Fig. 1: Theoretical scheme of coherent quantum fingerprinting with wavelength-division multiplexing.
From: Efficient experimental quantum fingerprinting with channel multiplexing and simultaneous detection
Alice (Bob) applies error-correction code to her (his) input x(y) and obtains E(x)(E(y)). Then she (he) divides E(x)(E(y)) into k subcodewords and prepares the corresponding subfingerprints Ej(x)(Ej(y)) in k-different wavelength channels. The k subfingerprints are multiplexed into one single-mode fiber through a multiplexer (MUX) and sent to Charlie’s beam splitter. On Charlie’s station, demultiplexing is not required. The k pairs of pulses interfere simultaneously and share a pair of single-photon detectors D0 and D1. Charlie records the total counts at D0 and D1, based on which Charlie determines whether the inputs are the same or different.
