The ability to coherently store and manipulate optical information across multiple degrees of freedom is a central requirement for scalable quantum information processing and multidimensional quantum computing. Although polarization- and space-division multiplexings have substantially increased the capacity of classical optical systems, their extension to coherent and reconfigurable photonic memories remains a key challenge. Here, we demonstrate a two-spin-channel-multiplexed photonic memory based on chiral stimulated Brillouin scattering in a chiral photonic crystal fiber. Exploiting the intrinsic preservation of circular polarization in the chiral photonic crystal fiber, left- and right-circularly polarized modes serve as two orthogonal and independent storage channels. Multiple optical data pulses can be selectively or simultaneously stored and retrieved by simply controlling the polarization states of the write-read pulses. The storage time is continuously tunable, and the underlying Brillouin process preserves coherence and channel orthogonality. The result establishes chiral Brillouin scattering as an effective mechanism for spin-channel-multiplexed optoacoustic light storage, providing a promising route toward multidimensional photonic memories based on multiple optical degrees of freedom. It also opens new opportunities for classic and quantum information processing, reconfigurable quantum networks, and hybrid light–matter interfaces based on coherent acoustic excitations.
The ability to coherently store and manipulate optical information across multiple degrees of freedom is a central requirement for scalable quantum information processing and multidimensional quantum computing. Although polarization- and space-division multiplexings have substantially increased the capacity of classical optical systems, their extension to coherent and reconfigurable photonic memories remains a key challenge. Here, we demonstrate a two-spin-channel-multiplexed photonic memory based on chiral stimulated Brillouin scattering in a chiral photonic crystal fiber. Exploiting the intrinsic preservation of circular polarization in the chiral photonic crystal fiber, left- and right-circularly polarized modes serve as two orthogonal and independent storage channels. Multiple optical data pulses can be selectively or simultaneously stored and retrieved by simply controlling the polarization states of the write-read pulses. The storage time is continuously tunable, and the underlying Brillouin process preserves coherence and channel orthogonality. The result establishes chiral Brillouin scattering as an effective mechanism for spin-channel-multiplexed optoacoustic light storage, providing a promising route toward multidimensional photonic memories based on multiple optical degrees of freedom. It also opens new opportunities for classic and quantum information processing, reconfigurable quantum networks, and hybrid light–matter interfaces based on coherent acoustic excitations.
Photonic memory is an important building block to delay, route, and buffer optical information, for instance, in optical interconnects or for recurrent optical signal processing. Photonic–phononic memory based on stimulated Brillouin–Mandelstam scattering (SBS) has been demonstrated as a coherent optical storage approach with broad bandwidth, frequency selectivity, and intrinsic nonreciprocity. Here, we experimentally demonstrate the storage of quadrature-phase encoded data at room temperature and at cryogenic temperatures. We store and retrieve the 2-bit states {00, 01, 10, 11} encoded as optical pulses with the phases {0,π2,π,3π2}—a quadrature phase shift keying signal. The 2-bit signals are retrieved from the acoustic domain with a global phase rotation of π, which is inherent in the process due to SBS. We also demonstrate full phase control over the retrieved data based on two different handles: by detuning slightly from the SBS resonance or by changing the storage time in the memory scheme, we can cover the full range [0, 2π). At a cryogenic temperature of 3.9 K, we have increased readout efficiency as well as gained access to longer storage times, which results in a detectable signal at 140 ns. All in all, the work sets the cornerstone for optoacoustic memory schemes with phase-encoded data.
High Resolution Image Download MS PowerPoint Slide In recent years, remarkable advances in photonic computing have highlighted the need for photonic memory, particularly high-speed and coherent random-access memory. Addressing the ongoing challenge of implementing photonic memories is required to fully harness the potential of photonic computing. A photonic-phononic memory based on stimulated Brillouin scattering is a possible solution, as it coherently transfers optical information into sound waves at high-speed. Such an optoacoustic memory has shown great potential as it fulfills key requirements for high-performance optical random-access memory due to its coherence, on-chip compatibility, frequency selectivity, and high bandwidth. However, the storage time has so far been limited to a few nanoseconds due to the nanosecond decay of the acoustic wave. In this work, we experimentally enhance the intrinsic storage time of an optoacoustic memory by more than 1 order of magnitude and coherently retrieve optical information after a storage time of 123 ns. This is achieved by employing the optoacoustic memory in a highly nonlinear fiber at 4.2 K, increasing the intrinsic phonon lifetime by a factor of 6. We demonstrate the capability of our scheme by measuring the initial and readout optical data pulses with a direct and double homodyne detection scheme. Finally, we analyze the dynamics of the optoacoustic memory at different cryogenic temperatures in the range of 4.2–20 K and compare the findings to continuous wave measurements. The extended storage time is beneficial not only for photonic computing but also for Brillouin applications that require long phonon lifetimes, such as optoacoustic filters, true-time delay networks, and synthesizers in microwave photonics.
We experimentally show an optoacoustic memory based on Brillouin scattering with one order of magnitude higher storage time that retrieves amplitude and phase information after 120ns. We increase the intrinsic phonon lifetime of a highly nonlinear fiber by a factor of six by cooling the fiber down to 4.2K. We demonstrate the performance enhancement of optoacoustic memory by measuring the amplitude and phase information of an initial data pulse and its corresponding retrieved readout pulse using direct and double homodyne detection. Furthermore, we present the influence of different cryogenic temperatures between 4.2K and 20K on the optoacoustic memory and compare the results with continuous-wave measurements. In conclusion, our work can not only accelerate photonic computing but also advance other applications of stimulated Brillouin scattering that require long phonon lifetimes, such as optoacoustic filters in microwave photonics. In addition, the presented long-lasting sound wave optoacoustic memory is compatible with active acoustic refreshment technique potentially leading to all-optical coherent memory beyond 1 μs.
Storage and retrieval of optical quantum states are key elements for the realization of quantum communication and quantum networks. Here, we propose to realize a memory for light states in Brillouin-active waveguides. It is achieved by transferring quantum states between optical photons and acoustic phonons via Brillouin anti-Stokes scattering. By controlling the optoacoustic interaction with pulsed pumps, we demonstrate that it is possible to write, store, and read out of optical quantum states with high fidelity in state-of-the-art Brillouin-active waveguides.
In order to deliberately control the flow of optically encoded information, optical storage is an indispensable tool, but it must maintain all the advantages of optics, such as i.e. the coherence, the bandwidth and capacity. An elegant approach to this problem is to coherently transfer the information from optical to acoustic waves via an opto-mechanical nonlinearity, such as stimulated Brillouin scattering (SBS). The basic concept was first demonstrated in highly nonlinear fiber by Zhu et al. [1]. Recently, we experimentally demonstrated the coherence of this memory concept by encoding different amplitude and phase levels in an integrated photonic circuit [2] and the compatibility with wavelength division multiplexing [3]. This concept is based on a straight waveguide without the need of a structural resonance as an opto-mechanical resonator or a photonic crystal cavity. Therefore, the memory operation can be arbitrarily positioned on the photonic chip and can even be repeated and cascaded several times, via external control light pulses.
Quantum memories for optical states are essential resources for quantum communication and information processing. We propose a quantum memory protocol based on coherent photon-phonon transduction in a Brillouin-active optical waveguide supporting traveling acoustic modes. A pulsed pump drives an effective beam-splitter interaction between optical and acoustic fields, enabling the mapping of a propagating optical quantum state onto a traveling phononic excitation and its subsequent retrieval on demand. Using a continuum optoacoustic model, we show that the protocol enables broadband quantum state storage in a distributed medium without relying on discrete cavity modes. Analytical and numerical results demonstrate high-fidelity storage and retrieval of squeezed and entangled states under experimentally realistic parameters. The memory bandwidth is set by the Brillouin interaction and can reach hundreds of MHz. Our results identify continuum Brillouin optomechanical systems as a scalable platform for broadband quantum memories and multimode quantum signal processing.