Ultra-low-energy programmable non-volatile silicon photonics based on phase-change materials with graphene heaters.

Silicon photonics is evolving from laboratory research to real-world applications with the potential to transform many technologies, including optical neural networks and quantum information processing. A key element for these applications is a reconfigurable switch operating at ultra-low programming energy-a challenging proposition for traditional thermo-optic or free carrier switches. Recent advances in non-volatile programmable silicon photonics based on phase-change materials (PCMs) provide an attractive solution to energy-efficient photonic switches with zero static power, but the programming energy density remains high (hundreds of attojoules per cubic nanometre).

Surface-emitting electroholographic SAW modulator.

We report the design and operation of a surface-emitting surface acoustic wave (SAW) acousto-optical modulator which behaves as a cm-scale linear hologram in response to an applied electronic waveform. The modulator is formed by an optical waveguide, transducer, and out-coupling surface grating on a 1 mm-thick lithium niobate substrate. We demonstrate the ability to load and illuminate a 9-region linear hologram into the modulator's 8 mm-long interaction region using applied waveforms of 280-320 MHz.

Efficient photon triplet generation in integrated nanophotonic waveguides.

Generation of entangled photons in nonlinear media constitutes a basic building block of modern photonic quantum technology. Current optical materials are severely limited in their ability to produce three or more entangled photons in a single event due to weak nonlinearities and challenges achieving phase-matching. We use integrated nanophotonics to enhance nonlinear interactions and develop protocols to design multimode waveguides that enable sustained phase-matching for third-order spontaneous parametric down-conversion (TOSPDC).