Si-Waveguide with Ferro-Electric Liquid Crystal Cladding for Use in Optical Switching Devices

Katsumi NAKATSUHARA  Toyokazu SASAKI  Hiroki SATO  Takakiyo NAKAGAMI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.5   pp.1055-1060
Publication Date: 2007/05/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.5.1055
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Advances in Integrated Photonic Devices)
Category: High Index Contrast and Photonic Crystal Devices
Keyword: 
optical switching device,  ferro-electric liquid crystal,  waveguide device,  

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Summary: 
We studied a silicon (Si) waveguide using ferro-electric liquid crystal (FLC) cladding for various applications in optical networks. The FLCs in the cladding layer change their effective refractive index corresponding to the applied voltage polarity, and give a phase shift to the traveling lightwave in the waveguides. The phase change coefficients of three-layer slab waveguides with FLC/Si/SiO2 structure were calculated. We observed an amplitude change in the output light of an experimental modulator consisting of a Mach-Zehnder interferometer with FLC-cladding Si-rib waveguides on a silicon-on-insulator wafer, and evaluated the phase shift at a wavelength of 1550 nm. We propose optical switching devices using Si-rib waveguide Mach-Zehnder interferometers having FLC cladding. Switching of experimental devices operating at 1550 nm wavelength was demonstrated.