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:
Jan. 06, 2026
Filed:
Sep. 15, 2023
Nec Laboratories America, Inc., Princeton, NJ (US);
Fatih Yaman, Princeton, NJ (US);
Shaobo Han, Princeton, NJ (US);
Eduardo Fabian Mateo Rodriguez, Tokyo, JP;
Yang Li, Atlanta, GA (US);
Yoshihisa Inada, Tokyo, JP;
Takanori Inoue, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
An advance in the art is made according to aspects of the present disclosure directed to methods for earthquake sensing that employ a supervisory system of undersea fiber optic cables. Earthquakes and other environmental disturbances are detected by monitoring the polarization of interrogation light instead of its phase. More specifically, our methods monitor the transfer matrix rather than just polarization and isolate disturbance location by monitoring eigenvalues of the polarization transfer matrix. From results obtained we have demonstrated experimentally that we can monitor disturbances that affect signal polarization on a span-by-span basis using High Loss Loop Back (HLLB) paths. It is shown that by measuring the polarization rotation matrix and determining the polarization rotation angle we can identify the span where the disturbance occurred with 35 dB extinction with no limitation on the magnitude of the disturbance and the number of affected spans.