CN101835065A - Method for using single mode fiber in Ethernet passive optical network system - Google Patents
Method for using single mode fiber in Ethernet passive optical network system Download PDFInfo
- Publication number
- CN101835065A CN101835065A CN200910118968A CN200910118968A CN101835065A CN 101835065 A CN101835065 A CN 101835065A CN 200910118968 A CN200910118968 A CN 200910118968A CN 200910118968 A CN200910118968 A CN 200910118968A CN 101835065 A CN101835065 A CN 101835065A
- Authority
- CN
- China
- Prior art keywords
- optical
- laser
- fiber
- optical network
- single mode
- 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.)
- Pending
Links
Images
Landscapes
- Optical Communication System (AREA)
Abstract
The invention provides a method for using a single mode optical fiber in an Ethernet passive optical network system, which comprises the following steps of: providing an optical line terminal used for sending signals to a user terminal and receiving signals from the user terminal; respectively connecting both ends of the single mode fiber to the optical line terminal and a first optical splitter; respectively connecting both ends of a single mode fiber to the first optical splitter and a second optical splitter; and connecting an optical network unit between the second optical splitter and the user terminal, wherein a single mode laser is provided in the optical network unit. A light-emitting module in the optical network unit adopts the single mode laser instead of a multimode laser, which is beneficial to avoiding packet loss phenomenon during uplink transmission.
Description
Technical field
The present invention relates to the wideband transmit communications field, relate in particular to the method for using single mode fiber in the Ethernet passive optical network system.
Background technology
As shown in Figure 1, a typical Ethernet passive optical network (EPON) system is made up of optical line terminal (OLT), optical network unit (ONU) and Optical Distribution Network (ODN).
As local side apparatus, OLT equipment centre machine room, the signal that will carry miscellaneous service converges on the one hand, sends into according to certain signal format and inserts part so that to terminal use's transmission, self terminal user's signal is sent into respectively in each service network according to type of service in the future on the other hand.The light signal that OLT sends will be broadcast to each ONU through passive optical splitters, so there are higher luminous power and demand on signal quality in system to the PON mouth of OLT, and the light emitting module of OLT adopts distributed Feedback (DFB) laser at present, is single longitudinal mode laser.The Distributed Feedback Laser Output optical power is big, the angle of divergence is less, spectrum is extremely narrow, modulation rate is high, is suitable for long haul communication.
As ustomer premises access equipment, ONU inserts the user downwards built-in or plug-in User Network Interface is provided, and the PON interface towards EPON upwards is provided, and receives the light signal that comes from OLT, and upstream data is sent to OLT.The light emitting module of ONU adopts Fabry-Perot (FP) laser usually at present, is Multi-Longitudinal Mode laser.The FP laser is used for the occasion of transmission range less than 50km, is mainly used in the operation wavelength of 1310nm.And at present typical EPON supports that transmitting range is 20km farthest, and up transmission wavelength 1310nm is under the situation of this distance and wavelength requirement, adopt the lower FP laser of price, under the prerequisite that does not influence transmission, can bigger saving ONU cost, hinder for promoting that Fiber to the home and reducing.
At present but the EPON system meeting on the optical fiber that G.652 ITU-T advise, contains B1.1, B1.3 and SMF, i.e. monomode fiber by the standard definition operate as normal.And develop in the early stage in the process of optical fiber access, to having laid multimode fiber between the floor in advance, general distance is a hundreds of rice to the part engineering at the sub-district machine room.The cost that this section optical fiber is laid again is higher, difficulty of construction is big, therefore must consider this section multimode fiber is rationally utilized, and makes the EPON system can continue to use under the multimode fiber environment.
Exist under the situation of multimode fiber, there is following problem in the EPON system of prior art:
1, the system descending direction does not have packet loss, and up direction has a small amount of packet loss;
2, long-term business The performance test results up direction packet loss＞10
-5, can not satisfy the requirement of transmission system.
Summary of the invention
The purpose of the inventive method is by a kind of method, makes full use of the multimode fiber section that existing sub-district machine room has been laid to floor, in conjunction with the trunk optical fiber and the section single-mould fiber of registering one's residence, realizes the normal transmission of EPON system under list, multimode mixed environment.
The invention provides a kind of in the Ethernet passive optical network system method of using single mode fiber, comprising:
Optical line terminal is provided, is used for sending signal and receiving signal from user terminal to user terminal;
The two ends of monomode fiber are connected respectively to the described optical line terminal and first optical splitter;
The two ends of multimode fiber are connected respectively to described first optical splitter and second optical splitter; With
Optical network unit is connected between described second optical splitter and the user terminal,
Wherein in described optical network unit, provide single-mode laser.
Realize the application of multimode fiber in the EPON system as the ONU light emitting module with the single mode Distributed Feedback Laser, with multimode FP laser at present commonly used as the ONU light emitting module and the EPON system entirely G.652 the standard single-mode fiber transmission compare, having easy enforcement, be suitable for flexibly, save advantage such as construction investment, is to solve a kind of feasible program that multimode fiber is used in the EPON system at present.
Description of drawings
Fig. 1 is the schematic diagram of EPON system organization structure;
Fig. 2 is the modal dispersion principle schematic;
Fig. 3 is the schematic diagram that adopts the EPON transmission system that the monomode and multimode fiber of up many longitudinal modes of transmission FP laser mixes;
Fig. 4 is the schematic diagram according to the EPON transmission system of the monomode and multimode fiber mixing of the up transmission single longitudinal mode of employing of the present invention Distributed Feedback Laser;
Fig. 5 is the spectrum of the up transmission laser of prior art;
Fig. 6 is the transmission spectrogram of the uplink optical signal of ordering according to the system B of Fig. 4 of the present invention;
Fig. 7 is the receiving spectrum figure of the uplink optical signal of ordering according to the system A of Fig. 4 of the present invention; With
Fig. 8 is the network example according to the EPON transmission system of monomode and multimode fiber mixing of the present invention.
Embodiment
The comparison of multimode fiber and monomode fiber
Multimode fiber: the center glass core is thicker, is generally 62.5 μ m or 50 μ m, and is relatively easy with the coupling of optical device.Allow a plurality of mode transfer in the multimode fiber fibre, so chromatic dispersion is bigger, not only exists wavelength dispersion also to have modal dispersion, i.e. inter-modal dispersion, this has just limited the frequency of transmission of digital signals, and more serious with the increase meeting of transmission range.Therefore, the transmission range of multimode fiber is closer, generally has only several kilometers.
Monomode fiber: the center glass core is very thin, and core diameter is generally 9 or 10 μ m, with the coupling relative difficult of optical device, the spectrum width and the stability of light source is had higher requirement, and promptly spectrum width is narrow, and stability will be got well.Can only transmit a kind of light of pattern in the monomode fiber, not have modal dispersion, only have material dispersion and waveguide dispersion, be referred to as wavelength dispersion again.
The comparison of FP laser and Distributed Feedback Laser
The FP laser is to be resonant cavity with the Fabry-Perot-type cavity, sends the light emitting semiconductor device of many longitudinal modes coherent light.Because longitudinal mode has determined the spectral characteristic of laser, so the spectrum width of FP laser is bigger, is 2-4nm.Because the FP laser works is at the multimode state, modal dispersion causes the performance of signal to noise ratio (snr) aspect to be affected.Therefore, the FP laser is unfavorable for the transmission of long Distance Transmission or high-quality analog signal.
Distributed Feedback Laser is on the basis of FP laser, selects accurate optical maser wavelength by the vertical grating in the laser chip by the light feedback.The effect of grating is to force emission to have the vertical zlasing mode of wall scroll or the laser rays of extremely narrow breadth of spectrum line (half maximum overall with (FWHM) is no more than 1MHz usually), usually side frequency section or edge mode is suppressed 40dB.Distributed Feedback Laser has the extremely narrow characteristic of spectrum, is subjected to the distance of chromatic dispersion restriction to be expected to reach 170-200km, is suitable for long haul communication.
Modal dispersion
Modal dispersion claims inter-modal dispersion again, is owing to the different chromatic dispersions that cause of different mode propagation velocity in the optical fiber, can only occur in the multimode fiber.As shown in Figure 2, the light pulse that width is L enters multimode fiber, the one group of small-pulse effect that is carried by single pattern is resolved in each pulse in optical fiber, the pattern that works in different wave length will be propagated with different speed, therefore some single small-pulse effects are in fiber-optic output combination again, small-pulse effect can overlap each other, and causes pulse stretching like this.
Pulse stretching is relevant with fibre core-covering refractive index contrast on the one hand, and fibre core-covering refractive index contrast is big more, and pulse stretching is also big more.On the other hand, along with the increase of fiber lengths, pulse stretching is also increasing, when pulse stretching acquires a certain degree, can have a strong impact on the signal to noise ratio of receiver end, causes professional packet loss.
The improvement of monomode and multimode fiber mixing EPON system
In the EPON system of single multimode fiber mixed transport shown in Figure 3, adopted many longitudinal modes FP laser to send uplink optical signal, it between OLT to the first optical splitter monomode fiber of 8km, be the 500m multimode fiber between first and second optical splitters, second optical splitter is connected to ONU by single-mode tail fiber.For example, first optical splitter can be 1: 2 optical splitter, and second optical splitter can be 1: 2 optical splitter.Test the long-term transmitting-receiving performance of this system with the data network analyzer, the result is that down direction does not have packet loss, up direction packet loss 10
-5
By the principle of modal dispersion as can be known, reduce multimode fiber length and can reduce the influence of modal dispersion to a certain extent business.Under above-mentioned test condition shown in Figure 3, the multimode fiber length of 500m is reduced to 250m, through the transmission of one period short time, the packet loss phenomenon still appears in up direction.Evidence only reduces the problem of up packet loss in the EPON system that multimode fiber length can not thoroughly solve list, multimode mixed transport.
In system shown in Figure 3, the packet loss problem only appears at up direction, and downlink business transmits all right.The problem that up packet loss occurs is because up transmission laser and descending transmission laser are inequality.The light emitting module that descending transmission laser is OLT is a Distributed Feedback Laser, and it is not obvious that the extremely narrow light of its spectrum that sends passes through multimode fiber afterpulse broadening, the unlikely reception that influences signal.And the light emitting module that up transmission laser is ONU is the FP laser, and its exemplary spectrum as shown in Figure 5.
Multi-Longitudinal Mode laser is when modulation, its each pattern generally is unsettled, even gross power does not become in time, but the power of each pattern is random fluctuation in time, at the receiver end electric current certain random fluctuation is arranged, itself is just poor in the signal to noise ratio of receiving terminal than single-mode laser; Add the transmission through one section multimode fiber, pulse stretching has aggravated the deterioration of signal to noise ratio.
Under the prerequisite that can not change multimode fiber, solve up packet loss problem and can only attempt the original many longitudinal modes FP of the light emitting module among ONU laser is replaced by the single longitudinal mode Distributed Feedback Laser.System behind the replacing laser adopts the single longitudinal mode Distributed Feedback Laser to send uplink optical signal as shown in Figure 4 in this system.Through long-term test, the professional transmission of system's up-downgoing is all right, the packet loss phenomenon all do not occur.
Though first optical splitter that draws among Fig. 3 and Fig. 4 and second optical splitter are respectively 1: 2 optical splitter and 1: 16 optical splitter, also can select the optical splitter of any other splitting ratio according to actual conditions for use, realize the purpose of beam split.
Fig. 6 is with the transmission spectrogram of spectrometer analysis according to the uplink optical signal of system's (B point) of Fig. 4 of the present invention.Fig. 7 is with the receiving spectrum figure of spectrometer analysis according to the uplink optical signal of system's (A point) of Fig. 4 of the present invention; As can be seen from Figures 6 and 7, through mixed transport single, multimode fiber, do not have tangible pulse stretching, the deterioration of signal to noise ratio is lighter, does not influence the normal reception of signal.
Except Distributed Feedback Laser, the light emitting module of ONU also can use other single-mode lasers.In addition, ONU can use pluggable light transceiving module, is convenient to change.
The application example of monomode and multimode fiber mixing EPON system
Chinese Guangdong somewhere EPON experimental network as shown in Figure 8.The center of housing estate machine room is to having laid 4 about 300 meters core multimode optical cables (62.5/125um, thick lines among the figure) between the floor IDF of sub-district.Need to prove that whole branch roads and ONU do not draw among Fig. 8.Can change first optical splitter and second optical splitter splitting ratio separately among Fig. 8 according to actual needs.
Single mode, multimode hybrid fiber environment, the result who tested 12 hours is: uplink service 512Byte, 90M speed, no packet loss; Downlink business 512Byte, 90M speed, no packet loss.
In the light emitting module of ONU, adopt Distributed Feedback Laser to substitute used FB laser usually, realized the operate as normal of EPON system under the multimode fiber condition.The sub-district of early stage laying multimode fiber be need not heavily to spread monomode fiber can utilize the construction of carrying out FTTH, save engineering construction investment in a large number.The present invention adopts the DBF single longitudinal mode laser to replace the light emitting module of existing FP Multi-Longitudinal Mode laser as ONU for solving the work of EPON system under the multimode fiber condition.With changing the multimode fiber of having laid is that monomode fiber is compared, and the ONU light emitting module of changing the EPON system is more economical convenient.The EPON system adopts the SFP pluggable light transceiving module more at present, and can replace the FP laser in the mode of changing the ONU light emitting module neatly when multimode fiber is used is Distributed Feedback Laser, is beneficial to the open-minded fast of EPON system.
Though compare with the FP laser, the Distributed Feedback Laser price is higher, along with the develop rapidly of grating manufacturing technology, the cost price gap of Distributed Feedback Laser and FP laser will be more and more little.Lay many areas at multimode fiber, can reduce the cost that ONU uses single-mode laser by the mode that carrier customization, manufacturer produce in batches.
Though specific embodiments of the invention described above should be understood that them just with example, rather than the mode that limits provide.What those skilled in the art will appreciate that is, does not break away from the spirit and scope of the present invention as defining in the appended claims, can make various changes to wherein form and details.Therefore scope of the present invention should not limited by above-mentioned any example embodiment, and can only determine according to claims.
Claims (4)
1. the method for a using single mode fiber in the Ethernet passive optical network system comprises:
Optical line terminal is provided, is used for sending signal and receiving signal from user terminal to user terminal;
The two ends of monomode fiber are connected respectively to the described optical line terminal and first optical splitter;
The two ends of multimode fiber are connected respectively to described first optical splitter and second optical splitter; And
Optical network unit is connected between described second optical splitter and the user terminal,
Wherein in described optical network unit, provide single-mode laser.
2. the described method of claim 1 wherein provides the step of single-mode laser to comprise the step that distributed feedback laser is provided in described optical network unit.
3. the described system of claim 1 wherein provides the step of single-mode laser to comprise the step that pluggable light transceiving module is provided in described optical network unit.
4. the described system of claim 1 also comprises step: utilize tail optical fiber to connect described second optical splitter and described optical network unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910118968A CN101835065A (en) | 2009-03-10 | 2009-03-10 | Method for using single mode fiber in Ethernet passive optical network system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910118968A CN101835065A (en) | 2009-03-10 | 2009-03-10 | Method for using single mode fiber in Ethernet passive optical network system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101835065A true CN101835065A (en) | 2010-09-15 |
Family
ID=42718964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910118968A Pending CN101835065A (en) | 2009-03-10 | 2009-03-10 | Method for using single mode fiber in Ethernet passive optical network system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101835065A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102216822A (en) * | 2011-05-09 | 2011-10-12 | 华为技术有限公司 | Passive optical splitter and passive optical network system |
-
2009
- 2009-03-10 CN CN200910118968A patent/CN101835065A/en active Pending
Non-Patent Citations (1)
| Title |
|---|
| 张凌等: "EPON系统在单、多模光纤混合条件下的应用", 《广东通信技术》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102216822A (en) * | 2011-05-09 | 2011-10-12 | 华为技术有限公司 | Passive optical splitter and passive optical network system |
| WO2011137761A2 (en) * | 2011-05-09 | 2011-11-10 | 华为技术有限公司 | Passive optical splitter and passive optical network system |
| WO2011137761A3 (en) * | 2011-05-09 | 2012-04-19 | 华为技术有限公司 | Passive optical splitter and passive optical network system |
| CN102216822B (en) * | 2011-05-09 | 2013-01-09 | 华为技术有限公司 | Passive optical splitter and passive optical network system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2139128B1 (en) | Wavelength multiplexed optical system with multimode optical fibres | |
| US6885802B2 (en) | Network for distributing signals to a plurality of user equipment | |
| EP1576746B8 (en) | An optical communication system for wireless radio signals | |
| US9917672B2 (en) | Wireless distributed antenna MIMO | |
| CN102656832B (en) | Split/smart channel allocated WDM-PON architecture | |
| US9621297B2 (en) | Optical communication system, method of bi-directional communication and method of operating a network element | |
| CN106576000A (en) | Optical splitter, signal transmission method, and passive optical network | |
| CN103139670A (en) | Coexisting passive optical network system and up and down optical signal transmitting method | |
| CN202334525U (en) | Optical network unit and passive optical network | |
| Chen et al. | Universal fiber for short-distance optical communications | |
| Vázquez et al. | Experiments on shared-and dedicated-power over fiber scenarios in multi-core fibers | |
| US9268093B2 (en) | Systems and methods for converting legacy multimode links to longer-wavelength links | |
| Nanni et al. | Modal noise in 850nm VCSEL-based radio over fiber systems for manifold applications | |
| Chen et al. | Chromatic dispersion compensated 25Gb/s multimode VCSEL transmission around 850nm with a MMF jumper | |
| CN202872790U (en) | System using mode multiplexing of multimode optical fiber to simultaneously transmit a plurality of signals | |
| CN101835064A (en) | Monomode and multimode fiber mixed Ethernet passive optical network system | |
| CN101835065A (en) | Method for using single mode fiber in Ethernet passive optical network system | |
| Giaretta et al. | 11Gb/sec Data Transmission Through 100m of Perfluorinated Graded-Index Polymer Optical Fiber | |
| CN103842870A (en) | Multimode fiber for modulatable source | |
| Montero et al. | Multimode graded-index optical fibers for next-generation broadband access | |
| Hayashi et al. | Multi-core fiber for high-capacity long-haul spatially-multiplexed transmission | |
| CN209496171U (en) | WDM device | |
| US6856736B2 (en) | Lightwaveguide cable and process for carrying an optical signal using dispersion management | |
| CN1829123B (en) | Method for data communication, a method for adapting a fibre optic network as well as a fibre optic network and transmission unit | |
| CN102916748A (en) | System and method for simultaneously transmitting multiple signals by using mode division multiplexing of multimode optical fiber |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20100915 |