Four Wave Mixing

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Four - Wave Mixing

• Adi Ben-Dor
• Herman Abel

January - 08, 2003
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FWM Overview

• FWM is generated by the intensity-dependent
  refractive index of the fiber.
• Exists in WDM systems with two or more channels.
• Depends strongly on dispersion.

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Mixing Product Power Estimation

• Peak power of the mixing products
• Efficiency is given

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Mixing Product Power Estimation (continue)

• Difference of propagation constants

• ?ß depends on
• Channel frequencies
• Local dispersion
• Dispersion slope

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Mixing Product Power Estimation (continue)

• If dispersion is low and all WDM channels have
  equal power, the formula is very simple

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Simple Example

• Three input channels (Dijk6)
• Leff 22 km, Aeff 55 µm2 , DSF (?01547.3
  nm)

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Simple Example (continue)
FWM as SNR penalty
Dispersion increases the ?ß and reduces penalty
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Reducing FWM penalty
A. Unequal channel spacing
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Reducing FWM penalty
B. Dispersion Management
Higher dispersion ? Lower FWM
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Our Experiment
DSF, ?0 1563.5 nm, Leff 13.26 km, Aeff 50
µm2
2 ITU channels (17,18) 100 GHz spacing
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Our Experiment (continue)
2 ITU channels (17,19) 200 GHz spacing