Quantum multiplexing in single photons

L. Lanco

X. Zhang, Y. H. Lee, Bryn A. Bell +4 more

Generating N single photons simultaneously is a formidable challenge due to the lack of deterministic single photon sources. Recent work [New J. Phys. 19, 063013 (2017] has proposed a relative multiplexing scheme that can enhance the N single photons probability with a minimum of active switching resources. We experimentally demonstrate relative temporal multiplexing on two photon sources with a 90% additional enhancement over the standard temporal multiplexing scheme demonstrated previously. 88 ± 11% visibility of Hong-Ou-Mandel quantum interference verifies the indistinguishability of the heralded single photons after the synchronization. This proof-of-principle demonstration points out the potential significance of the relative multiplexing scheme for large-scale photonic quantum information processing.

X. Zhang, Yee Hui Lee, Bryn A. Bell +4 more

Interference between single photons lies at the heart of linear optical quantum computing (LOQC). However, the lack of deterministic single photon sources hinders the large-scale experimental demonstration and its practical applications, as the probability to generate N single photons simultaneously (denoted by N-photon hereafter) decreases exponentially with the increasing number of single photon sources [1]. Multiplexing is the leading proposal to overcome this challenge by relocating single photon from different modes to one fixed mode. The theoretical work [2] indicates that the relative time multiplexing (RMUX) scheme could significantly enhance this probability and meanwhile reduce the requirements of multiplexing system, such as switching speed and system complexity. In this paper, RMUX of two heralded single photon sources is demonstrated for the first time. We observe around 90% enhancement on the heralded photon pair rate, compared to the standard time multiplexing (SMUX) scheme [3].

Chao‐Yang Lu

Matyas I. Mechler, Петер Адам

We develop a method for optimizing the structure of general binary-tree multiplexers realized with asymmetric photon routers aiming at improving the performance of spatially multiplexed single-photon sources. Our procedure systematically considers all possible binary-tree multiplexers that can be constructed using a certain number of photon routers. Using this method one can select the multiplexer structure that leads to the highest single-photon probability for a given set of loss parameters characterizing the system. We determine the optimal general binary-tree multiplexers for experimentally realizable values of the transmission coefficients of the photon routers and that of the detector efficiency. We show that single-photon sources based on such optimal multiplexers yield higher single-photon probabilities than what can be achieved with single-photon sources based on any other spatial multiplexer considered in the literature. Our approach improves the performance of multiplexed single-photon sources even for small system sizes which is the typical situation in current experiments.

P. M. Intallura