Abstract

An angular coupling configuration is shown to facilitate phase-matched second harmonic generation between the TE₁ fundamental and TE₄ second harmonic modes of a LiNbO₃ planar waveguide. For an incident coupling angle of 10°, 2.6% coupling efficiency is achieved for the TE₁ waveguide mode, thus permitting visible light generation at the wavelength of 402.4 nm through phase-matching to the TE₄ second harmonic mode. For a 2.8 mm-long LiNbO₃ planar waveguide excited at an energy of 1.8 nJ, the second harmonic generation conversion efficiency is 4.6 × 10⁻⁵. The ability of this angular coupling scheme to facilitate phase-matched frequency-conversion makes it ideal for use in optical computing, optical communications, and quantum computing.

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