US 11,722,297 B2
Device and method for generating a key
Martin Blasl, Dresden (DE); and Florenta Costache, Dresden (DE)
Assigned to Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V., Munich (DE)
Filed by Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V., Munich (DE)
Filed on Feb. 28, 2020, as Appl. No. 16/805,010.
Application 16/805,010 is a continuation of application No. PCT/EP2017/072241, filed on Sep. 5, 2017.
Prior Publication US 2020/0201134 A1, Jun. 25, 2020
Int. Cl. G02F 1/21 (2006.01); G02F 1/19 (2019.01); H04L 9/08 (2006.01)
CPC H04L 9/0861 (2013.01) [G02F 1/217 (2021.01); G02F 2201/122 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A device for generating a key, comprising:
a multimode interferometer which can be coupled to a light source and comprises a light path comprising a material comprising a controllable refraction index, the light path being configured to acquire light at an input side and influence the light under the influence of a locally varying refraction index of the material in order to provide influenced light at an output side;
a receiver configured to receive the influenced light that is influenced by the locally varying refraction index of the material at the output side; and
an evaluator configured to perform an evaluation based on the influenced light that is influenced by the locally varying refraction index of the material and to generate the key based on the evaluation;
an electrode arrangement configured to generate the locally varying refraction index based on locally varying electrical fields of the electrode arrangement;
wherein the receiver comprises an array of photodetectors and the evaluator is configured to perform, for each of the photodetectors, a threshold value decision as to whether a quantity detected in the respective photodetector is to be transferred to a binary 0 or a binary 1 and to acquire a bit sequence as the key by lining up the threshold value decisions.