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Switchable Optical Waveguide

IP.com Disclosure Number: IPCOM000075309D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Ash, EA: AUTHOR [+3]

Abstract

Waveguides switchable by selective application of voltages are provided in ferroelectric materials. Referring to illustration A, a grounded electrode 1 is provided on one surface of ferroelectric material 2 with electrodes 3 and 4 provided on the opposite side. The waveguide is formed in the ferroelectric material in the region between electrodes 3 and 4. With no voltage applied to electrodes 3 and 4, the ferroelectric material is polarized as in illustration B. When a voltage differential VA/+/ VB/++/ is applied across electrodes 3 and 4, 90 degree switching of polarization occurs as illustrated in C, providing a substantially higher effective index of refraction (lower velocity) in the switched region for light polarized essentially perpendicular to the surface.

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Switchable Optical Waveguide

Waveguides switchable by selective application of voltages are provided in ferroelectric materials. Referring to illustration A, a grounded electrode 1 is provided on one surface of ferroelectric material 2 with electrodes 3 and 4 provided on the opposite side. The waveguide is formed in the ferroelectric material in the region between electrodes 3 and 4. With no voltage applied to electrodes 3 and 4, the ferroelectric material is polarized as in illustration B. When a voltage differential VA/+/ VB/++/ is applied across electrodes 3 and 4, 90 degree switching of polarization occurs as illustrated in C, providing a substantially higher effective index of refraction (lower velocity) in the switched region for light polarized essentially perpendicular to the surface. The ferroelectric plate can be much thicker than the waveguide dimensions making use of a thin film non-essential.

Once the waveguide has been created, the voltages may be removed from the electrodes. To erase the waveguide, voltages VA/++/ VB/++/ are applied as in illustration D.

Ferroelectric mediums suitable for switching in this manner are ferroelectric ceramics such as those of the lead zirconate - lead titanate type (e.g., Pb(.97)La(.02)Zr(.65)Ti(.35)O(3)).

Phase modulation may be provided by applying a varying voltage across electrodes 3 and 4 as in illustration E.

In a leaky wave directional coupler as in illustration F, the region between waveguides 5 and 6 can be g...