QUANTUM CRYPTOGRAPHY COMMUNICATION APPARATUS

• Main Authors: HASEGAWA, TOSHIO, NISHIOKA, TSUYOSHI, ISHIZUKA, HIROKAZU
• Format: Patent
• Language: English; French; German
• Published: 17.11.2010
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; TRANSMISSION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

Provided is a quantum cryptography communication apparatus capable of preventing a go photon pulse from being phase modulated and also capable of freely selecting any repetitive frequency of a light source. In the quantum cryptography communication apparatus, a quantum receiver apparatus includes: a light source; an optical path loop having a multiplexing/interfering means for generating time difference twin photon pulses from the photon pulses of the light source and for multiplexing and causing interference between a signal optical pulse corresponding to a retrograde quantum and a reference optical pulse; a bypass optical path having a phase modulator for phase modulating only the received reference optical pulse; and a photon detector for observing the interfered light passed through the optical path loop, and a quantum transmitter apparatus includes: a polarized wave rotating means for rotating polarization planes of the twin photon pulses at a right angle in a non-reciprocal manner; a phase modulator for phase modulating and returning the signal optical pulse passed through the polarized wave rotating means, to the quantum receiver apparatus; and a beam attenuating means.