Remote distribution of non-classical correlations over 1250 modes between a telecom photon and a $^{171}$Yb$^{3+}$:Y$_2$SiO$_{5}$ crystal

Abstract

Quantum repeaters based on heralded entanglement require quantum nodes that are able to generate multimode quantum correlations between memories and telecommunication photons. The communication rate scales linearly with the number of modes, yet highly multimode quantum storage remains challenging. In this work, we demonstrate an atomic frequency comb quantum memory with a time-domain mode capacity of 1250 modes and a bandwidth of 100 MHz, to our knowledge the largest number of modes stored in the quantum regime. The memory is based on a Y2SiO5 crystal doped with 171 Yb 3+ ions, with a memory wavelength of 979 nm. The memory is interfaced with a source of non-degenerate photon pairs at 979 and 1550 nm, bandwidth-matched to the quantum memory. We obtain strong non-classical second-order cross correlations over all modes, for storage times of up to 25 µs. The telecommunication photons propagated through 5 km of fiber before the release of the memory photons, a key capability for quantum repeaters based on heralded entanglement and feed-forward operations. Building on this experiment should allow distribution of entanglement between remote quantum nodes, with enhanced rates owing to the high multimode capacity.

Storage of 1650 modes of single photons at telecom wavelength

“…Storage of multiple temporal modes in one spectral channel has also been achieved, for instance the storage of 1250 temporal modes in Yb 3+ :Y 2 SiO 5 at 979 nm [46]. Furthermore, the storage of multiple temporal modes in multiple channels has been reported, including storage of 12 spectro-spatial-temporal modes [39] and 130 spectro-temporal modes [40] in Pr 3+ :Y 2 SiO 5 at 606 nm.…”

“…Multiple storage channels have been demonstrated with the AFC protocol in the spatial domain 34 and in the spectral domain [27][28][29] , which is facilitated by the inhomogeneous broadening in REID materials. Storage of multiple temporal modes in one spectral channel has also been achieved, for instance the storage of 1250 temporal modes in Yb 3+ :Y 2 SiO 5 at 979 nm 46 . Furthermore, the storage of multiple temporal modes in multiple channels has been reported, including storage of 12 spectro-spatial-temporal modes 39 and 130 spectro-temporal modes 40 in Pr 3+ :Y 2 SiO 5 at 606 nm.…”