Quantum communications system having at least one waveplate to alter pulse polarization and associated methods

A method of operating a quantum communications system comprising a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node, the method comprising:

• operating the transmitter node to generate quantum pulses at a pulse transmitter and dividing the quantum pulses at a pulse divider to divide each pulse having a plurality of X photons into a plurality of Y time bins with Y>X, the transmitter node also comprising at least one first waveplate upstream from the pulse divider to alter a polarization state of pulses travelling therethrough;
• operating the receiver node to recombine the divided quantum pulses at a pulse recombiner, and receiving the recombined pulses at a pulse receiver, the receiver node also comprising at least one second waveplate downstream of the pulse recombiner and being a conjugate of the at least one first waveplate.