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Basics

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Effective Susceptibility

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Effective Refractive Index

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Effective TransmissionLength

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Effective Cross-Sectionalarea

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Non Linear

Intensity-dependent

Change in refractive index with optical

intensity (Kerr-effect)

Inelastic scattering phenomena

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Four Wave Mixing

Polarization induces nonlinearities

Originates form 3rd order susceptibility

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Quantum-MechanicalContext Photons from one or more waves are

absorbed

New photons are created at differentfrequencies

Net energy and momentum remainsconserved

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Properties

Independent of bit-rate

Inversely dependent on channel spacingand fiber dispersion

Effective Area, Effective Fiber Length,Intensity of transmitted signal

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Drawbacks

Results in power transfer from onechannel to other

Degrades performance of channel (BERis increased)

Additional power required to betransmitted  – Power penalty

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Inter-channel crosstalk

Interference of information from one channel

to another

Degrades system performance

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FWM reduction

Introduction of chromatic dispersion

Group velocity mismatch

Less power transfer

Reduced penalty

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Applications

Wavelength Conversion

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Real Time Holographic Imaging

Two waves interfere to form a realimage

It is intensity dependent modulation

Spatial and phase information signals

Diffraction signal

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Advanced Topics

Image Processing

VUV laser (extreme coherent laser)