WDM is a technology which multiplexes multiple optical
carrier signals on a single optical fiber by using different wavelengths of laser light to carry different signals.
There are two types of WDM—
> Coarse WDM > Dense WDM
What is dwdm ?? > Dense wavelength division multiplexing (DWDM) is a technology that uses more than eight multiplexed signals to transmit many wavelengths of light simultaneously over a single optical fiber .
HISTORY OF DWDM :: 64 to 160 channels in 1550 nm window Next generation DWDM system Channel spacing of 0.2 to 0.4 nm 16 to 40 channels in 1550nm window DWDM (Dense wdm) Channel spacing of 0.8 to 1.6 2 to 8 channels in 1550nm window Passive (or) 2nd generation WDM Channel spacing of~ 3.2nm 2 channels WWDM (Wideband WDM) 1310nm & 1550nm Late 1990’s Mid 1990’s Early 1990’s 1980’s
A dwdm system:: *A basic DWDM system contains several main components: (a) A DWDM terminal multiplexer (b) An intermediate line repeater (c) An intermediate optical terminal (d) A DWDM terminal demultiplexer (e) Optical Supervisory Channel (OSC)
Wavelength converting transponders translate the transmitted
wavelength of a client-layer signal into one of the DWDM system's equivalent internal wavelengths.
In the mid-1990s,wavelength converting transponders rapidly took
on the additional function of signal regeneration. Signal regeneration in transponders quickly evolved through 1R to 2R to 3R . 1R 2R 3R Retransmission Re-time, Re-transmit Re-time, Re-transmit, Re-shape
When the network topology is a mesh ,an additional fibre
interconnection device is needed to route the signals from an input port to the desired output port.These devices are called optical crossconnectors(OCXs).Various categories of OXCs include electronic, optical, and wavelength selective devices.
The minimum frequency separation between two different
multiplexed signals is known as the Channel Spacing. Since the wavelength of operation is inversely proportional to the frequency, a corresponding difference is introduced in the wavelength of each signal.
DWDM-FM (95.5 MHz Metro Manila) was a music FM radio station
owned by Eagle Broadcasting Corporation in the Philippines. The station's studio was located in EDSA, Quezon City and its transmitter located at Commonwealth Avenue, Quezon City.
IP OVER DWDM :: * The problem: The explosive growth of the Internet spurred by high speed access networks and flat-rate mobile billing plans has caused ferocious competition in the telecom service provider market. * Solutions: One potential answer is IP over DWDM.
The requirements in the metropolitan market may differ in some
respects from those in the long-haul network market. > Some key requirements for DWDM systems in the MAN include the following---- • Multiprotocol support • Scalability • Reliability and availability • Openness (interfaces, network management, standard fiber types,electromagnetic compatibility) • Ease of installation and management • Size and power consumption • Cost effectiveness
It was first deployed on long-haul routes in a time of fiber scarcity.
Then the equipment savings made it the solution of choice for new long-haul routes, even when ample fiber was available. Alternatives for capacity enhancement exist, such as pulling new cable and SONET overlays, but DWDMcan do more.
From both technical and economic perspectives, the ability to provide
potentially unlimited transmission capacity is the most obvious advantage of DWDM technology. The current investment in fiber plant can not only be preserved, but optimized by a factor of at least 32. capacity can be obtained for the cost of the equipment, and existing fiber plant investment is retained.