公开(公告)号：US20250044129A1

公开(公告)日：2025-02-06

申请号：US18680937

申请日：2024-05-31

Applicant: Nokia Solutions and Networks Oy

Inventor： Mikael Mazur ,  Nicolas Fontaine

IPC: G01D5/353 ,  G01H9/00

Abstract: A method and apparatus of OFDR are disclosed, in which a pair of probe signals are launched, on mutually orthogonal channels, into the optical fiber cable that is to be monitored. In a digital processing circuit, phase noise is cancelled from the return signals after detecting them in their respective mutually orthogonal channels and after demodulating them, by combining them such that noise components of the respective demodulated signals are mutually cancelled. In embodiments, a conjugate pair of probe signals are launched, on mutually orthogonal channels, into the optical fiber cable.

公开(公告)号：US20220286201A1

公开(公告)日：2022-09-08

申请号：US17580202

申请日：2022-01-20

Applicant: Nokia Solutions and Networks OY

Inventor： Mikael Mazur ,  Nicolas Fontaine

IPC: H04B10/07

Abstract: A fiber-optic communication system having two optical channels characterized by different respective group velocities. In an example embodiment, the system comprises an optical receiver capable of measuring a difference in the time of arrival thereto, by way of the two optical channels, of the corresponding signal disturbances caused by a remote ambient event, such as an earthquake or a lightning strike. A signal processor of the receiver can then use the measured time-of-arrival difference to estimate the distance, along the fiber, to the location of the remote ambient event. In some example embodiments, the two optical channels may be different wavelength channels or different spatial modes of a multimode fiber. In some example embodiments, at least one of the two channels may be a payload-data-bearing channel.