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  • 151.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Fiber Laser Overview and Medical Applications2008Ingår i: Tunable Laser Applications / [ed] F.J. Duarte, New York, USA: CRC Press, 2008, 2, s. 197-226Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    Tunability has added an important dimension to a variety of laser devices and led to new systems and applications. From laser spectroscopy to Bose-Einstein condensation, the one nexus is the tunable laser. Incorporating nine new chapters since the first edition, Tunable Laser Applications, Second Editionreflects the significant developments in tunable lasers that have taken place over the past decade. Internationally recognized experts describe the physics and architecture of widely applied tunable laser sources, emphasizing biomedical applications of fiber lasers and ultrashort pulsed lasers, as well as laser isotope separation and cancer photodynamic therapy. The Second Edition Covers- Advances in optical parametric oscillators Developments in tunable semiconductor lasers Solid-state dye lasers Laser isotope separation using diode lasers Medical applications of table-top coherent X-rays Outlining applications in biology and medicine, this second edition offers a much-needed account of the most promising tunable laser applications.

  • 152.
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Fiber laser overview and medical applications2016Ingår i: Tunable Laser Applications, Third Edition, CRC Press , 2016, s. 263-292Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 153.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101).
    Monochromator and method of use2001Patent (Övrig (populärvetenskap, debatt, mm))
  • 154.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Dong, Lin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Innocenti, Nicolas
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Sergeyev, Sergey
    Waterford Institute of Technology.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    External near-field resonance in coupled microcavities: mode enhancement and applications2010Ingår i: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010, 2010, s. 90-91Konferensbidrag (Refereegranskat)
    Abstract [en]

    Interference of the near optical field caused by evanescent waves leaking a coupled microcavity enhances the optical field between the cavity sections. This enhancement can be used for design of microcavity lasers with outside-cavity modes and for various sensors, for example, to precisely detect the direction of incident wavefront.

  • 155.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Dong, Lin
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Iyer, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Sergeyev, S.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101). Aalto University, Finland.
    Impact of dielectric permittivity of a substrate on the THz scattering enhanced due to near-field effect2010Ingår i: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010, IEEE , 2010, s. 330-331Konferensbidrag (Refereegranskat)
    Abstract [en]

    Enhanced scattering of the THz radiation caused by the interaction of near field component with plasmons in a substrate material results in sub-wavelength resolution within THz range. Variation of dielectric permittivity of organic materials placed on a metal substrate can improve contrast of the image obtained with such a technique.

  • 156.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Iyer, Srinivasan
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Sergeyev, Sergey
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT). Aalto University, Finland.
    Pulsed THz radiation in near-field domain: Enhanced scattering and exceeding diffraction limitations2010Ingår i: Frontiers in Optics 2010/Laser Science XXVI, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    SNOM technique used in THz range demonstrates enhanced scattering in far-field region and increased resolution of the scanned image. We develop a rigorous numerical model which can properly describe both these phenomena.

  • 157.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, Gunnar
    Sergeyev, Sergey
    High Capacity Coherent Optical Systems: Advanced Modulation Formats and Margins for Transmission Impairments2015Ingår i: 2015 17th International Conference on Transparent Optical Networks (ICTON), Institute of Electrical and Electronics Engineers (IEEE), 2015Konferensbidrag (Refereegranskat)
  • 158.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Kakkar, Aditya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Navarro, J. R.
    Pang, Xiaodan
    Ozolins, O.
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Louchet, H.
    Jacobsen, G.
    Equalization-Enhanced Phase Noise in Coherent Optical Communications Systems2016Ingår i: 2016 18TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), IEEE, 2016Konferensbidrag (Refereegranskat)
    Abstract
  • 159.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Li, Yanlu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, S.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology (TKK), Finland.
    Modeling of terahertz near-field imaging: Rigorous simulation and antenna approach2009Ingår i: CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009, s. 5192395-Konferensbidrag (Refereegranskat)
  • 160.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Li, Yanlu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, Sergey
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology (TKK), Finland.
    Terahertz Near-field Imaging: Rigorous Model for Interpreting "Antenna approach"2009Ingår i: 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009, IEEE , 2009, s. 3027-3028Konferensbidrag (Refereegranskat)
    Abstract [en]

    Classical Mie theory fails to explain high resolution of a terahertz imaging system exploiting scattering of the near-field radiation. Reported numerical model confirms the feasibility of an antenna model which proves the enhanced resolution.

  • 161.
    Popov, Sergei
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Marinins, Aleksandrs
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Sychugov, Ilya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Yan, Max
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Vasileva, Elena
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer.
    Udalcovs, Aleksejs
    RISE Acreo AB, Stockholm, Sweden..
    Ozolins, Oskars
    RISE Acreo AB, Stockholm, Sweden..
    Polymer photonics and nano-materials for optical communication2018Ingår i: 2018 17TH WORKSHOP ON INFORMATION OPTICS (WIO), Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Polymer materials offer process compatibility, design flexibility, and low cost technology as a multi-functional platform for optical communication and photonics applications. Design and thermal reflowing technology of low loss polymer waveguides, as well as demonstration of transparent wood laser are presented in this paper.

  • 162.
    Popov, Sergei
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, Oskars
    Olmedo, Miguel I
    Kakkar, Aditya
    Gaiarin, Simone
    Udalcovs, Aleksejs
    Lin, Rui
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik och mikrovågsteknik, FMI.
    Navarro, Jaime R
    Djupsjöbacka, Anders
    Zibar, Darko
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Westergren, Urban
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Jacobsen, Gunnar
    Ultra-Broadband High-Linear Integrated Transmitter for Low Complexity Optical Interconnect Applications2016Ingår i: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2016Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report on a high-speed optical transmitter using InP-based integrated externally modulated laser for optical interconnect applications with up to 30 dB static extinction ratio and over 100 GHz 3 dB bandwidth with 2 dB ripple. It is evaluated with up to 116 Gbit/s on-offkeying, 4-pulse amplitude modulation (PAM) and up to 105 Gbit/s 8-PAM optical signals with different digital equalization implementations. Low number of taps is required for a high and stable performance. Results reveal that digital equalization significantly boosts the passive optical interconnect scalability.

  • 163.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ricciardi, Sebastien
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, Sergey
    Even-mode generation in microcavity dye laser2007Ingår i: ICONO 2007: Coherent And Nonlinear Optical Phenomena / [ed] Belyi, VN; Drabovich, KN; Flytzanis, C, 2007, Vol. 6729, s. M7292-M7292Konferensbidrag (Refereegranskat)
    Abstract [en]

    A solid-state dye laser with a microcavity whose size is comparable to the lasing wavelength is modeled by means of the finite element method. The position of the pumping source affects the lasing mode spectrum. In comparison with a single point source at the edge of the cavity, a random distribution of excitation sources in the central gain part of the microcavity leads to depletion of odd longitudinal modes and to higher output efficiency of the laser radiation in even modes. The simulation results are explained by simple physical considerations.

  • 164.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ricciardi, Sebastien
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, Sergey
    Impact of cavity symmetry on mode suppression and increase of free spectral range in solid-state dye microlaser2007Ingår i: Chinese Optics Letters, ISSN 1671-7694, Vol. 5, nr 11, s. 651-653Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We describe modeling the solid-state dye laser with the microcavity size comparable to light wavelength. Certain symmetry in the allocation of gain material leads to depletion of odd longitudinal modes that, in turn, increases the tunability range of the microlaser. We provide simple physical explanation for the modeling results.

  • 165.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Ricciardi, Sébastien
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, Sergey
    Waterford Inst Technol.
    Mode suppression in a microcavity solid-state dye laser2007Ingår i: Journal of the european optical society-rapid publications, ISSN 1990-2573, Vol. 2, s. 07203-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A solid-state dye laser with a microcavity whose size is comparable to the lasing wavelength, is modeled by means of the finite element method. The position of the pumping source affects the lasing mode spectrum. In comparison with a single point source at the edge of the cavity, a random distribution of excitation sources in the central gain part of the microcavity leads to suppression of odd longitudinal modes and to higher output efficiency of the laser radiation in even modes. The modeling and simulation results are explained by simple physical considerations.

  • 166.
    Popov, Sergei
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Sergeyev, S.
    Friberg, Ari T.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    The impact of pump polarization on the polarization dependence of the Raman gain due to the breaking of a fibre's circular symmetry2004Ingår i: Journal of Optics. A, Pure and applied optics, ISSN 1464-4258, E-ISSN 1741-3567, Vol. 6, nr 3, s. S72-S76Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For many practical applications, the polarization dependence of the Raman gain (Raman PDG) is considered as a drawback. Most approaches used to reduce the PDG are based on depolarization or scrambling of the pump source polarization. We report on an experimentally observed effect and describe a method for reducing the Raman PDG by means of polarization control with a fully polarized pump source. The method makes it possible to maintain high efficiency of the Raman gain. The absence of circular symmetry (on average) in non-polarization maintaining fibres allows one to find a certain polarization state of the pump to minimize the Raman PDG. The observed phenomenon is inherently related to polarization mode dispersion which always exists in optical fibres.

  • 167.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Optik (Stängd 20120101).
    Vanin, Evgeny
    Acreo AB.
    Optical amplifier2001Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    For setting the optical gain of an optical amplifier such as a Raman amplifier that is connected in a wavelength division multiplexing (WDM) system, the gain of the amplifier is made dependent on the states of optical polarizers connected to individual inputs of a WDM multiplexer. The polarizers can be actively controlled by a device connected to sense the output power of the Raman fiber at different wavelengths. For an appropriate control the optical gain can be given any desired shape such as for example a reasonable flatness. The control of the polarization states of the WDM-channels allows for the use of a single wavelength pump source of the amplifier, instead of the conventionally used multiwavelength source.

  • 168.
    Popov, Sergei
    et al.
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Vanin, Evgeny
    Acreo AB.
    Use of OPA for switching and routing in WDM networks2000Patent (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The present invention is an arrangement for utilizing optical information sent through an optical network from a sending site to at least one receiving site. An optical parametric amplifier OPA receives the optical information sent at a set of input wavelengths. A mixer amplifier mixes the input wavelengths with an optical pump wavelength. A set of optical conjugate copy wavelengths are generated from the set of input wavelengths. A WDM-splitter separates the set of input wavelengths from the set of conjugate copy wavelengths. The set of input wavelengths and/or the set of conjugate copy wavelengths are forwarded individually to the at least one of the receiving site.

  • 169.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Zhang, Rui
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology, Finland.
    Sergeyev, S.
    Mode stability in robust microcavity solid-state dye laser2008Ingår i: Frontiers in Optics - Microcavities and Lasers (2008), Optical Society of America, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Polymeric microcavity dye laser modeled with finite element method demonstrates excellent tolerance against geometrical distortions of the cavity. Mode wavelengths remain stable with two types of potential impairments might occur during the manufacturing process.

  • 170.
    Popov, Sergei
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Zhang, Rui
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Sergeyev, Sergey
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Efficiency enhancement in a microcavity solid-state dye laser with Bragg grating reflectors2010Ingår i: Central European Journal of Physics, ISSN 1895-1082, E-ISSN 1644-3608, ISSN 1895-1082 print, Vol. 8, nr 2, s. 202-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bragg grating reflectors placed along microcavity facets can improve the efficiency of a polymer dye laser built with such a microcavity. The impact of different reflector designs on the mode pattern and resonance frequencies of the microcavity is numerically simulated and analyzed. This rigorous physical model is based on solving the Maxwell equations and includes such material properties as absorption, dispersion, fluorescence and optical gain. In certain cases, an asymmetrical layout of the reflectors can be more preferable than the pair of reflectors located on opposite sides of the microcavity as it is implemented for typical design.

  • 171.
    Reinhold, Ingo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Sitterberg, K.
    Müller, M.
    Abdulla, Mamat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Voit, W.
    Zapka, Werner
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK.
    Analysis of formation of an individual droplet using a high-resolution multi-exposure imaging system2013Ingår i: NIP29: Digital fabrication 2013, 29th international conference on digital printing technologies, September 29-October 3, 2013, Seattle, Washington : technical program and proceedings, The Society for Imaging Science and Technology, 2013, s. 354-358Konferensbidrag (Refereegranskat)
    Abstract [en]

    Localized dispensing of precious functional materials has attracted considerable interest in the academic as well as the industrial society. While the number of publications show numerous fields of applications in printed electronics, photovoltaics, display technologies and thin functional coatings, the transition into the industrial sector is often hindered by challenges resulting from ink-printhead combinations and their implications on reliability and stability of the process, as well as side-effects such as mist accumulation in heavy duty printing equipment. While measuring equipment to quantify various rheological and interfacial parameters for fluid optimization has been developed with the accompanying mathematical models, the physical jetting experiment as well as high-duty printing trials cannot yet be substituted by these methods. In order to quantify the generation of a droplet alongside with its tailing behavior and mist formation as well as statistics based on cross-talk effects and relaxation-related effects, high-resolution and high-speed imaging are required. This paper examines the optical setup and outlines the required calculations for establishing sharp, high-resolution images using a combination of a high power laser diode with a resonant ME MS micro mirror with a theoretical resolution of 1.8 pm. The limitations of the setup regarding the achievable resolution as well as potential improvements are assessed. Furthermore, the experimental setup, including repetitive generation of nanosecond-pulses necessary for motion-blur-free images, will be discussed. Additionally, results from imaging a droplet formation process using a Xaar 126 printhead are discussed.

  • 172.
    Reinhold, Ingo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, VinnExcellence Center for Intelligence in Paper and Packaging, iPACK. XaarJet ltd.
    Sitterberg, Karsten
    XaarJet ltd.
    Müller, Matthias
    XaarJet ltd.
    Abdulla, Mamat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Voit, Wolfgang
    XaarJet ltd.
    Zapka, Werner
    XaarJet ltd.
    Analysis of Formation of an Individual Droplet Using a High-ResolutionMulti-Exposure Imaging System2013Ingår i: International Conference on Digital Printing Technologies and Digital Fabrication / [ed] IS&T, 2013, s. 354-358Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Localized dispensing of precious functional materials has attracted considerable interest in the academic as well as the industrial society. While the number of publications show numerous fields of applications in printed electronics, photovoltaics, display technologies and thin functional coatings, the transition into the industrial sector is often hindered by challenges resulting from ink-printhead combinations and their implications on reliability and stability of the process, as well as side-effects such as mist accumulation in heavy duty printing equipment.While measuring equipment to quantify various rheological and interfacial parameters foor fluid optimization has been developed with the accompanying mathematical models, the physical jetting experiment as well as high-duty printing trials cannot yet be substituted by these methods. In order to quantify the generation of a droplet alongside with its tailing behavior and mist formation as well as statistics based on cross-talk effects and relaxation-related effects, high-resolution and high-speed imaging are required.This paper examines the optical setup and outlines the required calculations for establishing sharp, high-resolution images using a combination of a high power laser diode with a resonant MEMS micro mirror with a theoretical resolution of 1.8 μm. The limitations of the setup regarding the achievable resolution as well as potential improvements are assessed. Furthermore, the experimental setup, including repetitive generation of nanosecond-pulses necessary for motion-blur-free images, will be discussed. Additionally, results from imaging a droplet formation process using a Xaar 126 printhead are discussed.

  • 173.
    Ricciardi, Sebastien
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, Sergey
    Thermally induced wavelength tunability of microcavity solid-state dye lasers2007Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 15, nr 20, s. 12971-12978Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wavelength tunability of a microcavity solid-state dye laser is modeled and demonstrated by simulations making use of the finite element method. We investigate the application of two phenomena, thermoelastic expansion of the microcavity material and thermo-induced change of the refractive index, to tune the microcavity mode frequencies by a variation of the effective optical path. An optimized size of the laser microcavity is defined depending on the operation wavelength bandwidth and the glass transition temperature of the gain material.

  • 174.
    Ricciardi, Sebastien
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Sergeyev, Sergey
    Tunable microcavity solid-state dye laser for biometrics applications2007Ingår i: ICONO 2007: Coherent And Nonlinear Optical Phenomena / [ed] Belyi, VN; Drabovich, KN; Flytzanis, C, 2007, Vol. 6729, s. N7292-N7292Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wavelength tunability of a microcavity solid-state dye laser is modeled by means of the finite element method. We investigate the application of two phenomena, thermoelastic expansion of the microcavity material and thermo-induced change of refractive index, in order to tune microcavity mode frequencies by the variation of the effective optical path. An optimized size of the laser microcavity is defined depending on the operation wavelength bandwidth and the glass temperature of the gain material.

  • 175.
    Ricciardi, Sébastien
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Wavefront shaping: plane waves out of a point source2007Ingår i: Proceedings of the Comsol users conference, 2007, s. 761-764Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Using finite element method (FEM) implemented in Comsol Multiphysics simulation package, we present a model of beam shaper that converts spherical waves into one or two plane waves as a function of wavelength. Thus, the device can realize both wavefront shaping and beam splitting in only one structure. Comparing with different methods already presented, we introduce a solution for a smaller, simpler, and easier to manufacture device. We demonstrate a wavefront shaper using a microstructure of 8 x 8 μm size with commercially available material. We also discuss fabrication methods suitable for implementing the SU-8 polymer in the device.

  • 176.
    Ricciardi, Sébastien
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Sergeyev, Sergey
    Thermo-tuning and energy redistribution in microcavity solid-state dye lasers2008Ingår 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. 100Konferensbidrag (Refereegranskat)
    Abstract [en]

    Wavelength tunability of a microcavity solid-state dye laser is modeled by the finite element method (FEM). We investigate the combination of thermoelastic expansion and thermo-optic effects to tune the microcavity resonant wavelength. An optimized size of the laser microcavity is defined depending on the operation wavelength bandwidth and the glass temperature of the gain material. We also report a new effect of mode depletion specific to our microcavity and excitation scheme.

  • 177.
    Rodrigo Navarro, Jaime
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Kakkar, Aditya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Pang, Xiaodan
    Ozolins, Oskars
    Udalcovs, Aleksejs
    Schatz, Richard
    KTH, Tidigare Institutioner, Mikroelektronik och informationsteknik, IMIT.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, Gunnar
    Design of Multi-Stage Carrier Phase Recovery Schemes for  high  order  Coherent  Optical  mQAM  SystemsArtikel i tidskrift (Refereegranskat)
  • 178.
    Rodrigo Navarro, Jaime
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO. Acreo Swedish ICI'AB, Sweden.
    Kakkar, Aditya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. Acreo Swedish ICI'AB, Sweden.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Pang, X.
    Ozolins, O.
    Nordwall, F.
    Louchet, H.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Jacobsen, G.
    High performance and low complexity carrier phase recovery schemes for 64-QAM coherent optical systems2017Ingår i: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    We experimentally validate two novel CPR schemes outperforming existing CPRs in complexity and performance. A complexity reduction of at least a factor of 4 is reported compared to the BPS algorithm for a 64QAM system.

  • 179.
    Rodrigo Navarro, Jaime
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Kakkar, Aditya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Pang, Xiaodan
    Acreo Swedish, Sweden.
    Ozolins, Oskars
    Acreo Swedish, Sweden.
    Fredrik, Nordwall
    Louchet, Hadrien
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Jacobsen, Gunnnar
    High Performance and Low Complexity Carrier Phase Recovery Schemes for 64-QAM Coherent Optical Systems2017Ingår i: Optics InfoBase Conference Papers, Optical Society of America, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    We experimentally validate two novel CPR schemes outperforming existing CPRs in complexity and performance. A complexity reduction of at least a factor of 4 is reported compared to the BPS algorithm for a 64QAM system.

  • 180.
    Rodrigo Navarro, Jaime
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Kakkar, Aditya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Optik och Fotonik, OFO.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI).
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, Oskars
    Udalcovs, Aleksejs
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, Gunnnar
    Blind  phase  search  with  angular  quantization  noise mitigation for efficient carrier phase recovery2017Ingår i: Photonics, ISSN 2304-6732, Vol. 4, nr 2, artikel-id 37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The inherent discrete phase search nature of the conventional blind phase search (C-BPS) algorithm is found to introduce angular quantization noise in its phase noise estimator. The angular quantization noise found in the C-BPS is shown to limit its achievable performance and its potential low complexity implementation. A novel filtered BPS algorithm (F-BPS) is proposed and demonstrated to mitigate this quantization noise by performing a low pass filter operation on the C-BPS phase noise estimator. The improved performance of the proposed F-BPS algorithm makes it possible to significantly reduce the number of necessary test phases to achieve the C-BPS performance, thereby allowing for a drastic reduction of its practical implementation complexity. The proposed F-BPS scheme performance is evaluated on a 28-Gbaud 16QAM and 64QAM both in simulations and experimentally. Results confirm a substantial improvement of the performance along with a significant reduction of its potential implementation complexity compared to that of the C-BPS.

  • 181.
    Rodrigo Navarro, Jaime
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO. Acreo Swedish, Sweden.
    Pang, Xiaodan
    Kakkar, Aditya
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Ozolins, Oskars
    Schatz, Richard
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Adaptive Boundaries Scheme for Cycle-Slip Mitigation in C-mQAM Coherent Systems2015Ingår i: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 27, nr 20, s. 2154-2157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We propose a method for cycle-slip mitigation in circular multilevel quadrature amplitude modulation (C-mQAM) coherent optical systems, with constellation rotational asymmetry, based on an adaptive boundaries approach. The impact of cycle-slips in C-mQAM coming from Viterbi-Viterbi algorithm limits the phase noise tolerance. By introducing adaptive boundaries and a differential coding scheme, the ambiguity of asymmetrical rotation of constellation can be effectively removed. Performance of the proposed method is evaluated for a C-16QAM and C-64QAM for various laser linewidths. Results show a noticeable improvement in linewidth symbol duration product (Delta(upsilon) . T-S) tolerance compared with the previous studies on C-mQAM and mQAM constellations. The Delta(upsilon) . T-S tolerance reaches 4 x 10(-4) and 1.1 x 10(-4) for C-16QAM and C-64QAM, respectively, for 1 dB penalty at a symbol error rate of 10(-3).

  • 182. Rosa, P.
    et al.
    Rizzelli, G.
    Pang, Xiaodan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, O.
    Udalcovs, A.
    Tan, M.
    Sergeyev, S.
    Schatz, Richard
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Ania-Castañón, J. D.
    Unrepeatered 64QAM over SMF-28 using Raman amplification and digital backpropagation2017Ingår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Unrepeatered transmission over SMF-28 fibre is investigated using Raman based amplification. Experiments and simulations demonstrate a transmission up to 200 km (41 dB) span length using 28Gbaud 64 QAM modulation employing digital back propagation in DSP.

  • 183. Sergeyev, S.
    et al.
    O'Mahoney, K.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology, Finland.
    Pump-to-signal intensity noise transfer as the mechanism of self-pulsing in erbium doped fiber laser2009Ingår i: OFC: 2009 Conference on Optical Fiber Communication, IEEE , 2009, s. 2879-2881Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report experimental and theoretical characterization of self-pulsing in high concentration erbium doped fiber laser which is free from erbium clusters. Unlike previous models of self-pulsing which account for pair-induced quenching (PIQ) on the clustered erbium ions, new model includes statistical nature of the excitation migration and upconversion, and resonance-like pump-to-signal intensity noise transfer. The obtained results are in a good agreement with the experimental data.

  • 184. Sergeyev, S.
    et al.
    O'Mahoney, K.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology, Finland.
    Upconversion assisted auto-oscillations in erbium doped fiber laser2009Ingår i: 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009, 2009, s. 5225267-Konferensbidrag (Refereegranskat)
    Abstract [en]

    A new model of auto-oscillations in high concentration erbium doped fiber laser has been developed with accounting for statistical nature of the excitation migration and upconversion, as well as resonance-like pump-to-signal intensity noise transfer.

  • 185. Sergeyev, S.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology, Finland.
    Spun Aber Raman amplifiers with reduced polarization impairments2008Ingår i: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, nr 19, s. 14380-14389Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a novel vector model of Raman amplification in a fiber with randomly varying birefringence and unidirectional spin profile. Applying the model, we demonstrate for the first time simultaneous mitigation of polarization mode dispersion and polarization dependence of the Raman gain.

  • 186. Sergeyev, S.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology (TKK), Finland.
    Fiber Raman amplifiers with suppressed polarization impairments2009Ingår i: 2009 Conference on Lasers and Electro-Optics and 2009 Conference on Quantum Electronics and Laser Science Conference, CLEO/QELS 2009, 2009, s. 3103-3104Konferensbidrag (Refereegranskat)
    Abstract [en]

    By using two-section fiber where the first section has no spin and the second one is periodically spun, we demonstrate reduced polarization dependent gain and polarization mode dispersion in a distributed fiber Raman amplifier.

  • 187. Sergeyev, S.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Influence of the short-range coordination order of erbium ions on excitation migration and upconversion in multicomponent glasses2005Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 30, nr 11, s. 1258-1260Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Applying a pair-correlation function of erbium ions that is known from x-ray absorption fine structure spectroscopy, we develop a new statistical model of migration-assisted upconversion in erbium-doped glasses. The results of modeling show that short-range coordination order of erbium ions contributes to the upconversion rate for both low and high population inversion. In addition, we report the methods of suppression of the short-range order of erbium ions in multicomponent glasses.

  • 188. Sergeyev, S.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Modeling polarization-dependent gain in fiber Raman amplifiers with randomly varying birefringence2006Ingår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 262, nr 1, s. 114-119Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a new stochastic model for studying the polarization-dependent gain in Raman fiber amplifiers with randomly varying birefringence as a function of the pump state of polarization and the polarization mode dispersion parameter. Our theoretical results agree with the previously obtained experimental data.

  • 189. Sergeyev, S.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology, Finland.
    Spun fiber Raman amplifiers2008Ingår i: Frontiers in Optics (FiO) 2008, Optical Society of America, 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report a novel vector model of Raman amplification in a fiber with randomly varying birefringence and unidirectional spin profile. Based on this model, we demonstrate for the first time simultaneous mitigation of polarization mode dispersion and polarization dependent gain.

  • 190. Sergeyev, S.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP. Helsinki University of Technology, Finland.
    Two section fibre approach to suppression of polarization dependent gain in low PMD distributed fibre Raman amplifier2009Ingår i: CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009, s. 5192870-Konferensbidrag (Refereegranskat)
  • 191. Sergeyev, S. V.
    et al.
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Turitsyn, S. K.
    Dissipative vector solitons with fast evolving states of polarization2014Ingår i: Nonlinear Photonics, NP, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report on a new vector model of an erbium doped fiber laser mode locked with carbon nanotubes. This model goes beyond the limitations of the previously used models based on either coupled nonlinear Schrödinger or Ginzburg-Landau equations. It results in a new family of vector solitons with fast evolving states of polarization experimentally observed in our previous papers.

  • 192. Sergeyev, S. V.
    et al.
    Kolpakov, S. A.
    Mou, Ch.
    Jacobsen, G.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Optik och Fotonik, OFO.
    Kalashnikov, V.
    Slow deterministic vector rogue waves2016Ingår i: REAL-TIME MEASUREMENTS, ROGUE EVENTS, AND EMERGING APPLICATIONS, SPIE-INT SOC OPTICAL ENGINEERING , 2016, artikel-id UNSP 97320KKonferensbidrag (Refereegranskat)
    Abstract [en]

    For an erbium-doped fiber laser mode-locked by carbon nanotubes, we demonstrate experimentally and theoretically a new type of the vector rogue waves emerging as a result of the chaotic evolution of the trajectories between two orthogonal states of polarization on the Poincare sphere. In terms of fluctuation induced phenomena, by tuning polarization controller for the pump wave and in-cavity polarization controller, we are able to control the Kramers time, i.e. the residence time of the trajectory in vicinity of each orthogonal state of polarization, and so can cause the rare events satisfying rogue wave criteria and having the form of transitions from the state with the long residence time to the state with a short residence time.

  • 193. Sergeyev, S. V.
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och Informationsteknik, IMIT.
    A new PMD measurement technique with a fiber Raman amplifier2007Ingår i: 2007 European Conference on Lasers and Electro-Optics and the International Quantum Electronics Conference, 2007Konferensbidrag (Refereegranskat)
  • 194. Sergeyev, S. V.
    et al.
    Popov, Sergei Yu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    A new PMD measurement technique2007Ingår i: International Conference on Lasers, Applications, and Technologies 2007: Advanced Lasers and Systems, SPIE - International Society for Optical Engineering, 2007, s. 67310S-Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report measurements of beat and birefringence correlation lengths, and the PMD value on a long single mode fiber. The proposed technique is based on the analysis of maximum and minimum polarization dependent gain in a fiber Raman amplifier. Results are consistent with a standard technique based on differential group delay measurements.

  • 195. Sergeyev, S. V.
    et al.
    Popov, Sergei Yu
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Characterization of randomly varying birefringence in long single mode fibers2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report an application of new vector model of fiber Raman amplifier to charac-terize randomly varying birefringence in long single mode fiber. We find that analysis of the polarization dependent Raman gain can be used for the measurements of beat and birefrin-gence correlation lengths and the polarization mode dispersion value. The results for averaged PMD parameters are consistent with the values obtained by means of the Jones matrix eigenanalysis method.

  • 196. Sergeyev, Sergey
    et al.
    O'Mahoney, Kieran
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Coherence and anticoherence resonance in high-concentration erbium-doped fiber laser2010Ingår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 35, nr 22, s. 3736-3738Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report an experimental study of low-frequency (similar to 10 kHz) self-pulsing of the output intensity in a high-concentration erbium-doped fiber laser. We suggest that the fast intensity fluctuations caused by multimode and polarization instabilities play the role of an external noise source, leading to low-frequency auto-oscillations through a coherence resonance scenario.

  • 197. Sergeyev, Sergey
    et al.
    O'Mahoney, Kieran
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Friberg, Ari T.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Upconversion assisted self-pulsing in a high-concentration erbium doped fibre laser2010Ingår i: Central European Journal of Physics, ISSN 1895-1082, E-ISSN 1644-3608, ISSN 1895-1082 print, Vol. 8, nr 2, s. 159-163Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report results on experimental and theoretical characterisation of self-pulsing in high concentration erbium doped fibre laser which is free from erbium clusters. Unlike previous models of self-pulsing accounting for pair-induced quenching (PIQ) on the clustered erbium ions, new model has been developed with accounting for statistical nature of the excitation migration and upconversion and resonance-like pumpto-signal intensity noise transfer. The obtained results are in a good agreement with the experimental data.

  • 198. Sergeyev, Sergey
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Excitation back transfer in a statistical model for upconversion in Er-doped fibres2007Ingår i: Journal of the European Optical Society - Rapid Publications, ISSN 1990-2573, E-ISSN 1990-2573, Vol. 2, s. 07027-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report a new analytical method to evaluate the accuracy of a statistical model of the migration assisted upconversion in Er-doped fibres. Unlike the mean-field approach to the excitation back transfer which was used in a previous statistical model, we use a new approximation accounting for the variance of population of the first excited level. Such an approach presents more realistic physical description of the excitation - emission processes in heavily-doped Er-based fibres. Implementing these results, we find that the accuracy of upconversion rate calculations is within 13% if the concentration of erbium ions is smaller than the critical one.

  • 199. Sergeyev, Sergey
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Two-Section Fiber Optic Raman Polarizer2012Ingår i: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 48, nr 1, s. 56-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on a theoretical study of polarization impairments in periodically spun fiber Raman amplifiers. Based on the Stochastic Generator approach we have derived averaged equations to calculate polarization dependent gain and mean-square gain fluctuations. We show that periodically spun fiber can work as a Raman polarizer but it suffers from increased polarization dependent gain and gain fluctuations. Unlike this, application of a depolarizer can result in suppression of polarization dependent gain and gain fluctuations. We demonstrate that it is possible to design a new fiber Raman polarizer by combining a short fiber without spin and properly chosen parameters and a long periodically spun fiber. This polarizer provides almost the same polarization pulling for all input signal states of polarization and so has very small polarization dependent gain.

  • 200. Sergeyev, Sergey
    et al.
    Popov, Sergei
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Friberg, Ari
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Optik.
    Stochastic model of polarization-dependent gain and gain fluctuations in fiber Raman amplifier with randomly varying birefringence2007Ingår i: Laser Optics 2006: Solid State Lasers and Nonlinear Frequency Conversion / [ed] Vladimir I. Ustyugov, SPIE - International Society for Optical Engineering, 2007Konferensbidrag (Refereegranskat)
    Abstract [en]

    We report a new stochastic model for studying the polarization-dependent gain and gain fluctuations in Raman fiber amplifiers with randomly varying birefringence as a function of the pump state of polarization and the polarization mode dispersion parameter. Based on the presented model and our previous experimental data for polarization dependent gain we develop a new experimental technique for birefringence correlation length measurement.

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