Optical switch element and a liquid crystal light directional coupler used in the optical switch element

U.S. Patent Number: 5381251

Abstract: An optical switch element for selectively transmitting or shielding light from a first optical wave guide to a second optical wave guide is disclosed. The optical switch element includes a first optical switch portion and a second optical switch portion. The first optical switch portion includes: a part of said first optical wave guide; a first liquid crystal layer optically connected to said part of said first optical wave guide; a first part of said second optical wave guide optically connected to said first liquid crystal layer; and first voltage applying means for applying voltage to said first liquid crystal layer to change a refractive index of said first liquid crystal layer. The second optical switch portion includes: a second part of said second optical wave guide; a second liquid crystal layer optically connected to said second part of said second optical wave guide; and second voltage applying means for applying voltage to said second liquid crystal layer to change a refractive index of said second liquid crystal layer. In a case where light is transmitted from said first optical wave guide to said second optical wave guide, said first optical switch portion is in a transmitting state, and said second optical switch portion is in a shielding state, and in another case where light is shielded from said first optical wave guide to said second optical wave guide, said first optical switch portion is in a shielding state, and said second optical switch portion is in a transmitting state.

Inventors: Nonomura; Keisaku (Nara, JP), Shigeta; Mitsuhiro (Kyoto, JP)

Assignee: Sharp Kabushiki Kaisha (Osaka, JP)

Application Number: 08/044,144

Issued: 1995-01-10

Expired: 2007-01-10

Classes: 349/24 ; 349/172; 349/65; 385/1

Field of search: 359/42,38,39,94,100,245,246 385/4,8,9,16,17

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