Abstract: The subject matter described herein provides a method and a system for continuous-variable quantum key distribution, CVQKD, between a sender sub-system and a receiver sub-system. The method includes transmitting a quantum key distribution, QKD, signal from a quantum communication transmitter to a quantum communication receiver over a quantum communication channel. The method further includes performing post-processing including forward error correction, FEC as a part of reverse reconciliation between the receiver sub-system and the sender sub-system, where erroneous frames are discarded for key establishment. A value of the reconciliation efficiency, VRE ?, is set to be larger than 1.

Abstract: The present invention provides a performance monitoring device, an optical signal network with performance monitoring, and a performance monitoring method.

Abstract: Provided is a method for determining actual values of one or more characteristics of a phase-modulated optical signal. The method includes the steps of acquiring the phase-modulated optical signal by a non-linear device; generating an electrical spectrum based on the acquired phase-modulated optical signal; and extracting actual values of one or more characteristics of the phase-modulated optical signal from the electrical spectrum.

Abstract: A communication system transmits an input block of bits over a communication channel using a prefix tree that maps a dyadic distribution of compositions of output symbols to prefixes of variable lengths. A path to each leaf of the prefix tree is defined by a prefix formed by a unique sequence of binary values of a length equal to a depth of the leaf. Each leaf is associated with a composition that has at least a number of unique permutations equals to two in a power of a length of a suffix of the block of input bits. The system selects a composition identified in the prefix tree by a prefix in the input block of bits, permutes the selected composition according to a suffix in the input block of bits, and transmits the permuted composition over a communication channel.

Abstract: A communication system includes a data source to receive a block of bits, a processor, a memory, in connection with the processor, to store a distribution matcher associated with a probability mass function (PMF) configured to match a block of equally likely input bits to a fixed number of output bits with values distributed according to the PMF of the distribution matcher using the processor. In this case, the distribution matcher contains a set of parallel binary distribution matchers which specify fully a target PMF, and a transmitter front end to transmit a block of shaped bits over a communication channel, such that bits in a sequence of the blocks of shaped bits are distributed according to the target PMF.

Abstract: A communication system includes a data source to receive a block of bits, a memory to store a set of distribution matchers. Each distribution matcher is associated with a probability mass function (PMF) to match equally likely input bits to a fixed number of output bits with values distributed according to the PMF of the distribution matcher. Each distribution matcher is associated with a selection probability, such that a sum of joint probabilities of all distribution matchers equals a target PMF. A joint probability of a distribution matcher is a product of PMF of the distribution matcher with the selection probability of the distribution matcher.