Phase-matched frequency conversion in waveguides by means of transverse wavevector projections

Abstract

We present a versatile technique for modal phase-matched second-harmonic generation in a waveguide, which relies on the incident electromagnetic field having transverse wavevector components on the input facet of the waveguide. Such a requirement is satisfied by using an angular-coupling arrangement, which allows for the excitation of modes having an odd spatial distribution that contribute to modal phase-matched second-harmonic generation. The strength of the second-harmonic signal is directly related to the angle at which the incident field is coupled into these modes. This is critical for on-chip nonlinear frequency conversion processes in the areas of optical communication, optical computing, and quantum computing.