摘要:
According to this invention, silicon-based photodetectors using waveguides formed with silicide regions can have high speed and high efficiency for near IR applications. Utilizing the unique properties of silicides, the proposed method provides a simple and elegant way to implement a photodetector design in which photogenerated carriers travel perpendicular to the direction of light propagation. Therefore, the speed and quantum efficiency of the photodetector may be optimized independently. This device configuration may be implemented in one of the two approaches: (a) waveguides formed through surface silicidation of a silicon-based layer of a substrate (b) waveguides formed through silicidation of ridge waveguide side-walls of a silicon-based layer of a substrate; The use of mature silicon technology promises low cost of production and other benefits.
摘要:
An Echelle grating has alternate first (1a) and second (1b) sets of facets (1). The first set of facets (1a) is operative to reflect incident light (4) for diffraction and the second set of facets (1b) extends between adjacent facets of the first set (1a). Only the first set of facets (1a) is metallized to enhance reflection. The second set of facets (1b) is left unmetallized. This configuration reduces polarization dependent loss (PDL).
摘要:
In order to make a photonic device incorporating a waveguide, a waveguide is formed with a predetermined geometry. Birefringence is then controlled by determining the amount of stress induced within the waveguide.
摘要:
In order to fabricate a photonic device with an enhanced photoresponse at 155 nm, a plurality of undulating quantum well layers are grown on said substrate in a three dimensional growth mode to defeat the limitations imposed by strain on the maximum layer thickness. The quantum wells typically are formed by epitaxially growing alternating layers of Si1−x,Gex, and Si on a silicon substrate.
摘要:
Methods and devices relating to a sensor for use in detecting and monitoring molecular interactions. A silicon waveguide sensing element is provided along with a layer of silicon. A silicon oxide layer is also provided between the waveguide element and the layer of silicon. The sensing element is adjacent to an aqueous solution in which the molecular interactions are occurring. A light beam travelling in the silicon waveguide creates an evanescent optical field on the surface of the sensing element adjacent to the boundary between the sensing element and the aqueous medium. Molecular interactions occurring on this surface affect the intensity or the phase of the light beam travelling through the waveguide by changing the effective refractive index of the medium. By measuring the effect on the intensity, phase, or speed of the light beam, the molecular interactions can be detected and monitored in real time.
摘要:
A plurality of signals are mixed in a non-linear waveguide for generating a near field sum frequency output pattern. The near field output pattern is monitored for changes which correspond to changes in the phase relationship between the plurality of signals. A grating provides a mask through which the near field pattern may propagate. Detectors positioned above the grating at predetermined locations measure the intensity of the near field pattern and a change in the phase relationship between the input signals is determined from a change in the intensity of the near field output pattern.
摘要:
Quasi-phase matched (QPM) second-harmonic (SH) generation in the reflection geometry is described. The SH intensity can be strongly enhanced by spatially modulating the optical properties of the nonlinear medium. This type of quasi-phase matching is demonstrated using an Al.sub.0.8 Ga.sub.0.2 As/GaAs heterostructure designed for .lambda.=1.06 .mu.m incident light. The SH light intensity generated in reflection from the heterostructure is enhanced 70 times relative to the SH response of a homogeneous GaAs wafer. A Fabry-Perot resonant cavity design employs this structure to make thin films with extremely high SH generation efficiencies. This is of particular interest used in vertical cavity surface emitting lasers (VCSELs).
摘要:
An active surface-emitting harmonic generator based on a multilayer Al.sub.x Ga.sub.1-x As non linear waveguide integrated monlithically with a tunable InGaAs single quantum well laser is provided. Controlling the difference in frequency between a signal provided by the tunable laser and another input optical signal allows an output signal to be directed to any of a plurality of directions in space. Positioning detectors near the monolithic device allows spatial addressing. The controllable monolithic device may also be used to scan and thus to read data stored on holographic media.
摘要:
A complex of a cyclodextrin and an alkane, alkene, alkyne, aromatic compound, etc. can be prepared according to the method of the present invention. These complexes can be delivered to prokaryotic and eukaryotic cells, tissues, and organs in vitro and in vivo. In this manner, the toxic, genotoxic, and mitogenic effects of these compounds can be determined. Ternary complexes further including one or more biologically active molecules in addition to an alkane, etc. can be employed to determine the modulatory effects of such biologically active molecules on these alkanes, etc.