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Relative Terms In PON System

ODN (Optical Distribution Network)

ODN is a FTTH fiber optic cable network based on PON equipment. Its role is to provide optical transmission channel between the OLT and ONU. Accroding the function, ODN from the central office to the client can be divided into four parts: feeder fiber optic subsystems, cable wiring subsystem, home line of fiber optic subsystems and fiber terminal subsystems. The main components in ODN include optical fibers, optical connectors, optical splitters and corresponding equipments for installing them.

OLT (Optical line terminal)

OLT is a terminal equipment connected to the fiber backbone. It sends Ethernet data to the ONU, initiates and controls the ranging process, and records the ranging information. OLT allocates bandwidth to the ONU and controls the starting time and the transmission window size of the ONU transmission data.

ONU (Optical network unit)

ONU is a generic term denoting a device that terminates any one of the endpoints of a fiber to the premises network, implements a passive optical network (PON) protocol, and adapts PON PDUs to subscriber service interfaces. In some contexts, ONU implies a multiple subscriber device. Optical Network Terminal (ONT) is a special case of ONU that serves a single subscriber.

APON / BPON

APON (ATM PON) is the first PON system that achieved significant commercial deployment with an electrical layer built on Asynchronous Transfer Mode (ATM). BPON (Broadband PON) is the enhanced subsequence of APON, with the transmission speed up to 622Mb/s. At the same time, it added the dynamic bandwidth distribution, protection and other functions. APON/BPON systems typically have downstream capacity of 155 Mbps or 622 Mbps, with the latter now the most common.

GPON

GPON (Gigabit PON) is based on the TU-TG.984.x standard for the new generations of broadband passive optical access. Compared with the other PON standards, GPON provides the unprecedented high bandwidth downlink rate of up to 2.5 Gbit/s, the asymmetric features better adapt to the broadband data services market. It provides the QoS full business protection, at the same time carries ATM cells and (or) GEM frame, the good service level, the ability to support QoS assurance and service access. Carrying GEM frame, TDM traffic can be mapped to the GEM frame, 8kHz using a standard frame able to support TDM services. As a carrier-grade technology standards, GPON also provides access network level protection mechanism and full OAM functions. GPON is widely deployed in FTTH networks. It can develop into two directions which is 10 GPON and WDM-PON.

WDM-PON

WDM-PON uses wavelength division multiplexing technology to access to the passive optical network. It has four programs as following:

1. Each ONU is assigned with a pair of wavelength, for uplink and downlink transmission, thereby providing the OLT to each ONU fixed virtual point-to-point bidirectional connections.

2. ONU uses tunable lasers, according to the needs of the ONU to dynamically allocate the wavelength, and each ONU can be shared the wavelength, the network are reconfigurable.

3. Using colorless ONUs, the ONU are independent from the wavelength.

4. Using a combination of TDM and WDM technology, Composite PON (CPON). CPON uses WDM technology in the downstream, and TDMA technology in the upstream.

EPON / GEPON

EPON (Ethernet PON) is the rival activity to GPON which uses Ethernet packets instead of ATM cells. GEPON uses 1 gigabit per second upstream and downstream rates. It is a fast Ethernet over PONs which are point to multipoint to the premises (FTTP) or FTTH architecture in which single optical fiber is used to serve multiple premises or users. EPON is an emerging broadband access technology, through a single fiber-optic access system, to access the data, voice and video service, and it has a good economy.

40/100GbE MPO FIBER OPTIC CONNECTOR – NORTH AMERICA MARKET FORECAST

According to ElectroniCast, 12-fiber single mode MPO connector consumption value will increase 141% per year through 2016…

ElectroniCast Consultants, a leading market research & technology forecast consultancy addressing the fiber optics communications industry, today announced the release of their annual market forecast of the North American consumption of MPO Fiber Optic Connectors used in 40 and 100GbE communication links.

In 2006, the IEEE 802.3 working group formed the Higher Speed Study Group (HSSG) and found that the growth in bandwidth for network aggregation applications was outpacing the capabilities of networks employing link aggregation with 10 Gigabit Ethernet. (The standard was announced in July 2007 and was ratified on June 17, 2010).

Applications such as video, virtualization (cloud computing), switching/routing and convergence are driving the need for bandwidth expansion. We continue on the path of gradually developing of growth (and change) from 1G to 10G to 40G and 100G. For data center (DC) environments operating at 40GbE or 100GbE, fiber optic cabling is generally recommended because its reach supports a wider range of deployment configurations compared to copper solutions.

The capability to choose increased speed will enable networks to play with the 10GbE resources to the access layer allowing 40/100GbE to handle traffic at the aggregation and core layers. In this market research report, ElectroniCast Consultants provides their 2011-2016 forecast and analysis of MPO fiber optic connectors used in North American 40/100GbE optical communication networks.

The 10GbE movement into the data centers will continue; however, “future-proofing” is continuing with an accent (40/100G), which is driven by significant broadband expansion demands, especially in regards to network productivity and operating expenses (OPEX costs).

According to ElectroniCast, 12-fiber multimode MPO patchcord dominate the North American (Mexico, Canada and the United States) 40/100GbE MPO connector marketplace in 2012; however, 12-fiber single mode MPO connector consumption value will increase at the fastest pace of 141% per year through 2016.

According to ElectroniCast, 12-fiber multimode MPO connectors currently dominate the North American 40/100GbE MPO connector marketplace, based on consumption value…

40 and 100 GbE MPO Connector Value

North America Market Share (%) in 2012, by Type

(Source: ElectroniCast Consultants)

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, 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.

The Ion exchange process and the Glass choice of the PLC Splitter Chip

Along with development of the optical communication, its good environmental stability and compatibility with fiber, began to widely used optical communication components manufacturing.( Such as self-focusing lens, optical divider, optical amplifier, etc), And extend to the sensing area, (such as: all kinds of biological and chemical sensors , current sensors which is based on fading light waves, etc.)

Glass ion-exchange technology has several one hundred years long history, Its earliest used to change the light absorption characteristics of glass, glass coloring,then, the technology is widely used in processing on the surface of the glass surface (such as touch screen add hard processing). Along with development of the optical communication, its good environmental stability and compatibility with fiber, began to widely used optical communication components manufacturing.( Such as self-focusing lens, optical divider, optical amplifier, etc), And extend to the sensing area, (such as: all kinds of biological and chemical sensors , current sensors which is based on fading light waves, etc.)

Current mainstream technology of PLC Splitter chip includes: PECVD technology, flame hydrolysis technology, glass ion exchange technology. Glass principle and technological process of ion exchange technology as shown in figure 1,figure 2. The main process flow flame hydrolysis technology shown in figure 3. The process characteristics of contrast see table 1. From years of use and reliability experiment, the two technologies are used in mass production and the performance is good.The features of PECVD/flame hydrolysis technique are that equipment and raw materials is the existing material, but its process is very complicated, the production cycle is long, the processing tolerance is small; Glass ion exchange technology is characterized by equipment and raw materials need special customized, but its technology is relatively simple, high production efficiency, process tolerance is larger, the chip cost is relatively low.

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.

Planar Lightwave Circuit (PLC) Splitters Market Forecast

Telecommunication applications dominate the worldwide PLC splitter marketplace…

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.

This ElectroniCast study report details of last year’s consumption and forecasts to the year 2017 of PLC splitters by product-level (level of fabrication), in selected optical communication applications. There are actually three (3) separate market forecasts:

PLC Splitter Chips
Compact Devices
Modules

According to ElectroniCast, the PON, FTTx, and Telecommunication network applications dominate the worldwide PLC splitter compact device consumption value in 2012 with 77% in relative market share; followed by the cable TV segment, the PLC splitters used in Test/Measurement applications and then Harsh Environment (Military/Aerospace, Industrial) and finally Private Enterprise Networks.

In the report, ElectroniCast provides their market data covering the following optical communication applications:

Passive Optical Network (PON) / FTTX / Telecommunication Networks
Cable TV (CATV)
Fiber Optic Test/Measurement
Private Enterprise/Data Centers/Local Area Networks (LANs)
Harsh Environment (Military, Industrial, Other)

In 2012, the Asia Pacific region (APAC) region leads in the consumption of PLC splitter compact devices with 68% of the worldwide value, followed by the American region and finally the EMEA region.

According to ElectroniCast, the Asia Pacific region dominates the worldwide value of PLC splitters with 68% in 2012…

PLC Splitter Component-Level Compact Devices

2012 – Global Consumption Value Market Share (%), by Region

(Source: ElectroniCast Consultants)

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.

How Great Of Fiber Optic Cables

Fiber optic cables are used frequently for today’s telecommunication network because of their high bandwidth, high reliability and relatively low cost. For a layman, fiber optical cable or FOCs as they are often called, is a plastic or glass fiber which permits the transmission of communications over large distances and at higher rates. They present wire almost superfluous, because they pass the same, but there are a lot of loss. These cables are unique because they are not affected by electromagnetic interference. Use these cables in performing image used in the fiber.

Each cable can not beyond the permissible limit. Fiber optic cable is very safe and more reliable than the traditional copper wire. Most of these cable to work in high-pressure environments. A fiber optic cable assembly includes a tube, a track and fasteners in addition to the conventional fiber bundles.

The cable tubes have both front and rear surfaces to it. These cables operate with the help of photons. These photos are transmitted to a second quantum dot which is placed between mirrors. These mirrors absorb the photons and bounce them back to the quantum dot until it absorbs it.

The fiber optic cables are used for carrying different services pertaining to data, voice, cable TV, and video. The fiber optic cables keeps the electronic equipments far away from environment that are subjected to high temperature, stem, dust, smoke and so on. The unique feature of these fiber optic cable is that stainless steel lens and fiber cables can be easily replaced without any further calibration.

For the installation of fiber optic cables, fiber optic cable blowers are designed. The unique feature of these fiber optic is that they carry information in the form of light. These cables are very useful in transporting both audio and video signals over short and long distances. If a fiber optic cable is broken, another cable has to be fitted in between the connectors rather than soldering or twisting them. Fiber optic technologies have found its place in many applications. They are widely used in telecommunications, CCTV security places, and local area networks and so on.

Glass fibers are made use of for fiber optic cabling. They hardly provide any change in the signals they carry over long distances. Engineers found that by adding some additional chemicals into the existing silica, they can change the properties of the glass used for the cable (glass fiber cable). Althouth, both glass and plastic can be used in the manufacture of cable, glass is the preferred one used in the manufacture of cable, used for long distance transmission communication. The purpose of glasses in total internal reflection transmission.

A fiber optic cable consists of a core which is made of glass silica. Through this core, the light is guided. The core is covered with a material whose refractive index is slightly lower than that of the core. Two optical fibers are connected via mechanical splicing or fusion splicing. This process involves lots of skills as microscopic precision is required to align them.

Regardless of the application used in optical fiber, they will stay here. Their unique features and capabilities, to ensure that they will continue to spread widely used in communications industry for many years.

SC fiber optic connector basic structure

More than a dozen types of fiber optic connectors have been developed by various manufacturers since 1980s. Although the mechanical design varies a lot among different connector types, the most common elements in a fiber connector can be summarized in the following picture. The example shown is a SC connector which was developed by NTT (Nippon Telegraph and Telephone) of Japan.

A SC Connector Sample

SC Connector Structure

Elements in a SC connector

1. The fiber ferrule.

SC Connector Fiber Ferrule

SC connector is built around a long cylindrical 2.5mm diameter ferrule, made of ceramic (zirconia) or metal (stainless alloy). A 124~127um diameter high precision hole is drilled in the center of the ferrule, where stripped bare fiber is inserted through and usually bonded by epoxy or adhesive. The end of the fiber is at the end of the ferrule, where it typically is polished smooth.

2. The connector sub-assembly body.

The ferrule is then assembled in the SC sub-assembly body which has mechanisms to hold the cable and fiber in place. The end of the ferrule protrudes out of the sub-assembly body to mate with another SC connector inside a mating sleeve (also called adapter or coupler).

3. The connector housing

Connector sub-assembly body is then assembled together with the connector housing. Connector housing provides the mechanism for snapping into a mating sleeve (adapter) and hold the connector in place.

4. The fiber cable

Fiber cable and strength member (aramid yarn or Kevlar) are crimped onto the connector sub-assembly body with a crimp eyelet. This provides the strength for mechanical handing of the connector without putting stress on the fiber itself.

5. The stress relief boot.

Stress relief boot covers the joint between connector body and fiber cable and protects fiber cable from mechanical damage. Stress relief boot designs are different for 900um tight buffered fiber and 1.6mm~3mm fiber cable.

How are Optic Fiber Made?

Many People ask how fiber optics are made. You can’t just use “regular” glass. If you were to make optical fiber from ordinary window glass, the light that you shine through it would have a difficult time traveling more than a few kilometers, let alone the distances necessary for long distance transmission. That’s because ordinary glass contains distortions, discolorations and other impurities that would quickly absorb, reflect, or otherwise disperse light long before it could travel any great distance.

In contrast, because optical fiber is actually made from very pure glass, the light traverses great distances largely unimpeded by impurities and distortions.

Fiber Optic Cable – Light How it Works

To transmit light effectively, fiber optic cable must contain glass of the highest purity. The process of making glass with this level of purity is very demanding, requiring careful control over the materials and processes involved. Yet, the fundamental concept is simple. Essentially, optical fiber is made from drawing molten fiber from a heated glass blank or “preform.” The following provides a more detailed explanation of the three basic steps involved in making optical fiber.

Step #1

Create the Fiber Optic Preform

A preform is a cylindrical glass blank that provides the source material from which the glass fiber will be drawn in a single, continuous strand.

Making a preform involves a chemical process known as Modified Chemical Vapor Deposition (MCVD). This process involves bubbling oxygen through various chemical solutions including germanium chloride (GeC14) and silicon chloride (SiC14).

The bubbling chemicals produce gas that is directed into a hollow, rotating tube made of synthetic silica or quartz. A torch is moved up and down the rotating tube, resulting in very high temperatures that cause the gas to react with oxygen to form silicon dioxide (Si02) and germanium dioxide (Ge02). These two chemicals adhere to the inside of the rotating tube where they fuse together to form extremely pure glass.

Creating the preform takes several hours, after which additional time is required for the glass blank to cool. Once cooled, the glass is tested to ensure that it meets quality standards, especially in terms of index of refraction.

Step #2

Draw Optical Fiber from the Preform

In this step, the finished glass preform is installed at the top of a tower which supports various devices used in the fiber drawing process.

The process begins by lowering one end of the preform into an in-line furnace that produces heat in a range of 3,400 to 4,000 degrees Fahrenheit. As the lower end of the preform begins to melt, it forms a molten glob that is pulled downward by gravity. Trailing behind the glob is a thin strand of glass that cools and solidifies quickly.

The equipment operator threads this glass strand through the remainder of the devices on the tower, which include a number of buffer coating applicators and ultraviolet curing ovens. Finally, the operator connects the fiber to a tractor mechanism.

The tractor device pulls the glass strand from the preform at a rate of 33 to 66 feet per second. The actual speed at which the tractor pulls the strand is dependent upon the feedback information the device receives from a laser micrometer that continually measures the fiber’s diameter.

At the end of the run, the completed fiber is wound onto a spool.

Step # 3

Test the Fiber Optics

The completed optical fiber must undergo a number of tests to determine the quality of the finished product. The following are a few of the assessments involved:

• Refractive index profile

• Fiber geometry inspection, including core, cladding and coating

• Tensile strength • Bandwidth capacity

• Attenuation at different wavelengths

• Chromatic dispersion

• Operating temperature and humidity range

Quality Control in Optical Fiber Production

Various factors influence the quality and purity of the optical fiber produced. These include: Chemical Composition – Achieving optimal ratios of the various chemicals used to create the preform is important for achieving glass purity. This mixture of chemicals also determines the optical properties of the fiber that will be produced from the preform, including coefficient of expansion, index of refraction, and so forth. Gas Monitoring – It is crucial that the gas composition and rate of flow be monitored throughout the process of creating the preform. It is also important that any valves, tubes and pipes that come into contact with the gas be made of corrosion-resistant materials.

Heat and Rotation – The hollow cylinder that is used to create the preform must be heated at the proper temperature and continually rotated to enable the chemicals to be deposited evenly.

Application of optical communication is still broad prospects

Once the Nortel global leader in fiber optic communications during the Internet bubble in 2000, the money in the acquisition of a large number of optical communications research and the production of small and medium enterprises, the industry has been criticized in the subsequent bankruptcy of Nortel. In fact, Nortel grasp of technology trends, the direction is right, unfortunately, Nortel too hasty, global demand for optical communication was not to such an extent.

But now the situation is very different compared with around 2000. The rapid development of mobile Internet and the widespread popularity of smart mobile terminal equipment, being a huge challenge to the global telecommunications network capacity, transmission speed. The era of “data flood peak to optical communication technology has always been known by the transmission bit of new development opportunities and a huge space. Optical communication technology not only did not fall behind, the contrary, the optical communication industry chain, from fiber optic cable system equipment, terminal equipment to optical devices, a critical period in the comprehensive technology upgrade.

The field of optical communication is a noteworthy event, the National Development and Reform Commission recently organizing the preparation of strategic emerging industries key products and services Guidance Catalogue, which in conjunction with the relevant departments, the optical communication technology and product responsibility and selected emerging industries of strategic focus products.

In fiber optics, including FTTx G.657 optical fiber, broadband long-distance high speed large capacity optical fiber transmission with G.656 optical fiber, photonic crystal fiber, rare earth doped fiber (including ytterbium doped fiber, erbium doped fiber and thulium doped fiber, etc.) the laser energy transmission fiber, and has some special properties of new optical fiber, plastic optical fiber, polymer optical fiber is fully finalists. The upgrade of the fiber optic technology, will bring the data transmission capacity, distance, quality leap.

In the field of fiber access equipment, passive optical network (PON), wavelength division multiplexer (WDM),OLT and ONU on the list. Optical transmission equipment, especially the line rate of 40 Gbit/s, 100Gbit/s large capacity (1.6Tb/s and abobe) DWDM equipment, reconfigurable optical bifurcation Multiplexer (ROADM) wavelength division multiplexing system ran cross-connect (OXC) equipment, large-capacity high-speed OTN optical transport network equipment as well as packetized enhanced OTN equipment, PTN packet transport network equipment also impressively. These products are “broadband China” works to promote a powerful weapon; both long-distance backbone network, metropolitan area network or access network even close to the user’s “last mile” of these products will come in handy.

The major products are classified as strategic emerging industries in the field of optical devices, high-speed optical components (active and passive). This is the core and foundation of the field of optical communication technology, device development, the improvement of integration, function enhancement can bring significantly reduce the cost of system equipment and provide a performance boost.

At the same time, the annual OFC / NFOEC (fiber-optic communications exhibition) will be held in late March in California. This event will showcase the latest technology and research progress of the global optical component modules, systems, networks and fiber optic products, represents a new trend of development of optical communication technology.

100G for ultra-high-speed network technology is the current OFC hot one. 2012 100G technology on a global scale backbone network level scale application of 100G optical network applications will rapidly expand with the 100G device further mature. In the same time, the industry has also increased efforts to develop the 100G optical modules, silicon photonics technology pluggable multi-source agreement 100G CFP MSA CPAK optical module has been available. Outside the backbone network, 100G MAN application is the current one of OFC discussion topic.

The rise of cloud computing brings data center construction boom, 100G technology in the data center is a popular data center for high-speed pluggable optical devices is also a hot topic. Experts believe that photonic technology has a key role to play in the large enterprise data centers, but this is only a start, the size of the new cloud computing data center such as a warehouse, with more than 100,000 servers carrying the computing and storage resources, the required network bandwidth than PB level. These data centers only optical communications technology in order to achieve VCSEL (vertical cavity surface emitting lasers) and multi-mode fiber has played an important role, and will continue to introduce new fiber optic communication technology.