Second-harmonic generation in a periodic structure made from N pairs of optically contacted, birefringence phase-matched, walk-off-compensating bulk plates is theoretically investigated. In the undepleted-pump approximation, analytical (heuristic) expressions for conversion efficiency versus N are derived for both type I and type II phase matching. An explicit split-step beam propagation scheme that solves exactly the coupled paraxial-wave equations is used to check the validity of the heuristic results. For type II, stronger conversion enhancement than for bulk crystal is predicted in the low-depletion regime, whereas for type I such structures avoid harmonic beam ellipticity. The periodic structures are found to behave as nonlinear harmonic birefringent filters because of the presence of periodic wave-vector mismatch grating ±Δk that results from walk-off compensation. The effect of periodicity imperfections, such as residual plate orientation mismatches, was found to be responsible for broadening of the tuning bandwidth in walk-off-compensating devices.
© 2003 Optical Society of America
(190.2620) Nonlinear optics : Harmonic generation and mixing
(190.4360) Nonlinear optics : Nonlinear optics, devices
(260.1180) Physical optics : Crystal optics
(260.1440) Physical optics : Birefringence
(350.5500) Other areas of optics : Propagation
Jean-Jacques Zondy, Christophe Bonnin, and Dominique Lupinski, "Second-harmonic generation with monolithic walk-off-compensating periodic structures. I. Theory," J. Opt. Soc. Am. B 20, 1675-1694 (2003)