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:
Oct. 21, 2025
Filed:
Feb. 15, 2022
British Telecommunications Public Limited Company, London, GB;
BRITISH TELECOMMUNICATIONS PUBLIC LIMITED COMPANY, London, GB;
Abstract
This invention provides a method of detecting an electromagnetic field, and a device for 5 performing said method, the method comprising the steps of: transmitting a probe signal at a probe frequency in a first probe signal path and a second probe signal path to an optical receiver, wherein the first probe signal path passes through a transmission medium and the probe frequency is set to excite electrons of the transmission medium from a ground state to a first excited state; transmitting a coupling signal at a coupling frequency in a first coupling signal path, wherein the first coupling signal path overlaps with the first probe signal path in the transmission medium in a first overlapping section, wherein the coupling frequency is set to excite electrons of the transmission medium to a predetermined excited state so as to induce an Electromagnetic Induced Transparency, EIT, effect in the transmission medium such that an incident electromagnetic field at the transmission medium causes a change in refractive index in the transmission medium at the first overlapping section such that there is a change in an optical path length difference between the first probe signal path and the second probe signal path; combining the first path of the probe signal, following its passage of the first overlapping section of the transmission medium, with the second path of the probe signal; and monitoring, at the optical receiver, the intensity of the combined first and second paths of the probe signal so as to detect the incident electromagnetic field at the first overlapping section of the transmission medium as a change in the intensity caused by the change in the optical path length difference between the first probe signal path and the second probe signal path.