What Is a Fiber-Optic Multiplexer?–DK Photonics

What Is a Fiber-Optic Multiplexer?

A fiber-optic multiplexer is a device that processes two or more light signals through a single optical fiber, in order to increase the amount of information that can be carried through a network. Light wavelengths are narrow beams that ricochet through reflective optical tubing, sometimes over long distances, to provide instantaneous electronic signal processing at the speed of light. Multiplexers work by increasing a fiber’s transmission capacity using different techniques and light source technologies. When the signal arrives at its destination, a demultiplexer separates the data streams. Using a multiplexer also allows data to be sent farther, more securely, and with less electromagnetic and radio frequency interference.

Also known as a mux, the fiber-optic multiplexer saves time and cost by squeezing more information through the optical network pathway. It is possible to split signals by varying the schedule or period of each transmission. Time Division Multiplexing (TDM) combines multiple signals by rapidly alternating between them so that only one is transmitting at any given time. Statistical Time Division Multiplexing (STDM) assigns each signal a specific time slot in order to optimize bandwidth usage. Further techniques include divisions of wavelength and frequency.

Wavelength Division Multiplexing (WDM) utilizes the total available pass band of an optical fiber. It assigns individual information streams different wavelengths, or portions of the electromagnetic spectrum. Similarly, Frequency Division Multiplexing (FDM) assigns each signal a different frequency. Carrier frequencies contain the signal while unused guard frequencies provide buffering to reduce interference. This helps minimize audible and visual noise and preserves the integrity of the original signal throughout the network.

Fiber-optic multiplexer technology serves single-mode and multimode optical fibers with multichannel rack mount or standalone units. This makes mixing channels with different configurations possible for a range of interface combinations. These devices provide stronger, more reliable transmissions in areas that have a lot of electromagnetic, radio frequency, or lightning interference.

As technology improves and information needs grow to fill the capacities of existing networks, equipment such as the fiber-optic multiplexer lessens the need to upgrade the fiber-optic infrastructure itself. Multiplexers permit new configurations of transmission protocols by increasing the amount of wavelengths or frequencies of light signals. By upgrading repeaters and terminal equipment, existing network transmission capacity can expand with demand.

Used by cellular carriers, Internet service providers, public utilities, and businesses, fiber-optic multiplexer technology extends the reach and power of telecommunications technologies. Network management systems allow for system service and maintenance, and provide for security, fault management, and system configuration. With advantages like lower costs and longer life expectancies, current fiber-optical networks are aided by improvements in multiplexing technology, and may provide light speed data transmission well into the future.

DK Photonics – www.dkphotonics.com specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM,Optical Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.

Free Space Optics Global Market Forecast –DK Photonics

According to ElectroniCast, the worldwide value of FSO link devices in stationary non-military/aerospace applications was $33.49 million in 2013…

Aptos, CA (USA) – January 24, 2014 —ElectroniCast Consultants, a leading market research consultancy, today announced the release of a report presenting their market analysis and forecast of Free Space Optics (FSO) communication links used in non-military/aerospace applications.

The global consumption of fixed-location (stationary) Transmitter/Receiver (T/R) links (pairs) used in non-military/ aerospace Free Space Optic system equipment was $33.49 million in 2013, up 11 percent from $29.83 million in 2012. Free Space Optic (FSO) Transmitters and Receivers (pairs) used in link equipment with a range capability of less than 500 meters or less led in relative market share in 2013 with a global consumption value of $23.06 million.

According to the Free Space Optics Global Market Forecast & Analysis (January 2014), FSO is a line-of-sight (LOS) technology that uses directed laser beams, which provide optical bandwidth Transmitters and Receivers to link voice, video, and data intelligent transfer. A single FSO link product (from point A to point B) often may incorporate multiple transmitters along with receiver/s to ensure adequate performance, in case of interference.

Free Space Optic communication links can be installed along railroad/subway tracks, tunnels, airport terminals, parking lot/structures or other major un-obstructed right-of-way (ROW); outdoors on building rooftops (building-to-building and/or campus), exterior walls, towers, indoors (aimed out a window), or any combination; however, a direct line-of-sight and appropriate distance are required to enable a Transmitter/Receiver Link between two points (point-to-point).

FSO-based products accommodate Ethernet-based protocols, SONET/SDH, ATM, FDDI and other standard and proprietary protocols. Products can be used for metropolitan (Metro) network extension; DWDM services, access/last mile, wireless backhaul, disaster recovery (testing and communications), storage area networks (SANs) and LAN/first mile/FTTx, and an almost endless list of other solutions.

The increase in the consumption of FSO links in the America region will be attributed to not only continued upgrades and network facilitation in the United States and Canada, but partly from the accelerating economic growth of major cities in Latin America. Other market dynamics in the American region are increases in communication links needed for growing infrastructures, such as mass transit, security systems, broadcast and telecommunications.

European inner-city urban areas typically are difficult for wire-lines, including optical fiber cable installations; therefore, this fact promotes FSO or other wireless solutions. The APAC region has advanced communication technology deployed especially in Japan; however, other countries, such as Australia, China and India, are not as advanced in campus-wide and metropolitan optical communication deployment.

The APAC region has rapidly expanding market opportunities and therefore, our forecast shows the region with the fastest growth (2013-2019), with the region taking over the leadership position later on in the forecast period.

According to ElectroniCast, the APAC region is forecast to eventually take the lead in terms of relative market share of non-military/aerospace FSO-Links…

Non-Military/Aerospace

FSO Global Consumption Value Market Share (%), By Region

Source: ElectroniCast Consultants

Fiber Optic Sensors Global Market Forecast- DK Photonics

According to ElectroniCast, the combined use of Continuous Distributed and Point fiber optics sensors will reach $4.33 Billion in 2018…

Aptos, CA (USA) – February 14, 2014 —ElectroniCast Consultants, a leading market/technology forecast consultancy, today announced the release of their market forecast and analysis of the global consumption Fiber Optic Point Sensors and Continuous Distributed Fiber Optics Sensor systems.

According to ElectroniCast, the consumption value is forecast to increase at an impressive 18% per year from $1.89 billion in 2013 to $4.33 billion in 2018. Market forecast data refers to consumption for a particular calendar year; therefore, this data is not cumulative data.

Continuous Distributed fiber optic sensor systems involve the optic fiber with the sensors embedded with the fiber. ElectroniCast counts each Point fiber optic sensor as one unit; however, the volume of Distributed Continuous fiber optic sensors is based on a complete optical fiber line and associated other components, which are defined as a system.

The use of Distributed Continuous fiber optic sensors in the Military/Aerospace/Security application category maintains the lead in 2014, followed by the Petrochemical/ Energy sector. The Civil Engineering/Construction sector, which includes continuous fiber sensors used in Structural Health Monitoring (SHM) as well as other concerns in buildings, bridges, tunnels, towers, and other structures, is also forecast for strong growth. Inspection and quality control frequently constitute the largest portion of production costs for many industries.

“There is a growing need for improved measurement solutions, which offer higher precision, speed and accuracy and provide better in-process measurement of moving objects, resulting in lower costs for better products. Relatively speaking, the Manufacturing/ Factory segment tends to favor point sensors instead of distributed fiber systems,” stated Stephen Montgomery, Director of the Fiber Optics Components group at ElectroniCast Consultants.

“The Biomedical/ Science sector is a relatively minor user of Distributed Continuous fiber optic sensors, in terms of consumption value, since the length of optical fiber is (very) short versus the other applications; therefore the average selling prices for the distributed continuous fiber optic sensor systems are low compared to the larger (longer length of optical fiber) distributed continuous fiber optic sensor systems used in other applications. The consumption value of Distributed Continuous fiber optic sensor systems is forecast to grow at 23% per year from $1.099 billion in 2013 to $3.096 billion in the year 2018,” Montgomery added.

DATA FIGURE

According to ElectroniCast, the consumption value of fiber optic sensors (continuous distributed systems + Point-types) will increase from $1.89 billion in 2013 to $4.33 billion in 2018.

Fiber Optic Sensor Global Consumption Market Forecast

Point vs. Distributed Continuous
(Value Basis, $Million)

Note: Market forecast data refers to consumption for a particular calendar year; therefore, this data is not cumulative data.

Fiber Media Converters in Private Datacom Market Forecast (March 2014)

Fiber Media Converters in Private DatacomMarket Forecast (March 2014)

According to ElectroniCast, the global use of fiber media converters in private datacom networks is expected to reach $1.29 billion in 2014…

Aptos, CA (USA) – March 20, 2014 —ElectroniCast Consultants, a leader in fiber optic market research, announced the release of a new market analysis of the worldwide use of fiber optic / Fiber media converters in private data communications. A fiber media converter is a networking device that makes it possible to connect two dissimilar media types such as copper with fiber optic cabling, as well as (different) fiber-to-fiber (F2F), such as multimode to single mode optical fiber.

The worldwide value for selected fiber media converters used in private datacom networks reached $1.07 billion in 2013. The consumption value is forecast increase with strongly rising quantity growth partially offset by declining average prices.

The EMEA and the APAC regions are forecast for double-digit consumption value growth during the timeline covered in this study (2013-2018); however, the American region’s growth is forecast to “flatten” and eventually turn to negative. The worldwide use of private datacom fiber media converters, which are specified in the ElectroniCast market study, is forecast to peak at $1.646 billion in 2017, before slipping to $1.628 billion in 2018.

“The fiber media converters researched in this market study are typically used within an existing Private Enterprise Data Centers (DCs) and Local Area Networks (LANs), as well as other non-public data communication links. They are often used to connect newer 100-Mbps, Gigabit Ethernet, 10G, or other equipment in existing networks, which are generally (copper-based) 10BASE-T, 100BASE-T, or a mixture of both,” stated Stephen Montgomery, Director of the Fiber Optics Components group at ElectroniCast Consultants.

“Several factors make the conversion from copper to optical fiber a good choice, such as – longer link lengths in campuses and industrial plants; resistance to electromagnetic and radio-frequency interference (EMI/RFI) may be necessary; and wider bandwidth capability, just to point-out a few examples,” Montgomery added.

The strong user demand for greater bandwidth and increased interconnectivity to the desktop, throughout the buildings, campuses, from LAN-to-LAN (Metropolitan Area Network – MAN) continues in 2014.

This is matched by rapidly growing demand for global broadband interconnectivity. Interactive multimedia terminals, triple play (voice, video and data), quadruple-play (adding mobility as a communications function to the network), and numerous other dynamics/ applications, continuing bring rapid access to massive databases, which increase productivity while providing rapid ROI (return on investment).

Such expanded capability, however, must often be obtained without making the current network elements obsolete. Local area network (LAN) applications illustrate this trend. LANs are becoming larger and more complex. Reconfiguration, relocation, and extension of LANs are occurring more frequently, due to organization restructuring, advances in computer usage, and the trend toward decentralized computing.

These changes to LAN cabling represent a major ongoing operational expense and a disruption of work for many companies (enterprises). For example, adding capabilities often requires that network administrators upgrade their existing LANs to another media type: for example, copper-to-fiber, multimode-to-singlemode fiber, or even singlemode –to- different types of singlemode optical fiber (note: copper-to-copper conversion is not covered in the study). By using media converters, the network administrator can achieve these upgrades inexpensively.

According to ElectroniCast, the global use of fiber media converters in private datacom reached $1.07 billion in 2013 and is forecast to peak at $1.646 billion in 2017, before slipping to $1.628 billion in 2018.

Private Datacom Fiber Media Converter Global Market Forecast,
(Value Basis, $ Million) – Source: ElectroniCast Consultants

Note: Market forecast data in this study report refers to consumption (use) for a particular calendar year; therefore, this data is not cumulative data.

Where can WDM-PON go next? — DK Photonics

Where can WDM-PON go next?

The current generation of commercial WDM-PON/ 100GHz DWDM systems based on reflective ONU technology is optimized for applications up to 20 km, 40 channels, and 1 Gbps per customer. Current research focuses on how to scale WDM-PON toward higher bit rates and longer reach. Forward error correction is a key technology for scaling the current generation of WDM-PON technology to higher bit rates, longer reach, tighter channel spacing, or a combination thereof. An important challenge is to package the technology in an MSA form-factor pluggable module to maintain its benefits in cost and compatibility with third-party equipment.

A typical requirement for next generation metro/access systems is to enable node consolidation. That means operators can reduce opex by closing down portions of their central offices; at the same time, this goal requires the optical signals to bridge longer distances than what is typical of the access networks of today. Thus, when routing WDM-PON / 1064nm high power isolator signals through the metro part of the network, it becomes necessary to support ring architectures as an alternative to the basic tree structure.

In a ring structure, cascaded filters may decrease the effective channel passband. Since the spectral width of the WDM-PON signal is wider than the signals from a normal DFB source, such filtering effects may affect transmission.

In a recent evaluation project, a partnership between Transmode and Deutsche Telekom Hochschule für Telekommunikation of Leipzig, Germany, achieved 140-km long reach WDM-PON transmission over a ring-based access-network architecture. The partnership investigated the effects of using WDM-PON based on ASE-seeded wavelength-locked transmitters in a ring-based network architecture with cascaded CWDM OADM nodes. Transmission at 1.25 Gbps over 140-km singlemode fiber was demonstrated using an EDFA and dispersion compensation.

The results were first published at ECOC 2013 (In de Betou, Bunge, Åhlfeldt, and Olson, “140km Long-reach WDM-PON Test for Ring-based Access Network Architecture”). This partnership has investigated what opportunities could be provided by WDM-PON technology in such network topologies by studying experimentally the influence of narrow filtering and maximum reach.

The experimental testbed (in Leipzig) was built around Transmode’s TM-Series iWDM-PON system to create an optical line terminal (OLT) (see Figure 2). The OLT has a transponder line card that hosts pluggable wavelength-locked Fabry-Perot transceivers, ASE seed light sources, dual circulators for up- and downstream, and a 40-channel multiplexer based on an AWG.

To reach distances beyond 100 km, amplifiers dispersion compensation, and remote ASE seed sources were used. While an experimental field trial today, it shows that WDM-PON may well continue to evolve to support longer reach and more sophisticated network architectures in the future supporting a broader range of deployment scenarios.

DK Photonics – www.dkphotonics.com specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as High Power Isolator,1064nm Components,PM Components,Pump Combiner,Pump Laser Protector,which using for fiber laser applications.Also have Mini-size CWDM, Optical Circulator, PM Circulator,PM Isolator, Fused Coupler,Mini Size Fused WDM.More information,please contact us.

WDM-PON technology-DK Photonics

WDM-PON provides the dedicated bandwidth of a point-to-point network and the fiber sharing inherent in PONs. The architecture is somewhat similar to that of EPON and GPON; instead of the power-splitter approach used in TDM-PON architectures, WDM-PON uses an arrayed waveguide grating (AWG) filter that separates the wavelengths for individual delivery to the subscriber ONUs (see Figure 1).

A simple, plug-and-play implementation is based on wavelength-locked or tunable lasers. Self-tuning “colorless” ONUs can be used at the subscriber sites to simplify inventory and spare-part handling. Colorless optics not only simplify operations, but also reduce deployment costs, since they don’t need the expensive wavelength-stability components that traditional fixed and tunable optics require. There are multiple approaches to the colorless ONU technology.

In one approach, the wavelength of the ONU transmitter is controlled by injection of a “seed” signal into the transmitter (e.g., a wavelength-locked Fabry-Perot laser or reflective semiconductor optical amplifier). The seed signal injected into the transmitter could come from broadband ASE light sliced through the filters in the system or from a DFB laser array. In a self-seeding version of this approach, the seed light is provided by feedback of broadband light from the transmitter itself. The passive filtering of the seed light in the remote node determines the wavelength of the ONU transmitter.

In a different approach, the colorless ONU contains a singlemode optic coupler wavelength-tunable laser, which is able to tune to the appropriate wavelength that matches the remote node filter port.

Below 10-Gbps channel bit rates, the injection-seeded method provides a cost-efficient approach. As an example, a wavelength-locked Fabry-Perot transmitter can be integrated into an MSA SFP pluggable form-factor module, which enables the use of third-party CPE devices. A modified EDFA gain block in a 70×90 MSA form factor could be used to generate the broadband ASE light that’s used as a seed signal in the system.

At 10-Gbps bit rates, tunable-laser technology offers an alternative to the injection-seeded approach. The tunable-laser technology developed for the metro/long-haul market has matured significantly over the past couple of years and is able to give a good cost-per-bit ratio when high capacity is needed.

If the WDM-PON system is properly designed, then it’s possible to mix different transmission technologies. By following certain design rules during the installation of the WDM-PON system, it’s possible to allow step-wise channel upgrades to higher bit rates when the demand arises. These design rules ensure that channel OSNR requirements will be met in the presence of reflections and that inter-channel crosstalk is avoided. The result is an open and flexible access network that can support many applications and services over the same infrastructure. WDM-PON thus becomes an optical option for the access network as and where it makes sense.

Given its ability to help service providers cope with current bandwidth demands as well as the next potential broadband access bottleneck, WDM-PON/ 100GHz DWDM Module is becoming an important technology to consider in terms of its benefits and market timing. As with any emerging technology, service providers need to consider the optimal strategy for initial deployment of WDM-PON. That includes how they could use WDM-PON for additional network applications as the technology matures and its costs come down.

WDM-PON technology

FIGURE 2. Architectural scenario explored in the collaboration between Transmode and Deutsche Telekom Hochschule für Telekommunikation.

The latest generations of WDM-PON systems are now gaining traction with operators around the globe for field deployment, lab trials, and evaluations. It’s clearly the early stage of WDM-PON deployments, but progress has started and 2014 looks to be a pivotal year for the technology.

WDM-PON is a key component in next generation access(1)

Many industry analysts believe that the increasing requirements for bandwidth scalability, quality of service, and support of the emerging traffic patterns required by video and broadcast standards will make copper networks insufficient for many high-bandwidth services in the future. Fiber availability is not universal, and the economics of new fiber deployments are often challenging; nevertheless, fiber will undoubtedly push deeper into access networks to support business services, mobile backhaul/fronthaul, multitenant buildings/fiber to the cabinet, and in some cases fiber to the home (FTTH), too. Yet today‘s fiber-based approaches, including TDM-PON/PLC Splitter and active point-to-point Ethernet, probably won’t meet the likely requirements of the next generation of bandwidth-intensive traffic, either.

WDM-PON is a passive optical networking approach — currently being developed by several companies — that can be used to more adequately address these challenges over fiber-based networks. A WDM-PON design can be used to separate optical-network units (ONUs) into several virtual point-to-point connections over the same physical infrastructure, a feature that enables efficient use of fiber compared to point-to-point Ethernet and offers lower latency than TDM-based approaches. A notable advantage of this approach is the combination of high capacity per user, high security, and longer optical reach. WDM-PON therefore is highly suitable for applications such as mobile backhaul or business Ethernet service provision.

Thus WDM-PON is poised to become the disruptive next generation access architecture. It will enable high-speed access for businesses, mobile backhaul, and eventually FTTH. WDM-PON also will enable operators to build converged networks and consolidate existing access networks, including potentially eliminating central offices to reduce cost while boosting performance.

There are several types of WDM-PON systems under development. They all have in common the use of passive, temperature-hardened DWDM optical filters in the remote node and colorless ONUs.

FIGURE 1. Basic WDM-PON architecture.

DK Photonics – www.dkphotonics.com specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as High Power Isolator,1064nm Components,PM Components,Pump Combiner,Pump Laser Protector,which using for fiber laser applications.Also have Mini-size CWDM, Optical Circulator, PM Circulator,PM Isolator, Fused Coupler,Mini Size Fused WDM.More information,please contact us.

Planar Lightwave Circuit Splitters Market Forecast

Fiber-to-the-Home deployment dominates the PLC splitter marketplace…

Aptos, CA (USA) – February 20, 2014 — ElectroniCast Consultants, a leading market/technology consultancy, today announced the report release of their market forecast of the global consumption of Planar Lightwave Circuit (PLC) splitters used in Fiber Optic Communication Networks.

According to the ElectroniCast market study, the consumption value of component-level (compact device) PLC splitters reached $529.6 million in 2013. PLC splitters will continue to contribute an important role in Fiber to the Home (FTTH) networks by allowing a single passive optical network (PON) interface to be shared among many subscribers. PLC splitters are available in compact sizes; therefore, they can be used in aerial apparatus, pedestals or in-ground as well as rack mount or other module-based value-added product. Installation is simple using a variety of connector types or fusion splicing.

“The PON-based Fiber-to-the-Home network application dominates the worldwide PLC splitter consumption value in 2014,” stated Stephen Montgomery, Director of the Fiber Optics Components group at ElectroniCast Consultants.

“The American region is forecast for flat annual growth (just over 1%); however, the EMEA region is set for 7% per year and the APAC region is forecast to increase at 15% per year, for the component-level PLC splitters, during the 2013-2018 timeframe cover by the ElectroniCast study,” Montgomery added.

DK Photonics – www.dkphotonics.com  specializes in designing and manufacturing of high quality optical passive components mainly for telecommunication, fiber sensor and fiber laser applications,such as PLC Splitter, WDM, FWDM, CWDM, DWDM, OADM,Optical Circulator, Isolator, PM Circulator, PM Isolator, Fused Coupler, Fused WDM, Collimator, Optical Switch and Polarization Maintaining Components, Pump Combiner, High power isolator, Patch Cord and all kinds of connectors.

62.5/125 um Vs. 50/125um Multimode fiber Information

We have created this page to illustrate the very basic differences between 62.5 and 50/125 multimode fiber in selecting a patch cable for your existing cable plant.

The key thing to remember is to always use a patch cable of the same type as the cable that you are connecting to. It is virtually impossible to tell the difference between the two fiber types (62.5 and 50/125) by looking at the bare fiber* or the connectors*. Usually, this information will be written on the cable’s jacket.

The photos above illustrate that the outer diameters of the two fiber types are the same. What is different is the size of the center light carrying core of the fiber. You cannot see the fiber’s core without a microscope*. Therefore, you must rely on the writing that is on the fibers jacket to determine what type is.

Severe losses of light can occur when you try to match 50/125 and 62.5/125 fiber, as the illustration on the left shows.

* CAUTION: Never look directly into a fiber cable’s end face or into the ferrule of a connector (with fiber present) as there may be dangerous laser light present.

NOTE: This page was designed to help you know the difference between 62.5 and 50/125 fiber for the purpose of purchasing patch cables and products to connect to existing installed cabling. This page was not designed to provide information on choosing between the two types fiber for new installations.

Comparation Between EPON and GPON

With the continuous progress of science and technology, the Internet has gradually gone into the homes of the ordinary people, and the speed of broadband has increasingly become the topic of people in the entertainment and work often, from narrowband dial-up to broadband Internet, and then the fiber access Internet, broadband network, the rapid pace of PON technology gradually come to the front. Currently, there are two quite compelling PON standard has been officially released, which are GPON standard developed by the ITU / FSAN and EPON standard developed by IEEE 802.3ah working group. PON technology has been no doubt the ultimate solution for the future FTTH era. EPON and GPON who will the dominant FTTH tide has become a new hot debate. What’s the difference between EPON and GPON?

GPON and EPON Differences

Perhaps the most dramatic distinction between the two protocols is a marked difference in architectural approach. GPON provides three Layer 2 networks: ATM for voice, Ethernet for data, and proprietary encapsulation for voice. EPON, on the other hand, employs a single Layer 2 network that uses IP to carry data, voice, and video.

A multiprotocol transport solution supports the GPON structure (Figure 1). Using ATM technology, virtual circuits are provisioned for different types of services sent from a central office location primarily to business end users. This type of transport provides high-quality service, but involves significant overhead because virtual circuits need to be provisioned for each type of service. Additionally, GPON equipment requires multiple protocol conversions, segmentation and reassembly (SAR), virtual channel (VC) termination and point-to-point protocol (PPP).

Figure 1: Diagram showing a typical GPON network.

EPON provides seamless connectivity for any type of IP-based or other “packetized” “communications” (Figure 2). Since Ethernet devices are ubiquitous from the home network all the way through to regional, national and worldwide backbone networks, implementation of EPONs can be highly cost-effective. Furthermore, based on continuing advances in the transfer rate of Ethernet-based transport — now up to 10 Gigabit Ethernet — EPON service levels for customers are scalable from T1 (1.5 Mbit/s) up through 1 Gbit/s.

Figure 2: Diagram showing a typical EPON network.

Upstream Bandwidth

Subtracting the various system run overhead from the total bandwidth of the system uplink transmission is the upstream available bandwidth. It has a great relationship with the number of the ONU contained in the system, DBA (Dynamic Bandwidth Allocation) algorithm polling cycle, the type of bearer services, as well as the various business proportion. EPON and GPON are broadband access technology, hosted business IP data services. Below we will calculate the uplink the beared pure IP services available bandwidth of EPON and GPON that contain 32 ONUs, fiber optic coupler,the case of polling period 750s.

EPON

EPON upstream rate is 1.25 Gbit/s. Because the 8B/10B line coding, each 10bit are 8bit valid data, so its effective upstream transmission bandwidth is 1 Gbit/s. EPON upstream overhead of running the system and its proportion of the total bandwidth are as following:

1. Used for the the burst reception of physical layer overhead: about 3.5%;

2. Ethernet frame encapsulation overhead: about 7.4%;

3. MPCP (Multi-Point Control Protocol) and OAM operation and management of maintenance protocol overhead: about 2.9%;

4. DBA algorithm resulting in the remaining time slots (that is not sufficient to transfer a complete Ethernet frame time slot) wasted: about 0.6%;

5. EPON upstream total overhead is all of the above about 144 Mbit/s, the available bandwidth is about 856 Mbit/s.

GPON

GPON supports a variety of rate levels, has asymmetric rate that downlink is 2.5Gbps or 1.25Gbps, the upgoing is 1.25Gbps or 622 Mbps. NRZ encoding the uplink total bandwidth for 1.244 Gbit/s, GPON upstream overhead of running the system as following:

1. The proportion of its total bandwidth is used for the the burst reception of physical layer overhead: about 2.0%;

2. GEM (GPON encapsulation method) frame and the Ethernet frame encapsulation overhead: about 5.8%;

3. The PLOAM (physical layer operation, management and maintenance) protocol overhead: about 2.1%;

4. Remaining slots of the DBA algorithm introduced the additional encapsulation overhead: about 0.8%.

5. GPON upstream total overhead is all of the above about 133 Mbit/s, the available bandwidth about 1111 Mbit/s.