Abstract: A waveguide parametric device including a multi-mode waveguide having orientation layers formed in a propagation direction of a signal beam and a pump beam propagating down the waveguide. The orientation layers are oppositely oriented to provide non-linear coupling between the pump beam and the signal beam and have a periodicity that provides quasi-phase matching for a fundamental propagation mode, where the waveguide has a size to accommodate multi-mode wave propagation.

Abstract: A waveguide parametric device including a multi-mode waveguide having orientation layers formed in a propagation direction of a signal beam and a pump beam propagating down the waveguide. The orientation layers are oppositely oriented to provide non-linear coupling between the pump beam and the signal beam and have a periodicity that provides quasi-phase matching for a fundamental propagation mode, where the waveguide has a size to accommodate multi-mode wave propagation.

Abstract: An apparatus in one example has: first and second Fourier transform lenses, the first Fourier transform lens receiving an incident plane wavefront and focusing the plane wavefront down to a focal point in a focal plane, and the second Fourier transform lens reimaging the focused down plane wavefront to an output plane wavefront; a bead located substantially at the focal point and that is illuminated by radiation that comes in from the first lens, the bead reradiating a spherical wave, which interferes with light that passes around the bead to produce a diffraction pattern; an array of controllable light transmissive elements that support the bead in the focal plane; and a null seeking servomechanism for assigning an electrical value of phase departure of the incident plane wavefront from a reference thereof, the null seeking servomechanism controlling the light transmissive elements to produce phase shifts in light that passes around the bead to thereby remove aberrations in the incident plane wavefront.

Abstract: An apparatus in one example has: first and second Fourier transform lenses, the first Fourier transform lens receiving an incident plane wavefront and focusing the plane wavefront down to a focal point in a focal plane, and the second Fourier transform lens reimaging the focused down plane wavefront to an output plane wavefront; a bead located substantially at the focal point and that is illuminated by radiation that comes in from the first lens, the bead reradiating a spherical wave, which interferes with light that passes around the bead to produce a diffraction pattern; an array of controllable light transmissive elements that support the bead in the focal plane; and a null seeking servomechanism for assigning an electrical value of phase departure of the incident plane wavefront from a reference thereof, the null seeking servomechanism controlling the light transmissive elements to produce phase shifts in light that passes around the bead to thereby remove aberrations in the incident plane wavefront.