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 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 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.

Abstract: A novel class of semiconductor lasers, or “tilted cavity lasers” includes at least one active element with an active region generating an optical gain by injection of a current and mirrors. The active element is placed into a cavity. The cavity is designed such that the optical path of the resonant optical mode is tilted with respect to both the vertical direction and the lateral plane. Thus, the feedback both in the vertical and in the lateral direction is provided for the resonant optical mode. Depending on the particular embodiment, the laser operates as both a surface emitting laser and an edge-emitting laser. Employing a tilted optical mode allows the use of substantially fewer layers in the bottom and the top interference reflectors than in conventional lasers. This preserves the necessary high reflection coefficients. Also, a wavelength-stabilized laser is realized for edge-emitters.

Abstract: A semiconductor laser having a low beam divergence is disclosed. The laser includes at least one waveguide comprising an active layer generating an optical gain by injection of a current, a photonic band gap crystal having the refractive index modulation in the direction perpendicular to the propagation of the emitted light, and at least one defect. The active layer is preferably placed within the defect. The photonic band gap crystal and the defect are optimized such that the fundamental mode of laser radiation is localized at the defect and decays away from the defect, while the other optical modes are extended over the photonic band gap crystal. Localization of the fundamental mode at the defect results in the relative enhancement of the amplitude of the mode with respect to the other modes. Therefore, there is a larger confinement factor of the fundamental mode as compared to the confinement factor of the other modes. This enables efficient single-mode lasing from the laser having an extended waveguide.

Abstract: A novel class of semiconductor lasers, or “tilted cavity lasers” includes at least one active element with an active region generating an optical gain by injection of a current and mirrors. The active element is placed into a cavity. The cavity is designed such that the optical path of the resonant optical mode is tilted with respect to both the vertical direction and the lateral plane. Thus, the feedback both in the vertical and in the lateral direction is provided for the resonant optical mode. Depending on the particular embodiment, the laser operates as both a surface emitting laser and an edge-emitting laser. Employing a tilted optical mode allows the use of substantially fewer layers in the bottom and the top interference reflectors than in conventional lasers. This preserves the necessary high reflection coefficients. Also, a wavelength-stabilized laser is realized for edge-emitters.

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 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: Apparatus for frequency conversion of light, the apparatus comprises: a light-emitting device for emitting a light having a first frequency, the light-emitting device being an edge-emitting semiconductor light-emitting diode having an extended waveguide selected such that a fundamental transverse mode of the extended waveguide is characterized by a low beam divergence. The apparatus further comprises a light-reflector, constructed and designed so that the light passes a plurality of times through an external cavity, defined between the light-emitting device and the light-reflector, and provides a feedback for generating a laser light having the first frequency. The apparatus further comprises a non-linear optical crystal positioned in the external cavity and selected so that when the laser light having the first frequency passes a plurality of times through the non-linear optical crystal, the first frequency is converted to a second frequency being different from the first frequency.

Abstract: A novel class of optoelectronic devices incorporate an interference filter. The filter includes at least two optical cavities. Each of the cavities localizes al least one optical mode. The optical modes localized at two cavities are at resonance only at one or at a few discrete selective wavelengths. At resonance, the optical eigenmodes contain one mode having a zero intensity at a node position between the two cavities, where this position shifts as a function of the wavelength. A non-transparent element, which is preferably an absorbing element, a scatterer, or a reflector, is placed between two cavities. At a discrete selective wavelength, when the node of the optical mode matches with the non-transparent element, the filter is transparent for light. At other wavelengths, the filter is not transparent for light. This allows for the construction of various optoelectronic devices showing a strongly wavelength-selective operation.

Abstract: A novel class of semiconductor light-emitting devices, or “tilted cavity light-emitting devices” is disclosed. The device includes at least one active element, generally placed within a cavity, with an active region generating an optical gain by injection of a current and two mirrors. The device generates optical modes that propagate in directions, which are tilted with respect to both the p-n junction plane and the direction normal to this plane. A light-emitting diode is also disclosed, where the cavity and the mirrors are designed such that transmission of generated optical power within a certain spectral range and within a certain interval of angles to the substrate is minimized. Transmission of optical power within a certain spectral range, which corresponds to the emission range of the light-emitting active medium and within a certain interval of angles out of the device, is optimized to achieve a required output power level.

Abstract: A semiconductor laser having a low beam divergence is disclosed. The laser includes at least one waveguide comprising an active layer generating an optical gain by injection of a current, a photonic band gap crystal having the refractive index modulation in the direction perpendicular to the propagation of the emitted light, and at least one defect. The active layer is preferably placed within the defect. The photonic band gap crystal and the defect are optimized such that the fundamental mode of laser radiation is localized at the defect and decays away from the defect, while the other optical modes are extended over the photonic band gap crystal. Localization of the fundamental mode at the defect results in the relative enhancement of the amplitude of the mode with respect to the other modes. Therefore, there is a larger confinement factor of the fundamental mode as compared to the confinement factor of the other modes. This enables efficient single-mode lasing from the laser having an extended waveguide.

Abstract: A semiconductor laser having a low beam divergence is disclosed. The laser includes at least one waveguide comprising an active layer generating an optical gain by injection of a current, a photonic band gap crystal having the refractive index modulation in the direction perpendicular to the propagation of the emitted light, and at least one defect. The active layer is preferably placed within the defect. The photonic band gap crystal and the defect are optimized such that the fundamental mode of laser radiation is localized at the defect and decays away from the defect, while the other optical modes are extended over the photonic band gap crystal. Localization of the fundamental mode at the defect results in the relative enhancement of the amplitude of the mode with respect to the other modes. Therefore, there is a larger confinement factor of the fundamental mode as compared to the confinement factor of the other modes. This enables efficient single-mode lasing from the laser having an extended waveguide.

Abstract: A method for fabrication of defect-free epitaxial layers on top of a surface of a first defect-containing solid state material includes 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 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: The method produces coherent dislocation-free regions from initially dislocated and/or defect-rich lattice mismatched layer grown on top of the substrate having a different lattice constant, which does not contain any processing steps before of after the lattice-mismatched layer growth. The process preferably uses in situ formation of a cap layer on top of a dislocated layer. The cap layer preferably has a lattice parameter close to that in the underlying substrate, and different from that in the lattice mismatched layer in no strain state. Under these conditions, the cap layer undergoes elastic repulsion from the regions in the vicinity of the dislocations, where the lattice parameter is the most different from that in the substrate. The cap layer is absent in these regions.