Abstract: Optical modulators include active quantum well structures coherent with pseudosubstrates comprising relaxed buffer layers on a silicon substrate. In a preferred method the active structures, consisting of Si1?x Gex barrier and well layers with different Ge contents x, are chosen in order to be strain compensated. The Ge content in the active structures may vary in a step-wise fashion along the growth direction or in the form of parabolas within the quantum well regions. Optical modulation may be achieved by a plurality of physical effects, such as the Quantum Confined or Optical Stark Effect, the Franz-Keldysh Effect, exciton quenching by hole injection, phase space filling, or temperature modulation. In a preferred method the modulator structures are grown epitaxially by low-energy plasma-enhanced chemical vapor deposition (LEPCVD).

Abstract: A tunneling element includes a thin film layer of ferroelectric material and a pair of dissimilar electrically-conductive layers disposed on opposite sides of the ferroelectric layer. Because of the dissimilarity in composition or construction between the electrically-conductive layers, the electron transport behavior of the electrically-conductive layers is polarization dependent when the tunneling element is below the Curie temperature of the layer of ferroelectric material. The element can be used as a basis of compact 1R type non-volatile random access memory (RAM). The advantages include extremely simple architecture, ultimate scalability and fast access times generic for all ferroelectric memories.

Abstract: A spinner type irrigation sprinkler having a support bridge to which is coupled a spinner assembly for rotation about a vertical axis, the spinner assembly including a spinner body and an adjustable trajectory nozzle assembly with a removable nozzle member, the spinner body coupled to a brake module attached to the bridge and employing viscous fluid shear to control the speed of rotation of the spinner assembly and attached nozzle member.