Cavity-Enhanced Harmonic Generation In Silicon Rich Nitride Photonic Crystal Microresonators

We report second and third harmonic generation in photonic crystal cavities fabricated in a suspended silicon-rich nitride membrane under resonant continuous-wave excitation at telecom wavelength. Two-dimensional photonic crystal cavities with a far-field optimized line-width modulated design were employed. A quality factor at fundamental wavelength as high as Q = 1.3 x 10(4) and a coupling efficiency eta(c) approximate to 30% enabled us to exploit the cavity field enhancement to achieve the generation efficiencies rho(SH) = (4.7 +/- 0.2) x 10(-7) W-1 and rho(TH) = (5.9 +/- 0.3) x 10(-5) W-2. The absence of saturation effects at high power and the transparency of the device at the second harmonic wavelength suggest the absence of two-photon absorption and related detrimental effects. (C) 2019 Author(s).