EE DD FF AA

Seminar By:

Geno G James

EE-566

Optical Communication

What is EDFA

• Type of Optical amplifier• Stands for “Erbium Doped Fiber Amplifier”• Used to boost the intensity of optical signals being carried

through a fiber optic communications system • Has a fiber whose core is heavily doped with Erbium ions• Works on the concept of stimulated emission• Operates in the C band (1530-1560) and L band (1570-1610)

Origin of EDFA (Who, When and Where)

• Prof.David Payne and team• Published the research paper in the

year 1987• At the University of Southampton,

UK

Why Erbium?

• Erbium has several important properties that make it an excellent choice for an optical amplifier

• Erbium ions (Er3+) have quantum levels that allows them to be stimulated to emit in the 1540nm band, which is the band that has the least power loss in most silica-based fiber.

• Erbium's quantum levels also allow it to be excited by a signal at either 980nm or 1480nm, both of which silica-based fiber can carry without great losses

How it works

• Energy band of Erbium

Demo

Basic block diagram of EDFA

Block diagram of EDFA

• Copropogating Pump EDFA

Block diagram of EDFA

• Counterpropogating Pump EDFA

Characteristics of EDFA

• Gain and Noise

Characteristics of EDFA (Contd….)

Characteristics of EDFA (Contd….)

Advantages

• Commercially available in C-band & L-band

• Insensitivity to light polarization state

• High gain

• Low noise figure: 4.5 dB to 6dB

• No distortion at high bit rates

• Simultaneous amplification of wavelength division multiplexed signals

• Immunity to cross talk among wavelength multiplexed channels

Advantages (Cont…)

• Do not require high speed electronics• Independent of bit rate (Bit rate transparency)

Drawbacks

• Pump laser necessary• Need to use a gain equalizer for multistage amplification• Difficult to integrate with other components• Dropping channels can give rise to errors in surviving channels

Companies

• You name them………. and they are there

References

• DWDM Fundamentals, Components and Applications by Jean-Pierre Laude

• Fiber Optic Communication Technology by Djafar K.Mynbaev and Lowell L.Scheiner

• www.soton.ac.uk • www.photon-x.net/tech/edfa.htm • www.webopedia.com

• www.mse.vt.edu

Thank You