A Seminar On

Dense Wavelength Division Multiplexing (DWDM)

Presented BY –ANSH YADAVCSE 3rd Year

Contents

• Definition What is DWDM?• Component of DWDM• How It Works?• Benefits of DWDM• Application• Conclusion

What is DWDM?:

Definition- Dense wavelength division multiplexing (DWDM) is a technology that puts data from different sources together on an optical fiber, with each signal carried at the same time on its own separate light wavelength.

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 .

Components of DWDM

• Optical Fiber.• DWDM Terminal Multiplexer.• Intermediate Line Repeater.• DWDM Terminal De-Multiplexer.• Optical Supervisory Channel (OSC).

Optical Fiber• An optical fiber is a flexible, transparent fiber

made of extruded glass (silica) or plastic, slightly thicker than a human hair.

• It can function as a waveguide, or “light pipe”, to transmit light between the two ends of the fiber.

Working Principle

• Its work on total internal reflection.

DWDM Terminal Multiplexer

The terminal multiplexer actually contains one wavelength converting transponder for each wavelength signal it will carry. The wavelength converting transponders receive the input optical signal (i.e., from a client-layer or other signal), convert that signal into the electrical domain and then retransmit the signal using a band laser.

Intermediate Line Repeater

It is placed approx. every 80 – 100 km for compensating the loss in optical power, while the signal travels along the fiber. The signal is amplified by an EDFA which usually consists of several amplifier stages.

DWDM Terminal De-Multiplexer

The terminal de-multiplexer breaks the multi-wavelength signal back into individual signals and send its outputs on separate fibers for client-layer systems to detect. Originally, this de-multiplexing was performed entirely passively, except for some telemetry as most SONET systems can receive 1550-nm signals

Optical Supervisory Channel

This is an additional wavelength usually outside the EDFA amplification band. The OSC carries information about the multi-wavelength optical signal at the optical terminal. It is also normally used for remote software upgrades, user and Network Management information.

Block Diagram of DWDM

How It WorksDWDM fiber works by combining and transmitting multiple signals simultaneously at different wavelengths on the same fiber. In effect, one fiber is transformed into multiple virtual fibers.

A DWDM the system performs the following main functions:-

• Combining the signals.• Generating the signal.• Transmitting the signals.• Separating the received

signals.• Receiving the signals.

Conti..

In addition to these functions, a DWDM system must also be equipped with client-side interfaces to receive the input signal.

Benefits Of DWDM• Capacity increase : Large aggregate transmission

capacity. • Upgradability : Customer growth without requiring

additional fiber to be laid.• Scalability : The possibility to add new nodes to the

network.• Network Transparency : Independence of data rate,

format & protocols.

Application DWDM is ready made for long-distance

telecommunications operators that use either point-to-point or ring topologies.

Building or expanding networks Network wholesalers can lease capacity,

rather than entire fibers. The transparency of DWDM systems to

various bit rates and protocols. Utilize the existing thin fiber DWDM improves signal transmission

Conclusion• Robust and simple design• Works entirely in the Optical domain• Multiplies the capacity of the network many fold• Cheap Components• Handles the present BW demand cost effectively• Maximum utilization of untapped resources• Best suited for long-haul networks

Thank You!Queries ?