Editing Four-wave mixing (section)

=== Degenerate four-wave mixing ===

Four-wave mixing is also present if only two components interact. In this case the term

:<math> f_{0} = f_{1} + f_{1} - f_{2} </math>

couples three components, thus generating so-called '''degenerate four-wave mixing''', showing identical properties to the case of three interacting waves.<ref>{{Cite book|title=Advanced Optical Communication Systems and Networks|last=Cvijetic, Djordjevic|first=Milorad, Ivan B.|publisher=Artech House|year=2013|isbn=978-1-60807-555-3|pages=314 to 217}}</ref>