Educação matemática pela arte
Gusmão, Lucimar Donizete
2013-08-28
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20 records were found.
We discuss the background and technology of planar Bragg grating sensors, reviewing their development and describing the latest developments. The physical operating principles are discussed, relating device operation to user requirements. Recent performance of such devices includes a planar Bragg grating sensor design which allows refractive index resolution of 1.9×10-6?RIU and temperature resolution of 0.03°C. This sensor design is incorporated into industrialised applications allowing the sensor to be used for real time sensing in intrinsically safe, high-pressure pipelines, or for insertion probe applications such as fermentation. Initial data demonstrating the ability to identify solvents and monitor long term industrial processes is presented. A brief review of the technology used to fabricate the sensors is given along with examp...
A new technique for UV direct writing of Bragg gratings in planar silica is presented. In this method the Bragg gratings and the channels are defined simultaneously, conferring advantages in flexibility of design and grating performance. Photosensitive germanium-doped silica-on-silicon produced by flame hydrolysis deposition was used.
A waveguide laser with a neodymium-doped silica core is fabricated on a silicon substrate by a combination of flame hydrolysis deposition, solution doping, and direct UV writing. The neodymium-ion concentration is estimated to be ~8000 ppm. The propagation loss around 1.05μm is <0.8dB/cm. Lasing in the range 1048–1056 nm and 1356±1nm is observed. A slope efficiency of 33% for a high-reflectivity output coupler and a threshold of 4 mW of absorbed power for a 25% output coupler are measured for the 4F3/2 to 4I11/2 transition
A waveguide laser with a neodymium-doped silica core is fabricated on a silicon substrate by a combination of flame hydrolysis deposition, solution doping, and direct UV writing. The neodymium-ion concentration is estimated to be ~8000 ppm. The propagation loss around 1.05μm is <0.8dB/cm. Lasing in the range 1048–1056 nm and 1356±1nm is observed. A slope efficiency of 33% for a high-reflectivity output coupler and a threshold of 4 mW of absorbed power for a 25% output coupler are measured for the 4F3/2 to 4I11/2 transition
We present a single-step technique for defining 2-dimensional integrated channel waveguide structures with internal Bragg gratings in photosensitive germanosilica-on-silicon substrates using two interfering focussed UV beams. Detailed device analysis of the relationship between the photosensitive properties of the glass, UV writing conditions, and subsequent refractive index change and channel waveguide strength is presented based on grating characterisation. Through software control, 300nm wide grating detuning across the E, S, C, L, and U wavelength bands is demonstrated.
A waveguide laser with a neodymium-doped silica core is fabricated on a silicon substrate by a combination of flame hydrolysis deposition, solution doping, and direct UV writing. The neodymium-ion concentration is estimated to be ~8000 parts in 10^6. The propagation loss around 1.05 µm is < 0.8dB/cm. Lasing in the range 1048-1056 nm and 1356 ± 1 nm is observed. A slope efficiency of 33% for a high-reflectivity output coupler and a threshold of 4 mW of absorbed power for a 25% output coupler are measured for the 4F_3/2 <--> 4I_11/2 transition.
The technique of direct grating writing, based on direct ultraviolet writing, is demonstrated as a tool for highly accurate measurement of waveguide and material properties. Silica-on-silicon planar samples are processed using hydrogen loading and thermal locking before Bragg channel waveguides are defined in the photosensitive core layer. The refractive index is accurately probed to compare different thermal locking procedures and characterize waveguide thermal stability.
Direct UV writing provides an attractive route towards low-cost integrated optical components in photosensitive glasses. The technique may be applied to a wide range of different geometries including silica-on-silicon wafers, compound oxide glasses, directly bonded glass composites and GLS. This presentation will review research in this area and present an overview of the activities in Southampton in this field. Recent developments of the UV writing technique 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 Neodym...
Direct UV writing provides an attractive route towards low-cost integrated optical components in photosensitive silica-on-silicon wafers. Combining closely packed channel waveguides with a Bragg grating tailored spectral response would allow the creation of compact systems for wavelength division multiplexing on a single optical chip. To this end, we present our new technique for simultaneous definition of channel waveguides with integral Bragg gratings based on the interference of two focussed UV-writing beams. This single-step approach promotes optimal use of sample photosensitivity for both the waveguide geometry and Bragg grating structure and allows implementation of many aspects of advanced grating design, such as chirp and apodisation, with no need for a phase mask.
