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Publicações

Publicações por CAP

1997

Extraction of semiconductor intrinsic laser parameters by intermodulation distortion analysis

Autores
Salgado, HM; Ferreira, JM; OReilly, JJ;

Publicação
IEEE PHOTONICS TECHNOLOGY LETTERS

Abstract
A new technique is described for the extraction of the intrinsic semiconductor laser parameters from intermodulation measurements of composite second-order (CSO) and composite third-order (CTB) distortion products. The effect of the parasitics elements are eliminated, by taking the distortion measurements at constant optical modulation depth, which enables one to obtain the laser parameters on packaged laser diodes. An optimization algorithm is then described that extracts the relevant laser parameters from the distortion data. This method was applied to a commercially available packaged laser diode and very good agreement was obtained between the measured and theoretical results.

1997

Blue light emission in thulium doped silica-on-silicon waveguides

Autores
Bonar, JR; Vermelho, MVD; McLaughlin, AJ; Marques, PVS; Aitchison, JS; Martins, JF; Bezerra, AG; Gomes, ASL; deAraujo, CB;

Publicação
OPTICS COMMUNICATIONS

Abstract
We report the experimental observation of up-conversion in an integrated silica-on-silicon waveguide. Blue light at 455 nm and 475 nm was observed. In addition to the strong blue emission near infrared (similar to 800 nm), visible (648 nm) and UV (366 nm) lines were also detected. We investigated the excitation mechanisms by using different pumping wavelengths. (C) 1997 Elsevier Science B.V.

1997

Deep, vertical etching of hi-silica films for optical waveguide applications

Autores
McLaughlin, AJ; Bonar, JR; Jubber, MG; Marques, PVS; Hicks, SE; Wilkinson, CDW; Aitchison, JS;

Publicação
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS

Abstract
Flame hydrolysis deposited (FHD) silica waveguides are very important for use in planar lightwave circuits (PLC) because of their low loss and inherent compatibility with silica optical fibers. A low damage, anisotropic reactive ion etch process for the fabrication of single and multimode waveguides in silica for planar lightwave circuit applications is presented. The etch rate of the glass results in smooth sidewalls and deep anisotropic etching. Propagation losses and polarization sensitivity arising from the etch process are discussed.

1997

900-nm Nd:Ti:LiNbO3 waveguide laser

Autores
Brown, CTA; Amin, J; Shepherd, DP; Tropper, AC; Hempstead, M; Almeida, JM;

Publicação
OPTICS LETTERS

Abstract
We report what is to our knowledge the first laser operation of Nd3+-doped LiNbO3 near 900 nm. An absorbed power threshold of 26 mW was obtained when the device was pumped at 814 nm. The design of the waveguide geometry to favor laser operation at this wavelength is demonstrated. (C) 1997 Optical Society of America.

1996

Self-referencing resonant fiber optic intensity sensor based on a Mach-Zehnder topology

Autores
Baptista, JM; Cavaleiro, PM; Santos, JL;

Publicação
REVIEW OF SCIENTIFIC INSTRUMENTS

Abstract
An investigation is performed on the characteristics of the self-referencing resonant fiber optic intensity based sensor supported by a Mach-Zehnder topology. Both transmissive and reflective configurations are analyzed. Via the definition of the measurement parameter (R parameter) the linearity and sensitivity of the sensor are addressed. Theoretical and experimental results are compared. The problem of sensor design is under consideration. (C) 1996 American Institute of Physics.

1996

Demodulation scheme for fibre Bragg sensors based on source spectral characteristics

Autores
Ferreira, LA; Santos, JL;

Publicação
Pure and Applied Optics (Print edition) (United Kingdom)

Abstract
A passive all-fibre technique for Bragg wavelength shift detection is presented which can be considered as the minimum configuration for fibre grating sensing demodulation. The scheme involves a light source with a particular spectral profile that allows the direct tracking of Bragg wavelength shifts. Referencing to source power fluctuations is also provided. This simple technique shows satisfactory resolution over a large dynamic range. Experimental results are presented for temperature and strain measurements. © 1996 IOP Publishing Ltd.

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