Design, fabrication, and characterization of deep-etched waveguide gratings

Year: 2005

Authors: Kleckner T. C., Modotto D., Locatelli A., Mondia J. P., Linden S., Morandotti R., De Angelis C., Stanley C.R., van Driel H. M., Aitchison J.S.

Autors Affiliation: Lumerical Solut Inc, Vancouver, BC V6C 1H2, Canada; Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow G12 8LT, UK; Dipartimento di Elettronica per l’Automazione, Università di Brescia, Brescia 25123, Italy; Department of Physics, University of Toronto, Toronto ON M5S 1A7, Canada; Université du Québec, Varennes, QC J3X 1S2, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada.

Abstract: One-dimensional (I-D) deep-etched gratings on a specially grown AlGaAs wafer were designed and fabricated. The gratings were fabricated using state-of-the-art electron beam lithography and high-aspect-ratio reactive ion etching (RIE) in order to achieve the required narrow deep air slots with good accuracy and reproducibility. Since remarkable etch depths (up to 1.5 mu m), which completely cut through the waveguide core layer, have been attained, gratings composed of only five periods (and, thus, shorter than 6 mu m) have a bandgap larger than 100 nm. A defect was introduced by increasing the width of the central semiconductor tooth to create microcavities that exhibit a narrow transmission peak (less than 7 nm) around the wavelength of 1530 rim. The transmission spectra between 1460 and 1580 nm have been systematically measured, and the losses have been estimated for a set of gratings, both with and without a defect, for different periods and air slot dimensions. Numerical results obtained via a bidirectional beam propagation code allowed the evaluation of transmissivity, reflectivity, and diffraction losses. By comparing experimental results with the authors’ numerical findings, a clear picture of the role of the grating’s geometric parameters in determining its spectral features and diffractive losses is illustrated.

Journal/Review: JOURNAL OF LIGHTWAVE TECHNOLOGY

Volume: 23 (11)      Pages from: 3832  to: 3842

KeyWords: Integrated Optics
DOI: 10.1109/JLT.2005.857737

Citations: 15
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