Four-way multiplexed light source showing on-chip photon generation and routing.
The ability to produce single photons is integral to the success of quantum technologies, including quantum computing. Unfortunately, photons usually arrive in groups. Researchers from Australia and France have brought us a step closer to a reliable single-photon source with their hybrid technology approach (Laser Photon. Rev. DOI: 10.1002/1por.201400027).
The research team hails from Macquarie University and The University of Sydney in Australia, and the Université Nice Sophia Antipolis in France. The group used a “hybrid integration” approach to combine passive glass routers, nonlinear waveguides in an advanced chip, and fast optical switching elements into an optical device. Lead author Thomas Meany explains, “The hybrid integration approach is a significant departure from the current approach taken by most research groups and is key to the success of our technique. There are a whole host of different complimentary technologies working in unison in our computers, and that is the concept that inspired this work.”
The optical device can produce four spatially separated heralded photons, tunable across 1520-1580 nm. The team demonstrated that it could actively route photons to pairs of outputs and a single output using integrated electronically controlled switches. The output photon rates are an order of magnitude higher than a previous integrated spatial multiplexing demonstration and almost twice the rate of a previous display of integrated bidirectional multiplexing. According to the authors, there is also great value in the scalability and practicality of the technique—the combination of pre-existing platforms to create single and multiple photon states while maintaining a fixed signal-to-noise ratio through multiplexing.