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:
Jun. 29, 2021
Filed:
Jan. 26, 2018
Spi Lasers Uk Limited, Hedge End, GB;
Malcolm Paul Varnham, Alresford, GB;
SPI Lasers UK Limited, Hedge End, GB;
Abstract
Apparatus for optically isolating a laser () from external reflections, which apparatus comprises a mode filter () and a first optical fibre (), wherein: the first optical fibre () is a multimode optical fibre that supports a fundamental mode () and at least one higher order mode (); the mode filter () is defined by an optical attenuation which is higher for the higher order mode () than for the fundamental mode (); the mode filter () is configured to pass the fundamental mode () into the first optical fibre (); and the apparatus being characterized in that: the first optical fibre () comprises a long period grating (); and the long period grating () is defined by a period () selected to couple the fundamental mode () to the higher order mode () of the first optical fibre (); whereby if the fundamental mode () and the higher order mode () are reflected back into the first optical fibre () as back-reflected fundamental and higher order modes (), (), then the mode filter () optically attenuates the back-reflected higher order mode () more than the back-reflected fundamental mode () thereby isolating the external reflection.