Towards practical quantum repeaters using room-temperature vapor technology

Quantum entanglement sources and memories are critical for quantum networking architecture. To build memory-assisted quantum repeaters, the entanglement source needs to generate photons that are ideal for optical fiber transmission and are simultaneously suitable for storage and buffering in a quantum memory. It is ideal to address these challenges without the need of additional quantum devices such as frequency converters. Most of the available sources, such as spontaneous parametric down conversion sources (SPDC), generate photons that are too spectrally broad for interfacing with atomic quantum devices. The use of optical parametric amplifiers allows for addressing this issue with the cost of significantly increasing the complexity of the devices.   

In this talk we will discuss our progress towards building bichromatic entanglement sources using the process of spontaneous four wave mixing in a warm rubidium vapor. We customize this process to generate entangled photons at 1324nm, suitable for fiber transmission, and 795nm, ideal as an input for room temperature Rb-based quantum memories. Noticeably, the photons' linewidths are typically on the order of a few MHz, and are ultimately limited by the natural atomic processes, while maintaining high spectral brightness. In addition, we will present the results of our elementary quantum repeater node by interfacing these photons with our high fidelity quantum memories.