Abstract: A semiconductor optical element comprises a semiconductor substrate, a waveguide, an active layer and a clad layer mounted on said substrate; said active layer comprising first region and second region coupled optically with each other, and having opposite signs of .alpha. parameters with each other, where said parameter is ratio of change of refractive index to change of gain following change of carrier density; a first electrode common to all regions attached on one side of said substrate; and second electrodes for each region attached on the other side of said substrate. The invention is used for an AM modulation laser, or an FM modulation laser.

Abstract: A high speed sampling technique is proposed using a cascade of optical waveguide interferometers driven by CW sinusoidal traveling or standing microwaves. Each interferometer multiplies the optical signal by a function closely approximated by cos.sup.4 .omega.t, where .omega. is the frequency of its microwave drive. A cascade of four interferometers with 2.6 V microwave drives at 10, 20, 40, and 80 GHz and a total length of 2 cm can sample an optical signal with 2 ps resolution and 50 ps between samples.

Abstract: A semiconductor diode laser system with microwave mode locking. The system includes a semiconductor laser diode and an external reflector positioned to receive radiation that emits from the diode and reflects the same back into the diode, the microwave mode locking serving to modulate the radiation and the external reflector being properly positioned to return the radiation to the diode at a return time equal to the period of the drive signal or a submultiple thereof.

Abstract: A surface acoustic wave (SAW) device including a crystal substrate having two substantially planar surfaces and at least one SAW-to-plate mode coupler positioned on one of the surfaces. The SAW-to-plate mode coupler includes a plurality of parallel, linear surface perturbations. The surface perturbations are adapted to convert a portion of an incident SAW to a bulk acoustic wave (BAW). In addition, the coupler is adapted to convert a portion of an incident BAW (from the crystal bulk region) to a SAW at those surface perturbations. In addition, the planar surfaces of the crystal substrate are adapted to reflect portions of incident BAW's. The coupler is positioned with respect to the crystal characteristics so that SAW's and BAW's resonantly interact at the coupler. In alternative configurations, a second SAW-to-plate mode coupler is positioned on the second surface of the crystal substrate.

Abstract: Surface acoustic wave resonators are used to provide band pass filters. The length of each resonator is related to the lumped constant inductor and capacitor values of the components of the low pass filter equivalent. This invention allows high frequency s.a.w. type filters to be constructed by reference to already available inductor and capacitor values from tables of low pass filter designs.