Gigabit passive optical network

Theory My Results/Contribution Summary

GPON - Gigabit Passive Optical N/W

S. Srinath

Student, School of ElectronicsVIT University, Vellore

Optical Communication, April, 2014

1 TheoryBasic Terms and TheoryHistory of Passive Optical N/W

2 My Results/ContributionResultsSingle User ResultMultiple User Result

Basic Theory

There are two important types of systems that makefiber-to-the-home broadband connections possible. These areactive optical networks and passive optical networks. Eachoffers ways to separate data and route it to the proper place,and each has advantages and disadvantages as compared tothe other .AON - An active optical system uses electrically poweredswitching equipment, such as a router or a switch aggregator,to manage signal distribution and direct signals to specificcustomers. This switch opens and closes in various ways todirect the incoming and outgoing signals to the proper place.In such a system, a customer may have a dedicated fiberrunning to his or her house.PON - A passive optical network, on the other hand, does notinclude electrically powered switching equipment and insteaduses optical splitters to separate and collect optical signals asthey move through the network. A passive optical networkshares fiber optic strands for portions of the network.

Basic Theory

A passive optical network (PON) is a telecommunicationsnetwork that uses point-to-multipoint fiber to the premises inwhich unpowered optical splitters are used to enable asingle optical fiberto serve multiple premises. Upstream signalsare combined using a multiple access protocol, usually timedivision multiple access (TDMA).A PON takes advantage of wavelength divisionmultiplexing (WDM), using one wavelength for downstreamtraffic and another for upstream traffic on a single non-zerodispersion-shifted fiber (ITU-T G.652). BPON and GPONhave the same basic wavelength plan and use the 1,490nanometer (nm) wavelength for downstream traffic and1,310 nm wavelength for upstream traffic.A PON consists of a central office node, called an optical lineterminal (OLT), one or more user nodes, called opticalnetwork units (ONUs) or optical network terminals (ONTs),and the fibers and splitters between them, called the opticaldistribution network (ODN).

Basic Theory

Some basic definitons are given in the next slide.

These includeBERQ-FactorEye Pattern

Basic Theory

Some basic definitons are given in the next slide.

These includeBERQ-FactorEye Pattern

Basic Theory

Bit rate error is defined as the number of bit errors in thenumber of received bits of a data stream over acommunication channel that has been altered due to noise,interference, and distortion or bit synchronization errors. It isthe number of bit errors divided by the total number oftransferred bits during a studied time interval.Q-Factor describes how under damped an oscillator orresonator is. Higher Q factor indicates a lower loss of energy.Higher Q indicates a lower rate of energy loss relative to thestored energy of the resonator. A high-Q tuned circuit in aradio receiver would have more selectivity and hence betterjob of filtering out signals from other stations that lie nearbyon the spectrum.Eye patterns are a widely used tool for studying the qualityand stability of optical communication systems. The quality ofthe signals can be judged from the appearance of the eye.

Basic Theory

History of Passive Optical N/W

The International Telecommunications Union (ITU) did work, andstandardized on two generations of PON.

APON - The older ITU-T G.983 standard was basedon Asynchronous Transfer Mode (ATM), and has thereforebeen referred to as APON (ATM PON).Flexible optical fibre access network capable of supporting thebandwidth requirements of narrowband and broadbandservices.BPON - Further improvements to the original APON standard– as well as the gradual falling out of favor of ATM as aprotocol – led to the full, final version of ITU-T G.983 beingreferred to more often as broadband PON, or BPON.

For more information on GPON:https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.984.1-200803-I!!PDF-E&type=items

GPON - The ITU-T G.984 Gigabit-capable Passive OpticalNetworks (GPON) standard represented an increase, comparedto BPON, in both the total bandwidth and bandwidthefficiency through the use of larger, variable-length packets.Again, the standards permit several choices of bit rate.Recommendation ITU-T G.984.1 describes a flexible opticalfibre access network capable of supporting the bandwidthrequirements of business and residential services and coverssystems with nominal line rates of 2.4 Gbit/s in thedownstream direction and 1.2 Gbit/s and 2.4 Gbit/s in theupstream direction.10G PON - G.987 defined 10G-PON with 10 Gbit/sdownstream and 2.5 Gbit/s upstream.

Results

FactSimulation is performed at a data rate of 2.5Gbps

Results

FactSimulation is performed at a data rate of 2.5Gbps

Results

ExampleMultiple user Scenario.

ExampleData rate = 2.5 Gbps.

Results

ExampleMultiple user Scenario.

ExampleData rate = 2.5 Gbps.

Single User Result

Eye Diagram for Single User Scenario at a Simulation data rate of2.5 Gbps

Multiple User Result

Eye Diagram for Multiple User Scenario at a Simulation data rateof 2.5 Gbps

SummaryAs the wavelength is changed from 1490 nm to 1700 nm theeye diagram changes.As the wavelength increases the Q-Factor decreases.As the wavelength increases the BER increases.

AcknowledgementAt the outset, I would like to express my gratitude for myinstitute – Vellore Institute of Technology (V.I.T.) forproviding me with the opportunity to undergo myundergraduate training, and assimilate knowledge andexperience hitherto unknown to me.

Appendix

For Further Reading

Hesham A. Bakarman, Sahbudin Shaari and Mahamod IsmailSimulation of 1.25 Gb/s Downstream TransmissionPerformance of GPON-FTTxPhotonics (ICP), 2010 International Conference on. IEEE,2010.Srinath, S.Performance Analysis of 2.5 Gbps GPON.International Journal of Advanced Research in Electrical,Electronics and InstrumentationEngineering,Vol.3,Issue.6,June,2014.[2]

Appendix

For Further Reading

Thanks for reading.From Srinath Srivatsa.

Gigabit passive optical network

Engineering

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