LAUSR

We report a new class of optical parametric oscillators, based on a 20-μm-long semiconductor photonic crystal cavity and operating at telecom wavelengths. Because the confinement results from Bragg scattering, the optical cavity contains a few modes, approximately equispaced in frequency. Parametric oscillation is reached when these high-quality-factor modes are thermally tuned into a triply resonant configuration, whereas any other parametric interaction is strongly suppressed. The lowest pump power threshold is estimated to be 50–70 μW. This source behaves as an ideal degenerate optical parametric oscillator, addressing the needs in the field of quantum optical circuits and paving the way towards the dense integration of highly efficient nonlinear sources of squeezed light or entangled photons pairs. Photonic crystal-based optical parametric oscillators have remained elusive but have finally been demonstrated. Operating at telecom wavelengths, the source may prove particularly useful in quantum optics applications.