1,721,076 research outputs found
Nonlinearity in holey optical fibers: measurement and future opportunities - errata
No full textErrata to Nonlinearity in holey optical fibers: measurement and future opportunities. (1999) Optics Letters, 24 (20), 1395-1397. (doi:10.1364/OL.24.001395).Broderick, N.G.R., Monro, T.M., Bennett, P.J. and Richardson, D.J. <br/
Nonlinear optics in periodic media
No full textPeriodic media are in many ways ideal choices to observe nonlinear effects due to their flexibility. I shall discuss a variety of periodic systems ranging from Bragg gratings and quasi-phase matched materials to microstructured optical fibres and show how it is possible to design such structures to have the desired nonlinear response
Method for improving the spectral flatness of the supercontinuum at 1.55 µm in tapered microstructured optical fibers
No full textWe propose a method for enhancing the flatness of a supercontinuum centered at 1.55 µm by the use of specially designed tapered microstructured optical fibers (MOFs). Based on the procedure presented one can determine the linear taper profile parameters and the optimum launching conditions needed to achieve the broadest supercontinuum spectra (SC) and the best spectra flatness. We quantify the maximally broad and flat SC using the calculated standard deviation of the spectra at the required wavelength range and show that it is possible to obtain significantly better results than those obtained by using an untapered fiber
Guided modes in channel waveguides with a negative index of refraction
No full textThe guided modes of a negative refractive index channel waveguide have been numerically investigated. It has been found that the modes exhibit a number of unusual properties that differ considerably from those of a conventional waveguide. In particular, it has been shown that these waveguides can exhibit low or negative group velocity as well as extraordinarily large group velocity dispersion. Calculation of the Poynting vector reveals that it is possible to support a mode with a zero energy flux motivating a simple design for an optical trap
Broadband higher-order harmonic generation in two-dimensional nonlinear photonic crystals
No full textThis study shows that 2D nonlinear photonic crystals (NPCs) can be designed to support fourth harmonic generation (FHG) cascaded processes, which have bandwidths in excess of 60 nm. These crystals should find applications in areas such as frequency conversion of ultra-short pulses and wavelength tolerant designs
Optimising two dimensional nonlinear photonic crystals for cascaded third harmonic generation which complies with fabrication constraints
No full textThis study shows that 2D nonlinear photonic crystals (NPCs) can be designed to support fourth harmonic generation (FHG) cascaded processes, which have bandwidths in excess of 60 nm. These crystals should find applications in areas such as frequency conversion of ultra-short pulses and wavelength tolerant designs
Method for pulse transformations using dispersion varying optical fibre tapers
No full textI introduce the problem of transforming one optical pulse into another via nonlinear propagation in a length of dispersion varying optical fibre. Then using a genetic algorithm to design the dispersion profiles, I show that the problem can be solved leading to high quality pulse transforms that are significantly better than what has been published previously. Finally I suggestion further work and other applications for this method
Optical pulse transforms using tapered optical fibres
Full text linkA common problem in optics is optical pulse transformation which can be done in either the spatial or the temporal domain. In the spatial domain, beam reshaping has many different solutions from holography and phase plates to using a simple lens. Similarly in the temporal domain different solutions such as fibre Bragg gratings can be used to alter the profile of a pulse, producing square or parabolic pulses from a sech-shaped input for example. A common feature of all these schemes is the linear nature of the transformation which means that no new frequency components are introduced and thus for a transformed limited input pulse the transformed pulse will always be longer. If pulse compression and reshaping is desired then nonlinear effects must be introduced and in this paper I look at how to design long fibre tapers in order to control the output pulse characteristics in the nonlinear regime
Self-pulsation and chaos in micro-coil resonators
No full textOptical microcoil resonators are a new resonator design with several unique and attractive features. Practically they can be made by coiling a tapered fibre around a central rod so that light in each turn of the fibre can couple to the fibre directly above or below it. Importantly it is the coupling of light from one coil to the coil directly below that allows for the creation of effective high Q cavities resulting in resonate frequencies where light is trapped inside the coil indefinitely
Nonlinear propagation in long fibre Bragg gratings
No full textNonlinear propagation in long (40cm) fibre Bragg gratings is examined. We observe clear evidence of soliton formation and associated pulse reshaping. This is the first time such long gratings have been used in nonlinear experiments
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