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Abstract-We show that thin, shallow ridge, silicon-oninsulator waveguides exhibiting lateral leakage behaviour can be designed and fabricated using a standard silicon photonic foundry platform. We analyse the propagation loss through observation of the transmitted TM polarized guided mode and TE polarized radiation and experimentally demonstrate that propagation losses as low as 0.087 dB/mm can be achieved. This demonstration will open a new frontier for practical devices exploiting lateral leakage behaviour with potential applications in the fields of biosensing and quantum optics among others.

Adiabatic techniques have much potential to realise practical and robust optical waveguide devices. Traditionally photonic elements are limited to coupling schemes that rely on proximity to nearest neighbour elements. We combine adiabatic passage with a continuum based long-range optical bus to break free from such topological restraints and thereby outline a new approach to photonic quantum gate design. We explicitly show designs for adiabatic quantum gates that produce a Hadamard, 50:50 and 1/3:2/3 beam splitter, and non-deterministic CNOT gate based on planar thin, shallow ridge waveguides. Our calculations are performed under conditions of one and two-photon inputs.

We present a new approach to long range coupling based on a combination of adiabatic passage and lateral leakage in thin shallow ridge waveguides on a silicon photonic platform. The approach enables transport of light between two isolated waveguides through a mode of the silicon slab that acts as an optical bus. Due to the nature of the adiabatic protocol, the bus mode has minimal population and the transport is highly robust. We prove the concept and examine the robustness of this approach using rigorous modelling. We further demonstrate the utility of the approach by coupling power between two waveguides whilst bypassing an intermediate waveguide. This concept could form the basis of a new interconnect technology for silicon integrated photonic chips.

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We have investigated optical capture of neutral cesium atoms by radiation pressure forces in a stiff magneticquadrupole field. Permanent magnets were used to generate field gradients ranging from 60 G/cm to more than 300 G/cm. With increasing gradient we observe a step decrease in the equilibrium number of trapped atoms but only a moderate reduction of their density. From the dynamics of the trapped atomic sample we derive temperatures as low as 40p.K or 30% of the Doppler limit even in these strong magnetic-quadrupole fields.

Abstract:We demonstrate electrical tuning of the lateral leakage loss of TM-like modes in nematic liquid crystal (LC) clad shallow-etched Siliconon-Insulator (SOI) waveguides. The refractive index of the LC layer can be modulated by applying a voltage over it. This results in a modulation of the effective index of the SOI waveguide modes. Since the leakage loss is linked to these effective indices, tunable leakage loss of the waveguides is achieved. We switch the wavelength at which the minimum in leakage loss occurs by 39.5nm (from 1564nm to 1524.5nm) in a 785nm wide waveguide. We show that the leakage loss in this waveguide can either be increased or decreased by modulating the refractive index of the LC cladding at a fixed wavelength.

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