Integrated spatial multiplexing of heralded single-photon sources

Abstract

The non-deterministic nature of photon sources is a key limitation for single-photon quantum processors. Spatial multiplexing overcomes this by enhancing the heralded single-photon yield without enhancing the output noise. Here the intrinsic statistical limit of an individual source is surpassed by spatially multiplexing two monolithic silicon-based correlated photon pair sources in the telecommunications band, demonstrating a 62.4% increase in the heralded single-photon output without an increase in unwanted multipair generation. We further demonstrate the scalability of this scheme by multiplexing photons generated in two waveguides pumped via an integrated coupler with a 63.1% increase in the heralded photon rate. This demonstration paves the way for a scalable architecture for multiplexing many photon sources in a compact integrated platform and achieving efficient two-photon interference, required at the core of optical quantum computing and quantum communication protocols.

Single photons from dissipation in coupled cavities

“…An efficient single-photon source should be benchmarked against the current state-of-the-art, represented by quantum emitters in resonant cavities [4][5][6][7][8][9][10][11], and heralded sources [12][13][14][15][16]. Recent advances have led to closeto-ideal single-photon operation for both schemes.…”

“…Although the degree of control over these systems is steadily improving, they basically operate at cryogenic temperatures and (or) imply significant fabrication challenges, particularly with respect to integration and scalability in future photonic platforms. On the other hand, nondeterministic sources relying on heralding protocols are now operating at room temperature in Silicon [12][13][14][15][16], but they require a significant input power to trigger the four wave mixing mechanism.…”

Optimization of periodic single-photon sources based on combined multiplexing

“…(4) can describe losses due to coupling to a single-mode fiber [56] while expressions similar to Eqs. (5)- (7) with the choice V r = V t can describe the losses of fiber coupled optical switches [46][47][48]. However, in such waveguide-based systems the different transmission probabilities are smaller than the corresponding parameters of the bulk optical setups.…”

“…In addition, the growing number of required HSPSs appears as a drawback in an experimental implementation. Spatial multiplexing has been realized in experiments indeed, yet with only up to four heralded single-photon sources [46][47][48][49].…”

Generation and manipulation of entangled photons on silicon chips

“…However, further downsizing of the photon source is of great importance in a view to realizing quantum information processing systems with higher integration density. Such integration includes a multiplexed single-photon source [73][74][75][76], which was proposed to realize a near-deterministic heralded singlephoton source from probabilistic photon-pair sources based on spontaneous parametric processes. The source is a bundle of many identical heralded single-photon sources, each of which generates photon pairs at a low rate (~0.01 pairs/pulse).…”