Multiwavelength Effects: Coupled NLSE and Degenerate FWM

This lecture delves into the details of Four-Wave Mixing (FWM) using the coupled Nonlinear Schrödinger Equation (NLSE) and explores the case of non-depleted degenerate FWM. Starting with the simplifications of the coupled wave equations, the instructor explains the assumptions made for intense and un-depleted pump waves, identical transverse modes, and nonlinear coefficients. The lecture progresses to solving the coupled NLSE equations and discussing the implications of phase matching for maximizing the FWM process. Illustrations with degenerate cases and considerations for mismatch due to material dispersion are provided, along with an experimental illustration of FWM. The session concludes with a quiz on determining the pump power for phase matching in degenerate FWM.