Elimination of mode coupling in multimode continuous-variable key distribution
Radim Filip, Ladislav Mišta, Petr Marek · Physical Review A · 2005
A multimode channel can be utilized to substantially increase the capacity of quantum continuous-variable key distribution. Beyond losses in the channel, an uncontrollable coupling between the modes of the channel typically degrades the capacity of multimode channels. For the key distribution protocol with simultaneous measurement of both complementary quadratures we propose a feasible method to eliminate any undesirable mode coupling by only the receiver's appropriate measurement and data manipulation. It can be used to substantially increase the capacity of the channel, which has an important application in practical continuous-variable quantum cryptography.