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:
Dec. 24, 2002
Filed:
Aug. 05, 1999
Shigeru Nakamura, Tokyo, JP;
Kazuhito Tajima, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
Concerning an all-optical switch which makes use of a nonlinear change of a refractive index of a nonlinear waveguide caused by absorption of a control light, a method that an electrostatic field is applied to the nonlinear waveguide is known as an effective one for shortening a lifetime of the carrier which obstructs an improvement of a repetition frequency of a switching operation. The semiconductor nonlinear waveguide is constituted of a pin-structure which comprises a nondoped InGaAsP optical waveguide, an under cladding layer formed of a N-type InP substrate and an upper cladding layer formed of a p-type InP layer and etc. Moreover, the under and upper cladding layers are electrically shortcircuited via upper and lower electrodes. Since a builtin voltage caused by a difference in Fermi level between n and p-type cladding layers is applied to a InGaAsP optical waveguide, and electrostatic field can be applied to the optical waveguide of the pin structure to some extent without using a constant-voltage power supply. By application of the aforementioned electrostatic field, the effective lifetime of the carrier is shortened, and a repetition frequency of an switching operation of the all-optical switch can be improved.