What is Known as Fiber to the X

Fiber To The X (FTTx) is different from a traditional fiber optic network that would be used for a local area network (LAN) application. In most FTTX applications, only one optical fiber is used. That single optical fiber passes data in both directions. This is very different from a LAN application where the transmit optical fiber sends data in one direction and the receive optical fiber sends data in the other direction. In a LAN application, both optical fibers can have data passing through them at the same time.

In an FTTX single optical fiber application, full-duplex operation is typically not possible; Usually only half-duplex operation takes place. This means that part of the time the optical fiber is carrying a signal in one direction, and the rest of the time, it is carrying a signal in the other direction.

FTTx systems typically use multiple wavelengths. The downstream laser is always a different wavelength than the upstream laser. The downstream is typically the longer wavelength, such as 1480nm or 1550nm (or both), and the upstream laser is typically 1310nm.

FTTX is possible with optical fiber distances up to 20km because optical fiber is capable of transmitting information with a very low level of loss. The typical loss for an FTTX optical fiberat 1550nm is 0.25dB/km and 0.35dB/km at 1310nm.

Figure 1 A schematic illustrating how FTTX architectures vary — with regard to the distance between the optical fiber and the end-user

Fiber To the Home

A fiber-to-the-home (FTTH) PON uses optical fiber from the central office to the home; At the home, a converter box changes the optical signal from the optical fiber into electrical signals. Theconverter box interfaces with existing home cabling such as coaxial cabing for cable TV, twisted-pair cabling for telephone, and Category 5e or 6 cabling for Internet connectivity.

Fiber to the Building

A fiber-to-the-building (FTTB) PON is very similar to an FTTH PON. It uses optical fiber from the central office to the building and there are no electronics helping with transmission in between. The ptical signal from optical fiber is converter into electrical signals in a converter box at the building. The converter box interfaces with existing cabling such as coaxial cabling for cable TV, twisted-pair cabling for telephone, and Category 5e or 6 cabling for Internet connectivity.

Fiber optic setups enable higher speeds of delivery and greater bandwidth than some other kinds of infrastructure. Some of the fiber networks deploying signals to the most sophisticated equipment can benefit from a multimode fiber connection, where a specific kind of fiber optic cable may be used for optimal speed.

Fiber to the Curb

"Fiber to the curb" (FTTC) refers to the installation and use of Fiber Optical Cable directly to the curbs near homes or any business environment as a replacement for "plain old telephone service" (POTS). In a fiber-to-the-curb PON, optical fiber runs from the central office and stops at the curb. The "curb" may be right in front of the house or some distance down the block. The converter box is located where the optical fiber stops, and it changes the optical signal from the optical fiber into electrical signals. These electrical signals are usually brought into the home through the existing copper cabling. The electrical signal may need to be processed by another converter in interface with existing twisted pair cabling for phone, and cat 5e or 6 cabling for Internet connectivity.

Fiber to the Node

Fiber to the node (FTTN) is sometimes referred to as fiber to the neighborhood. A FTTN PON only has optical fiber from the central office to the node. The node is typically telecommunications cabinet that serves a neighborhood or section of a neighborhood. The optical signal from the optical fiber is converted into electrical signals inside the telecommunications cabinet. These electrical signals are distributed throughout the neighborhood through existing copper cables to the houses.

One of the main benefits of fiber to the node and similar systems is the ability to deliver data over more efficient fiber optic lines, rather than other lines with greater speed restrictions. The remaining area from the node to an individual destination, often called "last mile" service, can be achieved with copper or other types of wire. FTTN systems often use coaxial or twisted-pair cable in order to achieve delivery to multiple customers.

The Major Outside Plant Components for an FTTX PON

The outside plant components make up the PON infrastructure and are all designed for installation exterior to buildings. The cables connect different access points in the PON. Everything is initiated from the central office or central switching point.

* Cables

There are feeder, distribution, and drop cables are employed in an FTTX PON.

Feeder cables: Feeder cables run from the central switching point to the local convergence point. These cables typically contain multiple ribbons of 12 single mode optical fibers each. A common feeder cable will contain 18 ribbons for a total of 216 single mode optical fibers.

Distribution cable: Distribution cables run from the local convergence point to the network access point. A distribution cable can have as few as 12 optical fibers or as many as 144. A typical distribution cable has 72 optical fibers.

Drop Cables: A drop cable is a single optical fiber cable that is terminated at the factory, typically with SC connectors on both ends. The cable is environmentally sealed and the connectors are sealed when they are mated.

Figure 2 shows sc connector

* Local Convergence Point

The local convergence point (LCP) is the access point where the feeder cables are broken out into multiple distribution cables. Depending on the architecture of the PON, the local convergence point may or may not be the place where the optical signals are split. The optical signals may be split at the network access point with a Fiber Splitter like the one shown in Figure.

Figure 3 shows optical fiber field rated local convergence cabinet

Figure 4 shows optical splitter

* Network Access Point

The network access point (NAP) is located close to the homes or buildings it services. This is the point where a distribution cable is broken out into multiple drop cables. The NAP is a terminal that serves as a connection point for drop cables. The NAP is a terminal that serves as a connection point for drop cables. It may be installed in an aerial installation, in a pedestal, or in a hand hole.

* Network Interface Device

The drop cable runs from the NAP to the network interface device (NID). The NID is typically mounted to the outside of the house or building. It is an all-plastic enclosure designed to housethe electronics that support the network. The SC connector on the end of the drop cable mateswith the connector in the NID.

What are the Advantages and Disadvantages of Fiber Optic Cabling

Fiber optic cabling consists of strands of purified glass, or even plastic, rods that conduct specific wavelengths of light, analogous to the electrons carried along a Network Cables. However, light traveling through glass or plastic is not susceptible to the same problems that metal conductors are; The electromagnetic radiation that results from current traveling through a wire is not present in optical conductors, and optical conductors can be made much smaller than metal ones.

Advantages of Fiber Optic Cabling

There are four advantages of fiber optic cabling, these advantages explain why fiber is becoming the preferred network cabling medium for high bandwidth, long-distance applications:

1. Immunity to Electromagnetic Interference (EMI)

All copper cable network media sharing a common problem: they are susceptible to electromagnetic interference (EMI), fiber optic cabling is immune to crosstalk because optical fiber does not conduct electricity and uses light signals in a glass fiber, rather than electrical signals along a metallic conductor to transmit data. So it cannot produce a magnetic field and thus is immune to EMI.

2. Higher Possible Data Rates

Because light is immune to interference, can be modulated at very high frequencies, and travels almost instantaneously to its destination, much higher data rates are possible with fiber optic cabling technologies than with traditional copper systems. Data rates far exceeding the gigabit per second (Gbps) range and higher are possible, and the latest IEEE standards body is working on 100Gbps fiber based applications over much longer distances than copper cabling. Multimode is preferred fiber optic type for 100-550 meters seen in LAN network, and since single mode fiber optic cables are capable of transmitting at these multi-gigabit data rates over very long distances, they are the preferred media for transcontinental and oceanic applications.

3. Longer Maximum Distances

Typical copper media data transmission by the distance limits the maximum length of less than 100 meters. Because they do not suffer from the electromagnetic interference problems of traditional copper cabling and because they do not use electrical signals that can dramatically reduce the long distance, single-mode fiber optic cables can span 75 kilometers (about 46.6 miles) without using signal-boosting repeaters.

4. Better Security

The Copper cable transmission media is susceptible to eavesdropping through taps. A tap (short for wiretap) is a device that punctures through the outer jacket of a copper cable and touches the inner conductor. The tap intercepts signals sent on a LAN and sends them to another (unwanted) location. Electromagnetic (EM) taps are similar devices, but rather than puncturing the cable,they use the cable’s magnetic fields, which are similar to the pattern of electrical signals. Because fiber optic cabling uses light instead of electrical signals, it is immune to most types of eavesdropping. Traditional taps won’t work because any intrusion on the cable will cause the light to be blocked and the connection simply won’t function. EM taps won’t work because no magnetic field is generated. Because of its immunity to traditional eavesdropping tactics, fiber optic cabling is used in networks that must remain secure, such as government and research networks.

Disadvantages of Fiber Optic Cabling

With all of its advantages, many people use fiber optic cabling. However, fiber optic cabling does have a couple of disadvantages:

1. Higher Cost

The higher cost of fiber optic cabling has little to do with the cable these days. Increases in available Fiber Optical Cable manufacturing capacity have lowered cable prices to levels comparable to high end UTP on a per-foot basis, and the cables are no harder to pull. Ethernet hubs, switches, routers, NICs, and patch cords for UTP are very inexpensive. A high quality UTP-based 10/100/1000 auto-sensing Ethernet NIC for a PC can be purchased for less than $25. A fiber optic NIC for a PC costs at least four times as much. Similar price differences exist for hubs, routers, and switches. For an IT manager who has several hundred workstations to deploy and support, that translates to megabucks and keeps UTP a viable solution. The cost of network electronics keeps the total system cost of fiber-based networks higher than UTP, and ultimately, it is preventing a mass stampede to fiber-to-the-desk.

2. Installation

The other main disadvantage of fiber optic cabling is that it can be more difficult to install. Copper cable ends simply need a mechanical connection, and those connections don't have to be perfect. Fiber optic cable can be much trickier to make connections for mainly because of the nature of the glass or plastic core of the fiber cable. When you cut or cleave (in fiber optic terms) the fiber, the unpolished end consists of an irregular finish of glass that diffuses the light signal and prevents it form guiding into the receiver correctly. The end of the fiber must be polished and a special polishing tools to make it perfectly flat so that the light will shine through correctly.

Figure shows the difference between a polished and an unpolished fiber-optic cable end

Higher Data Throughput From Multimode Fiber Patch Cables

Information available at our fingertips in form of digital data today has swelled up to levels which had never been before. At the same time, real time communication has exponentially increased to extremely high levels. A whole class of applications have emerged that demand for transmission of high-speed data.

Necessity may be the mother of invention – optical fiber networks have been invented and deployed to solve the problem of high volume data exchange. And multimode fiber patch cables have grown to be the very first choice one of the different connectors of the wired carriers with endpoint devices.

What are the speed-hungry and volume-hungry data centric applications that have created this entire demand? Some examples of those applications are the Internet, the local area multi-computer networks, the phone networks and the ATM networks. There are many more applications with intense hunger for fast communication resources. For those practical purposes, these communication channels need a high-speed network that can carry enormous volumes of data with minimal attenuation and extreme accuracy. The modern fiber optic cable technology provides exactly this sort of communication.

The multimode patch cables are used to connect this data transmitted over the network towards the devices that they target to cater. These patches may also be used to connect the two loose ends of two fiber optic cables. The patch cables have to be multimode when the requirement is to support multimode optical fibers.

What is a multimode cable poor fiber optics? A multimode is one in which multiple packets of data can be simultaneously carried across the wire. The result is that the network can carry numerous data packets at a instant of time. The multimode mainline network cables are usually short long since the target with these cables is to support high speed and high power multiuser systems in a localized sense. The patches are compatible with the network cables to enable the machine remain aligned with the network objectives. Consequently the multimode patches support multiple user applications transferring data simultaneously, as well as retain the qualities of standard single mode patches like the high network speed, low network hindrances and occasional external interferences.

It’s also interesting to note that the end point devices these patch cables connect can be heterogeneous in nature. The aperture the end point device requires and types of applications supported may be diverse. There exist several different kinds of multimode fiber patch cables you can use based upon the requirements. And depending upon the exact reason why you have to install the patch on your fiber optic network, you shall need to select your patch and go ahead with the required installation.

Source: http://www.fiberstore.com/