9 research outputs found

    First demonstration of direct UV written Bragg gratings in collapsed fibre planar samples

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    First demonstration of planar Bragg gratings UV written into collapsed fibre planar samples with >200µm cladding thickness is presented. Multiple gratings were written across the sample profile to accurately determine core layer flatness and uniformity

    Evanescent field sensing in novel flat fiber

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    Recently developed novel 'flat fiber' substrate promises flexible, long-haul integrated optical devices. Here, we present the first demonstration of one such device; an evanescent field sensor, based upon direct UV written Bragg gratings

    Single-step fabrication of raised index X-couplers via direct UV writing

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    X-couplers having low polarization and wavelength dependency with 1.9-95% coupling ratios were fabricated in a single step via direct UV writing, exhibiting typical excess loss of 1.0dB. First experimental validation of analytical and BPM modeling is also presented

    UV written waveguide devices - Bragg gratings and applications in sensors

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    UV direct writing provides a powerful route for the fabrication of integrated optical devices. It has significant benefits in terms of simplicity, flexibility and cost which make it attractive for applying integrated optical concepts to other areas of science and technology. Within our group, we have developed a novel approach for creating Bragg gratings in a planar format, with great flexibility in terms of centre wavelength, bandwidth and position within chip. These planar Bragg grating devices are ideally suited for use in sensors in etched window is created that allows access of the evanescent field of the optical mode to a liquid measurand. The effective index of the mode is altered by the presence of the liquid, and this, in turn, alters the Bragg wavelength of the grating. By measuring the Bragg grating wavelength shift we can resolve refractive index changes of as small 1 part in 10 In this talk, we will present results on sensors for applications in chemical, phase change and biological sensing. Further recent results will show how this sensor configuration may be used with nematic liquid crystals to achieve tunable grating operation with tuning exceeding 100GHz

    Flat-optical fibre for a faster future

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    High-speed optical telecommunication has revolutionised the modern age, severing as a high-tech backbone for businesses and individuals. Through rethinking the design of optical fibres, this work aims to address global demand for a faster telecommunication infrastructure

    Small-angle (<5º) direct-UV-written crossed-waveguide on silica-on-silicon with potential for power switching applications

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    Experimental demonstration of crossed waveguides on silica-on-silicon at angles less than 5 degrees using the direct UV writing technique is presented for the first time. Such structure finds application in ultra-compact couplers and folded amplifiers

    Direct UV written waveguides and Bragg gratings in novel substrates

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    Direct UV writing provides a method to rapidly prototype planar waveguides with Bragg gratings. Typically performed in silica-on-silicon, here we introduce alternative geometries for planar lightwave circuits including an innovative flat fibre fabricated via MCVD. In Bragg grating devices etched windows provide access to the optical field to realise refractive index sensors and modulators. However, this geometry is limiting in the way in which the liquid can interact with the optical mode. Some of our current work we investigate the use of a machined groove to provide a vertical, high optical quality trench. Optical waveguides are then UV written to allow evanescent lateral access of the mode to a fluid placed in the trench. This seemingly subtle change in geometry provides greatly increased flexibility to tailor the interaction between the optical mode and the surrounding material. We shall present our continuing research in these areas

    All-UV written integrated glass devices including planar Bragg gratings and lasers

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    One attractive route to low-cost integrated optical components is the use of direct UV writing. This technique may be applied to a wide range of materials including silica-on-silicon wafers, compound oxide glasses, directly bonded glass composites and GLS. This presentation will focus on the first of these material systems - silica-on-silicon. This has a number of attractive features including fibre compatibility, industrial acceptance, stability and most importantly for our work a photosensitivity depends light intensity and not the thermal effects found in many materials. Recent developments of the UV writing technique at Southampton have allowed the realisation of high quality Bragg gratings in silica-on-silicon by simultaneous writing of the channel waveguides and gratings (the direct grating writing technique). This approach together with wavelength detuning, allows an unprecedented range of wavelengths to be written under software control. Latest results will be presented covering laser operation in Neodymium doped channels, small angle couplers, sensors based on planar gratings and liquid crystal tunable devices

    Recent developments in direct-UV-written planar waveguides, gratings, sensors and substrates

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    We present our recent developments in direct-UV-written integrated optical devices, based on applications in telecommunications, material characterisation, and optical sensing. The inherent advantages of this channel definition technique over traditional etching based approaches are reiterated and demonstrated in the production of small angle, low loss X-couplers with negligible polarisation dependence. Interfering two focussed UV spots also provides us with the capability to simultaneously define a channel waveguide and Bragg grating, opening new device and application opportunities. Such structures provide a method to quantify the photosensitivity effects observed in conventional multilayer substrates, and assess the core uniformity of a novel 'flat-fibre' format recently developed within the ORC. We will also discuss electrically tuned Bragg gratings via liquid crystal overlayers, displaying a dynamic range in excess of 100GHz for use in dynamic optical networks
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