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  • 1.
    Anand, Srinivasan
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mulot, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    High aspect ratio etching and characterization of 2D-photonic crystals in InP/InGaAsP/InP heterostructures2004In: Photonics: Design, Technology, And Packaging / [ed] Jagadish, C; Choquette, KD; Eggleton, BJ; Nener, BD; Nugent, KA, SPIE - International Society for Optical Engineering, 2004, p. 78-89Conference paper (Refereed)
    Abstract [en]

    We report on the fabrication and characterization of 2D photonic crystals (PhCs) in InP/InGaAsP/InP heterostructures. It is demonstrated that Ar/C12 based chemically assisted ion beam etching (CAIBE) is a very promising method to obtain high aspect ratio etching of PhCs in the InP-based materials. With this process, it is possible to obtain PC-holes as deep as 3 microns even for feature (PhC-hole) sizes as small as 200-250 nm. The optical characteristics of the fabricated PhC-based elements/devices such as line-defect waveguides, in-plane resonant cavities and drop-filter based on contra-directional coupling will be reported. The devices were measured using end-fire coupling and the obtained results were simulated using the 2D finite difference time domain (FDTD) method including an effective loss-approximation. The etched PhC-waveguides show low transmission losses, less than 1 dB/100 mum. A quality factor of 400 for a 6 micron long cavity with 6-hole mirrors is obtained. Finally, drop-functionality in a PhC-based filter using contra-directional coupling is demonstrated.

  • 2.
    Anand, Srinivasan
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Shahid, Naeem
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Naureen, Shagufta
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Li, Mingyu
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101). Zhejiang University, Hangzhou, China.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    InP-based photonic crystal waveguide filters2010In: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010, 2010, p. 104-105Conference paper (Refereed)
  • 3.
    Anand, Srinivasan
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Shahid, Naeem
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    InP-Based Photonic Crystal Waveguide Technology for Filtering and Sensing Applications2011In: 2011 13TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), NEW YORK: IEEE , 2011Conference paper (Refereed)
    Abstract [en]

    Photonic crystal (PhC) components in InP-based materials are of practical importance not only for their unique properties but also for integration with conventional optoelectronic components on InP substrate. Several PhC devices in the substrate approach such as filters, lasers, and waveguides have been demonstrated [1,2] and this has been possible due to the development of deep etching of PhCs in InP [3].

  • 4.
    Baghban, Mohammad Amin
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Gallo, Katia
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Second-Harmonic generation engineering in lithium niobate nanopillars2019In: Proceedings 2015 European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference, CLEO/Europe-EQEC 2015, Optical Society of America (OSA) , 2019Conference paper (Refereed)
  • 5.
    Bayraktar, Ömer
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Canalias, Carlota
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Björk, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Quantum-polarization state tomography2016In: PHYSICAL REVIEW A, ISSN 2469-9926, Vol. 94, no 2, article id 020105Article in journal (Refereed)
    Abstract [en]

    We propose and demonstrate a method for quantum-state tomography of qudits encoded in the quantum polarization of N-photon states. This is achieved by distributing N photons nondeterministically into three paths and their subsequent projection, which for N = 1 is equivalent to measuring the Stokes (or Pauli) operators. The statistics of the recorded N-fold coincidences determines the unknown N-photon polarization state uniquely. The proposed, fixed setup manifestly rules out any systematic measurement errors due to moving components and allows for simple switching between tomography of different states, which makes it ideal for adaptive tomography schemes.

  • 6. Benisty, H.
    et al.
    Olivier, S.
    Weisbuch, C.
    Agio, M.
    Kafesaki, M.
    Soukoulis, C. M.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Talneau, A.
    Moosburger, J.
    Kamp, M.
    Forchel, A.
    Ferrini, R.
    Houdre, R.
    Oesterle, U.
    Models and measurements for the transmission of submicron-width waveguide bends defined in two-dimensional photonic crystals2002In: IEEE Journal of Quantum Electronics, ISSN 0018-9197, E-ISSN 1558-1713, Vol. 38, no 7, p. 770-785Article in journal (Refereed)
    Abstract [en]

    One of the essential building-blocks of miniature photonic crystal (PC)-based photonic integrated circuits (PICs) is the sharp bend. Our group has focused on the 2-D photonic crystal based on a triangular lattice of holes perforating a standard heterostructure. The latter, GaAlAs-based or InP-based, is vertically a monomode waveguide. We consider essentially one or two 60 bends defined by one to five missing rows, spanning both cases of monomode and multimode channel waveguides. From intensive modeling and various experimental measurements (both on GaAs and InP), we point out the origin of the present level of bend insertion losses and discuss the merits of the many roads open for improved design.

  • 7. Benisty, H.
    et al.
    Weisbuch, C.
    Olivier, S.
    Houdré, R.
    Ferrini, R.
    Leuenberger, D.
    Wild, B.
    Lombardet, B.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mulot, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jazkorzynska, B.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Agio, M.
    Kafesaki, M.
    Soukoulis, C. M.
    Talneau, A.
    Kamp, M.
    Forchel, A.
    Moosburger, J.
    Happ, T.
    Duan, G. -H
    Cuisin, C.
    Chandouineau, J. -P
    Drisse, O.
    Gaborit, F.
    Legouézigou, L.
    Legouézigou, O.
    Lelarge, F.
    Poingt, F.
    Pommereau, F.
    Thedrez, B.
    Low-loss photonic-crystal and monolithic InP integration: Bands, bends, lasers, filters2004In: Photonic Crystal Materials and Devices II, SPIE - International Society for Optical Engineering, 2004, p. 119-128Conference paper (Refereed)
    Abstract [en]

    Practical realizations of 2D (planar) photonics crystal (PhC) are either on a membrane or etched through a conventional heterostructure. While fascinating objects can emerge from the first approach, only the latter approach lends itself to a progressive integration of more compact PhC's towards monolithic PICs based on InP. We describe in this talk the various aspects from technology to functions and devices, as emerged from the European collaboration "PCIC". The main technology tour de force is deep-etching with aspect ratio of about 10 and vertical sidewall, achieved by three techniques (CAIBE, ICP-RIE, ECR-RIE). The basic functions explored are bends, splitters/combiners, mirrors, tapers, and the devices are filters and lasers. At the end of the talk, I will emphasize some positive aspects of "broad" multimode PhC waveguides, in view of compact add-drop filtering action, notably.

  • 8.
    Berrier, Audrey
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mulot, Mikaël
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Talneau, A.
    CNRS, Lab Photon & Nanostruct.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Negative Refraction at Infrared Wavelengths in a Two-Dimensional Photonic Crystal2004In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 073902Article in journal (Refereed)
    Abstract [en]

    We report on the first experimental evidence of negative refraction at telecommunication wavelengths by a two-dimensional photonic crystal field. Samples were fabricated by chemically assisted ion beam etching in the InP-based low-index constrast system. Experiments of beam imaging and light collection show light focusing by the photonic crystal field. Finite-difference time-domain simulations confirm that the observed focusing is due to negative refraction in the photonic crystal area.

  • 9.
    Berrier, Audrey
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Le Thomas, N.
    Ecole Polytech Fed Lausanne, Inst Photon & Elect Quant.
    Houdré, R.
    Ecole Polytech Fed Lausanne, Inst Photon & Elect Quant.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Bloch mode excitation in two-dimensional photonic crystals imaged by Fourier optics2009In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 79, no 16, p. 165116-1-165116-6Article in journal (Refereed)
    Abstract [en]

    Coupling into the Bloch modes of a two-dimensional photonic crystal (PhC) field is investigated by Fourier optics. The PhC was designed to operate in the second band above the air-light line, close to the autocollimation regime for TE polarization. The sample was fabricated in an InP-based heterostructure and an access ridge waveguide provides in-plane excitation of the PhC. The spatial Fourier transform of the field maps obtained from finite-difference time-domain simulations and those calculated by plane-wave expansion are compared to the experimentally obtained equifrequency surfaces (EFS). The shape of the imaged EFS and its variation with the excitation wavelength is shown to be consistent with the theoretical simulations. Finally, the results indicate that if combined with different excitation geometries, Fourier optics can be a powerful technique to assess photonic crystal devices and to design efficient structures.

  • 10.
    Dainese, Matteo
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Shushunova, V.
    Belarussian Stt. Univ. Info./R., Minsk.
    Narrow band coupler based on one-dimensional Bragg reflection waveguide2003In: 2003 Optical Fiber Communication Conference: Altanta, Georgia, 2003, p. 44-46Conference paper (Refereed)
    Abstract [en]

    A new configuration based on the coupling between a conventional low loss, weakly guiding channel waveguide and a Bragg reflection waveguide (BRW) was discussed. The strong difference between the dispersion of a Bragg reflection waveguide and a channel waveguide was used to create a narrow band coupler. The two-dimensional analysis of the BRW was generally based on the transfer matrix method. The structure consisted of a weakly guiding conventional Ge-doped silica waveguide on the top of which a BRW was stacked. The number of periods in the mirror between the BRW and the silica waveguide affected the coupling length and ultimately the bandwidth.

  • 11.
    Dainese, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Effects of process parameters on the photosensitivity properties of Ge doped silica films deposited with plasma CVD2005In: Proceedings of the 13th International Congress on Thin Films, 2005Conference paper (Refereed)
  • 12.
    Dainese, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Spectroscopic investigation of the photosensitive properties of B-Ge codoped silica films2005In: Proceedings of the 13th International Congress on Thin Films, 2005Conference paper (Refereed)
  • 13.
    Dainese, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Directional coupler wavelength selective filter based on dispersive  Bragg Reflection Waveguide2006In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 260, no 2, p. 514-521Article in journal (Refereed)
    Abstract [en]

    A new type of wavelength selective filter, based on high differential dispersion between two coupled waveguides, is presented. The Bragg Reflection Waveguide displays high effective refractive index dispersion, due to the interaction of the guided mode with the two confining Bragg reflectors. When coupled with a weakly guided buried channel silica waveguide, a very narrow bandwidth filter (< 1 nm) can be easily produced, in a shorter length, with respect to directional couplers made with standard step index channel waveguides. The complete design methodology, fabrication and characterization are presented.

  • 14.
    Dainese, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Wavelength selective coupler based on Bragg Reflection Waveguide2005Conference paper (Refereed)
    Abstract [en]

    Highly wavelength selective optical filters are essential components for channel management in modern Dense Wavelength Division Multiplexed communication systems with 50GHz channel spacing and below 0.4nm channel bandwidth. We have designed, fabricated and characterized a new type of wavelength selective directional coupler, based on the high differential dispersion between a Bragg Reflection Waveguide (BRW) and a conventional buried channel silica waveguide.

    The bandwidth of the device is inversely proportional to the length of the coupler as well as to the differential effective refractive index dispersion of the coupled modal fields, at the wavelength of phase matching. The BRW is made of a high index (amorphous) silicon core layer, surrounded vertically by two periodic Bragg reflectors with alternating layers of silica and silicon. The silica waveguide with a Ge-doped core, vertically stacked with the BRW, allows fiber incoupling loss below 1dB which is essentially the insertion loss of the device. The device is operating within the optical bandgap of the Bragg reflectors. Both the bandwidth and the coupling wavelength can be tuned during the fabrication process: the fields’ overlap and the coupling coefficient between the two waveguide modes are controlled by one of the Bragg reflectors (coarse control) and a spacer layer (fine control); the position of the coupling wavelength is mainly determined by the BRW core thickness.

    The devices were fabricated by depositing SiO2 and a-Si:H films on a 4” <100> oriented Si substrate, by plasma enhanced chemical vapor deposition, at a temperature of 250ºC. The 5µm wide vertical stack of BRW and silica waveguide were defined by lithography and etched in an inductively coupled plasma reactor. The 8.8µm thick coupler structure was covered with a 16µm thick silica cladding. The device can be easily integrated in a standard silica-based planar lightwave circuit.

    The measured filter suppression is 14dB and the FWHM is 0.29nm for only a 1.73mm long device, which is close to the estimated value of 0.31nm, and one of the lowest ever reported for this type of coupler.

  • 15.
    Dainese, Matteo
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Wosinski, Lech
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    Phoxtal Communications AB.
    Photosensitivity of boron-codoped PECVD films in application to grating assisted WDM devices2004In: INTEGRATED OPTICS AND PHOTONIC INTEGRATED CIRCUITS / [ed] Righini, GC; Honkanen, S, BELLINGHAM: SPIE-INT SOC OPTICAL ENGINEERING , 2004, Vol. 5451, p. 191-198Conference paper (Refereed)
    Abstract [en]

    UV sensitivity of B-Ge codoped cores in PECVD silica waveguides has been investigated. Photoinduced refractive index changes have been introduced by KrF excimer laser irradiation at 248 rim, without any presensitization method. The effects of B codoping of Ge doped silica have been examined. It has been shown that B addition mildly increases glass network disorder, by broadening the O bridging angle distribution as from FTIR measurements, but on the other hand it does not produce point defects which may contribute to the absorption band at 5eV already generated by the presence of Ge doping. The fabricated channel waveguides show low optical loss even without high temperature annealing. Strong Bragg gratings imprinted into these waveguides confirm that in non thermally annealed Ge doped PECVD silica glass, where a small absorption band still exist at 5eV, B codoping supplies sufficient photosensitivity amplification to make hydrogen loading unnecessary.

  • 16.
    Dainese, Matteo
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Zhang, Ziyang
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Qiu, Min
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO (moved to SCI 2011-07-01).
    Experimental demonstration of a vertically coupled photonic crystal filter2005Conference paper (Refereed)
    Abstract [en]

    Design, fabrication, and characterization of an optical filter based on vertical coupling between a silicon wire waveguide and a cavity in a suspended silicon photonic crystal membrane is presented for the 1550 nm wavelength spectral region.

  • 17.
    De Luca, Eleonora
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Sanatinia, Reza
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Mensi, Mounir
    KTH, School of Information and Communication Technology (ICT).
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Modal phase matching in nanostructured zincblende semiconductors for second-harmonic generation2017In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2017Conference paper (Refereed)
    Abstract [en]

    Gallium phosphide nanowaveguide arrays, designed to fulfill the phase matching conditions and field-overlap, are characterized by second-harmonic generation. The bandwidth of 30nm with maximum conversion efficiency of 10-3 is measured for 150fs optical pulses.

  • 18.
    De Luca, Eleonora
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Sanatinia, Reza
    KTH, School of Engineering Sciences (SCI), Applied Physics, Laser Physics.
    Srinivasan, Anand
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Focused ion beam milling of gallium phosphide nanostructures for photonic applications2016In: Optical Materials Express, ISSN 2159-3930, E-ISSN 2159-3930, Vol. 6, no 2, p. 587-596Article in journal (Refereed)
    Abstract [en]

    We report on the fabrication of gallium phosphide (GaP) nanowaveguides of controlled dimensions, as small as 0.03 μm and aspect ratio in excess of 20, using focused ion beam (FIB) milling. A known limitation of this fabrication process for photonic applications is the formation of gallium droplets on the surface. We demonstrate a post-fabrication step using a pulsed laser to locally oxidize the excess surface gallium on the FIB milled nanostructures. The process significantly reduces the waveguide losses. The surface optical quality of the fabricated GaP nanowaveguides has been evaluated by second-harmonic generation experiments. Surface and bulk contributions to second-order optical nonlinearities have been identified by polarization measurements. The presented method can potentially be applied to other III-V nanostructures to reduce optical losses.

  • 19.
    De Luca, Eleonora
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum and Biophotonics.
    Visser, Dennis
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Anand, Srinivasan
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Gallium indium phosphide nanostructures with suppressed photoluminescence for applications in nonlinear optics2018In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2018Conference paper (Refereed)
    Abstract [en]

    Nanostructured GaInP shows remarkable second-order nonlinear properties. By measuring the second harmonic generation before and after stimulating intrinsic photobleaching, we observed suppressed photoluminescence and unchanged nonlinear properties, making it suitable for low-noise applications. 

  • 20.
    Dev Choudhury, Bikash
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Sahoo, Pankaj Kumar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA. Indian Institute of Technology, India.
    Sanatinia, Reza
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Andler, G.
    Stockholm University.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Surface second harmonic generation from silicon pillar arrays with strong geometrical dependence2015In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 40, no 9, p. 2072-2075Article in journal (Refereed)
    Abstract [en]

    We present experimental demonstration and analysis of enhanced surface second harmonic generation (SHG) from hexagonal arrays of silicon pillars. Three sets of Si pillar samples with truncated cone-shaped pillar arrays having periods of 500, 1000, and 2000 nm, and corresponding average diameters of 200, 585 and 1550 nm, respectively, are fabricated by colloidal lithography and plasma dry etching. We have observed strong dependence of SHG intensity on the pillar geometry. Pillar arrays with a 1000 nm period and a 585 nm average diameter give more than a one order of magnitude higher SHG signal compared to the other two samples. We theoretically verified the dependence of SHG intensity on pillar geometry by finite difference time domain simulations in terms of the surface normal E-field component. The enhanced surface SHG light can be useful for nonlinear silicon photonics, surface/interface characterization, and optical biosensing.

  • 21.
    Gallo, Katia
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Stensson, Katarina
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Levenius, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Björk, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Conforti, Matteo
    Twin-Beam Parametric Processes in Nonlinear Photonic Crystals2014Conference paper (Refereed)
    Abstract [en]

    The talk will briefly introduce the technology and design principles for quadratic nonlinear photonic crystals and provide a few examples of optical functionalities affordable on this platform, with a particular focus on recent developments concerning frequency down-conversion and their implications for the engineering of novel parametric light sources for classical and quantum optics applications.

  • 22.
    Jaskorzynska, Bozena
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Sergeyev, S.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Khoptyar, D.
    Nonlinear upconversion-rate in Er-doped fibers2001In: Acta Physica Polonica. A, ISSN 0587-4246, E-ISSN 1898-794X, Vol. 99, no 1, p. 147-153Article in journal (Refereed)
    Abstract [en]

    Energy transfer between excited rare-earth ions has been widely used for realizing upconversion lasers and also recognized as a gain limiting factor in high-concentration Er-doped amplifiers. The energy transfer leads to upconversion of the excitation which for randomly distributed (not clustered) ions is called homogeneous upconversion. It was commonly assumed that the rate of homogeneous upconversion is a linear function of the population inversion N-2. However, recently published Monte Carlo simulations predict that the homogeneous upconversion rate is a nonlinear function of N-2 and that it, moreover, depends on the pump and signals rates. In this paper we review some of our experimental results confirming those predictions. We also propose a statistical, analytical model describing the observed homogeneous upconversion behavior in Er-doped fibers.

  • 23.
    Jöns, Klaus D.
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics. AlbaNova University Center.
    Stensson, Katarina
    KTH, School of Engineering Sciences (SCI), Applied Physics. AlbaNova University Center.
    Reindl, Marcus
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics. AlbaNova University Center.
    Huo, Yongheng
    Zwiller, Val
    KTH, School of Engineering Sciences (SCI), Applied Physics. AlbaNova University Center.
    Rastelli, Armando
    Trotta, Rinaldo
    Björk, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics. AlbaNova University Center.
    Two-photon interference from two blinking quantum emitters2017In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, no 7, article id 075430Article in journal (Refereed)
    Abstract [en]

    We investigate the effect of blinking on the two-photon interference measurement from two independent quantum emitters. We find that blinking significantly alters the statistics in the Hong-Ou-Mandel second-order intensity correlation function g((2))(tau) and the outcome of two-photon interference measurements performed with independent quantum emitters. We theoretically demonstrate that the presence of blinking can be experimentally recognized by a deviation from the g(D)((2))(0) = 0.5 value when distinguishable photons from two emitters impinge on a beam splitter. Our findings explain the significant differences between linear losses and blinking for correlation measurements between independent sources and are experimentally verified using a parametric down-conversion photon-pair source. We show that blinking imposes a mandatory cross-check measurement to correctly estimate the degree of indistinguishability of photons emitted by independent quantum emitters.

  • 24. Mulot, M.
    et al.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Carlstrom, C. F.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Taineau, A.
    Dry etching of photonic crystals in InP based materials2002In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T101, p. 106-109Article in journal (Refereed)
    Abstract [en]

    Photonic crystal (PC) etching in InP/GaInAsP using two different processes, namely Ar/CH4/H-2 based Reactive Ion Etching (RIE) and Ar/Cl-2 based Chemically Assisted Ion Beam Etching (CAIBE), is investigated in detail and the results are compared. Our goal was to identify the limits of the processes and to optimize process parameters for PC etching. With Ar/CH4/H-2 RIE, we obtained PC holes with smooth profiles. However, the etch depth depends strongly on the hole diameter; the smaller the hole diameter, the smaller is the obtained hole depth. This together with the obtained hole profiles indicates the presence of an etch-limiting mechanism and is attributed to inefficient removal of etch-products. In the case of Ar/Cl-2 CAME, we find that both shape and depth of the holes, depend on sample temperature, Cl-2 flow and etching duration. By optimizing the process parameters, we show that it is possible to balance the physical and chemical components in the etch process. We demonstrate that Ar/Cl-2 CAME is a promising process for PC etching in InP. With this process, we can obtain sufficiently deep holes (2.3-2.5 mum) even for hole diameters as small as 220nm.

  • 25. Mulot, M.
    et al.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Talneau, A.
    Low-loss InP-based photonic-crystal waveguides etched with Ar/Cl-2 chemically assisted ion beam etching2003In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 21, no 2, p. 900-903Article in journal (Refereed)
    Abstract [en]

    We demonstrate low-loss photonic-crystal (PC) waveguides realized in InP by Ar/Cl-2 based chemically assisted ion,beam etching. The waveguides are obtained as line defects in a triangular lattice of holes etched through a three-layer InP/GaInAsP/InP heterostructure. By optimizing the etching parameters so that the physical and the chemical components are balanced we succeed in obtaining holes deeper than 2 mum even for a hole diameter as small as 220 nm. The quality of the PCs etched by two different process conditions is compared by using the shape and the position of one of the mode gaps as an assessment tool;The measured transmissions spectra indicate that the PC waveguides etched with an optimized process exhibit losses smaller than 1 dB/100 mum. This is to date the lowest loss value reported for PC waveguides in semiconductor heterostructures at optical communication wavelengths.

  • 26. Mulot, M.
    et al.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Talneau, A.
    In-plane resonant cavities with photonic crystal boundaries etched in InP-based heterostructure2003In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, no 6, p. 1095-1097Article in journal (Refereed)
    Abstract [en]

    The optical properties of in-plane cavities with photonic crystal boundaries fabricated into an InP/GaInAsP/InP slab waveguide structure are presented. The investigated cavities are realized as segments of different lengths bounded by V-shaped double or single mirrors in straight photonic crystal waveguides and were designed to have resonance in the 1.55 mum wavelength range. High aspect ratio etching of the photonic crystal is achieved using Ar/Cl-2-based chemically assisted ion beam etching. The optical loss inside the photonic crystal waveguide was determined by fitting the measured transmission spectra with two-dimensional finite-difference time-domain simulations. The experimental results, combined with the simulations, indicate that major sources of loss in these cavities are radiation through the cavity mirrors and out-of-plane scattering of the third-order mode inside of the cavity. The best results were obtained for a 6.2 mum long resonant cavity with double mirrors that had an appreciably high-quality factor of 460.

  • 27.
    Mulot, Mikael
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Qiu, Min
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Strassner, Martin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hede, M.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Fabry-Perot cavities based on two-dimensional photonic crystals fabricated in InP membranes2004In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 95, no 10, p. 5928-5930Article in journal (Refereed)
    Abstract [en]

    We measured the transmission and analyzed out-of-plane loss in Fabry-Perot filters based on photonic crystals etched in a suspended InP membrane. The resonant cavity of the Fabry-Perot filter is based on a single row line defect introduced in a triangular lattice of air holes. The transmission spectrum of these structures is measured by using the end-fire method. We measured a cavity quality factor of 3200 for a resonance wavelength in the 1.5 mum wavelength range. We identify that radiation through the holes at both extremities of the resonant cavity largely contributes to the loss in the device.

  • 28.
    Qiu, Min
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Azizi, K.
    Karlsson, Anders
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Numerical studies of mode gaps and coupling efficiency for line-defect waveguides in two-dimensional photonic crystals2001In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 6415, no 15Article in journal (Refereed)
    Abstract [en]

    Using conventional waveguides. for light coupling and collection we numerically study band structures and transmission spectra for guided modes in line-defect waveguides. obtained by removing rows of air holes in a lossless triangular-lattice two-dimensional photonic crystal. The two-dimensional finite-difference time-domain method combined with the effective index method and complemented with the coupled mode approximation is employed to analyze mode-gaps (or mini stopbands) arising from Bragg diffraction of the incident mode into the counterpropagating modes. We also show that more than 97% coupling efficiency between the ridge and the photonic crystal waveguides. is achievable by adjustment of the ridge waveguide width.

  • 29.
    Qiu, Min
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Benisty, H.
    Time-domain 2D modeling of slab-waveguide-based photonic-crystal devices in the presence of radiation losses2002In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 34, no 5, p. 387-393Article in journal (Refereed)
    Abstract [en]

    Devices based on two-dimensional (2D) photonic crystals (PCs) arc typically realized as 3D structures consisting of an array of holes (or rods) vertically etched through a slab waveguide. The existence of holes in a slob waveguide may induce strong radiation losses to the slab claddings. Exact modeling of devices affected by such losses requires 3D calculations. In the present Letter, with the use of the effective-index method to account for the vertical confinement and the effective losses method by the nonvanishing conductivity, the 3D modeling is reduced into 2D. It is then shown that good agreement with experiments can be obtained for slab-waveguide-based photonic crystal devices.

  • 30.
    Qiu, Min
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mulot, M.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Anand, Srinivasan
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Kamp, M.
    Forchel, A.
    Photonic crystal optical filter based on contra-directional waveguide coupling2003In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, no 25, p. 5121-5123Article in journal (Refereed)
    Abstract [en]

    Wavelength-selective operation of an optical filter (add/drop) based on a contra-directional photonic crystal waveguide coupler is demonstrated. The waveguides are defined as line defects in a two-dimensional triangular photonic crystal fabricated in an InP/GaInAsP heterostructure. The device is characterized using the end-fire method for the drop functionality. The experimental data are in good agreement with the theoretical results predicted by finite-difference time-domain simulations.

  • 31.
    Qiu, Min
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Mulot, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Srinivasan, Anand
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Optical add/drop filters using two-dimensional photonic crystals2004In: Proceedings of SPIE - The International Society for Optical Engineering, 2004, p. 286-295Conference paper (Refereed)
    Abstract [en]

    Optical add/drop filters using two-dimensional photonic crystals (PC's) are presented for different designs. In-plane channel add/drop filter composed of two waveguides and an optical resonator system is very compact, but sensitive to the losses. While add/drop filter based on a contra-directional PC waveguide coupler is much more robust to the losses, and reasonable compactness is possible with careful designs. The possibility to utilize the PC dispersion properties to design optical filters is also discussed briefly.

  • 32.
    Qiu, Min
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    Jaskorzynska, Bozena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Wave propagation through a photonic crystal in a negative phase refractive-index region2003In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 9, no 1, p. 106-110Article in journal (Refereed)
    Abstract [en]

    The wave propagation through a photonic crystal with a triangular lattice of air holes realized in the InP-InGaAsP heterostructure are studied theoretically for the transverse magnetic modes. The photonic crystal possesses a negative refractive index, and the self-focus of the beam is successfully observed. The weak side beams are observed due to high-order Bloch waves in the photonic crystal. The coupling efficiency for the outgoing waves to a waveguide is also studied.

  • 33.
    Qiu, Min
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Xiao, S.
    Berrier, A.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Mulot, M.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ruan, Z.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Negative refraction in two-dimensional photonic crystals2005In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 80, no 6, p. 1231-1236Article in journal (Refereed)
    Abstract [en]

    We present some of our recent results for negative refraction in photonic crystals. The concept of negative refraction in photonic crystals is firstly introduced. Then, the propagation of electromagnetic waves in photonic crystals is systematically studied. By the layer Korringa-Kohn-Rostoker method, the coupling efficiency between external plane waves and the Bloch waves in photonic crystals is investigated. It is found that the coupling coefficient is highly angular dependent even for an interface between air with n=1 and a photonic crystal with effective index n(eff)=-1. It is also shown that, for point imaging by a photonic crystal slab, owing to the negative refraction, the influence of the surface termination on the transmission and the imaging quality is significant. Finally, we present results experimentally demonstrating negative refraction in a two-dimensional photonic crystal at optical communication wavelengths.

  • 34.
    Sanatinia, Reza
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Experimental quantification of surface optical nonlinearity in GaP nanopillar waveguides2015In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 23, no 2, p. 756-764Article in journal (Refereed)
    Abstract [en]

    We report on surface second-order optical nonlinearity in single GaP nanopillars (nanowaveguides). The relative contribution of optical nonlinearity from the surface and the bulk is resolved by mode confinement analysis and polarization measurements. By investigating the thickness of nonlinear region at the surface of nanopillars, we estimated the nonlinear coefficient to be similar to 15 times higher at the surface with respect to the bulk. The presented results are interesting both from the fundamental aspects of light-matter interaction and for future nonlinear nanophotonic devices with smaller footprint.

  • 35.
    Sanatinia, Reza
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Modal Engineering of Second-Harmonic Generation in Single GaP Nanopillars2014In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 14, no 9, p. 5376-5381Article in journal (Refereed)
    Abstract [en]

    We report on modal dispersion engineering for second-harmonic generation (SHG) from single vertical GaP nanopillars/nanowaveguides, fabricated by a top-down approach, using optical modal overlap between the pump (830 nm) and SHG (415 nm). We present a modal analysis for the SHG process in GaP nanopillars and demonstrate efficient utilization of the longitudinal component of the nonlinear polarization density. Our SHG measurements show quantitatively the presented model. We experimentally demonstrate that polarization beam shaping and field distribution modification of the radiated SHG light, at nanometer scale, can be achieved by tuning the pillar diameter and linear pump polarization. SHG from single pillars can be used as femtosecond nanoscopic light sources at visible wavelengths applicable for single cell/molecular imaging and interesting for future integrated nanophotonics components. While this work focuses on GaP nanopillars, the results are applicable to other semiconductor nanowire materials and synthesis methods.

  • 36.
    Sanatinia, Reza
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Surface Second-Harmonic Generation from Vertical GaP Nanopillars2012In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 12, no 2, p. 820-826Article in journal (Refereed)
    Abstract [en]

    We report on the experimental observation and analysis of second-harmonic generation (SHG) from vertical GaP nanopillars. Periodic arrays of GaP nanopillars with varying diameters ranging from 100 to 250 nm were fabricated on (100) undoped GaP substrate by nanosphere lithography and dry etching. We observed a strong dependence of the SHG intensity on pillar diameter. Analysis of surface and bulk contributions to SHG from the pillars including the calculations of the electric field profiles and coupling efficiencies is in very good agreement with the experimental data. Complementary measurements of surface optical phonons by Raman spectroscopy are also in agreement with the calculated field intensities at the surface. Finally, polarization of the measured light is used to distinguish between the bulk and surface SHG from GaP nanopillars.

  • 37.
    Sanatinia, Reza
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Srinivasan, Anand
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Second harmonic generation in GaP nanopillars2011In: 2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011, 2011Conference paper (Refereed)
    Abstract [en]

    Semiconductor nanopillars and nanowires (NWs) exhibit interesting optical nonlinear effects [1,2]. These properties are attributed to the geometrical and optical properties of nanopillars which define optical field confinement [3] and the field discontinuity that contributes to bulk and surface nonlinearity [4,5]. Potential applications for these nonlinear effects include probing of the surface in nanostructures and nonlinear scanning laser microscopy

  • 38.
    Sanatinia, Reza
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Westendorp, S.
    KTH, School of Engineering Sciences (SCI).
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Enhanced second-harmonic generation in GaP nanopillars arrays by modal engineering2014In: Optics InfoBase Conference Papers, 2014Conference paper (Refereed)
    Abstract [en]

    Second harmonic generation from GaP nanopillars with optimized mode field overlap is analyzed and experimentally demonstrated. We present dispersion engineering in arrays of nanopillars to satisfy modal phase matching.

  • 39.
    Sauge, Sebastien
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A single-crystal source of path/polarization entanglement at non-degenerate wavelengths2010In: Optics and Spectroscopy, ISSN 0030-400X, E-ISSN 1562-6911, Vol. 108, no 2, p. 165-169Article in journal (Refereed)
    Abstract [en]

    We demonstrate a bright, narrowband, compact, quasi-phase-matched single-crystal source generating path-polarization-entangled photon pairs at 810 nm and 1550 nm at a maximum rate of 3 x 10(6) s(-1) THz(-1) mW(-1) after coupling to single-mode fiber, and with two-photon interference visibility above 90%. While the source can already be used to implement quantum communication protocols such as quantum key distribution, this work is also instrumental for narrowband applications such as entanglement transfer from photonic to atomic qubits, or entanglement of photons from independent sources.

  • 40.
    Sauge, Sebastien
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Albert-Seifried, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Waldebäck, Johan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tengner, Maria
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ljunggren, Daniel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Xavier, G. B.
    Narrowband polarization-entangled photon pairs distributed over a WDM link for qubit networks2007In: CLEO/Europe IQEC 2007: 17-22 June 2007, Munich, Germany, 2007, p. 4387014-Conference paper (Refereed)
  • 41.
    Sauge, Sebastien
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Albert-Seifried, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Xavier, Guilherme
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Waldebäck, Johan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tengner, Maria
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ljunggren, Daniel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Narrowband polarization-entangled photon pairs distributed over a WDM link for qubit networks2007In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 15, no 11, p. 6926-6933Article in journal (Refereed)
    Abstract [en]

    We present a bright, narrowband, portable, quasi-phase- matched two-crystal source generating polarization- entangled photon pairs at 809 nm and 1555 nm at a maximum rate of 1.2 x 10(6) s(-1) THz(-1) mW(-1) after coupling to single- mode fiber. The quantum channel at 1555 nm and the synchronization signal gating the single photon detector are multiplexed in the same optical fiber of length 27 km by means of wavelength division multiplexers (WDM) having 100 GHz (0.8 nm) spacing between channels. This implementation makes quantum communication applications compatible with current high-speed optical networks.

  • 42.
    Sauge, Sebastien
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Albert-Seifried, Sebastian
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Xavier, Guilherme
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Waldebäck, Johan
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tengner, Maria
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Ljunggren, Daniel
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Wang, Qin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Quantum communication in optical networks: an overview and selected recent results2007In: ICTON 2007: Proceedings of the 9th International Conference on Transparent Optical Networks, Vol 1 / [ed] Marciniak, M, 2007, p. 30-33Conference paper (Refereed)
    Abstract [en]

    We discuss recent work in quantum communication, and in some details present a bright, narrowband, portable, quasi-phase-matched two-crystal source generating polarization-entangled photon pairs at 809 nm and 1555 nm. We also show how the single-photon quantum channel at 1555 nm and a classical synchronization signal gating the single photon detector at the receiving side can be multiplexed in the same optical fiber of length 27 km by means of wavelength division multiplexers (WDM) having 100 GHz (0.8 nm) spacing between channels. This illustrates bow single-photon quantum communication applications is compatible with current high-speed optical networks.

  • 43.
    Sauge, Sebastien
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Tengner, Maria
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Karlsson, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A single-crystal source of path-polarization entangled photons at non-degenerate wavelengths2008In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 16, no 13, p. 9701-9707Article in journal (Refereed)
    Abstract [en]

    We demonstrate a bright, narrowband, compact, quasi-phase-matched single-crystal source generating path-polarization-entangled photon pairs at 810 nm and 1550 nm at a maximum rate of 3 x 10(6) s(-1) THz(-1) mW(-1) after coupling to single-mode fiber, and with two-photon interference visibility above 90%. While the source can already be used to implement quantum communication protocols such as quantum key distribution, this work is also instrumental for narrowband applications such as entanglement transfer from photonic to atomic qubits, or entanglement of photons from independent sources.

  • 44.
    Sauge, Sebastien
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Xavier, Guilherme
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Tengner, Maria
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Karlsson, Anders
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Single crystal source of polarization entangled photons at non-degenerate wavelengths2008In: 2008 Conference On Lasers And Electro-Optics & Quantum Electronics And Laser Science Conference: Vols 1-9, 2008, p. 2996-2997Conference paper (Refereed)
    Abstract [en]

    We demonstrate a bright, narrowband, compact single-crystal source of polarization entangled photon pairs at non-degenerate wavelength. This work is instrumental for quantum key distribution and entanglement transfer from photonic to atomic qubits.

  • 45.
    Shabbir, Saroosh
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Björk, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Arbitrary interference curves by coincidence detection: Theory and experiment2013In: Optical Society of America. Journal A: Optics, Image Science, and Vision, ISSN 1084-7529, E-ISSN 1520-8532, Vol. 30, no 10, p. 1921-1928Article in journal (Refereed)
    Abstract [en]

    We discuss how to use coincidence detection to generate unusual, nonsinusoidal interference curves by using not a single detector, but several in coincidence. The method works for both strong (classical) and weak (on the fewphoton level) light, although in the latter case the detection becomes probabilistic with low efficiency. Using the method, one can tailor the coincidence measurement setup to obtain essentially any interference pattern. We then use the method to experimentally demonstrate phase-difference state interference patterns in the few-photon regime that are highly nonsinusoidal. We also discuss optimal implementation of the method with regard to fluctuations and success probability, and we analyze the origin and magnitude of errors.

  • 46.
    Shabbir, Saroosh
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Björk, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Synthesis of arbitrary interference patterns with high visibility2013In: 2013 Conference on Lasers and Electro-Optics Europe and International Quantum Electronics Conference, CLEO/Europe-IQEC 2013, IEEE Computer Society, 2013, p. 6801668-Conference paper (Refereed)
    Abstract [en]

    In recent years there have been many demonstrations of phase super-resolution - previously thought to be a manifestly quantum phenomenon - using classical light [1, 2], but at the expense of reduced interference visibility [3]. It is therefore of interest to delineate what interference effects belong to the realm of classical world, and which require quantum states. Generalizing Hofmann's method of post-selection projection [4], we show that essentially any interference curve can be synthesized with high visibility with coherent state input. The method is based on the mathematical observation that any polynomial can be completely factored over the field of complex numbers. Hence, any two-mode, N-photon state can be written as a product of N single-photon, two-mode states, and the corresponding measurement projector can be experimentally implemented using beam splitters, phase-shifters, and N-photon coincidence measurements.

  • 47.
    Shabbir, Saroosh
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Swillo, Marcin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Björk, Gunnar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Quantum Electronics and Quantum Optics, QEO.
    Synthesis of arbitrary, two-mode, high-visibility N-photon interference patterns2013In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 87, no 5, p. 053821-Article in journal (Refereed)
    Abstract [en]

    Using coherent states, linear optics, and N-photon detection we demonstrate the synthesis of arbitrary interference patterns and establish that neither the shape nor the visibility of N-photon interference patterns can be used as a quantum signature in general. Specific examples include saw-curve and rectangle-curve interference patterns and phase super-resolution with period shortening of up to 60 times compared to ordinary interference. The former two have visibility close to 100% and the latter has visibility in excess of 57%.

  • 48.
    Shahid, Naeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Amin, Muhammad
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Naureen, Shagufta
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Junction-type photonic crystal waveguides for notch- and pass-band filtering2011In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 19, no 21, p. 21074-21080Article in journal (Refereed)
    Abstract [en]

    Evolution of the mode gap and the associated transmission mini stop-band (MSB) as a function of photonic crystal (PhC) waveguide width is theoretically and experimentally investigated. The change of line-defect width is identified to be the most appropriate way since it offers a wide MSB wavelength tuning range. A high transmission narrow-band filter is experimentally demonstrated in a junction-type waveguide composed of two PhC waveguides with slightly different widths. The full width at half maximum is 5.6 nm; the peak transmission is attenuated by only 5 dB and is 20 dB above the MSBs. Additionally, temperature tuning of the filter were also performed. The results show red-shift of the transmission peak and the MSB edges with a gradient of dλ/dT $=$ 0.1 nm/°C. It is proposed that the transmission MSBs in such junction-type cascaded PhC waveguides can be used to obtain different types of filters.

  • 49.
    Shahid, Naeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Li, Mingyu
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Naureen, Shagufta
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Material Physics (Closed 20120101), Semiconductor Materials, HMA (Closed 20120101).
    Engineering mode-gaps in photonic crystal waveguides for filtering applications2011In: Conf. Lasers Electro-Opt. Europe Eur. Quantum Electron. Conf., CLEO EUROPE/EQEC, 2011Conference paper (Refereed)
    Abstract [en]

    Photonic crystal (PhC) components in InP-based materials are of practical importance not only for their unique properties but also for integration with conventional optoelectronic components on InP substrate. PhC waveguides have been investigated extensively for their unique waveguiding and dispersive properties. One such interesting property is the mode-gap which results in a transmission mini-stop band (MSB) [1] and has been investigated for applications such as coarse wavelength selection [2]. However, the optical characteristics of the MSB have to be improved significantly. Single heterojunction PhC waveguides have received much less attention [3] and in particular the internal MSB effect due to mode-coupling could bring new functions in such waveguides.

  • 50.
    Shahid, Naeem
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Naureen, Shagufta
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Li, Min Yue
    KTH, School of Electrical Engineering (EES), Sound and Image Processing.
    Swillo, Marcin
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Quantum Electronics and Quantum Optics, QEO.
    Anand, Srinivasan
    KTH, School of Information and Communication Technology (ICT), Material Physics, Semiconductor Materials, HMA.
    Novel postetch process to realize high quality photonic crystals in InP2011In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 29, no 3, p. 031202-Article in journal (Refereed)
    Abstract [en]

    Thermally driven reflow of material during annealing was positively used to obtain near-vertical sidewall profiles for high-aspect-ratio nanostructures in InP fabricated by dry etching. This is very promising for achieving high optical quality in photonic crystal (PhC) components. Nearly cylindrical profiles were obtained for high-aspect-ratio PhC holes with diameters as small as 200350 nm. Mini stop bands (MSBs) in line-defect PhC waveguides were experimentally investigated for both as-etched and reshaped hole geometries, and their spectral characteristics were used to assess the quality of PhC fabrication. The spectral characteristics of the MSB in PhC waveguides with reshaped holes showed significant improvement in performance with a transmission dip as deep as 35 dB with sharp edges dropping in intensity more than 30 dB for similar to 4 nm of wavelength change. These results show potential for using high extinction drop-filters in InP-based monolithic photonic integrated circuit applications. Finally, it is proposed that other nanostructure geometries may also benefit from this reshaping process.

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