Coherent guiding of atoms in two-colour evanescent light fields of two fundamental modes of suspended optical rib waveguides is investigated theoretically. Special attention is paid to waveguides of widths larger than the wavelength of light, which provide better lateral stability of the surface traps and waveguides, and can be used in coherent Bragg beam splitters for matter waves, based on optical gratings formed by interference of evanescent light waves of two crossed optical waveguides. A single-mode regime for evanescent-wave waveguides for atoms is investigated. The general structure and key elements of all-optical atom chips are discussed.

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We present the design, fabrication, simulation and initial characterisation of tantalum pentoxide (Ta2O5) optical waveguides and micro-ring resonators for the purpose of supercontinuum and frequency comb generation. Spectral broadening results are presented for linear Ta2O5 waveguides for a range of central pump wavelengths between 900 nm and 1500 nm. These results are used as the basis for the dispersion engineering and development of Ta2O5 micro-ring resonators. The losses for sputtered and TEOS PECVD deposited SiO2 top cladded waveguides are characterised using a Fabry-Pérot loss measurement set-up. A solver based on the Lugiato-Lefever equation is presented and used to simulate the expected emission from the Ta2O5 micro-ring resonators. Promising initial experimental results show critical coupling and a Q-factor of 3.7×104.