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Experimental Quantum Key Distribution with Gaussian-modulated Coherent States (GMCS). Leilei Huang M.A.Sc Photonics Group. Key Distribution. Public-key: RSA Security relies on computational difficulties in solving certain mathematical problems. Private-key: One-time-pad. Bob. Alice.
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Experimental Quantum Key Distribution with Gaussian-modulated Coherent States(GMCS) Leilei Huang M.A.Sc Photonics Group
Key Distribution • Public-key: RSA Security relies on computational difficulties in solving certain mathematical problems. • Private-key: One-time-pad Bob Alice • Quantum Key Distribution ! • (QKD) • Provide Alice and Bob with a random secret key.
Continuous-variable Coherent State Protocol P M A M |X+iP> Homodyne detection Coherent source The non-commuting quadrature X and P shot-noise limited X or P Gaussian distribution Random number generator Bob Data Post-Processing Alice share correlated strings of continuous data, distill correlated bits PM: Phase Modulator AM: Amplitude Modulator
Continuous-variable Coherent State Protocol • Non-commuting quadrature X and P. • If Eve measures one quadrature, she will disturb the Gaussian distribution of the other one. Disturb Gaussian Distribution !!! Alice Bob
Experiment Setup Thank you! F. Grosshans et al., Nature 421, 238 (2003) Our proposed System • First fiber based demonstration 2. Truly random key transmission • 3. Improve the secret key rate 4. Extend transmission distance • 5. Commercially available components