Wavelength division <br />Multiplexing :<br /><ul><li>WDM is a technology which multiplexes multiple optical </li></ul> carrier signals on a single optical fiber by using different<br /> wavelengths of laser light to carry different signals.<br /><ul><li>There are two types of WDM—</li></ul> > Coarse WDM<br /> > Dense WDM<br />
What is dwdm ??<br />> Dense wavelength division multiplexing (DWDM) is a<br /> technology that uses more than eight multiplexed signals<br /> to transmit many wavelengths of light simultaneously<br /> over a single optical fiber .<br />
HISTORY OF DWDM ::<br />64 to 160 channels in 1550 nm window<br />Next generation DWDM system<br />Channel spacing of 0.2 to 0.4 nm<br />16 to 40 channels in 1550nm window<br />DWDM (Dense wdm)<br />Channel spacing of 0.8 to 1.6<br />2 to 8 channels in 1550nm window<br />Passive (or) 2nd generation WDM<br />Channel spacing of~ 3.2nm<br />2 channels WWDM (Wideband WDM)<br />1310nm & 1550nm<br />Late<br />1990’s<br /> Mid <br />1990’s<br /> Early<br /> 1990’s <br />1980’s<br />
A dwdm system::<br />*A basic DWDM system contains several main components:<br />(a) A DWDM terminal multiplexer<br />(b) An intermediate line repeater <br />(c) An intermediate optical terminal<br />(d) A DWDM terminal demultiplexer<br />(e) Optical Supervisory Channel (OSC)<br />
Itu-tg ::<br /><ul><li> ITU standards suggest that the OSC should utilize an OC-3 signal </li></ul> structure, though some vendors have opted to use 100 megabit <br /> Ethernet or another signal format.<br /><ul><li>Transponders in some systems supporting 40 GHz nominal operation</li></ul> may also perform forward error correction (FEC) via 'digital wrapper' <br /> technology, as described in the ITU-TG.709 standard.<br /><ul><li>Through ITU-TG.694.1frequency grid , it is easier to integrate WDM </li></ul> with older but more standard SONET/SDH systems.<br />
WAVELENGTH <br />CONVERTING TRANSPONDERS ::<br /><ul><li>Wavelength converting transponders translate the transmitted </li></ul> wavelength of a client-layer signal into one of the DWDM system's<br /> equivalent internal wavelengths.<br /><ul><li>In the mid-1990s,wavelength converting transponders rapidly took </li></ul> on the additional function of signal regeneration. <br /> Signal regeneration in transponders quickly evolved through 1R <br /> to 2R to 3R .<br />1R 2R 3R<br /> Retransmission Re-time, <br /> Re-transmit <br />Re-time,<br />Re-transmit,<br />Re-shape<br />
RECONFIGURABLE OPTICAL <br />ADD-DROP MULTIPLEXER ::<br /><ul><li> Intermediate optical amplification sites in DWDM systems may allow </li></ul> for the dropping and adding of certain wavelength channels. Adding or <br /> dropping wavelengths requires manually inserting or replacing <br /> wavelength-selective cards.<br />
OPTICAL CROSS CONNECTS::<br />(OXC)<br /><ul><li> When the network topology is a mesh ,an additional fibre </li></ul> interconnection device is needed to route the signals from an input <br /> port to the desired output port.These devices are called optical <br />crossconnectors(OCXs).Various categories of OXCs include electronic,<br /> optical, and wavelength selective devices.<br />
CHANNEL SPACING ::<br /><ul><li> The minimum frequency separation between two different </li></ul> multiplexed signals is known as the Channel Spacing. Since the <br /> wavelength of operation is inversely proportional to the frequency, <br /> a corresponding difference is introduced in the wavelength of each <br /> signal.<br />
CATeGORIES OF WAVELENGTH<br />SWITCHeS::<br /><ul><li> Non-reconfigurable switch.
DWDM , ideally it should have additional optical switching capability</li></ul> to implement dynamically reconfigurable interconnections necessary<br /> for the next generation systems. <br />
SONET WITH DWDM ::<br /><ul><li> By using DWDM as a transport for TDM, existing SONET equipment</li></ul> investments can be preserved. Often new implementations can <br /> eliminate layers of equipment.<br />SONET<br />TERMINAL<br />WDM<br />OC-n<br />FIBER<br />OC-48C<br />ATM<br />SWITCH<br />OC-48C<br />LAYER -3<br />SWITCH<br />
DWDM-FM ::<br /><ul><li> DWDM-FM (95.5 MHz Metro Manila) was a music FM radio station </li></ul>owned by Eagle Broadcasting Corporation in the Philippines. The <br />station's studio was located in EDSA, Quezon City and its transmitter <br /> located at Commonwealth Avenue, Quezon City.<br />
IP OVER DWDM ::<br />* The problem: The explosive growth of the Internet spurred by high <br /> speed access networks and flat-rate mobile billing plans has caused <br /> ferocious competition in the telecom service provider market.<br />* Solutions: One potential answer is IP over DWDM.<br />
REQUIRMENTS IN THE<br /> METROPOLITAN AREA ::<br /><ul><li> The requirements in the metropolitan market may differ in some</li></ul> respects from those in the long-haul network market. <br /> > Some key requirements for DWDM systems in the MAN include <br /> the following----<br /> • Multiprotocol support<br /> • Scalability<br /> • Reliability and availability<br /> • Openness (interfaces, network management, standard fiber<br />types,electromagnetic compatibility)<br /> • Ease of installation and management<br /> • Size and power consumption<br /> • Cost effectiveness<br />
VALUE OF DWDM IN <br />METROPOLITAN AREA ::<br /><ul><li>It was first deployed on long-haul routes in a time of fiber scarcity.</li></ul>Then the equipment savings made it the solution of choice for new<br />long-haul routes, even when ample fiber was available. Alternatives <br />for capacity enhancement exist, such as pulling new cable and SONET<br />overlays, but DWDMcan do more.<br />
WHY DWDM ??<br /><ul><li>From both technical and economic perspectives, the ability to provide</li></ul> potentially unlimited transmission capacity is the most obvious<br /> advantage of DWDM technology. The current investment in fiber plant <br /> can not only be preserved, but optimized by a factor of at least 32.<br /> capacity can be obtained for the cost of the equipment, and existing <br />fiber plant investment is retained.<br />
benefits OF DWDM ::<br /><ul><li> Capacity increase : Large aggregate transmission capacity.
Upgradability : Customer growth without requiring additional fiber</li></ul> to be laid.<br /><ul><li>Flexibility : Optical Add/Drop Multiplexing (OADM)</li></ul> Optical Cross connect (OXC)<br /><ul><li> Scalability : The possibility to add new nodes to the network.
Network Transparency : Independence of data rate, format &</li></ul> protocols. <br />