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Proceedings Paper

Temperature optical sensor based on a silicon bimodal Y branch
Author(s): Giovanni Breglio; Giuseppe Coppola; Antonello Cutolo; Andrea Irace; Marco Bellucci; Mario Iodice
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Paper Abstract

A novel temperature optical sensor configuration, based on mode mixing principle, is theoretically discussed. The sensing element consists of a single-mode all-silicon waveguide, followed by a two-modes section, which acts as sensing region, and an output Y branch to separate the two output channels. The fundamental mode coming from input waveguide excites both the fundamental mode and the first higher order mode in the sensing region. The interference between the two propagating modes in the sensing region produces a periodically repeated optical intensity distribution along the propagation axis. It is possible to observe a light steering from one output channel to the other caused by the temperature change of the structure itself. This fact is related to the variation of the material refractive index with the temperature, that is the thermo-optic effect, which implies a variation of the mode effective refractive indices, and, consequently, a phase shift between the modes themselves. In this way, a continuous variation of the power distribution on the two output waveguides as a function of the temperature can be observed. A simultaneous acquisition of both output signals, followed by a simple elaboration, allows obtaining a temperature evaluation independent on light source instability. Moreover, it is possible to design the device in order to obtain the desired initial output power distribution on two channels. This permits to design sensors characterized by greater accuracy, if we use the linear part of the optical transfer function, or larger measure range, if we utilize the whole output excursion.

Paper Details

Date Published: 18 May 2001
PDF: 7 pages
Proc. SPIE 4293, Silicon-based and Hybrid Optoelectronics III, (18 May 2001);
Show Author Affiliations
Giovanni Breglio, Univ. degli Studi di Napoli Federico II (Italy)
Giuseppe Coppola, Univ. degli Studi di Napoli Federico II (Italy)
Antonello Cutolo, Univ. degli Studi del Sannio (Italy)
Andrea Irace, Univ. degli Studi di Napoli Federico II (Italy)
Marco Bellucci, Istituto di Ricerca per l'Ellettromagnetismo e i Componenti Elettronici (Italy)
Mario Iodice, Istituto di Ricerca per a'Ellettromagnetismo e i Componenti Elettronici (Italy)

Published in SPIE Proceedings Vol. 4293:
Silicon-based and Hybrid Optoelectronics III
David J. Robbins; John Alfred Trezza; Ghassan E. Jabbour, Editor(s)

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