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  • 1.
    Aggerstam, Thomas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Andersson, T.G.
    Holmström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Liu, X. Y.
    Lourdudoss, Sebastian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    GaN/AlN multiple quantum well structures grown by MBE on GaN templates for 1.55 mu m intersubband absorption2007Inngår i: Quantum Sensing and Nanophotonic Devices IV / [ed] Razeghi, M; Brown, GJ, 2007, Vol. 6479, s. 64791E-1-64791E-12Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We have used MBE to grow MQW structures on MOVPE GaN/sapphire templates. The MQW devices are intended for high speed intersubband electroabsorption modulator devices operating at 1.55-mu m. The GaN/AlN multiple quantum well material was systematically studied regarding the surface morphology, structural characterization and optical property by atomic force microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, respectively. The intersubband resonance energy was also calculated considering many-body effects in n-type doped structures. The multiple quantum well structure showed superior performance in terms of linewidth when grown on GaN templates as compared on sapphire. GaN quantum well and AlN barriers with a thickness of 3.3 and 4.2 nm respectively resulted in FWHM of the intersubband absorption peak as low as 93 meV at an absorption energy of 700 meV. This is promising for intersubband modulator applications.

  • 2.
    Arve, Per
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Jänes, Peter
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Thylén, Lars
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Propagation of two-dimensional pulses in electromagnetically induced transparency media2004Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 69, nr 6, s. 063809-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The propagation in two dimensions of "optical" pulses in electromagnetically induced transparency media is analyzed. Results are presented for coupled Maxwell-Bloch equations with slowly varying envelope approximation, for both adiabatic and nonadiabatic situations. The possibility of changing the direction of the pulse by a switch of control beam direction is investigated in detail.

  • 3.
    Holmström, Petter
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Ekenberg, Ulf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Thylen, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Efficient electroabsorption for mid-infrared wavelengths using intersubband transitions2008Inngår i: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY / [ed] Johansson LSO, Andersen JN, Gothelid M, Helmersson U, Montelius L, Rubel M, Setina J, Wernersson LE, Bristol: IOP PUBLISHING LTD , 2008, Vol. 100Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We have demonstrated efficient intersubband (IS) electroabsorption in InGaAs/InAlGaAs/InAlAs step quantum wells grown by metal-organic vapor phase epitaxy (MOVPE). An absorption modulation of 2300 cm(-1) at lambda=5.7 mu m due to Stark shift of the IS resonance was achieved with a low applied voltage swing of +/-0.5 V in a multipass waveguide structure. Two useful wavelength ranges of lambda approximate to 5.4-5.8 mu m and 6.3-6.6 mu m were obtained by considering the two flanks of the IS resonance. Based on the experimental results it is estimated that an electroabsorption modulator with a low peak-to-peak voltage of V-PP = 0.9 V can yield a modulation speed of f(3dB) = 120 GHz with the present material by using a strongly confining surface plasmon waveguide of 30 mu m length.

  • 4.
    Holmström, Petter
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Jänes, Peter
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Ekenberg, Ulf
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Thylén, L.
    Design of intersubband optical modulators2002Inngår i: Proceedings of the 26th International Conference on the Physicsof Semiconductors (26th ICPS), Edinburgh, Scotland, 2002, 2002, s. P126-Konferansepaper (Fagfellevurdert)
  • 5.
    Holmström, Petter
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ekenberg, Ulf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Efficient infrared electroabsorption with 1 V applied voltage swing using intersubband transitions2008Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 93, nr 19, artikkel-id 191101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have demonstrated efficient intersubband electroabsorption in InGaAs/InAlGaAs/InAlAs step quantum wells grown by metal-organic vapor-phase epitaxy. An absorption modulation of 6 dB (Delta alpha=2300 cm(-1)) at lambda similar to 5.7 mu m due to Stark shift of the intersubband resonance was achieved at a low applied voltage swing of +/- 0.5 V in a multipass waveguide structure. The interface intermixing was estimated by comparing experimental and theoretical Stark shifts. It is predicted that the present material in a strongly confining surface plasmon waveguide can yield an electroabsorption modulator with a peak-to-peak voltage of V-pp=0.9 V and modulation speed of f(3dB)approximate to 130 GHz.

  • 6.
    Holmström, Petter
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Ekenberg, Ulf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Infrared modulator at 6 um with 1-V applied voltage swing using  intersubband transitions in step quantum wells grown by MOVPE2007Konferansepaper (Fagfellevurdert)
  • 7.
    Holmström, Petter
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ekenberg, Ulf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Strong electroabsorption using intersubb and transitions in InGaAs/InAlGaAs/InAlAs step quantum wells2006Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118Artikkel i tidsskrift (Annet vitenskapelig)
  • 8.
    Holmström, Petter
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Matsui, Satoshi
    Sophia University.
    Uchida, Hiroyuki
    Sophia University.
    Nakazato, Takuya
    Sophia University.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Aggerstam, Tomas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Kikuchi, Akihiko
    Sophia University.
    Kishino, Katsumi
    Sophia University.
    Electroabsorption modulator based on intersubband transitions in (Al)(Ga)N step quantum wells considering intermixing2005Konferansepaper (Fagfellevurdert)
  • 9.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Photonic Devices and Applications based on Intersubband Transitions and Electromagnetically Induced Transparency2006Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Although photonic devices have experienced a rapid development lately, there is still room for substantial improvements in performance. From a telecommunications perspective, improvements in speed, size, integration and power consumption are desired. There is also a general interest in photonic devices with new functionalities. Being a key component in fiber-optic systems, high-speed optical modulators often initiate the development towards higher bit-rates. The technology of current state-of-the-art modulators has matured suggesting new paths of development. In this thesis we investigate the potential of modulators based on intersubband (IS) transitions in quantum wells (QWs). Specific QW designs are suggested and complete modulator structures are simulated. IS absorption is also experimentally characterized. Absorption linewidth is critical for IS modulator performance since narrow linewidth implies high bandwidth and/or small driving voltage. High material quality is important, since linewidth is typically limited by well-width fluctuations and interface roughness.

    A mid-IR AlGaAs/GaAs-modulator is proposed having a RC-limited bandwidth of 130 GHz and a peak-to-peak voltage of 0.9 V. Experimentally, Stark shift is measured in InAlAs/InAlGaAs/InGaAs step QWs at λ ~ 6 μm predicting that an IS modulator based on this material would have a bandwidth of 90 GHz and a peak-to-peak voltage of 0.9 V. IS absorption at 1.55 μm requires material combinations with high conduction-band offset. Simulations of an InGaAs/InAlAs/AlAsSb-modulator predict a bandwidth of 90 GHz and a peak-to-peak voltage of 2.0 V. Experimental studies of IS absorption in AlN/GaN QWs are presented. IS absorption at 1.5-3.4 μm with linewidth below 100 meV is measured for well widths between 15-54 Å. Subpeaks corresponding to well-width fluctuations on the monolayer scale are identified with linewidths of ~60 meV. Agreement between theoretical calculations and measured spectra is encouraging. Theoretical simulations together with measured absorption linewidths suggest that high performance IS modulators operating at 1.55 μm are realizable.

    Photonic devices with new functionalities are addressed by investigating electromagnetically induced transparency (EIT) theoretically and considering potential applications based on EIT. Simulations of two-dimensional pulse-propagation based on the Maxwell-Bloch equations are performed with a focus on storing and reading out optical pulses. We explicitly formulate the phase-matching conditions for reading out stored pulses in a new direction and propose a serial-to-parallel converter based on this.

    For slow-light devices, e.g. optical buffers, we identify and analyze two main limitations on the medium bandwidth; the frequency dependent absorption and the group velocity dispersion. Since large bandwidth and large delay are contradictory requirements, the delay bandwidth product is considered. Analytical expressions are derived and analyzed and verified by simulations on pulse propagation. Insertion of parameters relevant for semiconductors indicates that development of materials with long coherence times are necessary for realizing optical buffers based on EIT.

  • 10.
    Jänes, Peter
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Arve, P.
    Thylén, L.
    All optical serial to parallel converter utilizing electromagnetically induced transparency2004Inngår i: Proceedings of 30th European Conference on Optical Communication (ECOC2004), vol. 3, Stockholm, Sweden, 2004., 2004, s. 692-693Konferansepaper (Fagfellevurdert)
  • 11.
    Jänes, Peter
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Holmström, Petter
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    High-speed optical modulator based on intersubband transitions in InGaAs/InAlAs/AlAsSb coupled quantum wells2003Inngår i: Conference Proceedings - International Conference on Indium Phosphide and Related Materials, 2003, s. 308-311Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate theoretically an optical modulator based on intersubband transitions in InGaAs/InAlAs/AlAsSb coupled quantum wells with an operating wavelength of 1.55 mum. We show that such a modulator has the potential to outperform conventional electroabsorption and electro-optic modulators with a combination of high speed, moderate voltage swing, negative chirp and high saturation power. The modulator studied here is predicted to have a RC-limited speed of 90 GHz with 10 dB extinction ratio at a peak-to-peak voltage of 2.0 V.

  • 12.
    Jänes, Peter
    et al.
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Holmström, Petter
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    Ekenberg, Ulf
    KTH, Tidigare Institutioner                               , Mikroelektronik och informationsteknik, IMIT.
    A high-speed intersubband modulator based on quantum interference in double quantum wells2002Inngår i: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 38, nr 2, s. 178-184Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Calculations on a modulator based on quantum interference in AlGaAs/GaAs asymmetric double quantum wells (QWs) are performed. The modulation of the absorption is based on the anti-crossing behavior of the two lowest states in the coupled wells. At anti-crossing, the oscillator strengths of the transitions from these two lowest states to a higher state are changed in opposite directions. The width of the barrier between the wells should be thick enough to allow a large change in oscillator strength with applied field, yet thin enough so that the absorption peaks of the transitions are resolved. The QWs are designed so that one absorption peak has only a small energy shift for the transition used for modulation while the absorption varies rapidly with the applied voltage. A complete structure including a surface plasmon waveguide is proposed enabling calculations of modal absorption. Parameters important for the performance of the modulator are then determined. An extinction ratio of 10 dB at a wavelength of 8.4 mum is predicted for a device length of 18 mum and a peak-to-peak voltage of 0.9 V. The resistance-capacitance-limited 3-dB bandwidth is 130 GHz. The predicted performance compares very favorably with present interband modulators based on the quantum-confined Stark effect.

  • 13.
    Jänes, Peter
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Tidström, Jonas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Limits on optical pulse compression and delay bandwidth product in electromagnetically induced transparency media2005Inngår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 23, nr 11, s. 3893-3899Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Delay bandwidth products (DBPs) and physical pulselengths obtainable in media exhibiting electromagnetically induced transparency (EIT) are analyzed. The study is performed in stationary media as well as for dynamic storing of light pulses in such media. In the latter case; the dispersion inherent in storage and readout of the pulses is analyzed. It is shown that absorption and the group velocity dispersion (GVD) are limiting factors. Analytical expressions for the minimum compressed 'pulselength and DBP are derived, and these expressions show good agreement with simulations of pulse propagation in EIT media.

  • 14. Liu, X. Y.
    et al.
    Fälth, J. F.
    Andersson, T. G.
    Holmström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Ekenberg, Ulf
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Structural and optical properties of GaN/AlN multiple quantum wells for intersubband applications2005Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 278, nr 1-4, s. 397-401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    GaN/AIN multiple quantum well structures of 1, 5 and 20 periods were grown by molecular beam epitaxy (MBE). To investigate structural parameters, symmetrical scan (0002) and reciprocal space mapping in the vicinity of the GaN (10 15) plane were made by X-ray diffraction (XRD). The layer thickness, composition and relaxation were determined and gave good agreement with simulated results. The 20 period multiple quantum well (MQW) sample exhibited an intersubband resonance at 360 meV, which corresponds well to the structure data determined by XRD.

  • 15. Liu, X. Y.
    et al.
    Holmström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Andersson, T.G.
    Intersubband absorption at 1.5-3.5 µm in GaN/AlN multiple quantum wells grown by molecular beam epitaxy on sapphire2007Inngår i: Physica status solidi, ISSN 0370-1972, Vol. 244, nr 8, s. 2892-2905Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ten and twenty period multiple quantum well structures with 1.5-5.4 nm GaN wells and 1.2-5.1 nm AlN barriers were grown on sapphire by molecular beam epitaxy. Layer thicknesses were determined by X-ray diffraction measurements and simulations. Reciprocal space mapping showed that the relaxation of the quantum well layers was independent of the buffer layer thickness. Intersubband absorption was observed by Fourier transform infrared spectroscopy at λ ∼ 1.5-3.5 μm. Monolayer fluctuations in the quantum well width induced multiple peaks in spectra, which were well fitted to Lorentzian peaks of only 57 meV linewidth. Samples were very homogeneous as the absorption peak energy varied less than 1% along ∼4 cm on 2 inch wafers. The intersubband transition energies were calculated considering the conduction-band nonparabolicity, built-in fields, strain, and many-body effects. The calculation and comparison to the fitted Lorentzian peak energies indicated a moderate blueshift due to many-body effects. It was shown by both experiments and calculations that the AlN barrier width affects the intersubband transition energy.

  • 16. Liu, X.Y
    et al.
    Aggerstam, Thomas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Holmström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Lourdudoss, Sebastian
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Halvledarmaterial, HMA.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Andersson, T. G.
    Investigation of intersubband absorption of GaN/AlN multiple quantum wells grown on different substrates by molecular beam epitaxy2007Inngår i: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 301, nr SPEC. ISS., s. 301-302Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ten period GaN/AlN multiple quantum well (MQW) structures were grown by plasma-assisted molecular beam epitaxy (MBE) on sapphire substrates and metal-organic vapour-phase epitaxy (MOVPE)-grown GaN templates. Samples were investigated by high-resolution X-ray diffraction (HR-XRD) and Fourier transform infrared (FT-IR) spectroscopy. Intersubband (IS) absorbances and FWHM of IS absorption peaks indicated that samples grown on the GaN templates had better characteristics, resulting in a FWHM as low as 93 meV at a peak energy of 700 meV.

  • 17.
    Thylén, Lars
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Arve, Per
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Hessmo, Björn
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Holmström, Petter
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Jänes, Peter
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Karlsson, Anders
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Qiu, Min
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Progress in opto-electronic devices2004Inngår i: / [ed] Lam, CF; Fan, CC; Hanik, N; Oguchi, K, BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING , 2004, Vol. 5280Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We discuss the statu,, of photonics technology and review its possible evolution by way of several representative examples of emerging research areas, which could have a significant impact over a long-term, say 10-year perspective. The selected areas are considered potentially capable of providing the quantum leap progress necessary to solve some of the shortcomings of current photonics technology.

  • 18.
    Thylén, Lars
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Holmström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Recent developments in high-speed optical modulators2008Inngår i: Optical Fiber Telecommunications V: A: Components and subsystems / [ed] I. P. Kaminow, T. Li, A. E. Willner, London: Academic Press, 2008, s. 183-220Kapittel i bok, del av antologi (Fagfellevurdert)
  • 19.
    Tidström, Jonas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Andersson, L. Mauritz
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Delay bandwidth product of electromagnetically induced transparency media2007Inngår i: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 75, nr 5, s. 053803-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The limitations on the delay-bandwidth product (DBP) in an electromagnetically induced transparency medium are investigated analytically by studying the susceptibility of the system, derived through Lindblad's master equation, including dephasing. The effect of inhomogeneous broadening is treated. It is shown that the DBP for a given material is fundamentally limited by the frequency-dependent absorption, while the residual absorption limits the penetration length of a pulse. Simple expression for the optimal choice of parameters to maximize the DBP are derived. Also, the length of a device is presented as a function of DBP and control-field Rabi frequency. Supporting these results, numerical calculations are carried out through the Maxwell-Bloch equations in the slowly varying envelope approximation. The results are scalable, hence they apply to the case of atoms or molecules in a gas as well as quantum dots and wells.

  • 20.
    Tidström, Jonas
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Andersson, L Mauritz
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Pulse distortion in EIT medium2006Inngår i: Slow and Fast Light 2006, 2006, s. WB6-Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    We analyze pulse-distortion due to propagation through medium exhibiting Electromagnetically Induced Transparency. Separately investigating real and imaginary parts of the susceptibility; the latter being the limiting factor, by analytical and numerical arguments.

  • 21.
    Westergren, Urban
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Yu, Yichuan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Jänes, Peter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Holmström, Petter
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, Kista Photonics Research Center, KPRC.
    Efficient and compact light-intensity modulators for high frequencies and high bitrates2006Inngår i: ICTON 2006: 8th International Conference on Transparent Optical Networks, Vol 2, Proceedings: ESPC, NAON / [ed] Marciniak, M, 2006, s. 142-145Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Electroabsorption modulators (EAM) based on quantum-confined Stark effect (QCSE) in multiple-quantum wells (MQW) have been demonstrated to provide high-speed, low drive voltage, and high extinction ratio. They are compact in size and can be monolithically integrated with source lasers. In order to achieve both high speed and low drive-voltage operation, travelling-wave (TW) electrode structures can be used for EAMs. Modulation bandwidths of 100 GHz (-3 dBe) have been accomplished and transmission at 80 Gbit/s with non-return-to-zero (NRZ) code has been demonstrated for InP-based TWEAMs, indicating the possibility of reaching speeds of IOOGbit/s and beyond. In order to further increase the efficiency and reduce the drive voltage, MQW structures using intersubband (IS) instead of interband (QCSE) absorption are being investigated. Materials systems with large conduction band offset, such as GaN/Al(Ga)N or InGaAs/AlAsSb, are required for IS modulators. Critical for the performance of IS modulators is the linewidth of the absorption peak, hence IS modulators have the potential to outperform interband modulators given that a sufficiently high material quality can be achieved.

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