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Proceedings Paper

Modal behavior of novel silicon-overlay LiNbO3 waveguides
Author(s): Tiziana Conese-Bond; Robert F. Tavlykaev; Ramu V. Ramaswamy
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Paper Abstract

LiNbO3 waveguides with Si overlays are emerging as a basic building block for a variety of integrated-optic components. However, the development and optimization of these devices are, in large part, hindered by the lack of understanding of the specifics of the Si-on-LiNbO3 structure which appear to differ dramatically from those of the Si and LiNbO3 waveguides, considered separately. In this work, we provide a specific insight into the waveguiding properties of vertically stacked Si-on-LiNbO3 waveguides. In particular, we present a detailed theoretical analysis of the effect of the Si film on the modal characteristics (propagation constant and field distribution) of the structure. We show that for approximately 70% of all Si thicknesses, in the range from 0 to 1.6 micrometer, the highest-order normal mode of the entire structure has more than 99.9% of the total energy confined in the LiNbO3 region, i.e., beneath the Si overlay. This fact is quite intriguing given the fact a planar Si layer of submicron thickness on bulk LiNbO3 is already multi-moded. Furthermore, we show that the effective mode index of the structure is considerably modified compared to that of the LiNbO3 waveguide while the propagation loss is, on the other hand, practically unaffected (approximately 0.3 dB/cm) even in the presence of the lossy Si film, as confirmed by our previous experimental results. Evidently, large modulation of the effective index and low-loss propagation provide an ideal combination of properties suitable for the fabrication of high-reflectance corrugated waveguide gratings, essential for a number of practical devices, in particular, WDM filters.

Paper Details

Date Published: 22 December 1997
PDF: 11 pages
Proc. SPIE 3290, Optoelectronic Integrated Circuits II, (22 December 1997); doi: 10.1117/12.298240
Show Author Affiliations
Tiziana Conese-Bond, Politecnico di Bari (United States)
Robert F. Tavlykaev, Univ. of Florida (United States)
Ramu V. Ramaswamy, Univ. of Florida (United States)


Published in SPIE Proceedings Vol. 3290:
Optoelectronic Integrated Circuits II
Shih-Yuan Wang; Yoon-Soo Park, Editor(s)

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