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We report the design, fabrication, and characterization of a photonic crystal microresonator exhibiting a constant free spectral range. More than 50 resonances with Q > 2 × 105 are observed in a 200 μm long and 650 nm wide III–V semiconductor cavity heterogeneously integrated on a silicon photonic circuit (Silicon on Insulator). We measured stimulated four wave mixing with a −12 dB signal to idler conversion. Two photon absorption is prevented owing to the wide electronic bandgap of the III–V semiconductor (indium gallium phosphide) enabling the possibility to use sufficiently large optical power densities for efficient nonlinear parametric interactions. [ABSTRACT FROM AUTHOR]

In a GaAs crystal, owing to the anomalous dispersion introduced by optical phonon absorption, a phase-matched interaction is possible between a near-infrared beam and a terahertz (THz) wave. We exploit this nonlinear optical process to allow the merging of THz-quantum-cascade-laser and telecom technologies by injecting a telecom beam into a suitably designed THz quantum-cascade laser. Within the optical cavity, the phase and amplitude of the THz wave are recorded onto the near-infrared beam, which can be transported through an optical fibre. We show that the process is phase-matched and can be tuned over the entire telecom range by waveguide engineering. This nonlinear up-conversion technique opens up new possibilities in the optical treatment of THz, by taking advantage of the highly developed telecom technology. [ABSTRACT FROM AUTHOR]

We demonstrate experimentally that the fiber to fiber total insertion loss into a single-mode waveguide in a suspended photonic crystal membrane can be reduced to less than 10 dB (input, output, and propagation) without introducing any supplementary processing step (e.g., polymer deposition and etching). This is achieved through a suitable design of the waveguide end-facets minimizing the impedance mismatch and thereby the residual reflectance at the waveguide ends. [ABSTRACT FROM AUTHOR]

We demonstrate all-optical modulation based on ultrafast optical carrier injection in a GaAs photonic crystal cavity using a degenerate pump-probe technique. The observations agree well with a coupled-mode model incorporating all relevant nonlinearities. The low switching energy (∼120 fJ), small energy absorption (∼10 fJ), fast on-off response (∼15 ps), limited only by carrier lifetime, and a minimum 10 dB modulation depth suggest practical all-optical switching applications at high repetition rates. [ABSTRACT FROM AUTHOR]

The authors propose highly resolved optical low-coherence reflectometry for investigating low-loss photonic crystal slab waveguides. This technique allows a fast, reliable, and straightforward measurement of the group delay and propagation losses for both TE and TM polarizations. The agreement with theory is very good. These measurements reveal effects related to structural disorder. The versatility and deep physical insight of this measurement technique will play a key role in the study of slow-light devices such as photonic crystal waveguides. [ABSTRACT FROM AUTHOR]

The authors investigate the nonlinear and bistable behavior of a high-Q GaAs photonic crystal heterostructure nanocavity, side coupled to a line-defect slab waveguide. The observations agree well with a model incorporating the relevant nonlinearities. The power threshold for bistable behavior is at least one order of magnitude lower than what is reported so far. [ABSTRACT FROM AUTHOR]

The authors realized an ultrahigh quality factor nanocavity in a GaAs membrane with the highest loaded Q reported to date of 250 000 in a side-coupled cavity-waveguide system. This result could be obtained using an original aluminum-free material system combined with a carefully adjusted fabrication technology, yielding a device with small roughness and very good verticality of holes as well as small disorder. The authors show that the intrinsic Q factor is around 3.0×105 using a coupled-mode model. [ABSTRACT FROM AUTHOR]