The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 02, 1992
Filed:
Feb. 28, 1990
Keiro Komatsu, Tokyo, JP;
Kunio Tada, Urawa, JP;
Hiroyasu Noguchi, Tagawa, JP;
Akira Suzuki, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
An optical directional coupler switch is fabricated from a semiconductor substrate having a (111) plane. Thus, refractive indexes are changed for TE and TM modes by electrooptic effect, although the change amount is different between TE and TM modes. Therefore, a switching operation is realized for an incident light having any polarization. A device length L is preferrably set to meet an equation of 'L.sub.TE .ltoreq.L.ltoreq.L.sub.TM ' (L.sub.TE and L.sub.TM are coupling lengths for TE and TM modes) to decrease a cross-talk, even if the coupling lengths are different between TE and TM modes, considering that the difference is small.