CN102122991B - Dual-mode optical fiber and communication system thereof - Google Patents
Dual-mode optical fiber and communication system thereof Download PDFInfo
- Publication number
- CN102122991B CN102122991B CN2010105890181A CN201010589018A CN102122991B CN 102122991 B CN102122991 B CN 102122991B CN 2010105890181 A CN2010105890181 A CN 2010105890181A CN 201010589018 A CN201010589018 A CN 201010589018A CN 102122991 B CN102122991 B CN 102122991B
- Authority
- CN
- China
- Prior art keywords
- optical fiber
- fiber
- mode
- dual mode
- dual
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Optical Communication System (AREA)
Abstract
The invention discloses a dual-mode optical fiber and a communication system thereof. The dual-mode optical fiber comprises an optical fiber core and a cladding, and in a wavelength range of between 1.25 and 1.65mu m, nclad-ncore is more than 0.004, and r is more than 4.5mu m, wherein the nclad is the cladding refractive index, the ncore is the optical fiber core refractive index, and the r is radius of the optical fiber core; the cut-off wavelength lambda c of an LP02 model of the optical fiber is between 1.1 and 1.25mu m, and the optical fiber maintains dual-mode transmission; and the mode field diameter M of the optical fiber equals to 8 to 10.5mu m at the wavelength of 1,310nm. The optical fiber communication system comprises a dual-mode optical fiber, a single-mode optical fiber, a light transmitter and a light receiver, wherein two ends of the dual-mode optical fiber are connected with the single-mode optical fiber respectively; and the other ends of the single-mode optical fiber are connected with the light transmitter and the light receiver respectively. The dual-mode optical fiber has low bending loss and large mode field, and the communication system can realize single-mode transmission and low connection loss of a broad range.
Description
Technical field
The present invention relates to fiber optic communication field, relate in particular to dual mode optical fiber and consisting of optical fiber telecommunications system.
Background technology
The main line network of at present optical fiber communication has substantially been laid and has been finished, and the short distance optical communication has become the target of giving priority to of optical fiber communication.Topmostly in the short distance optical communication refer to that Fiber to the home.For satisfying fiber-to-the-home application needs, ITU-T has proposed G.657 standard fiber.The optical cable that meets standard G.657 can be as copper cable, and install at very little turning in the building, and therefore non-professional technical staff also can grasp the method for construction.
Bend insensitive fiber mainly contains three types at present: step index section optical fiber [J. Lightwave Technol., 2005,23 (11): 3494], [patent No. is the patent of invention of ZL200610024532.4 to covering band groove refraction index profile optical fiber: the bend insensitive fiber with waveguiding structure, the patent No. is the patent of invention of ZL200410061392.9: bend insensitive fiber and preparation method thereof] and the hole help optical fiber [Opt. Express, 2005,13 (12): 4770].Although these three kinds of optical fiber all have resistant to bending characteristics, all be the mode field diameter that reduces optical fiber be cost.The bending loss of front two types of resulting optical fiber is still larger.The hole can obtain lower loss when helping optical fiber and ordinary optic fibre welding, and the bending loss of optical fiber is also very low, but owing to having introduced airport in the optical fiber, its fusion techniques is complicated, be unfavorable for the engineering application, and this optical fiber junction loss when being flexibly connected is large, and its application is restricted.
Summary of the invention
For above deficiency, the objective of the invention is to propose a kind of dual mode optical fiber, have low bend loss and large mould field.Another object of the present invention provides the communication system that this dual mode optical fiber forms, and this system can realize the single mode transport of wide region, and reduces junction loss.
The technical scheme of dual mode optical fiber of the present invention is: comprise fibre core and covering, in 1.25-1.65 mum wavelength scope, satisfy n
Clad-n
Core0.004 and r 4.5 μ m, wherein: n
CladBe cladding index, n
CoreBe fiber core refractive index, r is fiber core radius; The LP of optical fiber
02The cut-off wavelength λ of mould
cBetween 1.1-1.25 μ m, optical fiber keeps dual-transfer mode; When 1310 nm wavelength, the mode field diameter M=8 of optical fiber ~ 10.5 μ m.
The present invention utilizes the technical scheme of the optical fiber telecommunications system of above-mentioned dual mode optical fiber composition to be: bag dual mode optical fiber, monomode fiber, optical sender and optical receiver, the dual mode optical fiber two ends connect respectively monomode fiber, the monomode fiber other end connects respectively optical sender and optical receiver, and the transversion malposition that described dual mode optical fiber is connected with monomode fiber is less than 1.5 μ m.
Beneficial effect of the present invention: dual mode optical fiber utilizes the characteristics that have high index-contrast between fibre core and the covering, realizes the low bend loss transmission; Because core diameter is enough large, make optical fiber have large mode field diameter M simultaneously.The basic mode of this kind dual mode optical fiber can still have low bending loss when bending radius is very little, its structural design is simple, and manufacture craft is ripe, has eliminated the problem of the mechanical performance variation that complicated optical fiber structures such as introducing airport brings.
When dual mode optical fiber was connected with general single mode fiber in the communication system, because both basic mode mould fields are similar, so both junction losss were less.Because the high-rder mode of dual mode optical fiber (is LP
11Mould) basic mode with monomode fiber differs larger, and the coupling ratio between the basic mode of monomode fiber and the high-rder mode of dual mode optical fiber is extremely low, and transmission brings impact lower to certain transversion malposition on signal, and realizes the single mode transport of wide region.Light signal will mainly transmit in dual mode optical fiber with the basic mode form, thereby effectively suppresses the generation of the high-rder mode in the dual mode optical fiber, and is converted to the basic mode of monomode fiber in output inhibition high-rder mode, thereby makes high-rder mode drop to minimum to crosstalking of signal.
Description of drawings
Fig. 1 optical communication system schematic diagram;
The mode field diameter of dual mode optical fiber under the different core diameters of Fig. 2;
The junction loss figure of the basic mode of Fig. 3 dual mode optical fiber and the basic mode of general single mode fiber;
The basic mode of Fig. 4 monomode fiber is coupled to the junction loss of high-rder mode of dual mode optical fiber with the change curve of wavelength;
The basic mode of Fig. 5 monomode fiber is coupled to the junction loss of high-rder mode of dual mode optical fiber with the change curve of transversion malposition;
The bending loss of the basic mode of Fig. 6 dual mode optical fiber.
Embodiment
Dual mode optical fiber is a step index fiber, comprises fibre core and covering, in 1.25-1.65 mum wavelength scope, satisfies n
Clad-n
Core0.004 and r 4.5 μ m, wherein: n
CladBe cladding index, n
CoreBe fiber core refractive index, r is fiber core radius.The covering of optical fiber and fiber core refractive index are poor large as much as possible, thereby guarantee that optical fiber has low bending loss; Simultaneously, fiber core radius is also larger, thereby makes optical fiber have large mode field diameter M.
Dual mode optical fiber all can and can only transmit LP in operating wavelength range
01And LP
11Mould.For step index fiber, its transmission mode quantity is determined by the normalized frequency size:
Wherein,
,
,
Be respectively the fiber core radius of optical fiber, optical wavelength, fiber core refractive index and cladding index.Because than LP
11The mould more pattern of high-order is LP
21And LP
02Mould, its corresponding normalized frequency is 3.832.By theory of fiber, for dual mode optical fiber, require it
VValue in operating wavelength range less than 3.832.Because when fiber core radius was identical, the refringence of fibre core and covering was larger, the bending loss of optical fiber is just less.Therefore, under the prerequisite that guarantees dual-transfer mode, should increase the refringence of fibre core and covering, to reduce the bending loss of optical fiber as far as possible.Because in the situation that fiber core radius is constant, wavelength corresponding when higher order mode more occurring is shorter, just requires fibre core and cladding index poor less, thereby causes the increase of bending loss.According to the G657 sonet standard, the cut-off wavelength that requires optical fiber is 1.26 μ m, and namely optical fiber should can both work in greater than the wave-length coverage of 1.26 μ m.Therefore, its cut-off wavelength can not be too short.The LP of General Requirements dual mode optical fiber
02The cut-off wavelength λ of mould
cBetween 1.1-1.25 μ m.
In order to realize effectively being connected with general single mode fiber, reduce junction loss, also require mode field diameter and the monomode fiber of the basic mode of dual mode optical fiber to differ less.The junction loss of two kinds of optical fiber can be obtained by following formula:
Wherein
w SMF With
w DMF Be respectively the mode field diameter of monomode fiber and dual mode optical fiber.Its junction loss can be less when obviously, the mode field diameter of dual mode optical fiber and monomode fiber were close.The mode field diameter of dual mode optical fiber is generally also unsuitable excessive.This is because mode field diameter is larger just to mean that also fiber core radius is larger.To normalized frequency
VSize have under the prerequisite of requirement, this refringence that just means fibre core and covering is little, thereby can increase the bending loss of optical fiber.Therefore, according to the mode field diameter characteristics of general single mode fiber (requiring in the mode field diameter of 1310 nm such as G652 optical fiber is 9.3 ± 0.5 μ m), require when 1310 nm wavelength, the span of the mode field diameter M of dual mode optical fiber is between 8 ~ 10.5 μ m.
As shown in Figure 1, by optical fiber telecommunications system bag dual mode optical fiber, monomode fiber, optical sender and optical receiver that this dual mode optical fiber forms, the dual mode optical fiber two ends connect respectively monomode fiber, and the monomode fiber other end connects respectively optical sender and optical receiver.Light signal must be input to first monomode fiber from optical sender after out, and then enters dual mode optical fiber; Light signal is introduced into monomode fiber, and then is connected to optical receiver after dual mode optical fiber output.When reality was used, Receiver And Transmitter was all with tail optical fiber, and in fact this requirement can be met automatically.Dual mode optical fiber can be connected to form by the multistage dual mode optical fiber, and is same, also can be connected to each other between the monomode fiber, all can not affect the equivalent single mode transport of dual mode optical fiber.
It is 9,9.5,10,10.5 that Fig. 2 has provided the core diameter d that gets respectively dual mode optical fiber, 11 μ m, and require its LP
02When the cut-off wavelength of mould is 1.2 μ m, the mode field diameter of these several optical fiber.As seen from the figure, core diameter is larger, and mode field area is also larger.When Fig. 3 is different core diameter d, the junction loss figure of the basic mode of dual mode optical fiber and the basic mode of general single mode fiber, as seen from the figure, and junction loss and wavelength and pass, wavelength is longer, and junction loss is also larger.When its core diameter d is larger, can make it in very wide wave-length coverage, junction loss is all less than 0.3 dB.
When dual mode optical fiber was connected with general single mode fiber, because both basic mode mould fields are similar, so both junction losss were less.Simultaneously, because the high-rder mode of dual mode optical fiber (is LP
11Mould) basic mode with monomode fiber differs larger, and under the desirable condition of contact, the coupling ratio between the basic mode of monomode fiber and the high-rder mode of dual mode optical fiber is extremely low, can not bring impact to the signal transmission.Even there are the situations such as transversion malposition, as long as deviation is less, the signal cross-talk that high-rder mode produces still can be enough low.
When being connected with monomode fiber, dual mode optical fiber requires to reduce the transversion malposition between the optical fiber as far as possible, General Requirements is less than 1.5 μ m, coupling efficiency between the high-rder mode of the basic mode of monomode fiber and dual mode optical fiber is generally less than 10% at this moment, namely when light signal enters dual mode optical fiber from monomode fiber, it is the high-rder mode that is converted to dual mode optical fiber that 10% energy is approximately arranged, export from dual mode optical fiber and work as light, when entering monomode fiber, only there is again 10% high-rder mode to be converted into the basic mode of monomode fiber, therefore, finally be converted into 1% the energy of only to have an appointment in the energy of the basic mode in the monomode fiber from high-rder mode.Because the interference that this high-rder mode causes is very little, and is less on the impact of optical signal transmission.Further, transverse presentation dislocation during being connected of dual mode optical fiber and monomode fiber preferably can be less than 0.5 μ m, when light signal is exported from dual mode optical fiber, finally be converted into 0.01% the energy of only having an appointment in the energy of the basic mode in the monomode fiber from high-rder mode.
When Fig. 4 was core diameter d=10.5 μ m, the basic mode of the monomode fiber that different wave length is corresponding was coupled to the damage curve of the high-rder mode of dual mode optical fiber, and wavelength is larger, and junction loss is also larger.Therefore, as long as its junction loss is enough large when the short wavelength, then, the junction loss the during long wavelength only can be larger.Fig. 5 is core diameter d=10.5 μ m, when optical wavelength is 1.25 μ m, the basic mode of the monomode fiber that different transversion malpositions are corresponding is coupled to the damage curve of the high-rder mode of dual mode optical fiber.Transversion malposition is less, and junction loss is also just larger, and the laser propagation effect of optical fiber is just better.Therefore, need only transversion malposition less than certain value, junction loss just can be enough large.As shown in Figure 4, when optical wavelength during greater than 1.25 μ m, as long as the transversion malposition of dual mode optical fiber and monomode fiber is less than 0.5 μ m, its coupling loss just can reach more than 20 dB.Because in whole communication system, two coupling process are arranged between the high-rder mode of dual mode optical fiber and the basic mode of monomode fiber, its coupling loss value is suitable.This also just means, when finally arriving receiving terminal, is converted to the energy L of basic mode by high-rder mode
0With basic mode and the final energy L that arrives receiving terminal from monomode fiber
1Ratio can reach more than 40 dB, if namely high-rder mode is considered as noise, the signal to noise ratio during the arrival receiving terminal that then caused by high-rder mode can reach more than 40 dB.Therefore, the impact on the signal in the basic mode is to ignore owing to having high-rder mode in the dual mode optical fiber.Even the transversion malposition of dual mode optical fiber and monomode fiber reaches more than 1.5 microns, the high-rder mode (LP in the dual mode optical fiber
11Mould) with monomode fiber in the coupling loss of basic mode still can reach more than 10 dB, therefore, the signal to noise ratio of the light signal when arriving receiving terminal still can reach more than 20 dB.
Fig. 6 is for limiting the LP of optical fiber
02When the cut-off wavelength of mould is 1.2 μ m, the bending loss of dual mode optical fiber basic mode during different core diameter d.As seen from the figure, the bending radius of optical fiber is less, and bending loss is larger.Because the cut-off wavelength of optical fiber is identical, so core diameter is less, the refringence of its covering and fibre core is just larger, and its bending loss is also just less.During except core diameter d=11 μ m, outside the loss of optical fiber when bending radius is 5mm was large, other several optical fiber all had lower bending loss.
When reality was implemented, the complexity when when operating at the scene when dual mode optical fiber is connected with general single mode fiber optical fiber being connected control can also adopt the method for pre-connection, the tail optical fiber after namely being fused by factory-configured general single mode fiber and dual mode optical fiber.Thereby when reality was used, monomode fiber only needed to fuse or be flexibly connected with monomode fiber; Equally, dual mode optical fiber only needs to fuse or be flexibly connected with dual mode optical fiber, when causing dual mode optical fiber to be connected with general single mode fiber because of technical staff, equipment and environmental problem when effectively having avoided operating at the scene like this, the problem that the high-rder mode that the excessive grade of transversion malposition causes can not effectively be suppressed.
Embodiment:
Optical fiber is common step change type silica fiber, and core diameter d is 10.5 μ m, its LP
02The cut-off wavelength of mould is 1.2 μ m, and when being connected between optical fiber and the monomode fiber, because the junction loss that mould field difference causes can be less than 0.15 dB (when wavelength be 1.55 μ m), when the bending radius of optical fiber was 5 mm, its bending loss was less than 0.05 dB/ circle.
Above-mentioned accompanying drawing only is explanatory view, protection scope of the present invention is not formed restriction.Should be understood that these embodiment just in order to demonstrate the invention, but not limit the scope of the invention by any way.
Claims (3)
1. optical fiber telecommunications system, comprise dual mode optical fiber, monomode fiber, optical sender and optical receiver, it is characterized in that: described dual mode optical fiber two ends connect respectively monomode fiber, the monomode fiber other end connects respectively optical sender and optical receiver, and the transversion malposition that described dual mode optical fiber is connected with monomode fiber is less than 1.5 μ m; Described dual mode optical fiber comprises fibre core and covering, in 1.25-1.65 mum wavelength scope, satisfies n
Clad-n
Core0.004 and r 4.5 μ m, wherein: n
CladBe cladding index, n
CoreBe fiber core refractive index, r is fiber core radius; The LP of optical fiber
02The cut-off wavelength λ of mould
cBetween 1.1-1.25 μ m, optical fiber keeps dual-transfer mode; When 1310 nm wavelength, the mode field diameter M of optical fiber is between 8 ~ 10.5 μ m.
2. one kind by claims 1 described optical fiber telecommunications system, and it is characterized in that: described dual mode optical fiber is connected to form by the multistage dual mode optical fiber.
3. one kind by claims 1 or 2 described optical fiber telecommunications systems, and it is characterized in that: the transversion malposition that described dual mode optical fiber is connected with monomode fiber is less than 0.5 μ m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105890181A CN102122991B (en) | 2010-12-15 | 2010-12-15 | Dual-mode optical fiber and communication system thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105890181A CN102122991B (en) | 2010-12-15 | 2010-12-15 | Dual-mode optical fiber and communication system thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102122991A CN102122991A (en) | 2011-07-13 |
| CN102122991B true CN102122991B (en) | 2013-10-23 |
Family
ID=44251458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010105890181A Active CN102122991B (en) | 2010-12-15 | 2010-12-15 | Dual-mode optical fiber and communication system thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102122991B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103645539B (en) * | 2013-12-18 | 2015-12-09 | 江苏大学 | A kind of bend insensitive fiber |
| CN106289600A (en) * | 2016-09-21 | 2017-01-04 | 江苏大学 | A kind of optical fiber stress sensor part |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1184945A (en) * | 1997-12-26 | 1998-06-17 | 清华大学 | Nonreciprocal trasmission method of full optical fiber and full optical fiber isolator |
| CN1194382A (en) * | 1997-02-12 | 1998-09-30 | 住友电气工业株式会社 | Dispersion displacement optical fiber |
| CN1654995A (en) * | 2004-02-13 | 2005-08-17 | 三星电子株式会社 | Optical fiber having reduced residual stress discontinuity |
-
2010
- 2010-12-15 CN CN2010105890181A patent/CN102122991B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1194382A (en) * | 1997-02-12 | 1998-09-30 | 住友电气工业株式会社 | Dispersion displacement optical fiber |
| CN1184945A (en) * | 1997-12-26 | 1998-06-17 | 清华大学 | Nonreciprocal trasmission method of full optical fiber and full optical fiber isolator |
| CN1654995A (en) * | 2004-02-13 | 2005-08-17 | 三星电子株式会社 | Optical fiber having reduced residual stress discontinuity |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102122991A (en) | 2011-07-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102904641B (en) | Communication system based on few-mode optical fiber | |
| AU2001292225B2 (en) | Optical fibre for to-the-home distribution network | |
| WO2011116109A1 (en) | Techniques and devices for low-loss, modefield matched coupling to a multicore fiber | |
| US20120219301A1 (en) | Low-loss, low-latency, hollow core fiber communication system | |
| CN110542950B (en) | Mode demultiplexer of degenerated mode group based on space three-dimensional waveguide | |
| CN102650717A (en) | Multi-mode/single-mode optical fiber connector based on double-clad optical fiber | |
| CN107272115A (en) | A kind of pattern multiplexer/demultiplexer based on three core fibres | |
| CN104749707A (en) | Weak-confined large-cross-section optical waveguide based dual-polarization mode multiplexing-demultiplexing device | |
| CN111273394B (en) | Multi-core multimode optical fiber | |
| CN103698842A (en) | Optical fiber mode add-drop multiplexer | |
| JP5079664B2 (en) | Optical wavelength division multiplexing communication system, exciter and mode filter | |
| CN102122991B (en) | Dual-mode optical fiber and communication system thereof | |
| CN112612076B (en) | Few-mode multi-core microstructure optical fiber and few-mode optical fiber amplifier | |
| CN108152879B (en) | kinds of multicore optical fiber with controllable crosstalk | |
| CN113746555B (en) | Multimode optical fiber transmission system based on high-speed single-mode optical module | |
| CN102866455B (en) | Large mode field optical fiber transmission system | |
| CN113820780A (en) | Full MIMO double-step 7-core 6-mode optical fiber | |
| CN217521388U (en) | Multimode soft jump fiber | |
| CN101995602B (en) | Expanded core fiber | |
| US6856736B2 (en) | Lightwaveguide cable and process for carrying an optical signal using dispersion management | |
| CN117420680B (en) | Photon lantern design method with mode-dependent loss equalization function | |
| Liu et al. | Graded-index seven-core fiber optimized for high density and ultra-wideband parallel transmission application | |
| CN220553007U (en) | Multi-core optical fiber and optical communication system | |
| Hayashi | Design of multi-core and coupled-core fibers | |
| Nakanishi et al. | Advancements in Key Technological Building Blocks for Enabling MCF Implementation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee | ||
| CP02 | Change in the address of a patent holder |
Address after: 212114 Zhenjiang, Zhejiang Province, Dantu high capital street, Xiangshan Road, No. 1 Patentee after: Jiangsu University Address before: Zhenjiang City, Jiangsu Province, 212013 Jingkou District Road No. 301 Patentee before: Jiangsu University |