Asymmetric architecture for heralded single-photon sources

Abstract

Single-photon sources represent a fundamental building block for optical implementations of quantum information tasks ranging from basic tests of quantum physics to quantum communication and high-resolution quantum measurement. In this paper, in order to compare the effectiveness of different designs, we introduce a single-photon source performance index, based on the maximum probability of generating a single photon that still guarantees a given signal-to-noise ratio. We then investigate the performance of a multiplexed system based on asymmetric configuration of multiple heralded single-photon sources. The performance and scalability comparison with both currently existing multiple-source architectures and faint laser configurations reveals an advantage the proposed scheme offers in realistic scenarios. This analysis also provides insights on the potential of using such architectures for integrated implementation

Heralded single-photon sources for quantum-key-distribution applications

“…A thorough analysis of multiple heralded sources with post-selection has been performed in [16]. From their work, it emerges that, in the case of imperfect devices, the symmetric scheme suffers from a scalability issue, with a decrease in one photon probability when increasing the number of crystals.…”

“…From their work, it emerges that, in the case of imperfect devices, the symmetric scheme suffers from a scalability issue, with a decrease in one photon probability when increasing the number of crystals. In [16], a new asymmetric scheme (AMHPS) that does not present this problem was also proposed. The scheme is shown in Fig.…”

“…This article specializes the analysis to the case of the multiple-crystal heralded photon sources studied in [16], parametrizing them using their design parameters instead of the more experimentally relevant efficiency and second-order correlation. Moreover, the security analysis is extended to the case of general attacks by Eve [19].…”

“…We indicate the probability of emitting n photon by P M n (µ; m) for the MHPS and P S n (µ; m, η, γ) and P A n (µ; m, η, γ) for the SMHPS and the AMHPS, respectively [16] (see Appendix A for a more detailed description of the different architectures and the explicit expressions of P M n , P S n and P A n ) . The source is pumped by a pulsed laser, with phase randomization between each pulse [19].…”

“…In this work, we follow [16], and compare the performances of the different architectures and their efficacy in a practical QKD implementation. An ideal MHPS in the configuration proposed by Migdall et al, with perfect heralding efficiency and an m-to-1 optical switch with no losses, is studied first, in order to give an account of the maximum performance that can be obtained with this kind of sources.…”