Patent ID: 9246602
Filing Date: 2016-01-26
CPC Classification: H04B,H04L

Claim Text:
1. A quantum encryption communication apparatus of a transmission side which performs a communication process with a receiving apparatus based on quantum encryption, comprising: a light source unit which generates a light pulse; a polarization modulating unit which performs polarization modulation of the light pulse by using a variable wavelength plate; a controller which drives the variable wavelength plate to convert a polarization state of the light pulse to one of a plurality of predetermined polarization bases at random by generating a random number and supplying the random number to the polarization modulating unit, wherein the controller drives the variable wavelength plate at random based on the generated random number so that a phase difference occurring in polarization components along a FAST axis and a SLOW axis is one of 0 degrees, 90 degrees, 180 degrees, and 270 degrees according to a time point of an arrival of the light pulse, wherein the polarization modulating unit emits the light pulse with the polarization state converted to the one of the plurality of polarization bases to the receiving apparatus; and a communication unit which receives from the receiving apparatus a detection result identifying the polarization state, of the emitted light pulse, detected in the receiving apparatus, wherein the polarization state includes at least one of: