Abstract: A method for realizing an optical waveguide in a substrate by means of a femtosecond laser system, the waveguide including a birefringence axis tilted by a predetermined angle for at least a segment, is disclosed. The method includes preparing a substrate including a free surface, focusing a femtosecond laser beam into the substrate, in order to induce a refractive index modification of a volume of such substrate around the focal region. The method further includes varying a propagation direction of the femtosecond laser beam to reach a propagation direction describing a predetermined non-vanishing angle with respect to the normal to the free surface of the substrate, and translating the focal region with respect to the substrate, in order to generate the waveguide segment.

Abstract: A method for realizing an optical waveguide in a substrate by means of a femtosecond laser system, the waveguide including a birefringence axis tilted by a predetermined angle for at least a segment, is disclosed. The method includes preparing a substrate including a free surface, focusing a femtosecond laser beam into the substrate, in order to induce a refractive index modification of a volume of such substrate around the focal region. The method further includes varying a propagation direction of the femtosecond laser beam to reach a propagation direction describing a predetermined non-vanishing angle with respect to the normal to the free surface of the substrate, and translating the focal region with respect to the substrate, in order to generate the waveguide segment.

Abstract: A quantum logic gate for qubits, suitable for receiving as inputs at least two polarization-encoded qubits, includes at least one partially polarizing beam splitter (PPBS), the beam splitter comprising a first waveguide and a second waveguide which are constructed in integrated optics, the first and second waveguides having a refractive index contrast of between 0.1% and 6% and a birefringence of between 10?6 and 6*10?5.