Patent ID: 8331797
Filing Date: 2012-12-11
Classification: H04L

Abstract:
1. A polarization-controlled encoder comprising: a 2×2 3 dB beam splitter for splitting one injected optical pulse into two optical pulses, and for recombining the two optical pulses subjected to at least one of delay and modulation into one optical output; a delay line for delaying one of the two optical pulses; a phase modulator for phase-modulating the optical pulse according to a quantum key distribution protocol; and two 90 degree Faraday mirrors, wherein a first port on a first side of the 2×2 3 dB beam splitter is an output port of the polarization-controlled encoder, and a second port on the first side is an input port of the polarization-controlled encoder; a first port on a second side of the 2×2 3 dB beam splitter is connected to one of the two 90 degree Faraday mirrors, and a second port on the second side is connected to the other of the two 90 degree Faraday mirrors; the delay line being connected between one port of the 2×2 3 dB beam splitter and one of the two 90 degree Faraday mirrors; and the phase modulator being connected between a port of the 2×2 3 dB beam splitter and at least one of one of the two 90 degree Faraday mirrors and the output port of the polarization-controlled encoder.