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Journals and Conferences
A pair of reflection peaks/transmission dips, at twice the Bragg wavelength, were observed in spectra of a Type I fiber Bragg grating written with the standard phase mask technique. The occurrence of two peaks/dips, rather than one, is attributed to the interleaved refractive index modulations along the fiber core, with the periodicity of the phase mask… (More)
Apodized fiber Bragg gratings with > or = 30-dB sidelobe suppression +/-1 nm from the Bragg center wavelength are spatially characterized with side-scatter and side-diffraction techniques. Resonant side scatter is suppressed, indicating that little dispersion arises from reflections off the grating boundaries.
Recent advances in both nano-fabrication and nano- materials open up rich new avenues in the optical sensing area. Using nano-grid electrodes, nanometer-scale photo-alignment layers and deformed helix ferro-electric liquid crystals with a sub-wavelength helix pitch of 150 nm, we have realised a fully integrated polarisation-based photonic transducer which… (More)
The theoretical and experimental analysis of a multipoint fibre optic refractive index sensor is presented in this work. Experimental characterisation of the sensor shows excellent agreement with numerical analysis and a resolution in the order of 10<sup>−3</sup>.
The electro-optical behavior of deformed helix ferroelectric liquid crystal in reflective mode is described in this paper. The electrically controlled reflectance has been measured at subkilohertz driving voltage frequency for different polarizations of the incident light and compared quite successfully with the simulation results.
Use of a phase mask with 536 nm uniform pitch allowed the fabrication of a fiber Bragg grating for use at a Bragg wavelength of 785 nm. Reflection and transmission features at 1552 nm, i.e. twice the Bragg wavelength, associated with the phase mask periodicity were observed. However, when phase mask orders other than plusmn1 were absent during fabrication… (More)
In the context of current/voltage sensing by electric field monitoring it can be of importance to amplify the effect of the field at the sensor's head. We present such an amplification - or energy harvesting - device in the form of a simple antenna coupled with a liquid crystal-based sensor for the monitoring of high-power lines.
An alternative fabrication process targeting the etching of fibre Bragg gratings (FBGs) is presented. The performance of the resulting grating is demonstrated by developing a glycerine composition sensor based on refractive index changes.
Digital operation of an all-optical intensity switch is demonstrated in a two-mode interferometer constructed from ytterbium-doped fiber. We clamp the resonantly enhanced phase shift responsible for the switching by allowing the fiber to lase, resulting in a bistable, digital response. The degree of phase shift at the clamping point can be controlled by… (More)
The effect of transverse strain on a fiber Bragg grating fabricated using a phase mask with 536-nm pitch has been investigated through the study of its reflection and transmission features at twice the Bragg wavelength near 1552 nm, that are due to reflection/transmission from FBG periodicities associated with the phase mask periodicity. The occurrence of… (More)