Gallium arsenide (GaAs) quantum photonic waveguide circuits

Abstract

Integrated quantum photonics is a promising approach for future practical and large-scale quantum information processing technologies, with the prospect of on-chip generation, manipulation and measurement of complex quantum states of light. The gallium arsenide (GaAs) material system is a promising technology platform, and has already successfully demonstrated key components including waveguide integrated single-photon sources and integrated single-photon detectors. However, quantum circuits capable of manipulating quantum states of light have so far not been investigated in this material system. Here, we report GaAs photonic circuits for the manipulation of single-photon and two-photon states. Two-photon quantum interference with a visibility of 94.9±1.3% was observed in GaAs directional couplers. Classical and quantum interference fringes with visibilities of 98.6±1.3% and 84.4±1.5% respectively were demonstrated in Mach-Zehnder interferometers exploiting the electro-optic Pockels effect. This work paves the way for a fully integrated quantum technology platform based on the GaAs material system.

Single-photon emission of InAs/InP quantum dashes at 1.55 μm and temperatures up to 80 K

“…Manipulation of single photons already allowed for the demonstration of free space quantum key distribution [ 1,2 ], simple quantum algorithms [ 3 ], CNOT-gates and entanglement manipulation following integrated photonic circuits approach [ 4,5 ]. Key elements of such systems are pure and efficient sources of single photons.…”

Integrated AlGaAs source of highly indistinguishable and energy-time entangled photons

“…Its direct bandgap has already led to the monolithic integration of the primary laser source and the nonlinear medium into a single device emitting photon pairs under electrical injection at room temperature [22]. Moreover, GaAs strong electro-optical Pockels effect enables a fast control and manipulation of the generated photons, as recently demonstrated [23]. On the front of on-chip single photon detection as well, high-efficiency superconducting nanowire single-photon detectors have been integrated with GaAs waveguides [24].…”

Deterministic separation of arbitrary photon pair states in integrated quantum circuits

“…While virtually all on-chip interference experiments [7][8][9][10][11]14] have been conducted near degeneracy, they have sampled only a small subset of the total parameter space (e.g. central wavelength separations, polarizations, photon bandwidths, coupler characteristics).…”