Abstract: A semiconductor device structure capable of expanding a laser beam in one-dimension, collimating an expanding beam or focusing a nearly collimated beam. This semiconductor structure is typically comprised of three portions: a rib waveguide portion to propagate a beam of light in the quantum well region beneath the rib, an expansion region which incorporates a wider rib structure to allow the propagating beam to expand, and a rib etched lens portion to collimate the expanded beam of light. The shape of the rib etched lens portion is determined by Fermat's principle such that the optical pathlengths travelled by each ray of light are equated at a collimation plane positioned tangentially with the surface of the rib etched lens at the point at which an on-axis beam of light would strike the surface of the rib etched lens.

Abstract: A staggered quadrature phase shift keyed modulator which avoids the need for timing circuits. Three phase modulators serially change the phase of a laser beam so that it may sequentially have a total phase shift of .pi., .pi./2, 0, -.pi./2. The input signal is divided into two pulse trains, one of which is delayed to provide the stagger. The two pulse trains are logically combined to form three control signals for the modulators.

Abstract: A laser diode array produces one set of beams that are out of phase with those of another set of beams, with the beams of one set alternating with those of the other. The phase plate has first and second sets of regions, with the regions of one set alternating with those of the other. The phase plate is positioned in the near field of the beam pattern such that one set of beams passes through one set of regions and the other set of beams passes through the other set of regions. One set of regions changes the phase of the beams passing therethrough to create a substantially single lobed beam pattern in the far field.