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:
Mar. 30, 1999
Filed:
Feb. 10, 1997
Uziel Koren, Fair Haven, NJ (US);
Anat Sneh, Branchburg, NJ (US);
Jane Elisa Zucker, Miami, FL (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
Methods and apparatus for performing optical signal switching or other optical routing functions in an optical device or system, in which crosstalk induced by modal interference is suppressed by providing appropriate loss, gain and/or refractive index changes in different parts of a switch structure. An exemplary optical signal switch includes first and second branches each having a refraction-controlled section and an absorption-controlled section. An optical signal path over which an optical signal propagates in passing through the switch is selected to include a portion of at least one of the first and second branches, such that one of the first and second branches is a selected branch and the other branch is a non-selected branch. The refraction-controlled section of the selected branch is configured in a high effective refractive index state which allows the optical signal to propagate along at least a portion of the selected branch, while the refraction-controlled section of the non-selected branch is configured in a low effective refractive index state. The absorption-controlled section of the selected branch is configured in a low absorption state, while the absorption-controlled section of the non-selected branch is configured in a high absorption state to reduce crosstalk within the optical switch. An effective refractive index in a given refraction-controlled section may be provided using electro-refractive techniques such as the quantum-confined Stark effect (QCSE) or the Franz-Keldysh effect, or by carrier-induced effects such as carrier injection or carrier depletion. An absorption change in a given absorption-controlled section may be provided using electro-absorptive techniques or a gain-switching technique. The switch may be configured as a Y-branch switch, a directional coupler, or in other suitable configurations, and may be interconnected with other similar switches to construct 1.times.N, N.times.1, N.times.M and N.times.N switch arrays.