Christian Grillet

Slow light enhancement of nonlinear effects in silicon engineered photonic crystal waveguides.

We report nonlinear measurements on 80microm silicon photonic crystal waveguides that are designed to support dispersionless slow light with group velocities between c/20 and c/50. By launching picoseconds pulses into the waveguides and comparing their output spectral signatures, we show how self phase modulation induced spectral broadening is enhanced due to slow light. Comparison of the measurements and numerical simulations of the pulse propagation elucidates the contribution of the various effects that determine the output pulse shape and the waveguide transfer function. In particular, both experimental and simulated results highlight the significant role of two photon absorption and free carriers in the silicon waveguides and their reinforcement in the slow light regime.

Dispersion engineering of slow light photonic crystal waveguides using microfluidic infiltration

We present a technique based on the selective liquid infiltration of photonic crystal (PhC) waveguides to produce very small dispersion slow light over a substantial bandwidth. We numerically demonstrate that this approach allows one to control the group velocity (from c/20 to c/110) from a single PhC waveguide design, simply by choosing the index of the liquid to infiltrate. In addition, we show that this method is tolerant to deviations in the PhC parameters such as the hole size, which relaxes the constraint on the PhC fabrication accuracy as compared to previous structural-based methods for slow light dispersion engineering.

Low propagation loss silicon-on-sapphire waveguides for the mid-infrared

We report record low loss silicon-on-sapphire nanowires for applications to mid infrared optics. We achieve propagation losses as low as 0.8 dB/cm at λ = 1550 nm, ~1.1 to 1.4 dB/cm at λ = 2080 nm and < 2dB/cm at λ = 5.18 μm.We report record low loss silicon-on-sapphire nanowires for applications to mid infrared optics. We achieve propagation losses as low as 0.8dB/cm at uf06c=1550nm, uf07e 1.1 to 1.4dB/cm at uf06c=2080nm and < 2dB/cm at uf06c = 5.18 μm.

Four-wave mixing in slow light engineered silicon photonic crystal waveguides.

We experimentally investigate four-wave mixing (FWM) in short (80 μm) dispersion-engineered slow light silicon photonic crystal waveguides. The pump, probe and idler signals all lie in a 14 nm wide low dispersion region with a near-constant group velocity of c/30. We measure an instantaneous conversion efficiency of up to -9dB between the idler and the continuous-wave probe, with 1W peak pump power and 6 nm pump-probe detuning. This conversion efficiency is found to be considerably higher (>10 × ) than that of a Si nanowire with a group velocity ten times larger. In addition, we estimate the FWM bandwidth to be at least that of the flat band slow light window. These results, supported by numerical simulations, emphasize the importance of engineering the dispersion of PhC waveguides to exploit the slow light enhancement of FWM efficiency, even for short device lengths.

Slow-light enhanced correlated photon pair generation in a silicon photonic crystal waveguide

We report the generation of correlated photon pairs in the telecom C-band at room temperature from a dispersion-engineered silicon photonic crystal waveguide. The spontaneous four-wave mixing process producing the photon pairs is enhanced by slow-light propagation enabling an active device length of less than 100u2009μm. With a coincidence to accidental ratio of 12.8 at a pair generation rate of 0.006 per pulse, this ultracompact photon pair source paves the way toward scalable quantum information processing realized on-chip.

Microfluidic photonic crystal double heterostructures

The support of the Australian Research Council through nits Federation Fellow, Centres of Excellence, Denison Foundation, nand Discovery Grant programs is gratefully acknowledged.

Efficient coupling to chalcogenide glass photonic crystal waveguides via silica optical fiber nanowires

We demonstrate highly efficient evanescent coupling between a highly nonlinear chalcogenide glass two dimensional photonic crystal waveguide and a silica fiber nanowire. We achieve 98% insertion efficiency to the fundamental photonic crystal waveguide mode with a 3dB coupling bandwidth of 12nm, in good agreement with theory. This scheme provides a promising platform to realize low power nanocavity based all-optical switching and logic functions.

Photosensitive post tuning of chalcogenide photonic crystal waveguides.

We present experimental results on photosensitive post-tuning the dispersion of a two-dimensional photonic crystal waveguide made from chalcogenide glass. A 5 nm shift of the resonant wavelength is reported.

A proposal for enhancing four-wave mixing in slow light engineered photonic crystal waveguides and its application to optical regeneration

In this paper, we investigate both analytically and numerically four-wave mixing (FWM) in short (80 microm) dispersion engineered slow light photonic crystal waveguides. We demonstrate that both a larger FWM conversion efficiency and an increased FWM bandwidth (approximately 10 nm) can be achieved in these waveguides as compared to dispersive PhC waveguides. This improvement is achieved through the net slow light enhancement of the FWM efficiency (almost 30dB as compared to a fast nanowire of similar length), even in the presence of slow light increased linear and nonlinear losses, and the suitable dispersion profile of these waveguides. We show how such improved FWM operation can be advantageously exploited for designing a compact 2R and 3R regenerator with the appropriate nonlinear power transfer function.

Characterization and modeling of Fano resonances in chalcogenide photonic crystal membranes

We demonstrate resonant guiding in a chalcogenide glass photonic crystal membrane. We observe strong resonances in the optical transmission spectra at normal incidence, associated with Fano coupling between free space and guided modes. We obtain good agreement with modeling results based on three-dimensional finite-difference time-domain simulations, and identify the guided modes near the centre of the first Brillouin zone responsible for the main spectral features.