Publications

Publications by CAP

1999

<title>Surveillance of fiber optic and electric power cables using fiber Bragg grating sensors</title>

Authors
Araujo, FM; Teixeira, M; Ferreira, LAA; Dias, IM; Quintela, A; Castro, JL;

Publication
Fiber Optic and Laser Sensors and Applications; Including Distributed and Multiplexed Fiber Optic Sensors VII

Abstract

1999

Surveillance of fiber optic cables and electric power cables using fiber Bragg grating sensors

Authors
Araujo, FM; Teixeira, M; Ferreira, LA; Dias, I; Quintela, A; Castro, JL;

Publication
FIBER OPTIC AND LASER SENSORS AND APPLICATIONS: INCLUDING DISTRIBUTED AND MULTIPLEXED FIBER OPTIC SENSORS VII

Abstract
We report on the integration of optical fiber containing Bragg gratings in the structure of both optical and power cables. It is shown that fiber Bragg gratings provide an efficient method to monitor quasi-distributed mechanical strength along optical cables. This technology is also applied to the monitoring of temperature in power cables for transmission/distribution infrastructures. We show that there are no losses introduced during the cabling process, and the temperature sensitivity of the fiber Bragg grating was found to be only slightly affected by the extrusion process. Results are presented for cable operation in real environment.

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1999

Tunable optical oscillator based on a DFB-MQW laser and a fiber loop reflector

Authors
Frazâo, O; Tavarcs, P; Da, JF; Hocha,; Ribeiro, LB;

Publication
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL

Abstract
In this paper, we report experimental results on the frequency control of an optical oscillator based on a single-cavity DFB-MQW laser and a fiber loop reflector. Self-pulsation frequency can be controlled by changing the step amplitude of the laser bias current.

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1999

Continuous frequency control from 5 to 10 GHz of an optical oscillator

Authors
Frazao, O; Tavares, P; Cunha, AF; Ribeiro, L; Ferreira da Rocha, J;

Publication
Proceedings of the Annual IEEE International Frequency Control Symposium

Abstract
An experimental set-up configuration, which allows the self-pulsation frequency of an optical oscillator to be modified by simply adjusting the bias current between 25 and 100 mA, is presented. For lower currents, the self-pulsation frequency is near 6 GHz and the device is stable. For higher currents, the self-pulsation frequency increases to near 11 GHz.

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1999

Experimental results on high bit rate optical synchronization of RZ soliton type signals

Authors
Tavares, P; Frazao, O; Cunha, A; Ribeiro, LB; da Rocha, JF;

Publication
18TH CONGRESS OF THE INTERNATIONAL COMMISSION FOR OPTICS: OPTICS FOR THE NEXT MILLENNIUM, TECHNICAL DIGEST

Abstract
We report the development of a lab prototype for all optical synchronization at 10GHz. Adjusting the distance between the AR coated facet of the MQW semiconductor laser and the ferrule it was possible to induce the self-pulsation needed for correct operation. In the presence of optical RZ signals, the device leaves is natural pulsation frequency synchronizing with the input data.

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1999

High bit rate optical synchronization of RZ signals using eternal cavity DFB lasers

Authors
Tavares, P; Frazao, O; Cunha, A; Ribeiro, LB; da Rocha, JF;

Publication
3RD IBEROAMERICAN OPTICS MEETING AND 6TH LATIN AMERICAN MEETING ON OPTICS, LASERS, AND THEIR APPLICATIONS

Abstract
We report the development of two lab prototypes for all optical clock recovery and optical synchronization, composed by a DFB semiconductor laser driven by a ultra-fast switching current circuit. It was verified that a fast switch of the laser bias current accomplished by the strong feedback in the external cavity induce the self-pulsation needed for correct operation. In the presence of optical RZ signals, the device leaves is natural pulsation frequency synchronizing with the input data.

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