Abstract: A laser tuning mechanism which embodies “spectrally dependent spatial filtering” (SDSF) and contemplates two key elements of the tuning mechanism. The first element of the SDSF tuning mechanism is a spectrally dependent beam distortion (i.e. alteration of the amplitude and/or phase profile of the beam) provided by an SDSF tuning element in a laser cavity. The second element of the SDSF tuning mechanism is an intracavity spatial filter which makes the round trip cavity loss a sensitive function of both beam distortion and cavity alignment. Such a laser can be aligned so that a specific beam distortion, which is provided by the SDSF tuning element at a tunable wavelength, is required to obtain minimum round trip cavity loss, thereby providing tunable laser emission. A preferred embodiment of the SDSF tuning mechanism is an external cavity semiconductor laser having a zeroth order acousto-optic tuning element.

Abstract: A power supply with DC surge and spike protection having additional, optional power conditioning and control functions such as low voltage protection, electro mechanical interferences(EMI) protection and radio frequency interference(RFI) protection. The device is for attachment to vehicular electrical systems for protecting, conditioning or controlling the input power to electrical devices such as computers, audio and video systems, PDA's, wireless phones, and other electronic products. The power supply includes a housing having a male cigarette lighter plug inserted into a vehicular cigarette lighter plug or DC power outlet, electrical circuitry in the housing and one or more female power receptacles into which the powered electrical devices DC connectors are inserted.

Abstract: An optical device, including a monolithically integrated diode laser and semiconductor optical amplifier, that has reduced linewidth and improved side mode suppression for a given output power target. In a preferred embodiment, the diode laser is detuned from a gain peak wavelength to an emission wavelength. The semiconductor optical amplifier has an active region that is bandgap shifted to move its gain peak towards the emission wavelength of the laser diode, thus reducing its linewidth enhancement factor. The diode laser is preferably either a gain-coupled or index-coupled distributed feedback laser. The bandgap shift can be effected by known bandgap shifting methods, such as ion implantation, dielectric cap disordering, and laser induced disordering.

Abstract: A power supply with DC surge and spike protection having additional, optional power conditioning and control functions such as low voltage protection, electro mechanical interferences(EMI) protection and radio frequency interference(RFI) protection. The device is for attachment to vehicular electrical systems for protecting, conditioning or controlling the input power to electrical devices such as computers, audio and video systems, PDA's, wireless phones, and other electronic products.

Abstract: A laser tuning mechanism which embodies “spectrally dependent spatial filtering” (SDSF) and contemplates two key elements of the tuning mechanism. The first element of the SDSF tuning mechanism is a spectrally dependent beam distortion (i.e. alteration of the amplitude and/or phase profile of the beam) provided by an SDSF tuning element in a laser cavity. The second element of the SDSF tuning mechanism is an intracavity spatial filter which makes the round trip cavity loss a sensitive function of both beam distortion and cavity alignment. Such a laser can be aligned so that a specific beam distortion, which is provided by the SDSF tuning element at a tunable wavelength, is required to obtain minimum round trip cavity loss, thereby providing tunable laser emission. A preferred embodiment of the SDSF tuning mechanism is an external cavity semiconductor laser having a zeroth order acousto-optic tuning element.

Abstract: Groove patterns on substrates coated with photoresist are made using the technique of photolithography by exposing photoresist via a reticle. In the instant invention, the pattern is provided on the reticle with a period larger than the final period to be printed on the photoresist. The complete pattern is obtained by subjecting the photoresist to two or more exposures and aligning the substrate relative to the reticle between exposures. In a further embodiment the slits on the reticle defining the line width of the grooves are larger than required and photoresist is subjected to multiple partial exposure. Both embodiments significantly reduce diffraction caused by the reticle and improve the resolution of the technique.

Abstract: A semiconductor laser device structure comprising an active region provided by a quantum well of an indirect bandgap material, the quantum well being divided laterally to form an active region comprising a two dimensional array of localized cells. Preferably the quantum well of indirect band gap material is selected from group IV semiconductor materials and comprises a silicon-germanium alloy. A silicon/silicon-germanium alloy multi-quantum well (MQW) structure is described. In a preferred embodiment, a Si/SiGe alloy MQW laser diode comprises a coplanar double grating configuration etched through the MQW structure to provide distributed feedback. The double intersecting grating structure functions to define an array of "cells" or regions of finite dimensions in the quantum well structure which "localize" carriers within the cells thereby enhancing the radiative emission probability. The grating also provides for combined gain-coupled and index-coupled distributed feedback.

Abstract: An improved electromagnetic apparatus includes a core and an armature which is movable relative to the core. A shading ring is connected with the core to provide magnetic flux which is out of phase with magnetic flux from the core. The shading ring includes a base formed a first metal and a layer of a second metal clad to the base. The first metal forming the base work hardens and has a greater resistance to fatigue failure induced by vibration than the second metal of the layer which is clad to the base. However, the second metal forming the clad layer has a greater electrical conductivity than the first metal of the base. The base may be formed of aluminum and the layer of metal clad to the base may be formed of copper. The layer of copper may be clad to the base by an extrusion process.

Abstract: A Type II heterojunction formed of semiconductor material which normally forms a Type I heterojunction. The Type II heterojunction is created by using a carefully chosen stack of epitaxial semiconductor materials with modifications to the band structure through quantum mechanical confinement effects. This virtual type II heterojunction is incorporated adjacent to the active region in a single-quantum-well, ridge-waveguide laser structure. An anomalous "Negative-T.sub.o " region is observed in which threshold current decreases with increasing temperature. A reduction in the temperature sensitivity of the threshold current of the laser structure results.

Abstract: A method of reducing thermally-induced emission wavelength shift in laser diodes. In addition to the conventional ridge contact for supplying the modulation current to the laser diode a second ridge contact is formed on the device. A compensation current of substantially the same frequency as the modulation current but having an opposite phase is applied to the second contact. This compensation current is selected to substantially neutralize the transient temperature variations due to changes in the modulation signal and result in a generally steady state thermal situation.