Engineering Low-Loss Silicon Quantum Photonics in the Mid-Infrared

Quantum silicon photonics must overcome considerable loss engineering challenges before it can scale to the millions of physical qubits required for fault tolerant quantum computation [1] . The first such challenge is the intrinsic two-photon absorption (TPA), present in silicon at telecommunications wavelengths. This places fundamental limits on the heralding or Klyshko efficiency of silicon photon-pair sources based on spontaneous four-wave mixing (SFWM) [2] . We have recently shown that by moving to a pump wavelength beyond 2-microns, in the mid-infrared (MIR), TPA in silicon can be curtailed, and by using 340-nm thick silicon waveguides, phase matching can be achieved for efficient SFWM [2] .