Patent ID: 7106496

Claim:
An element for wavelength conversion and/or optical computing, the element comprising: a nonlinear optical crystal; and a periodically-poled structure formed on the nonlinear optical crystal for converting an incident light into an outgoing light by wavelength conversion and/or optical computing, wherein group velocity matching conditions synchronize a group velocity of the incident light with a group velocity of the outgoing light, and a polarization reversal period of the periodically-poled structure satisfies quasi-phase matching conditions for the wavelength conversion and/or optical computing, the nonlinear optical crystal has an optical constant of d 31 which is an off-diagonal component of d 31 , tensor, the polarization reversal period satisfies quasi-phase matching of the off-diagonal component d 31 , and the nonlinear optical crystal is adapted to receive the incident light having a polarized light direction that is perpendicular to a z-axis of nonlinear optical crystal, the nonlinear optical crystal is adapted to output the outgoing light having a polarized light direction that is parallel to the z-axis of the nonlinear optical crystal, and the group velocity of the incident light and the group velocity of the outgoing light are the same to achieve group velocity matching.