DFB Laser Concept

nanoplus DFB lasers

A key product of nanoplus are complex coupled distributed feedback laser diodes. nanoplus provides these monomode semiconductor lasers at any wavelength between 760 nm and 14000 nm.

Key features of nanoplus DFB lasers

nanoplus DFB lasers have the following advantages:

  • stable longitudinal and transversal single mode emission
  • precise selection of target wavelength
  • narrow laser line width
  • mode-hop-free wavelength tunability
  • fast wavelength tuning
  • typically > 5 mW output power
  • small size
  • easy usability
  • high efficiency
  • long-term stability

    Various application examples are provided in our applications section.

    Figure 1: Schematic design of a laterally coupled DFB laser diode and electron micrograph of a metal grating DFB structure defined by E-Beam lithography
    Schematic of nanoplus DFB concept

    Unique concept of nanoplus DFB lasers

    Semiconductor lasers in general are known as compact and reliable light sources with high wall-plug efficiency. While Fabry Perot laser diodes typically operate only transversal single mode, both Distributed Feedback and Distributed Bragg Reflector laser diodes contain an integrated grating structure for longitudinal mode selection, resulting in narrow band emission.

    DFB devices are ideally suited to provide longitudinal and transversal single mode emission at a precise wavelength with an extremely narrow line width. They guarantee high output power and mode-hop-free tunability compared to a DBR device and are ideally suited to meet the high requirements of TDLAS gas sensing applications.

    Conventionally the grating structure in a DFB or DBR device is defined by an etch process during a growth interruption step shortly after the growth of the active region of the laser structure. The pre-patterned structure is then inserted into the epitaxy reactor again and overgrown. As the growth on a pre-patterned surface is much more demanding as the usual growth on a planar substrate (different orientations requiring different overgrowth conditions, defects introduced in the overgrowths by residual impurities due to the pre-patterning process) the performance of single mode lasers made by this technique in most systems including e. g. the GaAs and the GaSb substrate system is significantly degraded by this type of processing.

    In contrast, the unique and patented nanoplus DFB concept (shown schematically in Figure 1) is based on an overgrowth-free approach avoiding the need to develop high quality orientation independent growth and avoiding per se the insertion of patterning induced defects near the active layer.

    nanoplus puts great value on R&D to provide our customers with cutting-edge products. Our technological advances resulted in a number of patents, such as patent numbers US 6.671.306, US 6.846.689 and EP0984535. In addition we have licence agreements with the US Department of the Navy, Naval Research Laboratory for the production of Interband Cascade Lasers as well as with Alcatel-Lucent USA Inc. for the production of Quantum Cascade Lasers.

    In nanoplus DFB lasers complex coupling is obtained by combining a ridge waveguide structure with metal gratings on top of the waveguide layer on both sides of the laser ridge. DFB lasers realized by this technique show

    • high performance (SMSR > 40 dB, feedback, tolerance)
    • independence of material system (GaAs, InP and GaSb)
    • low capitance BCB planarisation for high Gbit / s operation

    compared to conventional DFB laser diodes. Thresholds and efficiencies correspond to those of Fabry Perot lasers realized from the same layer structures, while mode-hop free operation combined with a high SMSR is guaranteed in the entire specified temperature and power range of operation.

    Most importantly, the nanoplus DFB concept is largely independent on the underlying laser structure and can easily be adopted to a variety of independent epitaxial designs. Based on this approach, nanoplus manufactures and sells DFB laser diodes in the entire wavelength range from 760 nm up to 3000 nm. In addition, nanoplus offers DFB interband cascade lasers from 3000 nm to 6000 nm and DFB quantum cascade lasers at wavelengths between 6000 nm and 14000 nm.

    Types of semiconductor lasers

    More specifically, from the general physics point-of-view, nanoplus offers three different types of semiconductor lasers based on slightly different lasing principles:

    I:Bipolar Laser Diodes from 760 nm to 3000 nm
    II:Interband Cascade Lasers from 3000 nm to 6000 nm
    III:Quantum Cascade Lasers from 6000 nm to 14000 nm

    Laser Diode

    Interband Cascade Laser

    Quantum Cascade Laser


    I: bipolar interband Laser Diodes from 760 nm to 3000 nm

    In a LD electrons and holes have an optical interband recombination at the p-n junction of a semiconductor diode. This transition has a high energy gap. This is the reason why we reach a shorter wavelength range with these devices.

    Figure 2: LD structure
    nanoplus structure of laser diode

    II: Interband Cascade Lasers type-II-W-QW from 3000 nm to 6000 nm

    In an ICL electrons and holes have an optical interband recombination at the W-shaped quantum well (QW) of the semiconductor material. The energy of this transition is between those of a LD and a QCL. This is the reason why we reach a medium wavelength range with these devices.

    Figure 3: ICL structure
    nanoplus structure of ICL

    III: Quantum Cascade Lasers from 6000 nm to 14000 nm

    In a QCL the valence band (VB) does not play any role for the optical transition. Electrons and holes have an optical intraband recombination within the conductive band (CB) of the semiconductor material. The energy of this transition low. This is the reason why we reach a longer wavelength range with these devices.

    Figure 4: QCL structure
    nanoplus structure of quantum cascade laser

    Please find below a selection of related papers from our literature list.

    Let us know if you published a paper with our lasers. We will be happy to include it in our literature list.

    #2 Advanced Gas Sensing Applications Above 3 µm with DFB Laser Diodes;
    L. Naehle, L. Hildebrandt, M. Fischer, J. Koeth, Gases & Instrumentation, March/April 2012, pp. 25-28.

    #3 Gas monitoring in the process industry using diode laser spectroscopy;
    I. Linnerud, P.Kaspersen, T. Jaeger, Appl. Phys. B 67, 1998, pp. 297-305.

    #6 Using diode lasers for atomic physics;
    C.E. Wieman, L. Hollberg, Rev. Sci. Instrum. 62 (l), 1991, pp. 1-20.

    #8 ICLs open opportuneties for mid-IR seinsing;
    L. Naehle, L. Hildebrandt, M. Kamp, S. Hoefling, Laser Focus World, May 2013, pp. 70-73.

    #9 DFB Lasers Between 760 nm and 16 µm for Sensing Applications;
    W. Zeller, L. Naehle, P. Fuchs, F. Gerschuetz, L. Hildebrandt, J. Koeth, Sensors 2010, 10, pp. 2492-2510.

    #11 Quantum cascade laser linewidth investigations for high resolution photoacoustic spectroscopy;
    M. Germer, M. Wolff, Appl. Opt. 48, 4, 2009, pp. B80-B86.

    #12 CO2 concentration and temperature sensor for combustion gases using diode-laser absorption near 2.7 µm;
    A. Farooq,  J.B. Jeffries, R.K. Hanson, Appl. Phys. B 90, 2008, pp. 619-628.

    #13 Continuous-wave operation of type-I quantum well DFB laser diodes emitting in 3.4 µm wavelength range around room temperature;
    L. Naehle, S. Belahsene, M. von Edlinger, M. Fischer, G. Boissier, P. Grech, G. Narcy, A. Vicet, Y. Rouillard, J. Koeth and L. Worschech, Electron. Lett. 47, 1, Jan 2011, pp. 46-47.

    #14 Evaluation of the Radiation Hardness of GaSbbased Laser Diodes for Space Applications;
    I. Esquivias, J.M.G. Tijero, J. Barbero, D. Lopez, M. Fischer, K. Roessner, J. Koeth, RADECS Proceedings 2011, pp. 349-352.

    #15 Scanned-wavelength-modulation spectroscopy near 2.5 µm for H2O and temperature in a hydrocarbon-fueled scramjet combustor;
    C. S. Goldenstein, I. A. Schultz, R. M. Spearrin, J. B. Jeffries, R.K. Hanson, Appl. Phys. B, 116, 3, Sept 2014, pp 717-727.

    #16 Diode laser measurements of linestrength and temperature-dependent lineshape parameters of H2O-, CO2-, and N2-perturbed H2O transitions near 2474 and 2482 nm;
    C.S. Goldenstein, J.B. Jeffries, R.K. Hanson, J. of Quantitative Spectr. & Radiative Transfer 130, 2013, pp. 100–111.

    #17 Wavelength-modulation spectroscopy near 2.5 µm for H2O and temperature in high-pressure and -temperature gases;
    C.S. Goldenstein, R.M. Spearrin, J.B. Jeffries, R.K. Hanson, Appl. Phys. B, 116, 3, Sept 2014, pp 705-716.

    #18 Monomode Interband Cascade Lasers at 5.2 µm for Nitric Oxide Sensing;
    M. von Edlinger, J. Scheuermann, R. Weih, C. Zimmermann, L. Naehle, M. Fischer, J. Koeth, IEEE Phot. Tech. Lett., 26, 5, 2014, pp. 480-482.

    #19 Measurements of Mars Methane at Gale Crater by the SAM Tunable Laser Spectrometer on the Curiosity Rover;
    C.R. Webster, P.R. Mahaffy, S.K. Atreya, G.J. Flesch, K.A. Farley, 44th Lunar and Planetary Science Conference, March 18-22, 2013, LPI Contribution No. 1719, p.1366.

    #20 Interband cascade lasers with room temperature threshold current densities below 100 A/cm2;
    R. Weih, M. Kamp, S. Hoefling, Appl. Phys. Lett., 102, 2013, pp. 231123-231123-4.

    #21 The airborne multi-wavelength water vapor differential absorption lidar WALES: system design and performance;
    M. Wirth, A. Fix, P. Mahnke, H. Schwarzer, F. Schrandt, G. Ehret, Appl. Phys. B, 96, 1, July 2009, pp. 201-213.

    #22 Sensing of formaldehyde using a distributed feedback interband cascade laser emitting around 3493 nm;
    S. Lundqvist, P. Kluczynski, R. Weih, M. von Edlinger, L. Naehle, M. Fischer, A. Bauer, S. Hoefling, J. Koeth, Appl. Opt., 51, 25, 2012, pp. 6009-6013.

    #26 Corrugated-sidewall interband cascade lasers with single-mode midwave-infrared emission at room temperature;
    C.S. Kim, M. Kim, W.W. Bewley, J.R. Lindle, C.L. Canedy, J. Abell, I. Vurgaftman, J.R. Meyer, Appl. Phys. Lett., 95, 2009, 231103.

    #28 In situ combustion measurements of H2O and temperature near 2.5 µm using tunable diode laser absorption;
    A. Farooq, J.B Jeffries, R.K Hanson, Meas. Sci. Technol., 19, 2008, 075604, pp. 11.

    #30 Kalman filtering real-time measurements of H2O isotopologue ratios by laser absorption spectroscopy at 2.73 µm;
    T. Wu, W. Chen, E. Kerstel, E. Fertein, X. Gao, J. Koeth, Karl Roessner, D. Brueckner, Opt. Lett., 35, 5, 2010, pp. 634.636.

    #31 QCL based NO Detection;
    M. Wolff, J. Koeth, L. Hildebrandt, P. Fuchs; 16th International Conference on Photoacoustic and Photothermal Phenomena.

    #32 Single-frequency Sb-based distributed-feedback lasers emitting at 2.3 µm above room temperature for application in tunable diode laser absorption spectroscopy;
    A. Salhi, D. Barat, D. Romanini, Y. Rouillard, A. Ouvrard, R. Werner, J. Seufert, J. Koeth, A. Vicet, A. Garnache, Appl. Opt., 45, 20., pp. 4957-4965.

    #33 DFB laser diodes in the wavelength range from 760 nm to 2.5 µm;
    J. Seufert, M. Fischer, M. Legge, J. Koeth, R. Werner, M. Kamp, A. Forchel, Spectroch. Acta Part A 60, 2004, pp. 3243-3247.

    #35 TDLAS-based sensors for in situ measurement of syngas composition in a pressurized, oxygen-blown, entrained flow coal gasifier;
    R. Sur, K. Sun, J.B. Jeffries, R.K. Hanson, R.J. Pummill, T. Waind, D.R. Wagner, K.J. Whitty, Appl. Phys. B, 116, 1, 2014, pp. 33-42.

    #36 Single mode interband cascade lasers based on lateral metal gratings;
    R. Weih, L. Naehle, Sven Hoefling, J. Koeth, M. Kamp, Appl. Phys. Lett., 105, 7, 2014, pp. 071111.

    #42 Line shapes of near-infrared DFB and VCSEL diode lasers under the influence of system back reflections;
    R. Engelbrecht, B. Lins, P. Zinn, R. Buchtal, B. Schmauss, Appl. Phys. B, 109, 3, Nov. 2012, pp. 441-452.

    #44 High sensitivity Faraday rotation spectrometer for hydroxyl radical detection at 2.8 µm;
    W. Zhao, G. Wysocki, W. Chen, W. Zhang, Appl. Phys. B, 109, 3, Nov. 2012, pp. 511-519.

    #45 Measurements of CO2 in a multipass cell and in a hollow-core photonic bandgap fiber at 2 µm;
    J. A. Nwaboh, J. Hald, J. K. Lyngsø, J. C. Petersen, O. Werhahn, Appl. Phys. B, 109, 3, Nov. 2012, pp. 187-194.

    #48 Absolute, spatially resolved, in situ CO profiles in atmospheric laminar counter-flow diffusion flames using 2.3 µm TDLAS;
    S. Wagner, M. Klein, T. Kathrotia, U. Riedel, T. Kissel, A. Dreizler, V. Ebert, Appl. Phys. B, 109, 3, Nov. 2012, pp. 533-540.

    #50 Mid-IR difference frequency laser-based sensors for ambient CH4, CO, and N2O monitoring;
    J. J. Scherer, J. B. Paul, H. J. Jost, Marc L. Fischer, Appl. Phys. B, 109, 3, Nov. 2012, pp. 271-277.

    #51 Noninvasive monitoring of gas in the lungs and intestines of newborn infants using diode lasers: feasibility study;
    P. Lundin, E.K. Svanberg, L. Cocola, M.L. Xu, G. Somesfalean, S. Andersson-Engels, J. Jahr, V. Fellman, K. Svanberg, S. Svanberg, J. of Biomed. Opt., 18(12), Dec. 2013, 127005.

    #52 Antireflection-coated blue GaN laser diodes in an external cavity and Doppler-free indium absorption spectroscopy;
    L. Hildebrandt, R. Knispel, S. Stry, J.R. Sacher, F. Schael, Appl. Opt., 42, No. 12, 2003, pp. 2110-2118.

    #53 CW DFB RT diode laser-based sensor for trace-gas detection of ethane using a novel compact multipass gas absorption cell;
    K. Krzempek, M. Jahjah, R. Lewicki, P. Stefanski, S. So, D. Thomazy, F.K. Tittel, Appl. Phys. B, 112, 4, Sept. 2013, pp. 461-465.

    #54 Demonstration of the self-mixing effect in interband cascade lasers;
    K. Bertling, Y.L. Lim, T. Taimre, D. Indjin, P. Dean, R. Weih, S. Hoefling, M. Kamp, M. von Edlinger, J. Koeth, A.D. Rakic, Appl. Phys. Lett., 103, 2013, 231107.

    #55 Photonic Crystal Laser Based Gas Sensor;
    M. Wolff, H. Bruhns, J. Koeth, W. Zeller, L. Naehle, Chapter 4 in "Optical Sensors - New Developments and Practical Applications", book edited by M. Yasin, S.W. Harun, H. Arof, ISBN 978-953-51-1233-4, March 19, 2014.

    #56 Widely tunable quantum cascade lasers with coupled cavities for gas detection;
    P. Fuchs, J. Seufert, J. Koeth, J. Semmel, S. Hoefling, L. Worschech, A. Forchel, App. Phys. Lett., 97, 2010, 181111.

    #57 Distributed feedback quantum cascade lasers at 13.8 µm on indium phosphide;
    P. Fuchs, J. Semmel, J. Friedl, S. Hoefling, J. Koeth, L. Worschech, A. Forchel, Appl. Phys. Lett. 98, 2011, 211118.

    #59 Semiconductor laser damage due to human-body-model electrostatic discharge;
    Y. Twu, L.S. Cheng, S.N.G. Chu, F.R. Nash, K.W. Wang, P. Parayanthal, J. Appl. Phys. 74 (3), Aug. 1993, 1510-1520.

    #60 Single mode quantum cascade lasers with shallow-etched distributed Bragg reflector;
    P. Fuchs, J. Friedl, S. Hoefling, J. Koeth, A. Forchel, L. Worschech, M. Kamp, Opt. Expr., 20, 4, 2012, pp. 3890-3897.

    #61 Demonstration of an Ethane Spectrometer for Methane Source Identification;
    T.I. Yacovitch, S.C. Herndon, J.R. Roscioli, C. Floerchinger, R.M. McGovern, M. Agnese, G. Petron, J. Kofler, C. Sweeney, A. Karion, S.A. Conley, E.A. Kort, L. Naehle, M. Fischer, L. Hildebrandt,.J. Koeth, J.B. McManus, D.D. Nelson, M.S. Zahniser, C.E. Kolb, Environ. Sci. Technol., 48, 2014, 8028-8034.

    #62 High-sensitivity interference-free diagnostic for measurement of methane in shock tubes;
    R. Sur, S. Wang, K. Sun, D. F. Davidson, J. B. Jeffries, R. K. Hanson, J. of Quant. Spectrosc. and Rad. Transfer, Vol. 156, May 2015, pp. 80–87.

    #64 Interband Cascade Lasers - Topical Review;
    I. Vurgaftman, R. Weih, M. Kamp, C.L. Canedy, C.S. Kim, M. Kim, W.W. Bewley, C.D. Merritt, J. Abell, S. Hoefling, Phys. D: Appl. Phys. 48, 2015, pp. 123001-12017.

    #65 H2O temperature sensor for low-pressure flames using tunable Diode laser Absorption near 2.9 µm;
    S. Li, A. Farooq, R.K. Hanson, Meas. Sci. Technol., 22, 2011, pp. 125301-125311.

    #79 InAs-based distributed feedback interband cascade lasers;
    M. Dallner, J. Scheuermann, L. Nähle, M. Fischer, J. Koeth, S. Höfling, M. Kamp, Appl. Phys. Lett. 107, 2015, 181105.

    #80 Single-mode interband cascade lasers emitting below 2.8 μm;
    J. Scheuermann, R. Weih, M. v. Edlinger, L. Nähle, M. Fischer, J. Koeth, M. Kamp, S. Höfling, Appl. Phys. Lett. 106, 2015, 161103.

    #81 Dynamic spectral characteristics measurement of DFB interband cascade laser under
    injection current tuning
    Z. Du, G. Luo, Y. An, J. Li, Appl. Phys. Lett. 109, 2016, 011903.

    # 85 Frequency modulation characteristics for interband cascade lasers emitting at 3 µm;
    J. Li, Z. Du, Y. An, Appl. Phys. B, 2015, 121:7–17.

    #100 Multiheterodyne spectroscopy using interband cascade lasers;
    L. A. Sterczewski, J. Westberg, C. L. Patrick, C. S. Kim, M. Kim, C. L. Canedy, W. W. Bewley, C. D. Merritt, I. Vurgaftman, J. R. Meyer and G. Wysocki, Opt. Eng. 57(1), 011014, Jan. 2018.

    Our DFB technology is protected by a number of international patents. For more information, please refer to the complete list of patents and licenses.

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