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:
Aug. 11, 2026
Filed:
Jul. 09, 2021
National University of Singapore, Singapore, SG;
NATIONAL UNIVERSITY OF SINGAPORE, Singapore, SG;
Abstract
An optical power limiter, a method of fabricating the optical power limiter, a method of limiting optical power, a method of upper bounding information leakage in quantum cryptography, and a quantum cryptography system. The optical power limiter comprises an optical input port; an optical output port; an effective medium disposed between the input port and the output port; and a diaphragm disposed between the effective medium and the output port; wherein the effective medium has a thermo-optic coefficient such that a light beam entering the effective medium from the direction of the input port experiences a refractive index gradient in a direction perpendicular to a propagation direction in the effective medium as a result of absorption; and wherein the diaphragm is disposed in a path of the light beam for limiting how much of the light beam reaches the output port.