CN103443673B - optical fiber and optical transmission system - Google Patents
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- CN103443673B CN103443673B CN201280013079.0A CN201280013079A CN103443673B CN 103443673 B CN103443673 B CN 103443673B CN 201280013079 A CN201280013079 A CN 201280013079A CN 103443673 B CN103443673 B CN 103443673B
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- 239000003365 glass fiber Substances 0.000 title claims abstract description 159
- 230000003287 optical Effects 0.000 title claims abstract description 119
- 230000005540 biological transmission Effects 0.000 title claims abstract description 75
- 239000011521 glass Substances 0.000 claims abstract description 31
- YBMRDBCBODYGJE-UHFFFAOYSA-N Germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 claims abstract description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000005452 bending Methods 0.000 claims description 44
- 239000011248 coating agent Substances 0.000 claims description 25
- 238000000576 coating method Methods 0.000 claims description 25
- 239000000835 fiber Substances 0.000 claims description 18
- 239000011737 fluorine Substances 0.000 claims description 8
- 229910052731 fluorine Inorganic materials 0.000 claims description 7
- YCKRFDGAMUMZLT-UHFFFAOYSA-N fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 7
- 230000001702 transmitter Effects 0.000 claims description 6
- 238000004804 winding Methods 0.000 claims description 3
- 230000000149 penetrating Effects 0.000 claims 1
- 238000010583 slow cooling Methods 0.000 description 16
- 238000010438 heat treatment Methods 0.000 description 13
- 238000001816 cooling Methods 0.000 description 9
- 229910052904 quartz Inorganic materials 0.000 description 7
- 238000001069 Raman spectroscopy Methods 0.000 description 6
- 239000011347 resin Substances 0.000 description 5
- 229920005989 resin Polymers 0.000 description 5
- 229910052783 alkali metal Inorganic materials 0.000 description 4
- 150000001340 alkali metals Chemical class 0.000 description 4
- 230000003321 amplification Effects 0.000 description 4
- 238000010276 construction Methods 0.000 description 4
- 238000003199 nucleic acid amplification method Methods 0.000 description 4
- 239000010453 quartz Substances 0.000 description 4
- 239000002585 base Substances 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 3
- 229910052906 cristobalite Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 229910052682 stishovite Inorganic materials 0.000 description 3
- 229910052905 tridymite Inorganic materials 0.000 description 3
- 238000005491 wire drawing Methods 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive Effects 0.000 description 2
- 239000002419 bulk glass Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229920002456 HOTAIR Polymers 0.000 description 1
- 210000002381 Plasma Anatomy 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 230000001808 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- PVADDRMAFCOOPC-UHFFFAOYSA-N germanium monoxide Inorganic materials [Ge]=O PVADDRMAFCOOPC-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 230000002093 peripheral Effects 0.000 description 1
- 230000000644 propagated Effects 0.000 description 1
- 230000002940 repellent Effects 0.000 description 1
- 239000005871 repellent Substances 0.000 description 1
- 230000003252 repetitive Effects 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 230000001340 slower Effects 0.000 description 1
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- 238000005211 surface analysis Methods 0.000 description 1
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Abstract
A kind of low cost being made up of quartz glass and low-loss optical fiber (1) preferably act as the light transmission path of Optical Access Network.This optical fiber is provided with core (11)；Optics covering (12), it is round core；And sheath (13), it is round optics covering.Core contains GeO2.Core is relative to the refractive index contrast (Δ of optics coveringCore) it is 0.35% to 0.50%, and the refractive index volumes of core is (v) 0.045 μm2To 0.095 μm2.The refractive index contrast (Δ J) of sheath is 0.03% to 0.20%.The fictive temperature of the glass constituting core is 1400 DEG C to 1590 DEG C.Residual stress in core be the absolute value of compressive stress and this residual pressure be more than 5MPa.
Description
Technical field
The present invention relates to optical fiber and optical transmission system.
Background technology
G.Talli et al., J.Lightw.Technol., Vol.24, No.7,2827-2834(2006) in describe and claimed
Optical Access Network for " long-reach passive optical network(PON) (long-distance passive optical network) ".Long
Distance PON is for being transferred in user family via shunt by the flashlight of the optical line terminal (OLT) from telephone office
The transmission system of optical network unit (ONU), and allow the length of optical transmission line between OLT and ONU longer, thus can drop
Low communication cost.
This optical transmission system is preferably by low attenuation optical fiber, in order to extend while keeping OSNR (OSNR)
Communication distance.About low attenuation optical fiber, M.Kato et al., Electron.Lett., Vol.35, No.19,1615-1617
(1999) optical fiber including pure quartz core portion is disclosed in.Regrettably, the optical fiber in typical pure quartz core portion is expensive, by
In this reason economically, the problem that the optical fiber in pure quartz core portion is introduced Optical Access Network does not the most make progress.
S.Sakaguchi et al., Appl.Opt., Vol.37, No.33,7708-7711(1998) and JP2006-58494A
Disclose the technology making the decay following in ITU-T universal optical fibre G.652 reduce.According to this technology, when stretching optical fiber is pre-
When product is to form optical fiber, cool down optical fiber lentamente, to reduce the fictive temperature of the glass being constituted optical fiber, thus reduce in optical fiber
Rayleigh scattering, be achieved in low decay.
Summary of the invention
<technical problem>
The present invention provides the cheap low attenuation optical fiber of a kind of optical transmission line being suitable for use as in Optical Access Network and incites somebody to action
This optical fiber is as the optical transmission system of transmission line.
<technical scheme>
The present invention provides a kind of Silica glass optical fiber, and described optical fiber includes: core, and it includes central axis；Optics bag
Layer, it is round described core；And sheath, it is round described optics covering.Described core contains GeO2, described core
Refractive index contrast ΔCoreMore than or equal to 0.35% and less than or equal to 0.50%, and the refractive index volumes of described core
More than or equal to 0.045 μm2And less than or equal to 0.095 μm2, wherein, Δ (r) represents the phase at radial coordinate r
Birefringence rate variance, a represents the radius of described core.The refractive index contrast Δ J of described sheath is more than or equal to 0.03% and little
In or equal to 0.20%.Constitute the fictive temperature of glass of described core greater than or equal to 1400 DEG C and less than or equal to 1590
℃.Residual stress in described core is the compressive stress that absolute value is more than or equal to 5MPa.
In this manual, term " refractive index contrast " refers to (n-nCovering)/nCoveringValue, this value is based on each several part (core
Portion or sheath) refractive index n relative to refractive index n of optics coveringCovering.Term " refractive index of core " refers to equivalence step folding
Penetrate rate (ESI).Term " external diameter of optics covering " refers to the interface between optics covering and sheath, and refractive index is about radially
The derivative of coordinate arrives the diameter at maximum.Term " refractive index of sheath " refers to having optics covering from optics covering
The part in footpath is to the meansigma methods of the refractive index of the most peripheral part of glass.
According in the optical fiber of the present invention, 2m fiber cut off wavelength can be more than or equal to 1260nm, 22m cable cutoff ripple
Length can be less than or equal to 1260nm, and the mode field diameter in the case of wavelength is 1310nm can more than or equal to 8.2 μm also
And less than or equal to 9 μm, and the decay in the case of wavelength is 1550nm can be less than or equal to 0.18dB/km.Institute
State in the cross section being perpendicular to axis of optical fiber, the residual stress of the part of more than 50% in the cross-sectional area of described sheath
It can be tension.The absolute value of the residual stress in described core can be less than or equal to 30MPa.Remnants in described core
The absolute value of stress can be less than or equal to 10MPa.Increase by the decay caused by OH base in the case of 1383nm at wavelength
Amount can be less than or equal to 0.02dB/km.Described core can contain fluorine.Described optical fiber can also include round described sheath
Primary coating and secondary coating.The Young's modulus of described secondary coating can be more than or equal to 800MPa, described primary coating
Young's modulus can be more than or equal to 0.2MPa and less than or equal to 1MPa.
According in the optical fiber of the present invention, in the case of wavelength is 1550nm, bending radius is that bending during 15mm is damaged
Consumption can be enclosed less than or equal to 0.002dB/, and bending radius is that bending loss during 10mm can enclose less than or equal to 0.2dB/,
Bending radius is that bending loss during 10mm can enclose less than or equal to 0.1dB/, and bending radius is bending loss during 7.5mm
Can enclose less than or equal to 0.5dB/.Additionally, according in the optical fiber of the present invention, in the case of wavelength is 1625nm, bend
Radius is that bending loss during 15mm can enclose less than or equal to 0.01dB/, and bending radius is that bending loss during 10mm is permissible
Enclosing less than or equal to 0.4dB/, bending radius is that bending loss during 10mm can enclose less than or equal to 0.2dB/, bending radius
Can enclose less than or equal to 1dB/ for bending loss during 7.5mm.
According in the optical fiber of the present invention, MAC value (=MFD/ λ c) can be less than or equal to 6.6, and described MAC value is at ripple
Mode field diameter MFD in the case of a length of 1310nm and the ratio of 2m fiber cut off wavelength λ c.Between attenuation alpha _ B and attenuation alpha _ t
Decay poor (α _ B-α _ t) 0.01dB/km, described attenuation alpha _ B can be less than be: in the case of wavelength is 1550nm, to twining
It is wound on the decay that the optical fiber of a length of 10km or longer on 140 φ mound bobbins records；Described attenuation alpha _ t is: at wavelength be
In the case of 1550nm, the decay that the optical fiber in lax winding ring is recorded.According in the optical fiber of the present invention, have cated
The external diameter of described optical fiber can be less than or equal to 210 μm.So can reduce cross-sectional area, thus improve the sky after arranging
Between utilization rate.In this case, for prevent fracture consideration, the thickness of described secondary coating can be more than or equal to 10 μ
m。
The present invention provides a kind of optical transmission system, and described optical transmission system is for by the optical line terminal from telephone office
The optical network unit that flashlight is transferred in user family via shunt, wherein, the optical line terminal of described telephone office is with described
The light between optical network unit in the length of the optical transmission line between shunt or described shunt and described user family passes
The length of defeated line be more than or equal to 15km, and be arranged on according to the optical fiber of the present invention described optical transmission line more than 90% district
Duan Zhong.The present invention also provides for a kind of optical transmission system, and described optical transmission system is for being transferred to the flashlight from transmitter
Receptor, wherein, the length of the optical transmission line between described transmitter and described receptor be more than or equal to 40km, and according to
The optical fiber of the present invention is arranged in the section of more than the 90% of described optical transmission line.
The present invention also provides for a kind of optical transmission system, and described optical transmission system is for by the optical line terminal from telephone office
The optical network unit that is transferred in user family via shunt of flashlight, wherein, be arranged on described according to the optical fiber of the present invention
In the section of more than 50% of the optical transmission line between optical network unit in the optical line terminal of telephone office and described user family,
And in described optical transmission line, do not amplify described flashlight.The present invention also provides for a kind of optical transmission system, described optical transport system
System is used for the optical network unit being transferred in user family by the flashlight of the optical line terminal from telephone office via shunt, its
In, it is arranged between the optical network unit in the optical line terminal of described telephone office and described user family according to the optical fiber of the present invention
Optical transmission line more than 50% section in, and in described optical transmission line, amplify described flashlight.
<beneficial effect>
According to the present invention, it is provided that the cheap low attenuation optical fiber of a kind of optical transmission line being suitable for use as in Optical Access Network.
Accompanying drawing explanation
Fig. 1 is the sectional view of optical fiber according to an embodiment of the invention.
Fig. 2 is to illustrate to include containing GeO2The accessible fictive temperature of optical fiber of core and the curve chart of the dependency of L/V.
Fig. 3 is the curve chart illustrating the decay in optical fiber with the dependency of fictive temperature.
Fig. 4 is the curve chart illustrating added losses with the dependency of the residual stress in core.
Fig. 5 is the radially-arranged curve chart illustrating the residual stress in optical fiber.
Fig. 6 is the curve chart illustrating the relation between raman scattering intensity and Raman shift.
Detailed description of the invention
Below, will be described in detail with reference to the attached drawings embodiments of the invention, accompanying drawing is only in order at the purpose of example, it is not intended to
Limit the scope of the present invention.In the accompanying drawings, identical reference represents identical parts, and omits repetitive description.Accompanying drawing
In size or ratio may not be accurate.
It was found by the inventors of the present invention that contain GeO at core2In the case of, reduce glass if, with Slow cooling
Fictive temperature, reduces Rayleigh scattering, then the loss component caused by the factor in addition to Rayleigh scattering is (hereinafter referred to as
" added losses (excess loss) ") may increase, and differ and obtain low attenuation optical fiber surely.According to the present inventor
Being understood, S.Sakaguchi et al. and JP2006-58494A disclose and reduce in optical fiber by cooling down glass lentamente
Decay, M.Ohashi et al.., IEEE Photon.Technol.Lett., Vol.5, No.7,812-814(1993) disclose profit
Reduce the decay in optical fiber by core-covering viscosity coupling, but these documents are the most not mentioned includes mixed with GeO2Core
Optical fiber in added losses and the residual stress in core between relation.
Fig. 1 is the sectional view of optical fiber 1 according to an embodiment of the invention.Optical fiber 1 is by SiO2The optical fiber that glass is constituted is also
Including: core 11, it includes central axis；Optics covering 12, it is round core 11；And sheath 13, it is round optics
Covering 12.Core 11 is containing GeO2And also fluorine can be contained.The refractive index of the refractive index ratio core 11 of optics covering 12 is low.Light
Learning covering 12 can be by pure SiO2Glass or the SiO mixed with fluorine2Glass is constituted.Sheath 13 is by pure SiO2Glass is constituted and permissible
Containing chlorine.
The Rayleigh scattering reduced in optical fiber 1 can reduce the decay in optical fiber 1.Reduce the imagination of the glass constituting optical fiber 1
Temperature is effective for reducing Rayleigh scattering.The method of the fictive temperature reducing glass includes as described below the first
Method and second method.
First method is following (Slow cooling method): at stretching optical fiber prefabricated component during forming optical fiber 1, slows down and is formed
The rate of cooling of optical fiber, relax accelerating the network structure of glass, thus reduce the fictive temperature of glass.Second method is such as
Under: in core 11, add minimal amount of additive, thus reduce the fictive temperature of glass, so in the structure accelerating core 11
While Song Chi, do not increase and absorbed caused decay by light.
First method or second method can be utilized to reduce the Rayleigh scattering of optical fiber 1, or can utilize above-mentioned
The appropriately combined Rayleigh scattering reducing optical fiber 1 of method.Slow cooling method is described below.
The method manufacturing optical fiber 1 is as follows.First, such as VAD (VAD), OVD are utilized
(OVD), the vapour phase glass such as modified chemical vapor deposition method (MCVD) or PCVD (Plasma Chemical Vapor Deposition) (PCVD) synthesis
Method forms the core propagated for light, utilizes VAD, OVD, advanced plasma vapor deposition (APVD), rod to collapse or it
Its similar method forms the restrictive coating surrounding core, is consequently formed fibre-optical preform.VAD, OVD, MCVD, rod can be utilized
Collapse or method that other is similar forms the intermediate optical covering between core and sheath.So formed with wire drawing machine clamping
Fibre-optical preform, the lower end of prefabricated component is heated and reaches at or above processing temperature, suitably stretch the drop of melted glass
Shape end, to form optical fiber, thus makes glass optical fiber.Restrained stretching speed, so that glass optical fiber has predetermined external diameter.With
Resin coating glass optical fiber, is consequently formed coated optical fiber.Coated optical fiber is wrapped on mound bobbins.
The coating of resin has double-decker and includes: primary coating, and it prevents glass optical fiber to be applied directly external force；With
And secondary coating, it prevents glass optical fiber by external damage.At optical fiber formation stages, can be continuously provided for applying painting
The mould of layer.It is alternatively possible to use the mould of two coatings of injection simultaneously to apply resinous coat.In this case, may be used
To reduce the height of wire drawing machine.Therefore, it can reduce the construction cost of the building for accommodating wire drawing machine.
Furthermore, it is possible to arrange the device of the rate of cooling of the glass optical fiber that control is formed between fiber drawing furnace and mould,
Such that it is able to surface temperature control when glass optical fiber enters mould is in suitable temperature.Preferably, control cooling is flowed through
The Reynolds number of the gas of the device of speed is relatively low, because the turbulent flow by occurring on the optical fiber formed so can be made to be caused
Vibration reduces.Additionally, by the rate of cooling controlling glass optical fiber, it is possible to reduce Rayleigh scattering, it is derived from the light of low decay
Fine.
For making, in the UV stove that resin solidifies, to be come suitably by the intensity of feedback control UV light and in-furnace temperature
Control the curing rate of resin.UV stove is suitable for use magnetron or ultraviolet LED.In the case of using ultraviolet LED,
Owing to this light source does not produce heat, so to arrange the mechanism of supply hot-air extraly, in order to stove is controlled suitable
Temperature.The inner surface of the furnace tube being likely attached to UV stove from the isolated composition of resin, so that arriving during La Shen
The power of the UV light of coating changes.Therefore, it can the minimizing degree monitoring UV luminous power in advance during stretching, and can
To control UV luminous power according to stretching time, thus the UV optical power control being applied in coating is constant power.Can
Selection of land, can monitor the UV light from furnace tube leakage, and can control this UV luminous power, thus the UV being applied in coating
Optical power control is constant power.This makes optical fiber have homogeneous fracture strength over the entire length.
Preferably, the thickness of secondary coating in two coatings is suitably set, to keep the resistance to external damage.
Typically, the thickness of secondary coating is preferably larger or equal than 10 μm, more preferably greater than or equal to 20 μm.So produce and twine
The optical fiber 1 being wound on mound bobbins is coloring when necessary, and is used as the such as final products such as optical cable or optical cord.
According to embodiments of the invention, optical fiber is formed in fiber drawing furnace, leave after fiber drawing furnace through Slow cooling unit and
Heating furnace, subsequently in mould.Slow cooling unit is with more than or equal to 1000 DEG C/s and less than or equal to 20000 DEG C/s
Rate of cooling cool down following region continuously: from the tapered portion being positioned at melted fibre-optical preform lower end, (diameter range is
The 90% to 5% of the diameter of fibre-optical preform) start, to the part that temperature is 1400 DEG C of the optical fiber formed.Heating furnace
It is arranged on such as the lower section of lower plane (outlet of fiber drawing furnace): this plane is the bottom of fiber drawing furnace, and the optical fiber formed is substantially
Discharge from fiber drawing furnace at this plane.Distance between outlet and the entrance of heating furnace of fiber drawing furnace is 1m or less.Preferably,
The Slow cooling unit being arranged between the outlet of fiber drawing furnace and the entrance of heating furnace has for preventing formed optical fiber
The heat insulating construction that temperature reduces.When optical fiber enters in heating furnace, the temperature of optical fiber is preferably higher than or equal to 1000 DEG C, more excellent
Selection of land is greater than or equal to 1400 DEG C.
This can reduce the length of heating furnace, and optical fiber is reheated to substantially allow in heating furnace structural relaxation
Temperature (generally, this temperature is at or greater than glass transition point).It is thus possible to increase the time needed for structural relaxation.If
Represent draw speed with V, then length L of heating furnace is arranged so that L/V is more than or equal to 0.05s.Preferably, heating furnace bag
Include multiple stove.As such, it is possible to be precisely controlled the rate of cooling of optical fiber.Preferably, rate of cooling more than or equal to 5000 DEG C/
S, until being cooled to less than 1100 DEG C by the optical fiber in heating furnace.Above-mentioned heating furnace is used to obtain in fiber manufacturing
The optical fiber that Rayleigh scattering reduces.
Increase L/V and can reduce the fictive temperature of glass.In view of economy, draw speed V is preferentially more than or equal to
20m/s.Such as, in order to realize L/V=0.2s, length L of heating furnace must reach 4m.As it has been described above, by the length shadow of heating furnace
Harmony between the equipment or the construction cost of building and the draw speed that ring has certain restriction.Fig. 2 is to illustrate to include containing
GeO2The accessible fictive temperature of optical fiber of core and the curve chart of the dependency of L/V.Fig. 2 is at K.Saito et al.,
J.Am.Ceram.Soc., Vol.89 [1], 65-69(2006) in table 1 data on the basis of formed.In view of economy
On requirement and allow L/V < in the case of 0.5s, accessible fictive temperature be 1400 DEG C.
Fig. 3 is the curve chart illustrating the decay in optical fiber with the dependency of fictive temperature, and Fig. 3 is at K.Saito etc.
Formed on the basis of the equation (2) of people.Term " added losses " in Fig. 3 refers to except by Rayleigh scattering, Brillouin scattering
Loss outside the loss caused with Raman scattering (includes that macrobend loss (macrobending loss) and microbend damage
Consumption).When added losses are more than or equal to 0.030dB/km, if fictive temperature is 1400 DEG C, then it is 1550nm's at wavelength
In the case of be difficult to the decay of 0.18dB/km.
As mentioned above, although by Slow cooling reduce glass fictive temperature so that Rayleigh scattering reduce, but by
Added losses that factor in addition to Rayleigh scattering component is caused increase, in which case it is difficult to make the wavelength be
Decay in the case of 1550nm is stably less than or equal to 0.18dB/km.Present inventor determined that and caused additional damage
The factor that consumption increases, and have found the good dependency between the residual stress in added losses and core.Fig. 4 be illustrate attached
Add the curve chart of loss and the dependency of the residual stress in core.This curve chart shows: when the residual stress in core is exhausted
To value more than or equal to 5MPa(in the diagram, at or below-5MPa) compressive stress time, added losses can be less than or equal to
0.02dB/km, more reliable is less than or equal to 0.025dB/km.
When the residual stress in core is the compressive stress that absolute value is more than or equal to 5MPa, added losses generally less than or
Equal to 0.02dB/km.Therefore, in the case of wavelength is 1550nm, at 1530 DEG C, 1560 DEG C and the fictive temperature of 1590 DEG C
Under, the decay of 0.180dB/km, 0.183dB/km and 0.185dB/km can be realized respectively.
The core 11 of optical fiber 1 is containing GeO2, the refractive index contrast Δ of core 11CoreMore than or equal to 0.35% and be less than
Or equal to 0.50%, the refractive index volumes ν of core 11 is more than or equal to 0.045 μm2And less than or equal to 0.095 μm2, refractive index
Volume is expressed as equation (2):
Wherein, Δ (r) represents the refractive index contrast at radial coordinate r, and a represents the radius of core.It is highly preferred that refraction
Rate volume ν is more than or equal to 0.06 μm2And less than or equal to 0.085 μm2.The refractive index contrast Δ J of sheath 13 more than or etc.
In 0.03% and less than or equal to 0.20%.The fictive temperature of the glass constituting core 11 greater than or equal to 1400 DEG C and is less than
Or equal to 1590 DEG C, preferably lower than or equal to 1560 DEG C, be more preferably less than or equal to 1530 DEG C.Additionally, in core 11
Residual stress is the compressive stress that absolute value is more than or equal to 5MPa.
In optical fiber 1, it is preferable that 2m fiber cut off wavelength more than or equal to 1260nm, 22m cable cutoff wavelength less than or
Equal to 1260nm, the mode field diameter in the case of wavelength is 1310nm is more than or equal to 8.2 μm and is less than or equal to 9 μm,
Decay in the case of wavelength is 1550nm is less than or equal to 0.18dB/km.It is highly preferred that be the situation of 1550nm at wavelength
Under decay less than or equal to 0.178dB/km, and 2m fiber cut off wavelength is more than or equal to 1290nm.
As described in JP2009-168813A, utilize the birefringence in optical fiber to the residual stress measuring in optical fiber.
It is alternatively possible to variable quantity based on refractive index and the intrinsic photoelastic coefficient of material measure the residual stress in optical fiber,
Wherein, the variable quantity of refractive index utilizes the surface analysis (area analysis) of the refractive index in cross section of optic fibre to obtain.Fig. 5
It it is the radially-arranged curve chart illustrating the residual stress in optical fiber.Including containing GeO2Core and be substantially made up of pure quartz
In the optical fiber of sheath, owing at that same temperature, the viscosity of core is less than the viscosity of sheath, so the core of the optical fiber drawn
Portion remains compressive stress (curve of L/V=0s in Fig. 5).This compressive stress changes based on pulling force.It is known that substantially
Pulling force is the biggest, and the compressive stress of residual is the biggest.
Additionally, in the optical fiber of Slow cooling, compressive stress is relaxed in Slow cooling unit, thus compressive stress
Absolute value reduce.The change of the residual stress that Fig. 5 is shown through making L/V become 0s, 0.12s and 0.40s and obtains.Known
It is that the increase optical fiber time of staying in Slow cooling unit can be gradually reduced the absolute value of the compressive stress in core.In order to make
The absolute value of the compressive stress in core is less than 0.4s more than or equal to 5MPa, preferably L/V.It addition, during cooling optical fiber, will
The temperature of optical fiber is maintained above the internal surface temperature of Slow cooling unit, until optical fiber arrives Slow cooling unit, by
This compressive stress being possible to prevent in core excessively reduces.Substantially, Slow cooling unit is the longest, and the effect of Slow cooling is the most aobvious
Write.Therefore, the variable quantity making compressive stress increases.
Such as, in the case of the length at Slow cooling unit is more than or equal to 2m, it is important that keep L/V to be equal to or low
In 0.2s.Additionally, the pulling force being applied on drawn fiber glass is preferably larger or equal than 50g, more preferably larger than or
Equal to 100g.
About the another kind of method of the stress controlled in core, add the additive for reducing core viscosity to core,
Such that it is able to the absolute value of the compressive stress of core is controlled as equal to or more than 5MPa.Preferably it is used as to add by alkali metal
Agent, this is because minimal amount of alkali metal just can significantly decrease the viscosity of quartz glass.Add alkali metal too much
Element can cause glass structure defect to increase unfortunately, causes hydrogen characteristic and radiation characteristic deterioration.It is therefore preferable that will add
The amount of agent is adjusted to appropriate value.Preferably, after the stretch, the concentration of the alkali metal in core is more than or equal to 1wtppb
And less than or equal to 10wtppm.
Fig. 6 is the curve chart illustrating the relation between raman scattering intensity and Raman shift.Can be based on each portion constituting optical fiber
The D1(490cm in microcosmic raman scattering spectrum in Fen-1) peak area and 800cm-1Relation between the ratio of peak area is estimated
The fictive temperature that photometric is fine.At 525cm-1With 475cm-1Between wave-number range in draw baseline, and calculate this baseline and spectrum
Between D1 peak area.Additionally, at 880cm-1With 740cm-1Between wave-number range in draw baseline, and calculate this baseline with
800cm between spectrum-1Peak area.Fictive temperature can utilize 800cm-1The ratio of peak area and D1 peak area with utilize example
As both bulk glasses (bulk glass) by IR method (D.-L.Kim and M.Tomozawa, J.Non-Cryst.Solids,
Vol.286,132-138(2001)) relation between the fictive temperature that records obtains.
G.657.A1 optical fiber according to the present embodiment preferably follow ITU-T, and the most also have and follow G.657.A2
Bending loss.Owing to G.657.A2 the optical fiber according to the present embodiment followed, thus this optical fiber can with follow G.652.D
The general purpose single mode fiber with low decay is connected, it is possible to be similarly used for transmission system with G.652.D optical fiber.
According in the optical fiber of the present embodiment, it is preferable that in the cross section being perpendicular to axis of optical fiber, sheath transversal
The residual stress of the part of more than 50% in the area of face is tension.In order to make the residual stress in core be compressive stress, it is necessary to
Tension is applied, so that the value of tension is equal to the value of the compressive stress applied to core to sheath.To pulling force, thermal history and optical fiber
Component be controlled making in the cross-sectional area of sheath more than 50% the residual stress of part be tension, thus easily
To make the residual stress in core be compressive stress.
According in the optical fiber of the present embodiment, it is preferable that the absolute value of the residual stress in core is less than or equal to
30MPa.It is highly preferred that the absolute value of the residual stress in core is less than or equal to 10MPa.Making the stress in core is that pressure should
Power also makes the absolute value of this stress be less than or equal to 30MPa, such that it is able to make added losses be less than or equal to 0.02dB/km,
And substantially simultaneously obtain and stretched the effect reducing Rayleigh scattering by Slow cooling.
According in the optical fiber of the present embodiment, it is preferable that by declining that OH base is caused in the case of wavelength is by 1383nm
Subtract increment less than or equal to 0.02dB/km.The existence that OH absorbs causes the decay in the case of wavelength is 1550nm to increase.When
When the attenuation incrementation caused by OH base in the case of wavelength is by 1383nm is less than or equal to 0.02dB/km, at wavelength it is
Attenuation incrementation in the case of 1550nm can be less than or equal to 0.004dB/km.
In an embodiment according to the present invention, it is preferable that core is mixed with fluorine.Owing to core contains fluorine, so core is glutinous
Degree reduces, such that it is able to easily making the residual stress in core is compressive stress.Therefore, it can make the decay unrelated with wavelength drop
Low.It should be noted that improve the Rayleigh scattering increase that Oil repellent can make to be caused by fluctuation of concentration.It is therefore preferred that add
The fluorine of following concentration: this concentration make the reduction of the relative index of refraction caused owing to adding fluorine more than or equal to-0.1% and
Less than or equal to 0%.
Optical fiber according to the present embodiment can also include primary coating and the secondary coating surrounding sheath.Preferably, two
The Young's modulus of secondary coating be more than or equal to 800MPa, the Young's modulus of primary coating more than or equal to 0.2MPa and less than or
Equal to 1MPa.Therefore, it can reduce microbend loss, being therefore prevented from the decay after cable is formed increases.
According to the optical fiber of the present embodiment, in the case of wavelength is 1550nm, bending radius is bending loss during 15mm
Preferably less or equal to 0.002dB/ circle, bending radius is that bending loss during 10mm is preferably less or equal to 0.2dB/
Circle, bending radius is that bending loss during 10mm is preferably less or equal to 0.1dB/ circle, and time bending radius is 7.5mm
Bending loss is preferably less or equal to 0.5dB/ circle.Additionally, according in the optical fiber of the present embodiment, be 1625nm's at wavelength
In the case of, bending radius is that bending loss during 15mm is preferably less or equal to 0.01dB/ circle, when bending radius is 10mm
Bending loss is preferably less or equal to 0.4dB/ circle, and bending radius is that bending loss during 10mm is preferably less or equal to
0.2dB/ encloses, and bending radius is that bending loss during 7.5mm is preferably less or equal to 1dB/ circle.
According in the optical fiber of the present embodiment, it is preferable that MAC value is less than or equal to 6.6, and wherein, MAC value is to be at wavelength
Mode field diameter MFD in the case of 1310nm and the ratio (MFD/ λ c) of 2m fiber cut off wavelength λ c.So controlling can be with height
Yield rate obtain there is the optical fiber of above-mentioned microbend loss.
According in the optical fiber of the present embodiment, it is preferable that the decay poor (α _ B-α _ t) between attenuation alpha _ B and attenuation alpha _ t is little
In 0.01dB/km, wherein, attenuation alpha _ B is in the case of wavelength is 1550nm, to the length being wrapped on 140 φ mound bobbins
The decay that the optical fiber that degree is 10km or longer records；Attenuation alpha _ t is in the case of wavelength is 1550nm, in lax winding ring
The decay that records of optical fiber.Assume that optical fiber shows low decay under coated state, if can not reduce actually used in
Decay, then possibly cannot obtain desired result.Make decay poor (α _ B-α _ t) decrease below 0.01dB/km and can reduce reality
Decay in the use of border.
According in the optical fiber of the present embodiment, it is preferable that the external diameter of coated optical fiber is less than or equal to 210 μm, secondary coating
Thickness more than or equal to 10 μm.It is likely to occur following demand: make much optical fiber through restricted pipeline, the most existing pipe
Road.This demand can be satisfied.
Preferred embodiment including the optical transmission system using the optical fiber according to the present invention as optical transmission line is as follows.
Optical transmission system according to first embodiment be for by the flashlight of the optical line terminal from telephone office via
The optical transmission system of the optical network unit that shunt is transferred in user family.Between optical line terminal and the shunt of telephone office
The length of optical transmission line is more than or equal to 15km.Optical fiber according to the present invention is arranged in the section of more than the 90% of optical transmission line.
Optical transmission system according to the second embodiment be for by the flashlight of the optical line terminal from telephone office via
The optical transmission system of the optical network unit that shunt is transferred in user family.Between optical network unit in shunt and user family
The length of optical transmission line more than or equal to 15km.Optical fiber according to the present invention is arranged on the section of more than the 90% of optical transmission line
In.
Optical transmission system according to the 3rd embodiment is the light for the flashlight from transmitter is transferred to receptor
Transmission system.The length of the optical transmission line between transmitter and receptor is more than or equal to 40km.Optical fiber according to the present invention sets
Put in the section of more than the 90% of optical transmission line.
Optical transmission system according to the 4th embodiment be for by the flashlight of the optical line terminal from telephone office via
The optical transmission system of the optical network unit that shunt is transferred in user family.Optical fiber according to the present invention is arranged on the light of telephone office
In the section of more than 50% of the optical transmission line between optical network unit in line terminal and user family.In optical transmission line not
Amplify flashlight.
Optical transmission system according to the 5th embodiment be for by the flashlight of the optical line terminal from telephone office via
The optical transmission system of the optical network unit that shunt is transferred in user family.Optical fiber according to the present invention is arranged on the light of telephone office
In the section of more than 50% of the optical transmission line between optical network unit in line terminal and user family.Optical transmission line is put
Big flashlight.
Compared with the system of the optical fiber using prior art, the optical fiber according to the present invention is used as the light in optical transmission system
Transmission line can improve OSNR=10log (Aeff × α)-α L.Here, Aeff represents the effective area under signal light wavelength, α
Representing the decay under signal light wavelength, L represents transmission range or length.
Along with conveying length L increases, the raising amount including the OSNR of the optical transmission system of the optical fiber according to the present invention also increases
Add.Compared with the system including following ITU-T general purpose single mode fiber G.652, if conveying length L is more than 15km, then wrap
The OSNR of the optical transmission system including the optical fiber according to the present invention improves more than 0.1dB.The typical junction loss of optical fiber is equal to or low
In 0.1dB.Therefore, employing can make OSNR improve the amount corresponding with once above connection according to the optical fiber of the present invention.This
Outward, it is provided that the OSNR allowance of opposing connection failure etc..Further, since conveying length can be increased, it is possible to improve one
The population coverage of individual telephone office.The construction cost that therefore, it can make the transmission system in Metro access networks reduces.
It is typically not possess that distance between OLT and ONU is in the system in the range of about 10km to about 25km
The access system of light amplification.More than at least 50% section of the optical transmission line between OLT and ONU uses according to the present invention
Optical fiber so that transmission range in the case of not possessing light amplification extends.
As access system based on light amplification, the distance between OLT and ONU is in about 20km to about 100km's
In the range of system be in research.The section of more than 50% of the optical transmission line between OLT and ONU uses according to this
The optical fiber of invention is so that the transmission range in the case of possessing light amplification extends further.Further, since can suppress to put
The noise of big period increases and can obtain high OSNR in this distance, it is possible to make the OSNR required for miscellaneous equipment
Reduce.Therefore, it can build the system with high economic benefit.
<industrial applicibility>
Optical fiber according to the present invention can serve as the optical transmission line in Optical Access Network.
Claims (22)
1. a Silica glass optical fiber, including:
Core, it has central axis；
Optics covering, it is round described core；And
Sheath, it is round described optics covering, wherein,
Described core contains GeO2, the refractive index contrast Δ of described coreCoreMore than or equal to 0.35% and be less than or equal to
0.50%, and the refractive index volumes of described core
More than or equal to 0.045 μm2And less than or equal to 0.095 μm2, wherein, Δ (r) represents the phase doubling at radial coordinate r
Penetrating rate variance, a represents the radius of described core,
The refractive index contrast Δ J of described sheath is more than or equal to 0.03% and is less than or equal to 0.20%,
The fictive temperature of the glass constituting described core greater than or equal to 1400 DEG C and is less than or equal to 1590 DEG C, and
Residual stress in described core is the compressive stress that absolute value is more than or equal to 5MPa.
Optical fiber the most according to claim 1, wherein,
Described fictive temperature is less than or equal to 1530 DEG C.
Optical fiber the most according to claim 1 and 2, wherein,
2m fiber cut off wavelength is more than or equal to 1260nm,
22m cable cutoff wavelength is less than or equal to 1260nm,
Mode field diameter in the case of wavelength is 1310nm is more than or equal to 8.2 μm and is less than or equal to 9 μm, and
Decay in the case of wavelength is 1550nm is less than or equal to 0.18dB/km.
Optical fiber the most according to claim 1 and 2, wherein,
In the cross section being perpendicular to axis of described optical fiber, the part of more than 50% in the cross-sectional area of described sheath
Residual stress is tension.
Optical fiber the most according to claim 1 and 2, wherein,
The absolute value of the residual stress in described core is less than or equal to 30MPa.
Optical fiber the most according to claim 1 and 2, wherein,
At wavelength by the attenuation incrementation caused by OH base in the case of 1383nm less than or equal to 0.02dB/km.
Optical fiber the most according to claim 1 and 2, wherein,
Described core is mixed with fluorine.
Optical fiber the most according to claim 1 and 2, also includes:
Primary coating and secondary coating, it is round described sheath, wherein,
The Young's modulus of described secondary coating is more than or equal to 800MPa, and the Young's modulus of described primary coating is more than or equal to
0.2MPa and less than or equal to 1MPa.
Optical fiber the most according to claim 1 and 2, wherein,
Bending loss in the case of bending radius is 15mm and wavelength is 1550nm encloses less than or equal to 0.002dB/.
Optical fiber the most according to claim 1 and 2, wherein,
Bending loss in the case of bending radius is 10mm and wavelength is 1550nm encloses less than or equal to 0.2dB/.
11. optical fiber according to claim 1 and 2, wherein,
Bending loss in the case of bending radius is 7.5mm and wavelength is 1550nm encloses less than or equal to 0.5dB/.
12. optical fiber according to claim 1 and 2, wherein,
Bending loss in the case of bending radius is 15mm and wavelength is 1625nm encloses less than or equal to 0.01dB/.
13. optical fiber according to claim 1 and 2, wherein,
Bending loss in the case of bending radius is 10mm and wavelength is 1625nm encloses less than or equal to 0.4dB/.
14. optical fiber according to claim 1 and 2, wherein,
Bending loss in the case of bending radius is 7.5mm and wavelength is 1625nm encloses less than or equal to 1dB/.
15. optical fiber according to claim 1 and 2, wherein,
MAC value is less than or equal to 6.6, and described MAC value is mode field diameter MFD in the case of wavelength is 1310nm and 2m optical fiber
The ratio of cut-off wavelength.
16. optical fiber according to claim 1 and 2, wherein,
Decay difference between attenuation alpha _ B and attenuation alpha _ t less than 0.01dB/km, described attenuation alpha _ B is: be 1550nm at wavelength
In the case of, the decay that the optical fiber of a length of 10km or longer being wrapped on 140 φ mound bobbins is recorded；Described attenuation alpha _ t
It is: in the case of wavelength is 1550nm, the decay that the optical fiber in lax winding ring is recorded.
17. optical fiber according to claim 8, wherein,
The external diameter having cated described optical fiber is more than or equal to 10 μm less than or equal to 210 μm, the thickness of described secondary coating.
18. 1 kinds of optical transmission systems, it is for being transferred to the flashlight of the optical line terminal from telephone office via shunt
Optical network unit in user family, wherein,
The length of the optical transmission line between optical line terminal and the described shunt of described telephone office is more than or equal to 15km, and
It is arranged on according to the optical fiber according to any one of claim 1 to 17 in the section of more than 90% of described optical transmission line.
19. 1 kinds of optical transmission systems, it is for being transferred to the flashlight of the optical line terminal from telephone office via shunt
Optical network unit in user family, wherein,
The length of the optical transmission line between optical network unit in described shunt and described user family is more than or equal to 15km, and
And
It is arranged on according to the optical fiber according to any one of claim 1 to 17 in the section of more than 90% of described optical transmission line.
20. 1 kinds of optical transmission systems, it is for being transferred to receptor by the flashlight from transmitter, wherein,
The length of the optical transmission line between described transmitter and described receptor is more than or equal to 40km, and
It is arranged on according to the optical fiber according to any one of claim 1 to 17 in the section of more than 90% of described optical transmission line.
21. 1 kinds of optical transmission systems, it is for being transferred to the flashlight of the optical line terminal from telephone office via shunt
Optical network unit in user family, wherein,
It is arranged on the optical line terminal of described telephone office and described user according to the optical fiber according to any one of claim 1 to 17
In the section of more than 50% of the optical transmission line between optical network unit in Jia, and
Described flashlight is not amplified in described optical transmission line.
22. 1 kinds of optical transmission systems, it is for being transferred to the flashlight of the optical line terminal from telephone office via shunt
Optical network unit in user family, wherein,
It is arranged on the optical line terminal of described telephone office and described user according to the optical fiber according to any one of claim 1 to 17
In the section of more than 50% of the optical transmission line between optical network unit in Jia, and
Described flashlight is amplified in described optical transmission line.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011-248479 | 2011-11-14 | ||
| JP2011248479 | 2011-11-14 | ||
| PCT/JP2012/077549 WO2013073354A1 (en) | 2011-11-14 | 2012-10-25 | Optical fiber and optical transmission system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103443673A CN103443673A (en) | 2013-12-11 |
| CN103443673B true CN103443673B (en) | 2016-11-30 |
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|---|---|---|---|---|
| JPH03196102A (en) * | 1989-12-26 | 1991-08-27 | Sumitomo Electric Ind Ltd | Polarization plane maintaining optical fiber |
| JPH11180725A (en) * | 1997-12-24 | 1999-07-06 | Sumitomo Electric Ind Ltd | Production of optical fiber preform |
| WO2009066429A1 (en) * | 2007-11-19 | 2009-05-28 | Mitsubishi Cable Industries, Ltd. | Optical fiber and method for producing the same |
| JP4459720B2 (en) * | 2004-05-31 | 2010-04-28 | 株式会社フジクラ | Manufacturing method of optical fiber |
| JP4663277B2 (en) * | 2004-08-18 | 2011-04-06 | 株式会社フジクラ | Optical fiber and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03196102A (en) * | 1989-12-26 | 1991-08-27 | Sumitomo Electric Ind Ltd | Polarization plane maintaining optical fiber |
| JPH11180725A (en) * | 1997-12-24 | 1999-07-06 | Sumitomo Electric Ind Ltd | Production of optical fiber preform |
| JP4459720B2 (en) * | 2004-05-31 | 2010-04-28 | 株式会社フジクラ | Manufacturing method of optical fiber |
| JP4663277B2 (en) * | 2004-08-18 | 2011-04-06 | 株式会社フジクラ | Optical fiber and manufacturing method thereof |
| WO2009066429A1 (en) * | 2007-11-19 | 2009-05-28 | Mitsubishi Cable Industries, Ltd. | Optical fiber and method for producing the same |
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