Raman-effect induced noise limits on χ(3) parametric amplifiers and wavelength converters

Paul L. Voss*, Prem Kumar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


The non-zero response time of the Kerr (χ(3)) nonlinearity determines the quantum-limited noise figure of χ(3) parametric amplifiers and wavelength converters. This non-zero response time of the nonlinearity requires coupling of the parametric amplification process to a molecular-vibration phonon bath, causing the addition of excess noise through Raman gain or loss. The effect of this excess noise on the noise figure of the amplifier can be significant. We derive analytical expressions for this quantum-limited noise figure in the case of non-degenerate phase-insensitive operation of a χ(3) parametric amplifier and show excellent agreement with experiment without any fitting parameter. We also derive analytical expressions for the quantum limited noise figure for χ(3)-based wavelength converters.

Original languageEnglish (US)
Pages (from-to)S762-S770
JournalJournal of Optics B: Quantum and Semiclassical Optics
Issue number8
StatePublished - Aug 2004


  • Four-wave mixing
  • Optical amplification
  • Optical parametric amplification
  • Quantum fluctuation
  • Raman amplification

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physics and Astronomy (miscellaneous)


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