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The design, fabrication and characterization of an optics based integrated flow rate sensor is presented where the light-fluid interaction is maximized by allowing the liquid and light to propagate along the same direction. The flow rate sensor consists of a 10 mu m deep microchannel placed between two waveguides. The optical waveguides were tapered to fit the channel width, to guide light in and out of the microchannel. A tapering mechanism is proposed to minimize the coupling and propagation losses. The power of the output signal from the designed device was calculate through simulation and it was compared with the actual output signal detected by a fast receiver (higher than 1 MHz). The dynamic change of the light intensity when fluid flows through the channel can also be recorded by this receiver. This scheme allows for a direct measurement of the liquid flow rate with higher interaction length between fluid and light with a dynamic range of up to 0.18. An integrated microfluidic device with high precision and sufficient coupling between the light source and the microfluidic channel is proposed., QC 20160331

We present what is to our knowledge the first demonstration of a tunable fiber Bragg grating device in polymer optical fiber that utilizes a thin-film resistive heater deposited on the surface of the fiber. The polymer fiber was coated via photochemical deposition of a Pd/Cu metallic layer with a procedure induced by vacuum-ultraviolet radiation at room temperature. The resulting device, when wavelength tuned via joule heating, underwent a wavelength shift of 2 nm for a moderate input power of 160 mW, a wavelength to input power coefficient of-13.4 pm/mW, and a time constant of 1.7 s-1.

We present a thorough study on the development of a polymer optical fibre-based tuneable filter utilizing an intra-core Bragg grating that is electrically tuneable, operating at 1.55 µm. The Bragg grating is made tuneable using a thin-film resistive heater deposited on the surface of the fibre. The polymer fibre was coated via the photochemical deposition of a Pd/Cu metallic layer with the procedure induced by VUV radiation at room temperature. The resulting device, when wavelength tuned via Joule heating, underwent a wavelength shift of 2 nm for a moderate input power of 160 mW, a wavelength to input power coefficient of -13.4 pm mW-1 and time constant of 1.7 s-1. A basic theoretical study verified that for this fibre type one can treat the device as a one-dimensional system. The model was extended to include the effect of input electrical power changes on the refractive index of the fibre and subsequently to changes in the Bragg wavelength of the grating, showing excellent agreement with the experimental measurements.

In this paper we report on investigations of some of the factors that have a bearing on the reliability and repeatability of polymer fibre Bragg gratings. The main issues discussed are the fibre preform composition, the fibre drawing conditions and the thermal history of the fibre grating.

We describe recent research into devices based on fibre Bragg gratings in polymer optical fibre. Firstly, we report on the inscription of gratings in a variety of microstructured polymer optical fibre: single mode, few moded and multimoded, as well as fibre doped with trans-4-stilbenmethanol. Secondly, we describe research into an electrically tuneable filter using a metallic coating on a polymer fibre Bragg grating. Finally we present initial results from attempts to produce more complex grating structures in polymer fibre: a Fabry-Perot cavity and a phase-shifted grating.

In this paper we report on investigation of some of the factors that have a bearing on the realiability and repeatability of polymer fibre Bragg gratings. The main issues discussed are the fibre preform composition, the fibre drawing conditions and the thermal history of the fibre grating.

We describe recent research into devices based on fibre Bragg gratings in polymer optical fibre. Firstly, we report on the inscription of gratings in a variety of microstructured polymer optical fibre: single mode, few moded and multimoded, as well as fibre doped with trans-4-stilbenmenthanol. Secondly, we describe research into an electrically tuneable filter using a metallic coating on a polymer fibre Bragg grating. Finally we present initial results from attempts to produce more complex grating structures in polymer fibre: a Fabry-Perot cavity and a phase-shifted grating.

We report the development and applications of finite-element-based numerical approaches for the characterization of a wide range of photonic devices. The full-vectorial finite-element method is considered for the modal solutions of uniform guided-wave sections and the least-squares boundary residual method is used to calculate the scattering coefficients for butt-coupled uniform waveguide sections. Several guided-wave components are discussed and their operating characteristics are illustrated. Particular emphasis is given to key photonic components such as the spot-size converters, Bragg gratings, polarization splitters, polarization rotators, multimode interference-based devices and modulators. Valuable results relating to the design and characterization of these important photonic components are presented