 | 27 | 2.4 |
| 14 | 0.52 | 0.00 | -0.20 | 3.31 | 13.23 | 18.53 | 4.0 | 5.6 | 34 | 3.2 |
| 15 | 0.52 | 0.00 | -0.40 | 3.36 | 10.08 | 15.45 | 3.0 | 4.6 | 55 | 2.4 |
| 16 | 0.52 | 0.00 | -0.40 | 3.35 | 10.06 | 20.13 | 3.0 | 6.0 | 122 | 2.4 |
| 17 | 0.52 | 0.00 | -0.40 | 3.31 | 13.25 | 18.55 | 4.0 | 5.6 | 67 | 3.2 |
| 18 | 0.52 | 0.00 | -0.40 | 3.31 | 13.26 | 23.20 | 4.0 | 7.0 | 145 | 3.2 |
| 19 | 0.52 | 0.00 | -0.60 | 3.36 | 10.08 | 13.78 | 3.0 | 4.1 | 53 | 2.4 |
| 20 | 0.52 | 0.00 | -0.60 | 3.32 | 13.27 | 16.93 | 4.0 | 5.1 | 66 | 3.2 |
| 21 | 0.45 | 0.00 | - | 3.72 | 11.15 | - | 3.0 | - | - | - |
| 22 | 0.45 | 0.00 | -0.25 | 3.61 | 10.82 | 16.23 | 3.0 | 4.5 | 37 | 2.4 |
| 23 | 0.45 | 0.00 | -0.35 | 3.61 | 10.83 | 16.25 | 3.0 | 4.5 | 51 | 2.4 |
| 24 | 0.45 | 0.00 | -0.40 | 3.61 | 10.84 | 21.68 | 3.0 | 6.0 | 141 | 2.4 |
| 25 | 0.45 | 0.00 | -0.40 | 3.57 | 14.27 | 24.98 | 4.0 | 7.0 | 168 | 3.2 |
| 26 | 0.45 | 0.00 | -0.60 | 3.62 | 10.85 | 19.90 | 3.0 | 5.5 | 167 | 2.4 |
| 27 | 0.45 | 0.00 | -0.60 | 3.57 | 14.28 | 23.20 | 4.0 | 6.5 | 201 | 3.2 |
| 28 | 0.35 | 0.00 | - | 4.28 | 12.84 | - | 3.0 | - | - | - |
| 29 | 0.35 | 0.00 | -0.40 | 4.10 | 12.31 | 16.42 | 3.0 | 4.0 | 47 | 2.4 |
| 30 | 0.35 | 0.00 | -0.40 | 4.15 | 10.79 | 14.94 | 2.6 | 3.6 | 64 | 2.2 |
| 31 | 0.35 | 0.00 | -0.20 | 4.05 | 16.19 | 28.33 | 4.0 | 7.0 | 108 | 3.2 |
| 32 | 0.35 | 0.00 | -0.40 | 4.10 | 12.31 | 24.63 | 3.0 | 6.0 | 182 | 2.4 |
| 33 | 0.35 | 0.00 | -0.25 | 4.14 | 10.35 | 14.49 | 2.50 | 3.50 | 25.71 | 2.06 |
| 34 | 0.35 | 0.00 | -0.25 | 4.10 | 12.29 | 16.38 | 3.00 | 4.00 | 29.35 | 2.44 |
| 35 | 0.32 | 0.00 | - | 4.51 | 13.54 | - | 3.00 | - | - | - |
| 36 | 0.32 | 0.00 | -0.25 | 4.29 | 12.86 | 17.15 | 3.00 | 4.00 | 32.17 | 2.44 |
| 37 | 0.32 | 0.00 | -0.25 | 4.29 | 12.86 | 19.30 | 3.00 | 4.50 | 51.71 | 2.44 |
| 38 | 0.25 | 0.00 | - | 5.21 | 15.63 | - | 3.00 | - | - | - |
| 39 | 0.25 | 0.00 | -0.25 | 4.86 | 14.57 | 19.43 | 3.00 | 4.00 | 41.27 | 2.44 |
| 40 | 0.25 | 0.00 | -0.25 | 4.92 | 12.29 | 17.21 | 2.50 | 3.50 | 36.27 | 2.07 |
Table 2
| Sample No. | Cutoff wavelength [μ m] | A eff at1310nm [μm 2] | MFD at1310nm [μm] | A eff at1550nm [μm 2] | MFD at1550nm [μm] | Zero-dispersion wavelength [nm] | Wavelength dispersion under the 1550nm [ps/nm/km] | Chromatic dispersion gradient [ps/nm under the 1550nm 2/km] |
| 1 | 1.25 | 34.2 | 6.58 | 42.4 | 7.44 | 1359.4 | 11.9 | 0.054 |
| 2 | 1.25 | 33.8 | 6.55 | 41.6 | 7.37 | 1353.7 | 13.2 | 0.059 |
| 3 | 1.25 | 33.7 | 6.54 | 41.8 | 7.39 | 1361.3 | 12.3 | 0.058 |
| 4 | 1.25 | 33.7 | 6.54 | 41.8 | 7.39 | 1360.0 | 12.5 | 0.059 |
| 5 | 1.25 | 37.2 | 6.86 | 46.1 | 7.75 | 1350.6 | 12.8 | 0.055 |
| 6 | 1.25 | 36.7 | 6.82 | 45.2 | 7.68 | 1348.3 | 13.7 | 0.060 |
| 7 | 1.25 | 36.6 | 6.81 | 45.4 | 7.70 | 1353.0 | 13.1 | 0.059 |
| 8 | 1.25 | 36.6 | 6.81 | 45.3 | 7.69 | 1352.2 | 13.2 | 0.059 |
| 9 | 1.25 | 38.5 | 6.98 | 47.7 | 7.89 | 1347.2 | 13.1 | 0.055 |
| 10 | 1.25 | 37.8 | 6.87 | 45.7 | 7.67 | 1332.0 | 14.5 | 0.057 |
| 11 | 1.25 | 32.8 | 6.82 | 44.8 | 7.55 | 1318.6 | 15.6 | 0.056 |
| 12 | 1.25 | 43.2 | 7.39 | 53.4 | 8.34 | 1337.5 | 14.1 | 0.056 |
| 13 | 1.25 | 42.3 | 7.32 | 52.4 | 8.28 | 1341.5 | 14.1 | 0.059 |
| 14 | 1.25 | 41.9 | 7.30 | 52.4 | 8.29 | 1347.0 | 13.3 | 0.057 |
| 15 | 1.25 | 42.4 | 7.33 | 52.4 | 8.27 | 1339.4 | 14.5 | 0.060 |
| 16 | 1.45 | 42.3 | 7.33 | 52.3 | 8.27 | 1339.7 | 14.4 | 0.060 |
| 17 | 1.25 | 41.9 | 7.30 | 52.4 | 8.29 | 1346.6 | 13.4 | 0.057 |
| 18 | 1.55 | 41.9 | 7.31 | 52.5 | 8.29 | 1346.5 | 13.4 | 0.057 |
| 19 | 1.25 | 42.4 | 7.33 | 52.3 | 8.26 | 1338.5 | 14.7 | 0.061 |
| 20 | 1.25 | 42.0 | 7.31 | 52.5 | 8.29 | 1345.9 | 13.5 | 0.058 |
| 21 | 1.25 | 50.3 | 7.97 | 62.0 | 8.98 | 1326.5 | 15.2 | 0.058 |
| 22 | 1.25 | 48.9 | 7.88 | 60.6 | 8.90 | 1330.8 | 15.3 | 0.060 |
| 23 | 1.25 | 49.0 | 7.88 | 60.5 | 8.89 | 1329.9 | 15.4 | 0.061 |
| 24 | 1.51 | 49.0 | 7.88 | 60.6 | 8.89 | 1329.5 | 15.5 | 0.061 |
| 25 | 1.60 | 48.6 | 7.86 | 60.7 | 8.92 | 1335.2 | 14.5 | 0.058 |
| 26 | 1.58 | 49.1 | 7.88 | 60.5 | 8.88 | 1328.6 | 15.7 | 0.062 |
| 27 | 1.62 | 48.6 | 7.86 | 60.7 | 8.92 | 1335.1 | 14.6 | 0.059 |
| 28 | 1.25 | 65.7 | 9.09 | 80.5 | 10.22 | 1311.9 | 16.9 | 0.059 |
| 29 | 1.25 | 63.2 | 8.95 | 78.0 | 10.08 | 1316.1 | 16.9 | 0.062 |
| 30 | 1.26 | 63.5 | 8.95 | 77.2 | 10.00 | 1310.2 | 17.9 | 0.064 |
| 31 | 1.25 | 62.5 | 8.92 | 78.2 | 10.12 | 1320.7 | 16.1 | 0.060 |
| 32 | 1.46 | 63.2 | 8.95 | 78.0 | 10.08 | 1316.0 | 16.9 | 0.063 |
| 33 | 1.25 | 63.43 | 8.95 | 77.43 | 10.03 | 1311.7 | 17.5 | 0.063 |
| 34 | 1.25 | 63.07 | 8.94 | 78.04 | 10.09 | 1317.0 | 16.7 | 0.061 |
| 35 | 1.25 | 72.39 | 9.53 | 88.50 | 10.71 | 1307.6 | 17.4 | 0.060 |
| 36 | 1.25 | 69.07 | 9.36 | 85.41 | 10.56 | 1312.9 | 17.2 | 0.062 |
| 37 | 1.25 | 69.09 | 9.36 | 85.41 | 10.56 | 1312.8 | 17.2 | 0.062 |
| 38 | 1.25 | 94.52 | 10.87 | 114.82 | 12.18 | 1298.4 | 18.5 | 0.061 |
| 39 | 1.25 | 88.57 | 10.60 | 109.38 | 11.94 | 1303.9 | 18.2 | 0.063 |
| 40 | 1.25 | 89.07 | 10.60 | 108.38 | 11.85 | 1300.0 | 18.9 | 0.063 |
Table 3
| Sample No. | Bending loses under the 1550nm | ||||||||
| 20φ | 15φ | 10φ | |||||||
| [dB/m] | ×10t [dB] | The bending loses ratio | [dB/m] | ×10t [dB] | The bending loses ratio | [dB/m] | ×10t [dB] | The bending loses ratio | |
| 1 | 0.002 | 0.001 | - | 0.015 | 0.007 | - | 1.063 | 0.334 | - |
| 2 | 0.000 | ＜0.001 | - | 0.003 | 0.002 | 0.00 | 0.142 | 0.045 | 0.13 |
| 3 | 0.001 | ＜0.001 | - | 0.003 | 0.002 | 0.00 | 0.136 | 0.043 | 0.13 |
| 4 | 0.000 | ＜0.001 | - | 0.002 | 0.001 | 0.00 | 0.067 | 0.021 | 0.06 |
| 5 | 0.009 | 0.006 | - | 0.067 | 0.042 | - | 3.517 | 2.210 | - |
| 6 | 0.002 | 0.001 | 0.00 | 0.011 | 0.005 | 0.12 | 0.302 | 0.142 | 0.06 |
| 7 | 0.002 | 0.002 | 0.00 | 0.012 | 0.006 | 0.14 | 0.349 | 0.164 | 0.07 |
| 8 | 0.001 | ＜0.001 | 0.00 | 0.007 | 0.003 | 0.08 | 0.167 | 0.079 | 0.04 |
| 9 | 0.017 | 0.011 | - | 0.115 | 0.054 | 1.30 | 5.257 | 2.477 | 1.12 |
| 10 | 0.002 | 0.001 | 0.00 | 0.007 | 0.003 | 0.08 | 0.172 | 0.081 | 0.04 |
| 11 | 0.001 | ＜0.001 | 0.00 | 0.004 | 0.002 | 0.04 | 0.083 | 0.039 | 0.02 |
| 12 | 0.133 | 0.084 | - | 0.731 | 0.344 | - | 25.75 | 8.090 | - |
| 13 | 0.043 | 0.027 | 0.32 | 0.159 | 0.075 | 0.22 | 3.020 | 0.949 | 0.12 |
| 14 | 0.051 | 0.032 | 0.39 | 0.179 | 0.084 | 0.24 | 3.111 | 0.977 | 0.12 |
| 15 | 0.012 | 0.007 | 0.09 | 0.035 | 0.016 | 0.05 | 0.485 | 0.152 | 0.02 |
| 16 | 0.001 | ＜0.001 | - | 0.002 | 0.001 | - | 0.013 | 0.004 | - |
| 17 | 0.014 | 0.009 | 0.11 | 0.040 | 0.019 | 0.06 | 0.504 | 0.158 | 0.02 |
| 18 | 0.001 | ＜0.001 | - | 0.002 | 0.001 | - | 0.016 | 0.005 | - |
| 19 | 0.012 | 0.008 | 0.09 | 0.037 | 0.017 | 0.05 | 0.522 | 0.164 | 0.02 |
| 20 | 0.015 | 0.009 | 0.11 | 0.043 | 0.020 | 0.06 | 0.556 | 0.175 | 0.02 |
| 21 | 0.845 | 0.531 | - | 3.280 | 1.546 | - | 71.12 | 22.34 | - |
| 22 | 0.214 | 0.134 | 0.25 | 0.553 | 0.260 | 0.17 | 6.454 | 2.028 | 0.25 |
| 23 | 0.109 | 0.068 | 0.13 | 0.253 | 0.119 | 0.08 | 2.493 | 0.783 | 0.10 |
| 24 | 0.004 | 0.003 | 0.00 | 0.006 | 0.003 | 0.00 | 0.023 | 0.007 | - |
| 25 | 0.005 | 0.003 | 0.01 | 0.006 | 0.003 | 0.00 | 0.023 | 0.007 | - |
| 26 | 0.002 | 0.001 | 0.00 | 0.002 | 0.001 | 0.00 | 0.007 | 0.002 | - |
| 27 | 0.002 | 0.001 | 0.00 | 0.002 | 0.001 | 0.00 | 0.007 | 0.002 | - |
| 28 | 14.00 | 8.796 | - | 37.98 | 17.90 | - | 516 | 162 | - |
| 29 | 1.854 | 1.165 | 0.13 | 3.036 | 1.431 | 0.08 | 19.12 | 6.007 | 0.04 |
| 30 | 0.637 | 0.400 | 0.05 | 0.911 | 0.429 | 0.02 | 4.592 | 1.443 | 0.01 |
| 31 | 0.367 | 0.231 | 0.03 | 0.426 | 0.201 | 0.01 | 1.546 | 0.486 | 0.06 |
| 32 | 0.015 | 0.010 | 0.00 | 0.011 | 0.005 | 0.01 | 0.019 | 0.006 | - |
| 33 | 4.150 | 2.608 | 0.30 | 8.028 | 3.783 | 0.21 | 66.11 | 20.77 | 0.13 |
| 34 | 4.180 | 2.626 | 0.30 | 7.764 | 3.659 | 0.20 | 59.93 | 18.83 | 0.12 |
| 35 | 30.20 | 18.98 | - | 76.23 | 35.92 | - | Can not measure | Can not measure | - |
| 36 | 7.290 | 4.580 | 0.24 | 11.84 | 5.579 | 0.16 | 75.97 | 23.87 | - |
| 37 | 3.220 | 2.023 | 0.11 | 4.548 | 2.143 | 0.06 | 23.33 | 7.330 | - |
| 38 | 160.0 | 100.5 | - | 321.3 | 151.4 | - | Can not measure | Can not measure | - |
| 39 | 22.50 | 14.14 | 0.14 | 26.81 | 12.63 | 0.08 | 111.9 | 35.16 | - |
| 40 | 21.60 | 13.57 | 0.14 | 26.37 | 12.43 | 0.08 | 114.0 | 35.80 | - |
Table 4
| Sample No. | Bending loses under the 1650nm | ||||||||
| 20φ | 15φ | 10φ | |||||||
| [dB/m] | ×10t [dB] | The bending loses ratio | [dB/m] | ×10t [dB] | The bending loses ratio | [dB/m] | ×10t [dB] | The bending loses ratio | |
| 1 | 0.024 | 0.015 | - | 0.152 | 0.071 | - | 6.327 | 1.988 | - |
| 2 | 0.008 | 0.005 | 0.00 | 0.035 | 0.017 | 0.23 | 0.892 | 0.280 | 0.14 |
| 3 | 0.008 | 0.005 | 0.33 | 0.035 | 0.017 | 0.23 | 0.829 | 0.260 | 0.13 |
| 4 | 0.005 | 0.003 | 0.00 | 0.020 | 0.009 | 0.13 | 0.421 | 0.132 | 0.07 |
| 5 | 0.095 | 0.060 | - | 0.502 | 0.316 | - | 16.60 | 5.215 | - |
| 6 | 0.023 | 0.011 | 0.18 | 0.084 | 0.040 | 0.13 | 1.522 | 0.478 | 0.09 |
| 7 | 0.027 | 0.013 | 0.21 | 0.095 | 0.045 | 0.14 | 1.709 | 0.537 | 0.10 |
| 8 | 0.016 | 0.008 | 0.13 | 0.054 | 0.025 | 0.08 | 0.839 | 0.264 | 0.05 |
| 9 | 0.159 | 0.075 | 1.26 | 0.772 | 0.364 | 1.15 | 22.47 | 7.059 | 1.35 |
| 10 | 0.018 | 0.008 | 0.14 | 0.057 | 0.027 | 0.09 | 0.871 | 0.274 | 0.05 |
| 11 | 0.010 | 0.005 | 0.08 | 0.031 | 0.015 | 0.05 | 0.450 | 0.141 | 0.03 |
| 12 | 0.863 | 0.542 | - | 3.522 | 1.660 | - | 83.83 | 26.34 | - |
| 13 | 0.281 | 0.176 | 0.33 | 0.781 | 0.368 | 0.22 | 10.23 | 3.214 | 0.12 |
| 14 | 0.325 | 0.204 | 0.38 | 0.854 | 0.403 | 0.24 | 10.31 | 3.238 | 0.12 |
| 15 | 0.080 | 0.050 | 0.09 | 0.183 | 0.086 | 0.05 | 1.762 | 0.553 | 0.02 |
| 16 | 0.007 | 0.004 | - | 0.011 | 0.005 | - | 0.052 | 0.016 | - |
| 17 | 0.094 | 0.059 | 0.11 | 0.203 | 0.096 | 0.06 | 1.781 | 0.560 | 0.02 |
| 18 | 0.009 | 0.006 | - | 0.013 | 0.006 | - | 0.063 | 0.020 | - |
| 19 | 0.083 | 0.052 | 0.10 | 0.194 | 0.091 | 0.06 | 1.915 | 0.602 | 0.02 |
| 20 | 0.098 | 0.061 | 0.11 | 0.216 | 0.102 | 0.06 | 1.972 | 0.619 | 0.02 |
| 21 | 3.724 | 2.340 | - | 11.26 | 5.305 | - | 176 | 55.16 | - |
| 22 | 0.958 | 0.602 | 0.26 | 1.956 | 0.922 | 0.17 | 16.78 | 5.272 | 0.10 |
| 23 | 0.500 | 0.314 | 0.13 | 0.923 | 0.435 | 0.08 | 6.726 | 2.113 | 0.04 |
| 24 | 0.022 | 0.014 | - | 0.024 | 0.011 | - | 0.073 | 0.023 | - |
| 25 | 0.024 | 0.015 | - | 0.025 | 0.012 | - | 0.073 | 0.023 | - |
| 26 | 0.010 | 0.006 | - | 0.009 | 0.004 | - | 0.024 | 0.007 | - |
| 27 | 0.011 | 0.007 | - | 0.010 | 0.005 | - | 0.024 | 0.008 | - |
| 28 | 36.35 | 22.84 | - | 81.39 | 38.36 | - | 860 | 270 | - |
| 29 | 5.060 | 3.179 | 0.14 | 7.001 | 3.299 | 0.09 | 35.28 | 11.08 | 0.04 |
| 30 | 1.873 | 1.777 | 0.05 | 2.269 | 1.069 | 0.03 | 9.220 | 2.897 | 0.01 |
| 31 | 1.026 | 0.645 | 0.03 | 1.019 | 0.480 | 0.01 | 3.016 | 0.948 | 0.00 |
| 32 | 0.050 | 0.031 | - | 0.032 | 0.015 | - | 0.046 | 0.014 | - |
| 33 | 11.20 | 7.037 | 0.31 | 18.19 | 8.571 | 0.22 | 118.4 | 37.21 | 0.14 |
| 34 | 11.05 | 6.943 | 0.30 | 17.29 | 8.146 | 0.21 | 106.2 | 33.35 | 0.12 |
| 35 | 68.87 | 43.27 | - | 146.9 | 69.20 | - | Can not measure | Can not measure | - |
| 36 | 16.82 | 10.57 | 0.24 | 23.44 | 11.04 | 0.16 | 122.5 | 38.48 | - |
| 37 | 7.585 | 4.766 | 0.11 | 9.229 | 4.349 | 0.06 | 38.767 | 12.18 | - |
| 38 | 265.4 | 166.8 | - | 466.4 | 219.8 | - | Can not measure | Can not measure | - |
| 39 | 38.48 | 24.18 | 0.14 | 40.92 | 19.28 | 0.09 | 146.3 | 45.95 | - |
| 40 | 37.85 | 23.78 | 0.14 | 41.10 | 19.37 | 0.09 | 151.9 | 47.71 | - |
Can find out from the result of table 1～table 4,, can reduce bending loses being provided with under the occasion of low-index layer.By observing according to the bending loses that has or not low-index layer to come the comparison bending loses, just can easily find out the effect that bending loses reduces than parameter.Such as, be example with the bending loses of 1550nm, 20mm Φ, for there not being the sample No.21,28,35,38 of low-index layer, the bending loses that every coiling is ten times surpasses 0.5dB.Especially for sample No.35,38, the bending loses of 10dB has taken place to surpass.Yet for sample No.22,23,29～34,36,37,39,40, its bending loses ratio is below 0.4.For sample No.22,23,30,31, the bending loses that every coiling is ten times is lower than 0.5dB.Shown in sample No.1,5,9,12,, also can carry out 20mm Φ and be wound as the following design of 0.5db for ten times even be not provided with the structure of low-index layer.Yet in not being provided with the structure of these low-index layers, under the 1310nm condition, MFD will be lower than 7.5 μ m, compare with the design of having adopted low-index layer of the present invention, aggravate with the loss that is connected of SMF, thereby be bad in this.In addition, although the bending loses of No.29,33,34,36,37 under 20mm Φ and ten coiling conditions surpasses 1dB,, can realize that 5dB and above loss thereof reduce, and the bending loses of number dB only takes place for the No.28 that becomes benchmark, 35.These samples, have G.652 MFD, cutoff wavelength, the zero-dispersion wavelength of the single-mode fiber of standard code based on ITU-T, but also have the effect of very big inhibition, the bending that is produced when suppressing common line with cable laying in addition in addition and the effect of the loss increment that causes based on the loss increment of bending.
On the other hand, although refractive index volume V at 110% μ m
2And above sample No.16,18,24～27,32 has minimum bending loses, but cutoff wavelength is very long, can not realize transmitting as 1260nm of the object of the invention and following single mode thereof.
For having added the optical fiber of this low-index layer, even, also can carry out to keep MFD, and almost can not lose the design of increment to the 15mm Φ of minor diameter more.Such as, sample No.13～15,17,19,20, the bending loses under 1550nm, 15mm Φ, this condition of reeling for ten times is 0.1dB and following, the MFD under the 1310nm also is about 7.3 μ m.Even be not provided with the single peak type of low-index layer, also can make the bending loses under 15mm Φ, this condition of reeling for ten times under 1550nm, be 0.1dB and following by adopting No.1,5,9 structure.Yet the MFD under the 1310nm will compare with the optical fiber of the structure of the present invention with equal flexural property less than 6.9 μ m, with the connection performance deterioration of SMF.
The sample No.1,5,9 that under 15mm Φ, has a minimum bending loses too, under 10mm Φ (also abbreviating 10 Φ as) condition, loss just bends.Even this very little bending diameter of 10mm Φ by adopting the additional structure that low-index layer is arranged, also can reduce bending loses.Such as, sample No.2～4,6～8 have the MFD almost same with sample No.1,5 respectively, and under 1550mm, 10mm Φ condition, can obtain 0.13 and following bending loses.Sample No.10,11 compares with sample No.6～8 of MFD equal extent under the 1310nm, has littler bending loses.Its reason is some Δs
2The specific refractivity difference be made as effect after the negative value.
(embodiment 1)
Fig. 4 represents the index distribution of optical fiber in the present embodiment.
For the optical fiber of present embodiment, generate zone shown in (a) among the figure with the VAD method.Then, the core that is obtained by the VAD method is extended, attached outside carrying out again, thus generate zone (b).Next, this mother metal is extended, and then attached outside carrying out, thus zone (c) generated.When generating zone (b), in the vitrifacation process, import SiF
4Gas, and add F, obtain being lower than the refractive index of silicon material thus.Fig. 4 represents to have measured the result of the index distribution of the mother metal that obtains by aforementioned operation with prefabricated analyser (trade name: MODEL 2600, PhotonKinetics/York Technology company produces).Can find out from this figure,, can obtain effect of the present invention though the index distribution of present embodiment optical fiber is not complete rank type.
Each parameter of present embodiment optical fiber is as follows.
The radius a of core 1
1: 3.09 μ m
The radius a of first coating 2
2: 11.83 μ m
The radius a of second coating 3
3: 16.95 μ m
The ratio a of the radius of first coating 2 and the radius of core 1
2/ a
1: 3.83
Optical fiber external diameter: 125 μ m
The refractive index volume (V) of second coating 3: 36.8% μ m
2
In addition, utilize aforementioned core diameter a
1Specific refractivity difference Δ to core 1
1After carrying out the substep conversion, obtain the specific refractivity difference Δ of 0.50%, the first coating
2Be the specific refractivity difference Δ of-0.03%, second coating
3Be-0.25%.
To the optical fiber of present embodiment, transmission loss, cutoff wavelength, MFD, wavelength dispersion, chromatic dispersion gradient, zero-dispersion wavelength and bending loses under the wavelength 1550nm have been measured.Its result of table 5 expression.Measured with the ITU-T standard G.652 in common 1.3 mu m ranges of regulation be connected loss when welding with single-mode fiber, be 0.18dB under 1550nm, problem can not take place in this value.
Utilization is based on ITU-T standard Definitions and test methods for linear G.650.1, and the assay method of deterministic attributes of single-mode fiber and cable has carried out cutoff wavelength mensuration to 2m optical fiber.
(comparative example 1)
In previous embodiment 1, produced the optical fiber that the index distribution of optical fiber is changed to the single peak type that is not provided with second coating 3.
That is, the core mother metal to till the extremely zone (a) used in the previous embodiment 1 does not carry out the outer attached of zone (b), and only carries out the outer attached of zone (c), produces fibre parent material with this.At this moment, adjusted the thickness in zone (c), thereby made cutoff wavelength and embodiment 1 be equal extent.
Same with previous embodiment 1, the optical fiber that is obtained has been measured each optical characteristics.Represented its result in the table 5 in the lump.
Table 5
| Project | Unit | Measure wavelength | Embodiment 1 | Comparative example 1 | |
| Transmit loss | [dB/km] | 1550nm | 0.208 | 0.205 | |
| Cutoff wavelength | [μm] | - | 1.20 | 1.20 | |
| MFD | [μm] | 1310nm | 7.37 | 7.35 | |
| 1550nm | 8.54 | 8.51 | |||
| Wavelength dispersion | [ps/nm/km] | 1550nm | 11.43 | 14.50 | |
| Chromatic dispersion gradient | [ps/nm 2/km] | 1550nm | 0.060 | 0.060 | |
| Zero-dispersion wavelength | [nm] | - | 1381 | 1342 | |
| Bending loses | 20φ×10t | [dB] | 1550nm | 0.08 | 0.15 |
| 1650nm | 0.38 | 2.33 | |||
| 15φ×10t | [dB] | 1550nm | 0.34 | 0.64 | |
| 1650nm | 1.11 | 6.22 | |||
| 10φ×10t | [dB] | 1550nm | 1.40 | 10.2 | |
| 1650nm | 3.90 | 62.0 | |||
(embodiment 2)
Fig. 5 represents the index distribution of optical fiber in the present embodiment.The optical fiber of present embodiment adopts the operation identical with previous embodiment 1 to make.Fig. 5 represents to have measured with prefabricated analyser the result of the index distribution of mother metal.Can find out from this figure,, can obtain effect of the present invention though the index distribution of present embodiment optical fiber is not complete rank type.
Each parameter of present embodiment optical fiber is as follows.
The radius a of core 1
1: 3.40 μ m
The radius a of first coating 2
2: 11.48 μ m
The radius a of second coating 3
3: 16.45 μ m
The ratio a of the radius of first coating 2 and the radius of core 1
2/ a
1: 3.37
Optical fiber external diameter: 125 μ m
The refractive index volume (V) of second coating 3: 55.8% μ m
2
In addition, utilize aforementioned core diameter a
1Specific refractivity difference Δ to core 1
1After carrying out the substep conversion, obtain the specific refractivity difference Δ of 0.40%, the first coating
2Be the specific refractivity difference Δ of-0.02%, second coating
3Be-0.4%.
Same with previous embodiment 1, to the optical fiber of present embodiment, measured transmission loss, cutoff wavelength, MFD, wavelength dispersion, chromatic dispersion gradient, zero-dispersion wavelength and bending loses under the wavelength 1550nm.Its result of table 6 expression.Similarly to Example 1, under 1550nm, the connection loss of being measured is 0.05dB, and this value problem can not take place.
(comparative example 2)
In previous embodiment 2, produced the optical fiber that the index distribution of optical fiber is changed to the single peak type that is not provided with second coating 3.
That is, the core mother metal to till the extremely zone (a) used in the previous embodiment 1 does not carry out the outer attached of zone (b), and only carries out the outer attached of zone (c), produces fibre parent material with this.At this moment, adjusted the thickness in zone (c), thereby made cutoff wavelength and embodiment 2 be equal extent.
Same with previous embodiment 2, the optical fiber that is obtained has been measured each optical characteristics.Represented its result in the table 6 in the lump.
Table 6
| Project | Unit | | Embodiment | 2 | Comparative example 2 | |
| Transmit loss | [dB/km] | 1550nm | 0.215 | 0.212 | ||
| Cutoff wavelength | [μm] | - | 1.22 | 1.22 | ||
| MFD | [μm] | 1310nm | 8.27 | 8.42 | ||
| 1550nm | 9.49 | 9.50 | ||||
| Wavelength dispersion | [ps/nm/km] | 1550nm | 14.03 | 15.92 | ||
| Chromatic dispersion gradient | [ps/nm 2/km] | 1550nm | 0.064 | 0.060 | ||
| Zero-dispersion wavelength | [nm] | - | 1351 | 1326 | ||
| Bending loses | 20φ×10t | [dB] | 1550nm | 0.69 | 2.09 | |
| 1650nm | 1.67 | 17.29 | ||||
| 15φ×10t | [dB] | 1550nm | 1.02 | 5.43 | ||
| 1650nm | 3.21 | 31.19 | ||||
| 10φ×10t | [dB] | 1550nm | 2.20 | 41.8 | ||
| 1650nm | 4.80 | 122 | ||||
(embodiment 3)
Fig. 6 represents the index distribution of optical fiber in the present embodiment.
For the optical fiber of present embodiment, generate zone shown in (a) among the figure with the MCVD method.(b) is the quartz ampoule that sets out in the CVD method among the figure.The core that is obtained by the MCVD method is carried out outer attached, thereby generate zone (c).Fig. 6 represents to use prefabricated analyser, has measured the result of the index distribution of mother metal.Can find out from this figure,, can obtain effect of the present invention although the index distribution of present embodiment optical fiber is not complete rank type.
Each parameter of present embodiment optical fiber is as follows.
The radius a of core 1
1: 3.12 μ m
The radius a of first coating 2
2: 10.30 μ m
The radius a of second coating 3
3: 16.62 μ m
The ratio a of the radius of first coating 2 and the radius of core 1
2/ a
1=3.30
Optical fiber external diameter: 125 μ m
The refractive index volume (V) of second coating 3: 42.0% μ m
2
In addition, utilize aforementioned core diameter a
1Specific refractivity difference Δ to core 1
1After carrying out the substep conversion, obtain the specific refractivity difference Δ of 0.52%, the first coating
2Be the specific refractivity difference Δ of-0.07%, second coating
3Be-0.25%.
Same with previous embodiment 1, to the optical fiber of present embodiment, measured transmission loss, cutoff wavelength, MFD, wavelength dispersion, chromatic dispersion gradient, zero-dispersion wavelength and bending loses under the wavelength 1550nm.Following its result of table 7 expression.
Similarly to Example 1, the connection of being measured is lost in and is 0.29dB under the 1550nm.
(comparative example 3)
In previous embodiment 3, produced the optical fiber that the index distribution of optical fiber is changed to the single peak type that is not provided with second coating 3.
Promptly, in previous embodiment 3, in the processing of the MCVD method of synthesizing zone (a), be the synthetic low-index layer suitable with second coating, and adopted fluorine family gas, but in this comparative example, do not adopt this fluorine family gas to synthesize and the silicon index layer of degree much at one, thereby preparation core mother metal.Next, this core mother metal is carried out the outer attached of zone (c), produce fibre parent material with this.At this moment, adjusted the thickness in zone (c), thereby made cutoff wavelength and embodiment 3 same degree.
Same with previous embodiment 3, the optical fiber that is obtained has been measured each optical characteristics.Represented its result in the table 7 in the lump.
Table 7
| Project | Unit | | Embodiment | 3 | Comparative example 3 | |
| Transmit loss | [dB/km] | 1550nm | 0.216 | 0.215 | ||
| Cutoff wavelength | [μm] | - | 1.23 | 1.23 | ||
| MFD | [μm] | 1310nm | 7.12 | 7.20 | ||
| 1550nm | 8.03 | 8.05 | ||||
| Wavelength dispersion | [ps/nm/km] | 1550nm | 13.03 | 15.35 | ||
| Chromatic dispersion gradient | [ps/nm 2/km] | 1550nm | 0.057 | 0.057 | ||
| Zero-dispersion wavelength | [nm] | - | 1352 | 1325 | ||
| Bending loses | 20φ×10t | [dB] | 1550nm | 0.02 | 0.05 | |
| 1650nm | 0.15 | 0.33 | ||||
| 15φ×10t | [dB] | 1550nm | 0.08 | 0.66 | ||
| 1650nm | 0.34 | 2.79 | ||||
| 10φ×10t | [dB] | 1550nm | 0.30 | 8.80 | ||
| 1650nm | 0.96 | 21.5 | ||||
(embodiment 4)
Fig. 7 represents the index distribution of optical fiber in the present embodiment.
For the optical fiber of present embodiment, generate zone shown in (a) among the figure with the VAD method.Then, the core that is obtained by the VAD method is extended, attached outside carrying out again, thus generate zone (b).Next, this mother metal is extended, and then attached outside carrying out, thus zone (c) generated.When generating zone (a), internally the burner of the synthetic usefulness of side cladding imports CF
4Gas obtains being lower than quartzy refractive index thus.When generating zone (b), in the vitrifacation process, import SiF
4Gas, and add F, obtain being lower than the refractive index of silicon material thus.Fig. 7 represents to have measured with prefabricated analyser the result of the index distribution of mother metal.Can find out from this figure, same in the present embodiment, though the distribution of optical fiber is not complete rank type, can obtain effect of the present invention.
Each parameter of present embodiment optical fiber is as follows.
The radius a of core 1
1: 3.15 μ m
The radius a of first coating 2
2: 10.37 μ m
The radius a of second coating 3
3: 16.62 μ m
The ratio a of the radius of first coating 2 and the radius of core 1
2/ a
1: 3.30
Optical fiber external diameter: 80 μ m
The refractive index volume (V) of second coating 3: 42.2% μ m
2
In addition, utilize aforementioned core diameter a
1Specific refractivity difference Δ to core 1
1After carrying out the substep conversion, obtain the specific refractivity difference Δ of 0.56%, the first coating
2Be the specific refractivity difference Δ of-0.09%, second coating
3Be-0.25%.
Same with previous embodiment 1, the optical fiber of present embodiment has been measured cutoff wavelength, transmitted loss, MFD, wavelength dispersion, chromatic dispersion gradient, zero-dispersion wavelength and bending loses.Its result of table 8 expression.Put down in writing the mensuration wavelength of each characteristic in the table.
In the present embodiment, the 2m fiber cut off wavelength is 1.30 μ m, is longer than 1.26 μ m a little.Based on ITU-T standard Definitions and test methods for linear G.650.1, deterministic attributes of single-mode fiber and cable, 5.3.4Alternative testmethod for the cut-off wavelength (1cc) of the cable fiber, utilize 22m optical fiber, carried out the assessment of cable cutoff wavelength, consequently, the optical fiber of present embodiment is 1.23 μ m, confirms not have the use problem.
Same with present embodiment 1, the connection of being measured is lost in 1550nm and is 0.4dB down.
(comparative example 4)
In previous embodiment 4, produced the optical fiber that the index distribution of optical fiber is changed to the structure that is not provided with second coating 3.
That is, the core mother metal to till the extremely zone (a) used in the previous embodiment 4 does not carry out the outer attached of zone (b), and only carries out the outer attached of zone (c), produces fibre parent material with this.That is, first coating keeps below the value of silicon.At this moment, adjusted the thickness in zone (c), thereby made cutoff wavelength and previous embodiment 4 equal extent.
Same with previous embodiment 4, the optical fiber that is obtained has been measured each optical characteristics.Represented its result in the table 8 in the lump.
Table 8
| Project | |||||
| Transmit loss | [dB/km] | 1550nm | 0.205 | 0.204 | |
| Cutoff wavelength | [μm] | - | 1.30 | 1.30 | |
| The cable cutoff wavelength | 1.23 | 1.24 | |||
| MFD | [μm] | 1310nm | 6.90 | 7.02 | |
| 1550nm | 7.77 | 7.82 | |||
| Wavelength dispersion | [ps/nm/km] | 1550nm | 13.07 | 15.27 | |
| Chromatic dispersion gradient | [ps/nm 2/km] | 1550nm | 0.057 | 0.058 | |
| Zero-dispersion wavelength | [nm] | - | 1353 | 1.327 | |
| Bending loses | 20φ×10t | [dB] | 1550nm | ＜0.01 | ＜0.01 |
| 1650nm | ＜0.14 | 0.05 | |||
| 15φ×10t | [dB] | 1550nm | 0.06 | 0.07 | |
| 1650nm | 0.16 | 0.51 | |||
| 10φ×10t | [dB] | 1550nm | 0.10 | 1.30 | |
| 1650nm | 0.74 | 5.9 | |||
Utilizability on the industry
The present invention relates to the good optical fiber of flexural property. According to the present invention, can with low cost, obtain less based on the loss of bending and good with the connectivity of common transmission usefulness optical fiber optical fiber.
Claims (20)
1. optical fiber has:
Be disposed at the core at center;
Be disposed at first coating on the circumference of aforementioned core;
Be disposed at second coating on the circumference of aforementioned first coating;
Be disposed at the 3rd coating on the circumference of aforementioned second coating,
This optical fiber is characterised in that,
The largest refractive index of aforementioned core, greater than any one of each largest refractive index of aforementioned first coating, second coating and the 3rd coating, the largest refractive index of aforementioned second coating, less than any one of each largest refractive index of aforementioned first coating and the 3rd coating, and
When the radius with aforementioned core is made as a
1, the outer rim radius of aforementioned first coating is made as a
2The time, a
2/ a
1Value be between 2.5 to 4.5,
When with the refractive index of aforementioned the 3rd coating during as benchmark, the specific refractivity difference of aforementioned core is between 0.20% to 0.70%,
Following formula (1) refractive index volume V expressed, aforementioned second coating is 25% μ m
2More than 110% μ m
2Below:
In the following formula (1),
R: radius,
Δ n (r): radius is that the specific refractivity of r is poor, and benchmark is the largest refractive index of the 3rd coating,
a
2: the outer rim radius of first coating,
a
3: the outer rim radius of second coating.
2. optical fiber according to claim 1 is characterized in that: cutoff wavelength is below the 1260nm.
3. optical fiber according to claim 1 is characterized in that: the refractive index volume V of aforementioned second coating is 50% μ m
2More than.
4. optical fiber according to claim 1 is characterized in that: when with the largest refractive index of aforementioned the 3rd coating during as benchmark, the specific refractivity difference of aforementioned first coating is more than-0.10% below 0.05%.
5. optical fiber according to claim 1 is characterized in that: when with the largest refractive index of aforementioned the 3rd coating during as benchmark, the specific refractivity difference of aforementioned second coating is more than-0.60%-and below 0.20%.
6. optical fiber according to claim 1, it is characterized in that: in the time will making the bending loses added value that has under the wavelength 1550nm that is produced when not having the identical single peak type optical fiber of the single peak type of second coating index distribution and cutoff wavelength on diameter is the mandrel of 20mm, to twine ten circles be made as 1, be below 0.4 with the bending loses ratio of recently expressing of the bending loses added value of same mensuration.
7. optical fiber according to claim 1, it is characterized in that: in the time will making the bending loses added value that has under the wavelength 1550nm that is produced when not having the identical single peak type optical fiber of the single peak type of second coating index distribution and cutoff wavelength on diameter is the mandrel of 15mm, to twine ten circles be made as 1, be below 0.55 with the bending loses ratio of recently expressing of the bending loses added value of same mensuration.
8. optical fiber according to claim 1 is characterized in that: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle below the 0.05dB, and the mode field diameter under the wavelength 1550nm is more than the 8.3 μ m.
9. optical fiber according to claim 8 is characterized in that: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1650nm is that every circle is below the 0.05dB.
10. optical fiber according to claim 8 is characterized in that: when reeling by bending diameter 15mm, the bending loses value under the wavelength 1550nm is every circle below the 0.05dB, and the mode field diameter under the wavelength 1310nm is more than the 6.8 μ m.
11. optical fiber according to claim 10 is characterized in that: when reeling by bending diameter 15mm, the bending loses value under the wavelength 1650nm is that every circle is below the 0.05dB.
12. optical fiber according to claim 8 is characterized in that: when reeling by bending diameter 15mm, the bending loses value under the wavelength 1550nm is every circle below the 0.05dB, and the mode field diameter under the wavelength 1550nm is more than the 7.8 μ m.
13. optical fiber according to claim 1, it is characterized in that: do not have the identical mode field diameter (MFD) of single peak type optical fiber under 1550nm of the single peak type of second coating index distribution and cutoff wavelength when value is made as 1 when having, the ratio of the same MFD value of measuring is more than 0.98.
14. optical fiber according to claim 1 is characterized in that: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is every circle below the 0.05dB, and the mode field diameter under the wavelength 1310nm is more than the 7.3 μ m.
15. optical fiber according to claim 1 is characterized in that: when reeling by bending diameter 10mm, the bending loses value under the wavelength 1550nm is every circle below the 0.05dB, and the mode field diameter under the wavelength 1310nm is more than the 6.3 μ m.
16. optical fiber according to claim 15 is characterized in that: the mode field diameter under the wavelength 1550nm is more than the 7.3 μ m.
17. optical fiber according to claim 15 is characterized in that: when reeling by bending diameter 10mm, the bending loses value under the wavelength 1650nm is that every circle is below the 0.05dB.
18. optical fiber according to claim 1, it is characterized in that: when reeling by bending diameter 20mm, bending loses value under the wavelength 1550nm is every circle below the 1dB, and the mode field diameter under the wavelength 1310nm is more than the 7.9 μ m, and zero-dispersion wavelength is below the above 1324nm of 1300nm.
19. optical fiber according to claim 18 is characterized in that: when reeling by bending diameter 20mm, the bending loses value under the wavelength 1550nm is that every circle is below the 0.5dB.
20. optical fiber according to claim 18 is characterized in that: when pressing bending diameter 15mm coiling 10 circles, the bending loses value under the wavelength 1650nm is below the 19.37dB.
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| CN102149648A (en) * | 2008-09-09 | 2011-08-10 | 信越化学工业株式会社 | Process for producing optical-fiber base material |
| US8396340B2 (en) | 2007-11-19 | 2013-03-12 | Mitsubishi Cable Industries, Ltd. | Optical fiber and method for fabricating the same |
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| CN101680994B (en) * | 2008-02-22 | 2013-02-20 | 住友电气工业株式会社 | Optical fiber cable and optical cable |
| KR20100091710A (en) * | 2009-02-11 | 2010-08-19 | 엘에스전선 주식회사 | Method for manufacturing optical fiber improvement of bending loss and optical fiber manufactured using the same |
| JP5478116B2 (en) * | 2009-05-20 | 2014-04-23 | 信越化学工業株式会社 | Optical fiber |
| ES2684474T3 (en) * | 2010-02-01 | 2018-10-03 | Draka Comteq B.V. | Optical fiber with non-zero offset dispersion having a small wavelength |
| DK2656127T3 (en) * | 2010-12-23 | 2019-05-20 | Prysmian Spa | Single mode optical fiber with low curvature loss |
| JP2015184371A (en) * | 2014-03-20 | 2015-10-22 | 株式会社フジクラ | Polarization holding optical fiber |
| CN105158843B (en) * | 2015-08-31 | 2018-10-12 | 中天科技光纤有限公司 | A kind of thin footpath bend insensitive fiber and preparation method thereof |
| US9989699B2 (en) * | 2016-10-27 | 2018-06-05 | Corning Incorporated | Low bend loss single mode optical fiber |
| CN108983351A (en) * | 2018-07-19 | 2018-12-11 | 江苏南方光纤科技有限公司 | A kind of counter-bending single mode optical fiber and preparation method thereof |
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| JP3098828B2 (en) * | 1991-12-09 | 2000-10-16 | 住友電気工業株式会社 | Dispersion shifted fiber and method of manufacturing the same |
| US5559921A (en) * | 1994-06-24 | 1996-09-24 | Sumitomo Electric Industries, Ltd. | Single mode optical fiber |
| JPH09288220A (en) * | 1996-02-20 | 1997-11-04 | Kokusai Denshin Denwa Co Ltd <Kdd> | Optical fiber |
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|---|---|---|---|---|
| US8396340B2 (en) | 2007-11-19 | 2013-03-12 | Mitsubishi Cable Industries, Ltd. | Optical fiber and method for fabricating the same |
| CN102149648A (en) * | 2008-09-09 | 2011-08-10 | 信越化学工业株式会社 | Process for producing optical-fiber base material |
| US8820121B2 (en) | 2008-09-09 | 2014-09-02 | Shin-Etsu Chemical Co., Ltd. | Method of manufacturing optical fiber base material |
| CN102149648B (en) * | 2008-09-09 | 2015-06-03 | 信越化学工业株式会社 | Process for producing optical-fiber base material |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100374888C (en) | 2008-03-12 |
| CN100549740C (en) | 2009-10-14 |
| CN1768282A (en) | 2006-05-03 |
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