Polarization quantum walk on a chip

Although most optical quantum computing experiments rely on polarization-encoded qubits, the majority of standard integrated-optic devices are unable to deal with such qubits, because of fast relative phase or amplitude decoherence. We are replacing the standardly used dual-rail encoding (where a qubit is encoded in two spatial modes) by laser-written waveguides that allow the processing of polarization- and path-encoded qubits.