Abstract: An optoelectronic semiconductor device with at least one laser and two mutually parallel, strip-shaped active regions, whose ends are optically coupled at one side, is a very suitable radiation source or amplifier, for example as a tunable radiation source. More than one kind of radiation is often present in such a device, whereas it is desirable for only one kind of radiation to pass through a gate of the device. To achieve this in prior devices, an additional component, such as a filter or isolator, is necessary.

Abstract: A buried heterostructure semiconductor laser formed on a substrate having a first semiconductor of p-type conductivity has a mesa-striped active layer region having a height extending from a first p-type semiconductor layer at the foot of the mesa to a n-type cladding layer on the top of the mesa. On both sides of the mesa-striped region, a second p-type semiconductor layer, a first n-type semiconductor layer, a third p-type semiconductor layer, and a second semiconductor layer having a band gap smaller than that of the other layers except the active layer are sequentially formed from the substrate side. Additionally, the entire structure is further buried with a n-type semiconductor layer. The second semiconductor layer may be inserted in between the second p-type semiconductor layer and the first n-type semiconductor layer as well.

Abstract: In a slant plane light emission type semiconductor laser whose laser structure can be formed on a stepped substrate by a series of MOCVD growth processes, the width of the active layer at the slant portion is set to 2.5 .mu.m or less or the angle between the flat portion and slant portion is set to 12 degrees or less. The semiconductor laser having such a structure can emit light having a single peak at the near field.

Abstract: The present invention is an optical fiber connector with an internal structure which allows the polarization axis of an optical element to be freely rotated and fixed with respect to an rotational orientation-indicating reference on an external surface of the connector. The reference then provides an external physical indication of the spatial direction of the birefringence axes of the optical element.

Abstract: The present invention provides a resonant microcavity which includes a periodic dielectric waveguide, and a local defect in the periodic dielectric waveguide which accommodates spacial confinement of radiation generated within the waveguide around the defect. In an alternative embodiment, the present invention provides a method of enhancing radiation confinement within a resonant microcavity and minimizing radiation losses into an associated substrate, the microcavity configured within a periodic dielectric waveguide as a local defect which exhibits spacial radiation confinement, the method including the step of increasing the refractive index contrast between the microcavity and the substrate.

Abstract: An integrated monolithic laser-modulator component having a multiple quantum well structure. This component includes an InP substrate, a laser (L) formed from a stack of semiconductor layers epitaxied on the substrate, including an active and absorbent layer and a periodic Bragg grating fixing the emission wavelength of the laser to a value slightly above an optimum wavelength of the laser gain peak. An electrooptical modulator (M) is formed from the same stack of semiconductor layers, with the exception of the Bragg grating, the active layer of the laser and the absorbing layer of the modulator being formed by the same epitaxied structure having several constrained or unconstrained quantum wells, the modulator functioning according to a confined Stark effect. The semiconductor layers of the laser and those of the modulator are electrically controlled.

Abstract: A monolithically integrated laser which is rapidly tunable over a wide optical frequency range comprises a frequency router formed in a semiconductive wafer defining a tuned cavity. A control circuit applies electrical energy to predetermined controllably transmissive waveguides connecting the frequency routing device with reflective elements defined in the wafer. This tunes the laser to a desired one of a plurality of optical frequencies. Application of such electrical energy creates frequency selective pathways through the wafer able to support selected lasing frequencies. This laser is economical to construct and is useful in high capacity, high speed optical communications networks.

Abstract: A grating (461) coupling the output of a semiconductor laser (410) in a semiconductor waveguide to a dielectric waveguide (451) having a core (458) which may be efficiently butt-coupled to the core of an optical fiber (470); the laser and semiconductor waveguide, coupling grating, and dielectric waveguide are integrated on a single substrate. Further, multiple lasers (410, 420, 430, 440) with differing lasing frequencies may be integrated and their outputs grating coupled into a single dielectric waveguide (450) for wavelength division multiplexing.

Abstract: A chuck is provided to hold a fibre optic light guide of the type typically used in medical dental procedures involving the curing of resins by exposure to light. The chuck has an internal bore and configuration to releasably support and retain a fibre optic light guide so that fibre optic light guides may be readily substituted between patients. The chuck thus facilitates sterilization/disinfection procedures. The outside diameter and configuration of the chuck is adapted to fit a particularly manufacturer's curing light device to adapt a particular manufacturer's instrument for use with the replaceable fibre optic light guides. A set of chucks may be manufactured with the outside diameter of the chucks adapted to be received in a number of different manufacturers' light emitting devices but all such chucks have a common internal diameter so that the replaceable fibre optic light guides may be used with any of the plurality of manufacturers' instruments.

Abstract: In a semiconductor laser module, a semiconductor laser element is disposed on a side surface of a submount perpendicular to a front surface of a pedestal. The semiconductor laser element, the submount, a lens, and an optical fiber are positioned on the front surface of the pedestal so that laser light emitted from the semiconductor laser element is applied through the lens to a prescribed portion of the optical fiber with high reliability. Positioning of the laser element in the direction perpendicular to the front surface of the pedestal is facilitated, and positioning accuracy is improved, resulting in a low-cost and high-performance semiconductor laser module.

Abstract: A fibre Bragg grating is used to stabilize the intensity and frequency fluctuations of a diode laser. The diode laser is connected with an opto-mechanical apparatus to the fibre which contains the grating. A polarization maintaining fibre is used. The grating is formed in the guided-mode region of the optical fibre using photorefractive techniques. The wavelength of maximum grating reflectivity is selected to lie near the maximum of the diode laser gain bandwidth. The magnitude and bandwidth of the grating reflectivity is sufficient to stabilize the diode laser output without appreciably reducing the optical output power from the end of the fibre. The bandwidth of the optical spectrum of the diode laser is increased or decreased relative to the solitary diode laser operating characteristics depending on the distance of the grating from the diode laser.

Abstract: Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5.times.10.sup.11 /cm.sup.3 and hole mobilities of about 500 cm.sup.2 /V-sec, measured at 250.degree. K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.

Abstract: An optical waveguide device comprising an optical waveguide for guiding an optical wave therethrough and a grating coupler, which is located on a surface of or in the vicinity of the optical waveguide and which couples the guided optical wave traveling in the optical waveguide with an external optical wave. The grating coupler is provided with a row of teeth spaced apart by a gap and positioned periodically or quasi-periodically with a pitch along the optical axis. The teeth have front and rear sidewalls, width and height, front and rear blaze angles less than 90.degree., and preferably have a parallelogramic profile. The width to period ratio of the grating teeth can be variable along the guided wave propagation direction so that the radiated beam can be shaped to a designed profile. The guided wave is radiated very efficiently with a predetermined profile out of the optical waveguide; or an external optical wave, which takes a known form, is introduced very efficiently into the optical waveguide.

Abstract: A II-VI group compound semiconductor light-emitting device can emit light of a short wavelength at room temperature. Operation characteristics, such as current--voltage characteristics and current--light output characteristics can be stabilized and a life of this semiconductor light-emitting device can be extended. The semiconductor light-emitting device comprises a substrate (1), at least a first cladding layer (2) of a first conductivity type, an active layer (3) and a second cladding layer (4) of a second conductivity type, wherein at least the active layer (3) is made of a II-VI group compound semiconductor and the active layer (3) is doped by either or both of n-type and p-type dopants.

Abstract: An alignment piece (1, 13) for a connector for optical conductors (10) comprises a support plate (2, 14), a guiding plate (3, 15) manufactured with very high accuracy and one or more alignment channels (4) for the conductors. At least the ends (11) of the alignment channels are formed in the guiding plate. The guiding plate (3, 15) is further provided with an inclining guiding plate part (5) in which the alignment channels (4) are formed. The support plate (2, 14) has a recess (6) in which the free end of the inclining guiding plate part (5) is received. The support plate includes a guiding surface (7) for the conductors (10), the guiding surface with its side directed towards the inclining guiding plate part lying above the free end of the guiding plate part.

Abstract: Three-layer light guide transports light from a source of low aspect ratio (e.g. nearly circular or nearly square) to one of high aspect ratio (e.g. narrow slit) to produce an output beam of low output divergence angles at high transfer efficiency. The design principle eliminates tapers or bends in the guide surfaces. Thereby, light from a conventional round lamp may be redirected with high optical efficiency to an aperture constrained to a long, narrow area, as in a slit headlight, a nacelle-rim light, a radome-edge light, or a landing light embedded in a wing having a sharp leading edge. The resulting far field intensity pattern is similar to that of a conventional sealed beam lamp.

Abstract: In a semiconductor laser device including a stack of semiconductor laser chips, each semiconductor laser chip includes opposite upper and lower surfaces, an upper electrode disposed on a portion of the upper surface, and a lower electrode disposed on a portion of the lower surface. Two adjacent semiconductor laser chips in the stack are connected such that the lower electrode of an upper laser chip is bonded to the upper electrode of a lower laser chip with solder. Since the upper electrode (lower electrode) is disposed on a portion of the upper surface (lower surface) of each laser chip, i.e., it is not disposed over the entire upper surface (lower surface) of the laser chip, the solder hardly flows over the side surface of the laser chip, so that unwanted short-circuiting between the upper electrode and the lower electrode of the laser chip is avoided.

Abstract: An optical transmission apparatus characterized by comprising a transmission system for transmitting an optical frequency-division multiplex signal, and an optical reception system which contains a semiconductor laser as a light source for reception and receives the optical signal, wherein the semiconductor laser contains first oscillation wavelength control device for controlling its oscillation wavelength according to temperature and second oscillation wavelength control device for controlling its oscillation wavelength according to carrier density, causes the first oscillation wavelength control device to scan oscillation wavelengths over a range from a first frequency to a second wavelength and simultaneously, causes the second oscillation wavelength control device to change the oscillation frequency, and selects wavelengths in the range from the first wavelength to the second wavelength stepwise sequentially.

Abstract: A semiconductor light-emitting device capable of emitting blue to green light is disclosed. The device comprises a first cladding layer of the first conduction type stacked on a compound semiconductor substrate and made of ZnMgSSe compound semiconductor; an active layer stacked on the first cladding layer; a second cladding layer of the second conduction type stacked on the active layer and made of a ZnMgSSe compound semiconductor; and ZnSSe compound semiconductor layers provided on the second cladding layer and/or between the compound semiconductor substrate and the first cladding layer. The device has good optical confinement characteristics and carrier confinement characteristics, generates only a small amount of heat during its operation, and is fabricated easily.

Abstract: An optical amplifier for use in a WDM transmission system has a circulator two of whose ports constitute the input and output ports of the amplifier, and to whose third port is connected an optically amplifying fibre. Bragg grating reflectors are formed at specific intervals along this fibre chosen such that each WDM channel is reflected back to the circulator at a distance in inverse proportion to the gain per unit length experienced by that channel in the amplifier fibre, whereby all channels are amplified by the amplifier to the same extent.