ANALYSIS OF SHG IN A PLANAR DOUBLE WAVE-GUIDE STRUCTURE

The possibility of second harmonic generation (SHG) has been analysed for a system of two planar waveguides separated by a barrier. The system has been modelled for ion implanted planar waveguides in quartz. For this system the phase-matching condition can be met for the mode conversions TE0-omega --> TE2(2-omega) and Te0-omega --> TE3(2-omega). The efficiencies of SHG for the double structure are evaluated by calculating the normalized spatial coupling between the fundamental and harmonic field distributions. We show that the two parallel waveguide system increases the phase-matching possibilities, and depending on the dimensions of the system, it is possible to obtain at least 40% more SH power compared with that from a single well phase match. The influence on the nonlinear response of the barrier is discussed; since in principle, a double well structure with an active barrier could increase the SH power by 400% relative to the single well example.