Abstract: A device representing a reflector, for example, an evanescent reflector or a multilayer interference reflector with at least one reflectivity stopband is disclosed. A medium with means of generating optical gain is introduced into the layer or several layers of the reflector. The optical gain spectrum preferably overlaps with the spectral range of the reflectivity stopband. This device can be attached to air, semiconductor or dielectric material or multilayer structures and provide a tool for preferential amplification of the optical waves propagating at larger angles with respect to the interface with the evanescent or the multilayer interference reflector. Thus angle selective amplification or generation of light is possible. Several evanescent or interference reflectors can be used to serve the goal of preferable amplification the said optical waves.

Abstract: A wavelength division multiplexing system has an array of wavelength-tunable lasers with at least two wavelength-tunable lasers emitting laser light at mutually different wavelengths, a first diffraction grating, an optical fiber, a second diffraction grating, and an array of photodetectors. The laser light emitted by the different wavelength-tunable lasers wavelengths impinges upon the first diffraction grating where it is reflected so as to impinge on an input end of the optical fiber. The light then propagates in the optical fiber and comes out from an output end of the optical fiber. Then the laser light having at least two different wavelengths further impinges on a second diffraction grating, whereupon it is reflected such that laser light having a first wavelength impinges on a first photodetector, and laser light having a second wavelength impinges on a second photodetector, which is different from the first photodetector.

Abstract: Semiconductor electrooptic medium shows behavior different from a medium based on quantum confined Stark Effect. A preferred embodiment has a type-II heterojunction, selected such, that, in zero electric field, an electron and a hole are localized on the opposite sides of the heterojunction having a negligible or very small overlap of the wave functions, and correspondingly, a zero or a very small exciton oscillator strength. Applying an electric field results in squeezing of the wave functions to the heterojunction which strongly increases the overlap of the electron and the hole wave functions, resulting in a strong increase of the exciton oscillator strength. Another embodiment of the novel electrooptic medium includes a heterojunction between a layer and a superlattice, wherein an electron and a hole in the zero electric field are localized on the opposite sides of the heterojunction, the latter being effectively a type-II heterojunction.

Abstract: A method is disclosed for improving the functionality of a semiconductor diode laser with an extended vertical waveguide, wherein the active medium is located close to the top cladding layer of the waveguide, and the laser aims to emit light in a narrow beam with high brightness and/or to operate in the wavelength-stabilized regime. The goal is to suppress parasitic optical modes localized close to the top cladding layer of the waveguide. Unpumped sections and groves perpendicular to the stripe serve to suppress these parasitic modes. Deep (preferably a few tens of micrometers) groves parallel to the stripe suppress parasitic emission of light and the feedback in the closed lateral modes. In a tilted wave laser the longitudinal resonator can be preferably configured to have a selected length to ensure closed loops formed in the longitudinal direction by the tilted wave.

Abstract: A device contains at least one wavelength-tunable multilayer interference reflector controlled by an applied voltage and at least one cavity. The stopband edge wavelength of the wavelength-tunable multilayer interference reflector is preferably electrooptically tuned using the quantum confined Stark effect in the vicinity of the cavity mode (or a composite cavity mode), resulting in a modulated transmittance of the multilayer interference reflector. A light-emitting medium is preferably introduced in the cavity or in one of the cavities permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply forward or reverse bias and may operate as a vertical cavity surface-emitting light emitter or modulator or as an edge-emitting light emitter or modulator.

Abstract: A device contains at least one wavelength-tunable multilayer interference reflector controlled by an applied voltage and at least one cavity. The stopband edge wavelength of the wavelength-tunable multilayer interference reflector is preferably electrooptically tuned using the quantum confined Stark effect in the vicinity of the cavity mode (or a composite cavity mode), resulting in a modulated transmittance of the multilayer interference reflector. A light-emitting medium is preferably introduced in the cavity or in one of the cavities permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply forward or reverse bias and may operate as a vertical cavity surface emitting light-emitter or modulator or as an edge-emitting light emitter or modulator.

Abstract: A light emitting device is disclosed that emits light from the surface in a broad spectral range and in a broad range of angles tilted with respect to the direction normal to the exit surface. An apparatus for generating wavelength-stabilized light is formed of a light-emitting device, an external cavity and at least one external mirror. Light emitted by the light-emitting device at a certain preselected angle, propagates through the external cavity, impinges on the external mirror and is reflected back. Light emitted at other angles does not impinge on the external mirror. Thus, a feedback occurs only for the light emitted at a preselected angle. Light impinged on the external mirror and reflected back undergoes interference with the emitted light. The interference can be constructive or destructive. Constructive interference results in a positive feedback. The positive feedback occurs, if light emitted by the light-emitting device is reflected back and reaches the active region in phase, i.e.

Abstract: A semiconductor diode laser having a broad vertical waveguide and a broad lateral waveguide is disclosed emitting laser-light in a single vertical mode and a single lateral mode narrow beam. The vertical waveguide comprises a coupled cavity structure, wherein light, generated in the active medium placed in the first cavity leaks into the second cavity and returns back. Phase matching conditions govern the selection of a single vertical mode. A multi-stripe lateral waveguide comprises preferably a lateral photonic band crystal with a lateral optical defect created by selected pumping of multistripes. This approach allows the selection of a single lateral mode having a higher optical confinement factor and/or a lower absorption loss and/or a lower leakage loss compared to the rest lateral optical modes. This enables a single lateral mode lasing from a broad area field coupled laser array.

Abstract: Semiconductor electrooptic medium shows behavior different from a medium based on quantum confined Stark Effect. A preferred embodiment has a type-II heterojunction, selected such, that, in zero electric field, an electron and a hole are localized on the opposite sides of the heterojunction having a negligible or very small overlap of the wave functions, and correspondingly, a zero or a very small exciton oscillator strength. Applying an electric field results in squeezing of the wave functions to the heterojunction which strongly increases the overlap of the electron and the hole wave functions, resulting in a strong increase of the exciton oscillator strength. Another embodiment of the novel electrooptic medium includes a heterojunction between a layer and a superlattice, wherein an electron and a hole in the zero electric field are localized on the opposite sides of the heterojunction, the latter being effectively a type-II heterojunction.

Abstract: A device contains at least one leaky waveguide layer, and has a transparent substrate, having a higher refractive index. The leakage loss of the waveguide exceeds the modal gain needed to initiate waveguide lasing. The leaky emission is going into the substrate at a certain angle, is reflected from the substrate back surface, and returns towards the leaky waveguide layer exhibiting constructive or destructive interference. As the leakage emission is returned to the active medium, the low threshold current density lasing is possible. As the leakage angle is defined for a given wavelength, interference enables lasing only at certain wavelengths making it possible to realize wavelength-selectivity. The lobes of the output emission can be made arbitrarily narrow by increasing the thickness of the substrate and the exit angle of the lobes is controlled by the leakage angle of the waveguide.

Abstract: A device contains at least one wavelength-tunable element controlled by an applied voltage and at least two resonant cavities, where the resonant wavelength of the tunable element is preferably elecrooptically tuned using the quantum confined Stark effect around the resonant wavelength of the other cavity or cavities, resulting in a modulated transmittance of the system. A light-emitting medium is preferably introduced into one of the cavities, permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply a forward or a reverse bias and may operate as a vertical cavity surface emitting light-emitter or modulator or as a tilted cavity light emitter or modulator. Adding a few modulator sections enables applications in semiconductor optical amplifiers, frequency converters or lock-in optical amplifiers.

Abstract: A device contains at least one leaky waveguide layer, and has a transparent substrate, having a higher refractive index. The leakage loss of the waveguide exceeds the modal gain needed to initiate waveguide lasing. The leaky emission is going into the substrate at a certain angle, is reflected from the substrate back surface, and returns towards the leaky waveguide layer exhibiting constructive or destructive interference. As the leakage emission is returned to the active medium, the low threshold current density lasing is possible. As the leakage angle is defined for a given wavelength, interference enables lasing only at certain wavelengths making it possible to realize wavelength-selectivity. The lobes of the output emission can be made arbitrarily narrow by increasing the thickness of the substrate and the exit angle of the lobes is controlled by the leakage angle of the waveguide.

Abstract: A semiconductor optoelectronic device includes at least one cavity and one multilayered interference reflector. The cavity is designed preferably to possess properties of an antiwaveguiding cavity, where no optical modes propagate in the lateral plane. The existing optical modes are the modes propagating in the vertical direction or in a direction tilted to the vertical direction at an angle smaller than the angle of the total internal reflection at the semiconductor/air interface. This design reduces the influence of parasitic optical modes and improves characteristics of optoelectronic devices including vertical cavity surface emitting lasers, tilted cavity lasers emitting through the top surface or the substrate, vertical or tilted cavity resonant photodetectors, vertical or tilted cavity resonant optical amplifiers, and light-emitting diodes.

Abstract: A device contains at least one wavelength-tunable multilayer interference reflector controlled by an applied voltage and at least one cavity. The stopband edge wavelength of the wavelength-tunable multilayer interference reflector is preferably electrooptically tuned using the quantum confined Stark effect in the vicinity of the cavity mode (or a composite cavity mode), resulting in a modulated transmittance of the multilayer interference reflector. A light-emitting medium is preferably introduced in the cavity or in one of the cavities permitting the optoelectronic device to work as an intensity-modulated light-emitting diode or diode laser by applying an injection current. The device preferably contains at least three electric contacts to apply forward or reverse bias and may operate as a vertical cavity surface emitting light-emitter or modulator or as an edge-emitting light emitter or modulator.

Abstract: A optoelectronic device is disclosed containing at least one multilayer interference reflector, having at least two periodicities in the refractive index. At least one of the periodicities, or quasi-periodicities, prohibits the light emission in a range of angles tilted with respect to the intentionally selected direction, for example, in the direction perpendicular to the layer planes, preventing the emission of light in the optical modes propagating in a certain interval of angles, dangerous for the device, and thus reducing the effect of parasitic modes on the device performance. A light generating element emitting light in a certain wavelength range is preferably introduced in one of the layers. The light is then channeled into the required angle range. The device can additionally contain a cavity. A second periodicity of the refractive index is preferably selected to ensure a high reflectivity in the vertical direction enabling advanced vertical cavity surface-emitting lasers.

Abstract: A light emitting device is disclosed that emits light from the surface in a broad spectral range and in a broad range of angles tilted with respect to the direction normal to the exit surface. An apparatus for generating wavelength-stabilized light is formed of a light-emitting device, an external cavity and at least one external mirror. Light emitted by the light-emitting device at a certain preselected angle, propagates through the external cavity, impinges on the external mirror and is reflected back. Light emitted at other angles does not impinge on the external mirror. Thus, a feedback occurs only for the light emitted at a preselected angle. Light impinged on the external mirror and reflected back undergoes interference with the emitted light. The interference can be constructive or destructive. Constructive interference results in a positive feedback. The positive feedback occurs, if light emitted by the light-emitting device is reflected back and reaches the active region in phase, i.e.

Abstract: A semiconductor light-emitting diode having a low beam divergence includes at least one waveguide comprising an active region generating light by injection of a current, a photonic band crystal having the refractive index modulation in the direction perpendicular to the propagation of the emitted light, and at least one optical defect. The photonic band crystal and the optical defect are optimized such that the fundamental optical mode of the device is localized at the defect and decays away from the defect, while the other optical modes are extended over the photonic band crystal. The optical confinement factor of the localized optical mode preferably exceeds the optical confinement factor of the rest of the optical modes by at least a factor of three.

Abstract: A semiconductor device includes at least one defect-free epitaxial layer. At least a part of the device is manufactured by a method of fabrication of defect-free epitaxial layers on top of a surface of a first solid state material having a first thermal evaporation rate and a plurality of defects, where the surface comprises at least one defect-free surface region, and at least one surface region in a vicinity of the defects, the method including the steps of selective deposition of a second material, having a high temperature stability, on defect-free regions of the first solid state material, followed by subsequent evaporation of the regions in the vicinity of the defects, and subsequent overgrowth by a third material forming a defect-free layer.

Abstract: A selective reflector, for selectively preventing reflection of light passing therethrough. The selective reflector comprising at least one layer characterized by an angle-dependent reflectivity function. The angle-dependent reflectivity function being decreasing upon at least one interval of increasing impinging angle of the light on a surface of the at least one layer, such that when said impinging angle is within a predetermined range, the reflection of light is substantially prevented.

Abstract: A wavelength division multiplexing system based on arrays of wavelength tunable lasers and wavelength tunable resonant photodetectors is disclosed. The system allows self-adjusting of the resonance wavelength of the wavelength tunable photodetectors to the wavelengths of the laser light emitted by the lasers. No precise wavelength stabilization of the lasers is required.