Optical Fiber Communications 4th Edition by Gerd Keiser

Exercise 5

Consider three copropagating optical signals at frequencies V₁, v 2 , and v 3.
( a ) If these frequencies are evenly spaced so that V₁= v 2 - v and v 3 = v 2 + v , where v is an incremental frequency change, list the third-order waves that are generated due to FWM and plot them in relation to the original three waves. Note that several of these FWM-generated waves coincide with the original frequencies.
( b ) Now examine the case when V₁= v 2 - v
and Find the FWM- generated frequencies and plot them in relation to the original three waves.