Rca Inc.

General Electric Company

Michael Ettenberg

Henry Kressel

Harry Francis Lockwood

Dan Botez

Ivan Ladany

Gregory H Olsen

Charles J Nuese

Jacques I Pankove

Ramon Ubaldo Martinelli

William J Burke

Bernard Goldstein

Donald B Carlin

Paul A Longeway

Stephen L Palfrey

Victor Korsun

Nancy A Dinkel

An optical fiber has a beveled end surface and a Bragg reflector grating formed on the end surface to form a single mode reflector for a semiconductor laser. A transmission fiber with a beveled end is fused to the beveled grating to form a continuous transmission line having an internal reflective grating.

Optical device with mode selecting grating

A phase-locked semiconductor laser array is dephased-locked by forming at least two p-type contacts electrically isolated from one another coupled to one side of the active region and a single contact layer coupled to the other side of the active region. The same current is applied to two p-type contacts to form a single phase-locked far-field lobe. A different current is applied to one of the two p-type contacts to drive one contact harder than the other to form a dephased multiple lobe beam. An effective aperture at the receiver receives the in-phase single lobe and blocks the multiple lobes to produce a modulation effect at the receiver.

Phase modulation semiconductor laser array

Semiconductor devices such as lasers which include a substrate with a channel therein with a clad layer overlying the substrate and filling the channel exhibit irregularities such as terraces in the surface of the clad layer which are detrimental to device performance. These irregularities are substantially eliminated by forming the channel in a surface of a buffer layer greater than about 4 micrometers thick on the substrate and forming the clad layer over the buffer layer and the channel. CW lasers incorporating the principles of the invention exhibit the highest output power in a single spatial mode and maximum output power which have been observed to date.

Semiconductor structure and devices

A photodetector includes a cap layer over an absorptive layer with the P-N junction formed in the absorptive layer by diffusion of conductivity modifiers from the cap layer. If this diffusion extends too far into the absorptive layer, the detector is rendered useless. The invention includes a photodetector with a buffer layer between the absorptive and cap layers. The concentration of conductivity modifiers is substantially constant in the cap layer, decreases with distance in the buffer layer from the cap layer and extends into the absorptive layer. The invention also includes a method of making this device which includes the steps of forming a buffer layer over the absorptive layer, forming a cap layer over the buffer layer and diffusing the opposite type conductivity modifiers from the cap layer into the buffer and absorptive layers.

Photodetector

The invention comprises an improved optical recording medium and information record wherein the light sensitive layer comprises a tracking layer having one or more openings extending therethrough and an absorber layer overlying the tracking layer and the openings therein thereby forming first and second regions of the light sensitive layer having different reflectivities which can be used to provide radial tracking information. The method of the invention includes the steps of depositing a tracking layer onto a light reflective layer, forming one or more openings through the tracking layer and depositing an absorber layer over the tracking layer and into the openings therein.

Optical recording medium and information record and method of making same

The invention is an improved buried heterostructure laser wherein the improvement comprises a cladding layer which is interposed between the mesa and the burying region and has a refractive index less than that of the burying region and the effective refractive index of the fundamental transverse mode. The discrimination against higher order modes of propagation provided by the structure permits the use of a wider active layer and thus a larger emitting area.

W-Guide buried heterostructure laser

An improved overcoated optical recording medium comprises a light absorptive layer and an overcoat overlying the absorptive layer wherein the overcoat has a plurality of indentations in the surface which contacts the absorptive layer thereby forming a first region of the recording medium wherein the overcoat layer does not contact the absorptive layer and a second region wherein the overcoat layer does contact the absorptive layer. The recording sensitivity in the first region is greater since the heat loss to the overcoat layer in these regions is reduced and the mechanical constraints on the formation of deformations in the absorptive layer are relaxed. The invention also includes an improved information record having information recorded in a portion of the first region as a change in the local optical properties.

Optical recording medium and information record with indented overcoat

A thin plate of III-V direct-bandgap semiconductor, preferably with anti-reflective coatings, operates as superior optical filter for light having a wavelength which exceeds a given wavelength in the visible or infra-red spectrum. Such a filter is particularly suitable for use in a duplex optical communication system employing a fiber-optic transmission line.

III-V Direct-bandgap semiconductor optical filter

In an optical memory device, such as an optical video disk, an injection laser is used as the source of the light, as the detector of the light reflected from the memory element and as the detector for controlling the proper focus of the light on the memory element. The light reflected from the memory element is fed back into the injection laser and variations in certain characteristics of the injection laser, such as the optical output at constant current, the electrical current through the laser at constant voltage and the voltage drop across the laser at constant current, are used to read the memory device and to maintain the focus.

Optical memory with injection laser as light source and detector

A light emitting diode includes a substrate having a body of single crystalline semiconductor material, preferably a Group III-V compound or alloy thereof, on a surface of the substrate. The body includes a window layer directly on the substrate and one or more other layers on the window layer. The layers of the body are of appropriate conductivety types to form a recombination region in which light can be generated. The substrate has an opening therethrough to the window layer. The window layer is of a material which is substantially transparent to the light generated in the recombination region and is of a thickness, 15 to 30 microns, to provide rigidity to the diode.

Light emitting diode

An injection laser diode is at one end of an optical fiber to direct modulated optical radiation into the fiber. At the other end of the fiber is a detector, such as a semiconductor photodetector, for the modulated radiation. Between the other end of the optical fiber and the detector is a reflecting shutter which is adapted to periodically reflect some of the radiation, at a lower frequency rate, back along the optical fiber to the injection laser. The radiation reflected back into the injection laser causes a variation in the characteristics of the laser so that the laser operates as a detector for the reflected radiation.

Two-way single fiber optical communication system

A new low cost high efficiency gallium arsenide homojunction solar cell incorporating a passivating surface layer of indium gallium phosphide. The thickness of the indium gallium phosphide layer is selected so that it is transmissive to photons having wavelengths shorter than its bandgap energy.

Low cost high efficiency gallium arsenide homojunction solar cell

A body of semiconductor material of an injection laser device, capable of operating at a power level up to a few milliwatts per micrometer of emitting width, has two opposed facet surfaces. On at least one of the facet surfaces is a protection layer of an insulating material having an optical thickness equal to approximately one-half the vacuum wavelength of the optical radiation emitted by the device.

Half wave protection layers on injection lasers

A reflector of optical radiation is on at least one radiation emitting facet of an electroluminescent device. The reflector includes a plurality of contiguous layers of alternating composition. The layers are of silicon and a material selected from the group consisting of aluminum oxide, magnesium fluoride and silicon dioxide. Each of the layers is approximately .lambda./4n in thickness where '.lambda.' is the free space wavelength of radiation emitted from the electroluminescent device, and 'n' is the index of refraction of the layer. Two of the alternating contiguous layers provide a reflector which is partially reflecting, while six of the layers provide a reflector substantially reflecting to optical radiation.

Growing community of inventors

Freehold, NJ, United States of America

Michael Ettenberg