A proposal to generate modal and polarization hyperentangled photons using Bragg reflection waveguides is discussed. A high quality of entanglement is achievable with spectral filtering using filter bandwidths of a few nanometers.
We propose and analyze the performance of a technique to generate mode and polarization hyperentangled photons in monolithic semiconductor waveguides using two concurrent type-II spontaneous parametric downconversion (SPDC) processes.These two SPDC processes are achieved by waveguide engineering which allows for simultaneous modal phase matching with the pump beam in a higher-order mode.Paired photons generated in each process are cross polarized and guided by different guiding mechanisms, which produces entanglement in both polarization and spatial mode.Theoretical analysis shows that the output quantum state has a high quality of hyperentanglement by spectral filtering with a bandwidth of a few nanometers, while off-chip compensation is not needed.This technique offers a path to realize an electrically pumped hyperentangled photon source.
An on-chip waveguide-based source of entangled photons capable of switching between generating time-energy entangled and hyperentangled (entangled in both time energy and polarization) photon pairs is proposed. The switching can be done all-optically by rotating the pump polarization. The source is based on multichannel phase matching in Bragg reflection waveguides achieved by engineering the Fresnel reflection of photonic bandgap claddings for differently polarized modes. Analytical results are confirmed in fully vectorial numerical simulations.