All Optical NetworksSamir Chatterjee & Suzanne Pawlowski

Presenter: Pengfei Liu

Outline

To present a general overview of optical networks;

To discuss how all-optical networks can be integrated into existing and future broadband network architectures;

All-optical

Current fiber networks use electronic switching and are therefore limited to electronic speeds of a few gigabits per second. For higher speeds, it is important that the signal remain photonic throughout its path. Such networks, which use optical switching and routing, are called all-optical.

Drivers for Optical Networks

Internet and Web browsing.Bandwidth requirement *8

More users

Response time

Graphics and visualization.2000*2000 12-bit color pixels/frame & 24 frame/sec

adds up to 1Gbps

Drivers for Optical Networks

Medical image access and distribution.

Multimedia conferencing.Video: 10-40Mbps HDTV

2-6Mpbs MPEG

Broadband services to the home.

Optical Transmission System

Three basic elementsLight Source: infrared light-

emitting diodes( LEDs ) or Injection Laser

diodes( ILDs )

Transmission medium:single-mode or multimode fi

ber, ultra-thin glass fiber.

Detector: photodiode and phototransistor

Optical fiber principles

Central core, surrounded by a cladding layer, which is covered by protective jacket

ray of light travels through by reflecting along the interface between the two transparent mediums.

Optical fiber principles

Total Internal ReflectionTotal internal reflection causes the light to be guided down the fiber. Total internal reflection is directly related to the fact that the refractive index of the cladding( n1 ) is less than the refractive index of the core( n2 ).

n1 < n2

Optical Networking Technology

Erbium-doped fiber amplifier( EDFA )Optical signals are regenerated electronically to overcome the attenuation inherent in the silica fiber as well as other losses due to optical components along the line.

Optical Networking Technology

Wavelength division multiplexing(WDM)

All-optical networks

Tree dominant types of optical networks

All-optical networks

All-optical networks

Optical Services

Network services are provided in the form of layers of various protocols.

Optical Services

UNI( User Network Interface )

ON( Optical Network )

Circuits (POTS, T-1, SONET),

Datagram (IP with its best-effort service)

Virtual circuits (frame-relay and ATM).

Conclusion

Briefly reviewed the state of the technology and possible future directions for fiber-optic networks.

There’s still a long way to go.

End of Presentation