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: A multi-quantum barrier layer includes alternatingly laminated barrier layers of a III-V compound semiconductor material and well layers of a III-V compound semiconductor material including the same Group V element as in the barrier layers. During the formation of the multi-quantum barrier layer it is not necessary to switch the Group V element source gas at the interface between a barrier layer and a well layer so that this interface is abrupt, improving the electron reflection efficiency of the multi-quantum barrier layer.

Abstract: A multiquantum-well semiconductor laser having a long wavelength, for use in optical communication systems, comprises an active region including a plurality of quantum-well layers each made of InGaAs or InGaAsP, and a plurality of barrier laminates each made of InGaAsP having a bandgap wider than that of the quantum-well layers. Each barrier laminate includes three barrier layers of different compositions of InGaAsP having different bandgaps. Each barrier laminate has a thickness such that the wave functions of carriers in adjacent quantum-well layers do not overlap each other, while carriers supplied to the active region can be effectively injected into the quantum-well layers, thereby obtaining a low threshold current and a high slope efficiency.

Abstract: An SEL array having improved optical isolation and heat conduction. The SEL array is constructed from a light generation layer and first and second mirror layers that sandwich the light generation layer. The first mirror and second mirrors reflect light generated in the light generation layer back toward the light generation layer. The first mirror includes a plurality of light isolation regions, each light isolation region extending through the first mirror. The light isolation regions divide the light generation layer into a plurality of light generation regions. Each light generation region corresponds to one of the SELs. Each light isolation region is positioned to prevent light generated in one of the light generation regions from propagating into a neighboring light generation region. In one embodiment of the present invention, the light isolation regions are constructed by providing trenches that extend from the surface of the SEL array through the first mirror.

Abstract: In an optical pickup apparatus, a laser beam emitted from a semiconductor laser device is reflected upward by a reflecting member, transmitted through a transmission type diffraction grating and split into at least three beams, and which beams are transmitted through a transmission type holographic optical element and condensed onto an optical recording medium by a condenser portion. A return beam reflected by the optical recording medium passes through the condenser portion and diffracted not to impinge upon the transmission type diffraction grating by the holographic optical element and directed to a photodetector portion of a light receiving device. The semiconductor laser device and the light receiving device are disposed in a mount member.

Abstract: A vertical-cavity surface-emitting laser that generates light having a fixed direction of polarization. The laser has a plane light-generating region sandwiched between a first conductive mirror region and a second conductive mirror region. The first conductive mirror region has an opposite conductivity mode from the second conductive mirror region. The first conductive mirror region has a remote surface substantially parallel to the light-generating region and an electrode formed on the remote surface. The electrode bounds a light emission port from which the light is emitted in a direction defining an axis. A reduced-conductivity region is formed in the first conductive mirror region surrounding the axis and extending from the remote surface towards the light-emitting region to define a core region in the first conductive mirror region. The light emission port and/or the core region has first and second dimensions in orthogonal directions in a plane parallel to the light-generating region.

Abstract: A semiconductor laser includes (a) a semiconductor substrate of a first conductivity type on which is provided (b) a mesa stripe portion having a multilayer structure. The multilayer structure includes (b-1) an active layer provided on the semiconductor substrate. The laser also includes (c) a buried current blocking layer arranged on both sides of the mesa stripe portion, (d) a clad layer of a second conductivity type provided on the semiconductor substrate through at least a portion of the active layer, and (e) a contact layer of the second conductivity type provided on the clad layer. The contact layer includes a first contact layer contacting the clad layer and a second contact layer provided on the first contact layer. The first contact layer has an energy gap smaller than that of the clad layer and larger than that of the second contact layer. Preferably, the first contact layer is an InGaAsP semiconductor layer having an energy gap within the range of from 0.82 eV to 1.

Abstract: An optimized waveguide structure enables the functional integration of various passive optic components on a single substrate. The optimized waveguide structure is characterized by a thicker core layer than used for square core waveguides and a core width that changes according to different functional regions of the optic circuit within which it is incorporated. The height (H) of the waveguide core is determined by the thickness of the core layer defined during the fabrication process and is ideally uniform across the circuit. The width (W) of the core, however, is changed between functional regions by the photo-lithographic mask and the chemical etching during the fabrication process. By way of example, an optimized waveguide structure for a P-doped silica planar waveguide with a .DELTA. approximately 0.6% for wavelength .lambda.=1.2-1.7 .mu.m, has a single uniform height of H=6.7 .mu.m and a width that changes between W=4 .mu.m in a coupler region, W=5.5 .mu.m in a bend region, W=9 .mu.

Abstract: An index-guided semiconductor laser diode made by impurity-induced layer disordering (IILD) of AlInP, GaInP and AlGaInP heterostructures. Several techniques for reducing parasitic leakage current via the n-type IILD regions, are described. These include removing the upper portions of the material outside the laser stripe, which can be accomplished by wet or dry etching of the material in a self-aligned manner. As an alternative, after formation of the waveguide, appropriately doped layers are grown over the disordered and as-grown regions of the structure to contact the active waveguide and simultaneously block parasitic shunt current from the disordered regions. Another method provides shallow inset insulating regions to replace the n-type disordered regions at the vicinity of a cap layer used to reduce a current barrier.

Abstract: A semiconductor laser device includes a substrate having one of p- and n-conductivity types, and a current constrictive layer formed on a surface of the substrate and having the other type of conductivity. The current constrictive layer has a through-channel extending to the surface of the substrate for defining a current path in a direction perpendicular to the surface of the substrate. The through-channel is of a belt-like pattern extending in a direction perpendicular to end surfaces of the substrate. A third cladding layer having the one type of conductivity is filled in the through-channel, a surface of the third cladding layer being flush with a surface of a current constrictive layer. A first cladding layer, an active layer, and a second cladding layer which constitute a double heterostructure are formed over the third cladding layer and current constrictive layer.

Abstract: A travelling-wave semiconductor laser amplifier having suppressed self-oscillation is provided. When incorporated into a master oscillator power amplifier device, such a device has improved light output versus amplifier current characteristics. Also provided is a method for suppressing self-oscillation in travelling-wave semiconductor laser amplifier structures for improving the characteristics of the device into which the amplifier is incorporated.

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. The grating is formed in the guided-mode region of the optical fibre. 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 stabilizes 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 selected depending on the distance of the grating from the diode laser.

Abstract: A temperature-insensitive vertical-cavity surface-emitting laser (VCSEL) and method for fabrication thereof. The temperature-insensitive VCSEL comprises a quantum-well active region within a resonant cavity, the active region having a gain spectrum with a high-order subband (n.gtoreq.2) contribution thereto for broadening and flattening the gain spectrum, thereby substantially reducing any variation in operating characteristics of the VCSEL over a temperature range of interest. The method for forming the temperature-insensitive VCSEL comprises the steps of providing a substrate and forming a plurality of layers thereon for providing first and second distributed Bragg reflector (DBR) mirror stacks with an active region sandwiched therebetween, the active region including at least one quantum-well layer providing a gain spectrum having a high-order subband (n.gtoreq.

Abstract: A fabrication process and several structures for an index-guided laser diode formed by IILD or for a multiple wavelength laser array containing stacked semi-conductive active layers with quantum wells. The laser wavelength is varied laterally by effectively inactivating quantum wells which have transition wavelengths longer than that desired in the selected portion of the device. The quantum wells are inactivated by intermixing them with the surrounding high band gap semiconductor layers. To accomplish this intermixing without affecting the active layer in nearby regions, a finite source of impurity inducing or promoting intermixing is located in proximity to the quantum well to be intermixed, and the sample is annealed under conditions which allow for lateral patterning of the impurity-induced intermixing.

Abstract: The inventive system, which is used in transmitting illumination from a central source to a variety of remote locations, efficiently couples the light originating from an arc lamp, or similar source, into a multiplicity of flexible macroscopic fibers. The combination of the several elements of the inventive system results in a very efficient transfer of the energy of the light source to the fibers. The system also provides a very flexible mechanical means for distributing the energy to the fibers and to the remote locations at which the light is used.

Abstract: A semiconductor opto-electronic device including at least one electronic function component (62), at least one optical function component (60) and a mode transformer associated with the optical function component. At least some layers of semiconductor material constituting the electronic function component also form optical layers in the mode transformer zone and, at least in the mode transformer zone, these semiconductor material layers are non-absorbent at the operating wavelength. The mode transformer is preferably etched in the shape of an hourglass.

Abstract: Disclosed herein is a laser diode module having a thermoelectric cooling element, a laser diode, and a thermistor in a housing. The thermoelectric cooling element has a first surface and a second surface between which heat exchange is performed. The first surface is in close contact with an inner surface of the housing. A base is provided on the second surface in close contact therewith. A laser carrier and a thermistor carrier are provided on the base in close contact therewith. The laser diode and the thermistor are provided on the laser carrier and the thermistor carrier in close contact therewith, respectively. A portion of the base in the vicinity of the laser carrier is thermally connected to the housing by a metal plate, for example, thereby allowing high-precision temperature control of the laser diode.

Abstract: Optical, opto-electronic or photonic component comprising, for a given operating wavelength, at least one optical cavity defined between two reflectors and confined laterally. The reflectors are of the phase change type and the area between the reflectors that corresponds to the optical cavity has a cut-off wavelength greater than the cut-off wavelength of the area surrounding it laterally, the operating wavelength lying between the two cut-off wavelengths. The method enables manufacture of a component of this kind using relatively shallow etching.

Abstract: An optical fiber sensor which comprises a substrate having a groove pattern, an optical fiber which includes a shaped, bare optical fiber portion of an inverted U form and capable of being received or accommodated in the groove pattern of the substrate, and jacketed optical fiber portions extending from the shaped optical fiber rod portion at opposite ends thereof, and an optical modulation unit which is fixedly provided in a light path of the bare optical fiber portion and placed in at least one groove formed in the substrate. A method for fabricating the sensor is also described. The sensors include magnetic filed/current, electric field/voltage and temperature sensors.

Abstract: The present invention relates to a sensor for measuring pressure and stra The sensor is formed by an optical fiber having at least one section wherein the fiber is twisted about itself. The at least one twisted section acts as an intrinsically self-deforming microbend deformer. The sensor further includes a source of light attached to a first end of the fiber and a power meter for measuring the amount of light lost in the at least one section. The optical fiber may have multiple twisted sections with different twist pitches and thus different sensitivities. In an alternative embodiment, the sensor may have two optical fibers twisted about each other.