Second harmonic generation in composite waveguides (A)

Second harmonic generation in optical waveguides has been demonstrated using (1) a nonlinear guide and substrate,1 (2) a nonlinear guide on a linear substrate,2 (3) a linear guide on a nonlinear substrate with the harmonic coupled back into the guide,3 and (4) a linear guide on a nonlinear substrate with the harmonic generated as Cerenkov radiation.4