Christopher G. Poulton

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We report the first demonstration of a photonic chip based dynamically reconfigurable, widely tunable, narrow pass-band, high Q microwave photonic filter (MPF). We exploit stimulated Brillouin scattering (SBS) in a 6.5 cm long chalcogenide (As2S3) photonic chip to demonstrate a MPF that exhibited a high quality factor of ~520 and narrow bandwidth and was(More)
We demonstrate a direct, single measurement technique for characterizing the dispersion of a photonic crystal waveguide (PCWG) using a tapered fiber evanescent coupling method. A highly curved fiber taper is used to probe the Fabry-Pérot spectrum of a closed PCWG over a broad k-space range, and from this measurement the dispersive properties of the(More)
There is an increasing demand for pulsed all-fibre lasers with gigahertz repetition rates for applications in telecommunications and metrology. The repetition rate of conventional passively mode-locked fibre lasers is fundamentally linked to the laser cavity length and is therefore typically ~10-100 MHz, which is orders of magnitude lower than required.(More)
We investigate the role of the spatial evolution of the acoustic field in stimulated Brillouin scattering processes in short high-gain structures. When the gain is strong enough that the gain length becomes comparable to the acoustic wave decay length of order 100 microns, standard approximations treating the acoustic field as a local response no longer(More)
Overcoming stimulated Brillouin scattering (SBS) is a major challenge in optical telecommunications networks and in fiber lasers. We evaluate the SBS gain coefficient for an all-dielectric composite material comprising a cubic, subwavelength array of spheres in a uniform background. We demonstrate total SBS suppression in fused silica using GaAs spheres.
We present methods for retrieving the effective impedance of metamaterials from the Fresnel reflection coefficients at the interface between two semi-infinite media. The derivation involves the projection of modal expansions onto the dominant modes of the two semi-infinite media. It is shown that a number of effective impedance formulas, previously obtained(More)