Patents Assigned to Koheras A/S
  • Publication number: 20100172018
    Abstract: A new deep blue extended super continuum light source is provided wherein said super continuum at least extends to a low wavelength border ?lowlow below 480 nm comprising a pump source which operates at a at least one wavelength ?pumpand produces pump pulses of a duration (full width half maximum) longer than 0.1 picoseconds with a repetition rate higher than 1 MHz, and a peak power ?peak, and a micro-structured optical transmission medium having at least one wavelength of zero dispersion ?zero, and for the parameters for said pump source exhibiting a second order dispersion parameter ?2, and a non-linear parameter ? arranged so that the optical transmission medium exhibits a modulation instability gain extending to wavelengths above a wavelength ?high?1300 nm and a phase match between ?1ow and a wavelength ?match??high, wherein the the pump is adapted to provide energy within the region of anomalous dispersion of the transmission medium.
    Type: Application
    Filed: December 10, 2007
    Publication date: July 8, 2010
    Applicant: KOHERAS A/S
    Inventors: Kent Mattsson, Michael Henoch Frosz
  • Publication number: 20100040335
    Abstract: The invention relates to an optical fibre comprising a core and a cladding comprising a core material and a cladding material, respectively, wherein said fibre is a non-linear microstructured optical fibre, said microstructured optical fibre being obtainable by a method comprising loading said core material and optionally said cladding material with hydrogen and/or deuterium whereby the lifetime of the fibre may be extended in high pulse applications.
    Type: Application
    Filed: January 14, 2008
    Publication date: February 18, 2010
    Applicant: KOHERAS A/S
    Inventor: Carsten L. Thomsen
  • Publication number: 20090262764
    Abstract: A new blue extended super continuum light source is claimed. When pulses of partly coherent monochromatic “pump” radiation of essentially constant amplitude is propagating through a microstructure fibre medium within a region of anomalous dispersion of the medium, then, provided the medium has a finite nonlinear coefficient of the index of refraction, the pump pulse is subject to a modulation instability. This instability results in the generation and exponential growth of sidebands, the two closest to the “pump” frequency being the dominant ones. The modulation frequency is proportional to the square root of the power in the carrier wave. In the time domain this leads to that the interaction between the medium and the radiation results in contraction of the width of the amplitude peaks, which results in formation of a train of narrow pulses with Tera Hertz repetition rate.
    Type: Application
    Filed: June 28, 2006
    Publication date: October 22, 2009
    Applicant: Koheras A/S
    Inventor: Kent Mattsson
  • Publication number: 20090238215
    Abstract: Refractive index modifications such as e.g. Fiber Bragg gratings in micro-structured Fiber are according to an aspect of the invention fabricated by first filling and/or purging the holes of the micro-structured fiber with inert gas or by evacuation and, optionally subsequently scaling the ends. Alternatively, the ends of the micro-structured fiber may be sealed without a preceding purging or evacuation of the holes. In this way hydrogen or deuterium present in the holes after photosensitizing loading will not react with atmospheric oxygen to form water. Water formed this way would otherwise seriously impair the grating formation process. Bragg gratings and other refractive index structures can thus be fabricated with high quality and predictable specifications in micro-structured fiber. Sealing the fiber ends also prevents in-diffusion of moisture. The invention may e.g. find application in connection with fiber optical sensors, high-power fiber lasers, etc.
    Type: Application
    Filed: August 24, 2005
    Publication date: September 24, 2009
    Applicant: KOHERAS A/S
    Inventor: Poul Varming
  • Publication number: 20090074023
    Abstract: The light includes a laser (4), which operates at or near its fundamental wavelength and produces pulses of a duration longer than 0.5 ns, and a micro-structured optical fibre (9) arranged to guide the pulses, wherein the light is generated by the pulses in the fibre (9). The light source may e.g. be useful in applications such as spectral testing of fibre components and spectral analysis of chemical and biological samples.
    Type: Application
    Filed: December 22, 2004
    Publication date: March 19, 2009
    Applicant: KOHERAS A/S
    Inventor: William Wadsworth
  • Publication number: 20080226242
    Abstract: A method of generating supercontinuum optical radiation, the method comprising: (a) providing an optical wave-guide (22), said optical waveguide exhibiting a dispersion characteristic of guided optical radiation, said dis-persion characteristic comprising: (i) a first dispersion parameter (?21) at a first wavelength (?1), (ii) a second dispersion parameter (?22) at a second shorter wavelengths (?2), and (iii)a zero-dispersion parameter at a wavelength in between said first and said second shorter wavelengths; said optical waveguide further comprising at least one entrance for receiving optical radiation, and at least one exit for emitting guided optical radiation; (b) applying at least two laser radiation of said first (25) wavelength, (?1) at a first power (P1) and applying laser radiation of said second (26) shorter wavelength (?2) at a second power (P2) into said optical waveguide, said laser radiations at least partially overlapping between said at least one entrance and said at least one exit of said opt
    Type: Application
    Filed: January 24, 2005
    Publication date: September 18, 2008
    Applicant: KOHERAS A/S
    Inventors: Scott Charles Buchter, Hanne Elisabeth Ludvigsen, Matti Kaivola
  • Publication number: 20070263676
    Abstract: The invention relates to a system comprising a waveguide laser for exciting laser light at a lasing wavelength ?s and a pump for pumping the waveguide laser at a pumping wavelength ?p. The invention further relates to a method of providing such a system and its use. The object of the present invention is to provide a system comprising a waveguide laser with a reduced phase noise. The problem is solved in that the pump is a single frequency laser. The invention may e.g. be used in systems where an ultra-low phase noise and/or linewidth is required, e.g. in LIDAR or interferometric systems.
    Type: Application
    Filed: June 21, 2005
    Publication date: November 15, 2007
    Applicant: KOHERAS A/S
    Inventors: Martijn Beukema, Christian Poulsen, Jens Pedersen, Poul Varming
  • Publication number: 20070183464
    Abstract: The invention relates to an article comprising a length of an optical fibre and a package, the optical fibre comprising a fibre Bragg grating dispersed over a FBG-section of the length of the optical fibre, the package comprising a carrier with a carrier surface for supporting at least a supported part of the optical fibre including the FBG-section. The invention further relates to an apparatus comprising the article, to its use and to a method of manufacturing such an article. The object of the present invention is to seek to provide an optimized (e.g. elongate) package having a relatively low sensitivity to mechanical vibrations from the environment. This is achieved by providing that the carrier surface for supporting the optical fibre comprising a fibre Bragg grating is convex in a longitudinal direction of the optical fibre during use of the article.
    Type: Application
    Filed: June 17, 2005
    Publication date: August 9, 2007
    Applicant: KOHERAS A/S
    Inventors: Christian Poulsen, Lars Hansen, Ole Sigmund, Jens Pedersen, Martijn Beukema
  • Publication number: 20070153839
    Abstract: The invention relates to an optical waveguide laser comprising a) an active region formed over a length of the optical waveguide, comprising an excitable material emitting light in response to stimulation by pump light thereby defining an optical gain profile and the excitable material comprises Tm; b) a frequency discriminated feedback element adapted to select a single longitudinal lasing mode by coordination with the frequency response of the optical gain of the excitable material; and c) a polarisation asymmetry element adapted for selecting a single polarisation mode of a given longitudinal mode by selectively suppressing propagation of the other polarisation mode of said longitudinal mode. The object of the present invention is to provide relatively simple, compact and economic lasers for single-frequency operation in the wavelength range of 1.7 um to 2.2 um; in particular for a number of applications, including spectroscopy and for eye-safe optical sources in sensing and in LIDAR, etc.
    Type: Application
    Filed: December 13, 2004
    Publication date: July 5, 2007
    Applicant: KOHERAS A/S
    Inventors: Poul Varming, Soren Agger
  • Patent number: 6603779
    Abstract: A method of packaging an optical fiber laser incorporates an optical fiber laser (11) in a matrix of a curable viscous material (15). The matrix has a loss coefficient/dissipation factor high enough to dampen acoustic vibrations and a thermal diffusivity low enough to reduce transient heat flow into the optical fiber laser.
    Type: Grant
    Filed: June 26, 2002
    Date of Patent: August 5, 2003
    Assignee: Koheras A/S
    Inventors: Jens Engholm Pedersen, Martijn Beukema, Christian Vestergaard Poulsen, Lars Erik Eskildsen
  • Publication number: 20020181908
    Abstract: A method of temperature stabilizing an optical waveguide having positive thermal optical path length expansion, in particular a stable single polarization mode optical fiber distributed feed back laser or a distributed Bragg reflector optical fiber laser, comprising affixing optical waveguide to at least two points of a composite material having negative thermal expansion; said composite material comprising a resin matrix having embedded therein fibers having a negative thermal expansion coefficient, and optionally fibers having a positive thermal expansion coefficient. Further a method of packaging optical fiber lasers that acts to reduce frequency jitter and hence reduce the spectral linewidth of the laser through damping of thermal fluctuations and acoustic vibrations originating from the environment; said packaging method comprising encapsulating the fiber laser within a curable viscous substance such as silicone or other elastomer.
    Type: Application
    Filed: June 26, 2002
    Publication date: December 5, 2002
    Applicant: KOHERAS A/S
    Inventors: Jens Engholm Pedersen, Martijn Beukema, Christian Vestergaard Poulsen, Lars Erik Eskildsen