Periodic Structures For Phase-Matching In Second Harmonic Generation In Titanium Lithium Niobate Wave Guides

Use of periodic modulation of lithium niobate waveguide properties to achieve phase-matching for second harmonic generation has been investigated both theoretically and experimentally. The mathematical description has been reduced to the same form of differential equations as for the unperturbed case, but with a modified coupling coefficient. A compact expression for the conversion efficiency has been derived for the case when simultaneous modulation of both the linear and nonlinear properties are taken into account. For the case of modulation of only the linear properties, second harmonic light has been obtained experimentally.