Patents Assigned to NL Nanosemiconductor GmbH
  • Publication number: 20070248128
    Abstract: An optoelectronic module includes a semiconductor structure with a substrate having a first side and a second side, a first layered structure deposited on the first side, and a second layered structure deposited on the second side. The optoelectronic module also includes driver circuitry fabricated of the first layered structure and a diode laser fabricated of the second layered structure. The driver circuitry produces a drive electrical signal supplied to the diode laser, and the diode laser produces an optical output in response to the drive electrical signal. In a preferred embodiment, the optoelectronic module also includes a temperature-sensitive element fabricated of the first or the second layered structure. The temperature-sensitive element produces a temperature dependent control signal related to the diode laser temperature.
    Type: Application
    Filed: April 25, 2006
    Publication date: October 25, 2007
    Applicant: NL Nanosemiconductor GmbH
    Inventors: Igor Krestnikov, Jurgen Kurb, Alexey Kovsh, Alexey Zhukov, Daniil Livshits, Sergey Mikhrin
  • Publication number: 20070223549
    Abstract: An optoelectronic device includes a planar active element, a vertical waveguide surrounding the active element in the vertical direction, and a lateral waveguide comprising at least one active section and at least one filter section following each other in the longitudinal direction. At least part of the active element within the active section generates optical gain in response to above-threshold pumping. The broad lateral waveguide in the active section can localize multiple lateral optical modes. In the filter section, no lateral confinement is provided for the lateral optical modes. The device further comprises means to ensure low absorption loss in the filter section and, therefore, ensure high efficiency. In one embodiment low absorption loss is achieved by pumping of at least part of the active element within the filter section. In another embodiment, the active element has small overlap with the vertical optical modes.
    Type: Application
    Filed: March 23, 2006
    Publication date: September 27, 2007
    Applicant: NL NANOSEMICONDUCTOR GMBH
    Inventors: Daniil Livshits, Alexey Kovsh, Alexey Zhukov
  • Publication number: 20070127531
    Abstract: A quantum dot laser operates on a quantum dot ground-state optical transition. The laser has a broadband (preferably?15 nm) spectrum of emission and a high output power (preferably?100 mW). Special measures control the maximum useful pump level, the total number of quantum dots in the laser active region, the carrier relaxation to the quantum dot ground states, and the carrier excitation from the quantum dot ground states. In one embodiment, a spectrally-selective loss is introduced into the laser resonator in order to suppress lasing on a quantum dot excited-state optical transition, thereby increasing the bandwidth of the emission spectrum.
    Type: Application
    Filed: December 7, 2005
    Publication date: June 7, 2007
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Alexey Kovsh, Alexey Zhukov, Daniil Livshits, Igor Krestnikov
  • Publication number: 20060227825
    Abstract: The optical gain and the differential gain of a quantum dot gain region in a gain section of a passive or hybrid mode-locked laser is varied by stacking at least two planes of quantum dots. All quantum dot planes are preferably formed by the same fabrication method and under the same fabrication conditions. The number of stacked planes of quantum dots is selected such that the optical gain and the differential gain are both in their optimal range with respect to the optical loss in the laser resonator and to the differential gain in the saturable absorber element. This results in a device with a short pulse width, stable mode-locking, high-power, and temperature-independent operation.
    Type: Application
    Filed: April 7, 2005
    Publication date: October 12, 2006
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Alexey Kovsh, Alexey Zhukov
  • Publication number: 20060227818
    Abstract: A monolithic mode-locked diode laser with improved uniformity of light distribution along the cavity. The laser includes a multiple gain section with more than one gain subsection where the length of each subsection is less than the reciprocal gain coefficient in the gain subsection and a multiple saturable absorber section with more than one saturable absorber subsection where the length of each subsection is less than the reciprocal absorption coefficient in the saturable absorber subsection. The gain subsections alternate with the saturable absorber subsections and are optically coupled in a single waveguide. They are also allocated inside the monolithic cavity such that the total length of the gain subsections and the saturable absorber subsections is equal or close to the total cavity length. The cavity length preferably corresponds to a sufficiently low fundamental repetition frequency. Special measures are preferably provided to ensure mode-locking at the fundamental frequency.
    Type: Application
    Filed: July 5, 2005
    Publication date: October 12, 2006
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Alexey Gubenko, Alexey Kovsh, Alexey Zhukov, Efim Portnoi
  • Patent number: 7101444
    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.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: September 5, 2006
    Assignee: NL Nanosemiconductor GmbH
    Inventors: Vitaly Shchukin, Nikolai Ledentsov
  • Patent number: 7075954
    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.
    Type: Grant
    Filed: June 5, 2003
    Date of Patent: July 11, 2006
    Assignee: NL Nanosemiconductor GmbH
    Inventors: Nikolai Ledentsov, Vitaly Shchukin
  • Patent number: 7031360
    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.
    Type: Grant
    Filed: February 12, 2002
    Date of Patent: April 18, 2006
    Assignee: NL Nanosemiconductor GmbH
    Inventors: Nikolai Ledentsov, Vitaly Shchukin
  • Publication number: 20050271092
    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.
    Type: Application
    Filed: June 2, 2005
    Publication date: December 8, 2005
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Nikolai Ledentsov, Vitaly Shchukin
  • Publication number: 20050226294
    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.
    Type: Application
    Filed: April 5, 2005
    Publication date: October 13, 2005
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Nikolai Ledentsov, Vitaly Shchukin
  • Publication number: 20050117623
    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.
    Type: Application
    Filed: November 30, 2004
    Publication date: June 2, 2005
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Vitaly Shchukin, Nikolai Ledentsov
  • Publication number: 20050040410
    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.
    Type: Application
    Filed: September 16, 2004
    Publication date: February 24, 2005
    Applicant: NL-Nanosemiconductor GmbH
    Inventors: Nikolai Ledentsov, Vitaly Shchukin