B.J. Eggleton

Microfluidic tunable photonic band-gap device

We introduce a method for tuning a photonic band-gap material by means of displacing microfluidic plugs. The fluid is introduced into air voids that constitute the structure of the photonic crystal and is displaced using a capillary heater. The photonic crystal geometry is obtained using a microstructured optical fiber, comprising a periodically spaced array of air holes that is interrogated in the transverse direction, creating a “tall microchip.” Optical spectra are compared to band structure calculations of an idealized band-gap material.

High-intensity pulse propagation in uniform gratings and grating superstructures

We briefly review our recent nonlinear propagation experiments in optical fiber Bragg gratings (FBGs). These experiments demonstrate nonlinear pulse compression, and pulse shaping, and also show how a train of pulses may be generated from a single input pulse. Our results also demonstrate the existence of Bragg grating solitons, solitons which exist by balancing of the nonlinearity of the glass and the dispersion of the grating.

Accurate characterization of fiber Bragg grating index modulation by side-diffraction technique

The performance of fiber Bragg grating (FBG) devices is determined by spatial distribution of FBG parameters. For many applications, like chirped FBG used for dispersion compensation, it is sufficient to control these parameters with spatial resolution of around 1 mm. We improve the sensitivity and accuracy of the side-diffraction FBG characterization at the cost of reducing the spatial resolution and demonstrate simultaneous measurement of fiber grating refractive index modulation with accuracy of 2/spl middot/10/sup -6/, grating period variation with accuracy of 5 pm, and spatial resolution of /spl sim/1 mm. The group delay ripple of a chirped FBG calculated from our side-diffraction characterization is in a good agreement with spectroscopic measurements.

Optical rogue waves and soliton turbulence in nonlinear fibre optics

There is currently intense research into extreme value fluctuations (optical rogue waves) in long pulse fibre supercontinuum (SC) generation [1]. This interest is motivated by the possibility to obtain important insights into related hydrodynamic instabilities, as well as by potential applications in generating stable SC [2]. Optical rogue waves are generated under conditions where SC broadening develops from initial spontaneous modulation instability. Following the appearance of a noise-driven temporal modulation on the input pulse, a large number of distinct solitons emerge, a small number of which undergo extreme Raman frequency shifts to longer wavelengths. Although this suggests that Raman scattering plays a central role in their formation through inelastic energy exchange [3], here we revisit the dynamics of optical rogue wave formation in terms of the well-known soliton turbulence description in which solitons play the role of statistical attractors in any non-integrable nonlinear Schrödinger equation (NLSE) model [4]. Specifically, we show that Raman scattering is unnecessary for intense rogue pulses to emerge from SC generation, and third-order dispersion on its own is sufficient to stimulate a single large rogue soliton in the long distance limit. An additional novel result is that the rogue soliton undergoes a continuous frequency shift to longer wavelengths with propagation as a result of interaction with the turbulent background, even in the absence of Raman scattering.

Optical signal processing in highly-nonlinear chalcogenide planar waveguides

Bit-error rate performance of newly developed AS2S3 planar waveguides in applications of highspeed all-optical time-division demultiplexing and wavelength conversion of 40-160 Gb/s optical signals through the use of four-wave mixing and cross-phase modulation is investigated.

Narrow-band spectral enhancement of a self-phase modulated pulse

We develop a simple physical model to describe narrow-band enhancement of spectrally filtered ultrashort pulses in the presence of self-phase modulation. An experiment using pulse shaping and propagation in photonic crystal fibre confirms this model.

Chalcogenide Glass Chip Based Nonlinear Signal Processing

We review the latest advances in dispersion-shifted, highly nonlinear planar rib waveguides fabricated in As2S3 glass for enabling broadband wavelength conversion and phase conjugation of high-speed, phase shift keyed signals via CW pumped four-wave mixing.

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

We demonstrate enhanced nonlinear self-phase modulation through short silicon photonic crystal waveguides due to slow light using picosecond pulses. The measurements are supported by simulations, highlighting the simultaneous reinforcement of nonlinear absorption and free carriers.

Optical rogue wave dynamics in supercontinuum generation

We study the physical origin and propagation dynamics of ldquooptical rogue wavesrdquo, statistically-rare extreme red-shifted soliton pulses arising from broadband supercontinuum generation in optical fibre.

Characterisation of chalcogenide 2D photonic crystal waveguides using silica fibre nanowires.

We describe the fabrication of low-loss, highly flexible silica fibre nanowires which are used to characterise chalcogenide two-dimensional photonic crystal waveguide circuits. Localised coupling is achieved in good agreement with theory.