By Topic

Transparent Optical Networks, 2008. ICTON 2008. 10th Anniversary International Conference on

Date 22-26 June 2008

Go

Filter Results

Displaying Results 1 - 25 of 107
  • Proceedings of 2008 10th anniversary international conference on transparent optical networks

    Page(s): I - II
    Save to Project icon | Request Permissions | PDF file iconPDF (136 KB)  
    Freely Available from IEEE
  • Committees

    Page(s): III - VI
    Save to Project icon | Request Permissions | PDF file iconPDF (150 KB)  
    Freely Available from IEEE
  • Contents

    Page(s): VII - XII
    Save to Project icon | Request Permissions | PDF file iconPDF (169 KB)  
    Freely Available from IEEE
  • Propagation of short lightpulses in microring resonators

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    The propagation of short lightpulses in waveguiding structures with optical feedback, in our case optical microresonators, has been studied theoretically and experimentally. It appears that, dependent on the measurement set-up, ballistic transport or interference in the time domain of fs and ps laser pulses can be observed. The experiments are analyzed in terms of characteristic time scales of the source, the waveguide device and the detector arrangement and are related to Heisenbergpsilas uncertainty principle. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Label-free biological sensors based on ring resonators

    Page(s): 2 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (657 KB) |  | HTML iconHTML  

    This paper reports the progress (design, fabrication and measurement) in label-free biological sensors based on ring resonator technology originally developed for telecommunication. These sensors are made in silicon-on-insulator (SOI), a high index contrast material platform that provides enhanced sensitivity and allows compact waveguide geometries by employing very small bend radii. A double spiral shape allows designing millimetre-long resonator in a compact size (100-150 mum) compatible with spotting technology used for large biochip assays. The detection limit estimated from the resonance shift measurement is ~5 fg of streptavidin adsorbed on the sensor surface functionalised with biotin. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Microcapillary resonators with submicrometric wall

    Page(s): 6 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (604 KB) |  | HTML iconHTML  

    Microcapillary resonators are intrinsically tunable microcavities readily compatible with microfluidic systems. Whispering-gallery modes resonances of submicrometric wall capillaries exhibit large wavelength shifts as a function of the refractive index of the fluid that fills the inside. These microresonators have some unique properties as (a) the spatial separation between the surface where the total internal reflection takes place and the surface where the evanescent fields interact with the fluids and (b) the possibility of using fluids with refractive index values higher than the refractive index of the capillary material. The fabrication of microcapillaries with a submicrometric wall follows two steps. First, we prepare capillaries of about 100 mum by pulling commercial silica tubes. Second, the capillaries are pressurized and tapered down to the final diameter using a travelling-flame elongation method. The experimental characterization of these microresonators demonstrates the feasibility of different applications as chemical and biological sensors, tunable microlasers, tunable filters, etc. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical theorem helps understand thresholds of lasing in open semiconductor microcavities

    Page(s): 10 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    We discuss the application of the optical theorem to the analysis of lasing as a linear eigenvalue problem. This yields clear insight into the lasing thresholds of individual modes and easily accounts for the matching of the active-region geometry with the modal electric-field pattern. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Inherently directional lasing from a thermal-induced-deformation high-Q microcavity

    Page(s): 14 - 15
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    We experimentally report a novel asymmetrical spherical microcavity with thermal-induced deformation, in which whispering gallery modes possess not only ultra-high quality factors (Q) but also remarkably directional escape emission from the microsphere boundary. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tracking spatial modes in nearly hemispherical microcavities

    Page(s): 16 - 19
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB) |  | HTML iconHTML  

    We measure experimentally the spatial intensity profiles and resonant frequencies of the transverse modes of nearly hemi-spherical microcavities with cavity length and mirror curvatures below 10 mum. These resonators possess axially-symmetric Gauss-Laguerre-like modes, but do not display the frequency degeneracies typical of large-scale optical cavities. It is possible to interpret these results using a paraxial model of cavity propagation that includes non-parabolic optical elements. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quasi-phase matched second harmonic generation in high-Q spherical micro-resonators

    Page(s): 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (125 KB)  

    Some spherical or other kinds of circular micro-resonators exhibit high Q factors which result in very sharp resonances for the light that propagates in the so-called whispering gallery modes. In active devices one may take advantage of such high Q factors to enhance laser light generation or nonlinear interactions. In recent years, there has been some work with the goal to achieve efficient second or third harmonic generation [1 ,2]. In such circular configuration phase matching amounts to angular momentum conservation, which may be achieved using different radial whispering gallery modes for the fundamental and harmonic fields. In that case, however, the overall overlap of the two or three interacting waves is limited. Quasi-phase matching is an alternative route that offers, in principle, more flexibility [3]. Here we will present the design and fabrication of a nonlinear spherical resonator to experimentally measure quasi-phase matched second harmonic generation (SHG) from a low number of molecules per unit area. For such process is advantageous that molecules are placed on the surface of the micro-sphere where the inversion symmetry is broken as required for a second order nonlinear interaction in the dipole approximation. In addition, for the lowest order whispering gallery radial mode, the field is confined by the sphere surface around one equatorial plane. On such molecular monolayer, we wrote a periodical pattern on roughly one quarter of the sphere around the equator perpendicular to the stem that holds it. The pattern consists of alternated periods of nonlinear molecules 8.8 mum in width at the equator and periods of the same width but with no nonlinear molecules. The width of each domain must be exactly one coherence length of the corresponding nonlinear interaction. Using a tunable laser as a pumping source, we saw that SHG, strongly peaks at exactly 403 nm very close to the 403.5 nm predicted from the theory in [3]. This agreement is remarkable and the- - 0.5 nm displacement could be attributed to a small error in measuring the diameter of the sphere. To conclude, we have demonstrated SHG in a new configuration that could have interesting applications in sensing of label-free or unmarked molecules. Sensitivity may be brought to the level of measuring SHG from single molecules since there is no fundamental physics aspect that prevents taking advantage of quality factors of up to 109 found routinely in microspheres. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical coupling of two microcavities with time-varying properties

    Page(s): 21 - 22
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    The paper is devoted to the study the optical coupling by whispering gallery modes (WGM) between two micro-resonators and sensitivity of such a coupling to the time material variation of individual resonator. Semi-analytical solution for the case of instantaneous refractive index changes is obtained. Possibility of frequency shift is demonstrated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Mode manipulation in small microsphere systems

    Page(s): 23 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (694 KB) |  | HTML iconHTML  

    In this work we demonstrate the possibility of mode manipulation in systems of symmetric photonic molecules formed by placing several microspheres in contact. We observe photonic nanojets that reflect the symmetry of the photonic molecule, with 3 jets located at 120 degrees with respect to each other for the triangular molecule. We also present some results showing the coexistence of whispering gallery modes and nanojets in the same structure. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Photonic molecules in the Terahertz - mode splitting in coupled dielectric whispering gallery mode resonators

    Page(s): 27 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (307 KB) |  | HTML iconHTML  

    We present an investigation of photonic molecules in the (sub-) terahertz range. We couple two dielectric whispering gallery mode resonators with matched resonance spectra over tens of resonances. The (loaded) quality (Q)-factors of the individual disks range from 50 - 800. We observe mode splitting for all modes in the range of 0.15 - 0.33 (0.29) THz for a set of polyethylene (quartz) disks with radius = 3 mm (1.8 mm). With increasing distance of the resonators, the splitting decreases due to reduced mode overlap, in very good agreement with numerical calculations. The frequency splitting of different modes is also in good agreement with the numerical calculation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Phase disorder effects in coupled-resonator optical waveguides

    Page(s): 30 - 33
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (274 KB) |  | HTML iconHTML  

    Coupled resonator optical waveguides (CROWs) are widely considered promising building blocks for the on-chip processing of wideband data-streams. The performances of these structures are much sensitive to disorder effects, affecting both losses and the maximum achievable slowing ratio. To date, how and how much disorder influences the slow-wave propagation regime is still an open issue. In this contribution, an analytical model is presented, showing the relation between the back-reflected power due to random variations in the resonant frequencies of the CROW resonators, referred to as phase disorder, and the actual group velocity of the disordered structure. The model can be applied to any CROW, independently of the architecture and technology, and is supported by numerical simulations and experimental results. The effects of an increasing phase disorder were observed in the frequency response of ring-resonator (RR) CROWs, where the resonance frequency of each RR is independently controlled by a thermal activation of the optical waveguide. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Mirrorless optical parametric oscillations in negative-index microstructures

    Page(s): 34 - 37
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (225 KB) |  | HTML iconHTML  

    The unique properties of resonant four-wave mixing of backward waves in negative-index materials are investigated. The possibility of realizing miniature mirrorless optical parametric oscillators is shown and their properties are numerically simulated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Sagnac effect and frequency splitting in rotating optical microcavities

    Page(s): 38
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB)  

    The Sagnac effect in rotating microcavities is studied theoretically and numerically. The frequency splitting due to the Sagnac effect occurs as a threshold-like phenomenon for the angular velocity in a rotating microcavity. Above the threshold, the eigenfunctions of a rotating microcavity become rotating waves while they are standing waves below the threshold. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ultrahigh-Q nanocavities and their dynamic control

    Page(s): 39
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (111 KB)  

    Summary form only given. High-Q photonic-crystal nanocavities are currently the focus of much interest because they can strongly confine photons in a tiny space. Nanocavities with ultra-high quality (Q) factors exceeding 2,000,000 and modal volumes of a cubic wavelength have been successfully realized. If the Q factor could be dynamically controlled within the lifetime of a photon, significant advances would be expected in areas of physics and engineering such as the slowing and/or stopping of light and quantum information processing. For these applications, the transfer, storage, and exchange of photons in nanocavity systems on such a time-scale are highly desirable. In the present talk, I will at first describe the recent progress of ultra-high-Q nanocavities from the experimental and theoretical points of views. Then, I will present the demonstration of dynamic control of the Q factor, by constructing a system composed of a nanocavity, a waveguide with nonlinear optical response, and a photonic-crystal hetero-interface mirror. The Q factor of the nanocavity is successfully changed from ~3,800 to ~22,000 within picoseconds. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Investigation on photonic-corral-mode quantum ring lasers by laser scanning microscopy

    Page(s): 40 - 42
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (993 KB) |  | HTML iconHTML  

    Ultra low threshold microcavity lasers are ideal candidates for high-density optical interconnect light sources. Although they have been extensively studied for the last decade, muA-level electro-pumped quantum confined lasers are still under investigation. Photonic-corral-mode quantum ring (PQR) lasers with the linewidth narrower than 0.55 Aring generate micro-to-nano-ampere thresholds, and become ideal for CMOS-driven high-density emitter arrays for intra-chip optical interconnect as well as other applications such as displays. The PQR offers the following advantages for extremely high-density emitter source chip, over other semiconductor lasers presently available: a photonic quantum corral effect leads to naturally-born quantum wire behaviours for imminently recombinant carriers; the muA - nA threshold current capabilities mean kilo to mega PQR chip; radicT - dependent spectral red shifts are smaller at high operating temperatures, allowing uniform and reliable chip emission with minimal temperature sensitivities. By using laser beam induced current technique (LBIC) technique in laser scanning microscopy (LSM) we investigated the photocurrent confinement in the laser structure. The photocurrent map gives the possibility to analyze the laser structure uniformity. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Resonance-enhanced chaos-assisted optical pumping of a deformed microcavity

    Page(s): 43 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (170 KB) |  | HTML iconHTML  

    We have measured pumping efficiency experimentally in a deformed microcavity laser. We observed a tenfold enhancement in the pumping efficiency via chaos-assisted nonresonant optical pumping at properly chosen pumping angle and position. When the pump wavelength was scanned at the optimal pumping angle and position in a manner of excitation spectroscopy, we observed an additional hundredfold enhancement when the pump wavelength was resonant to a cavity mode spatially overlapping much with the lasing cavity mode. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Numerical investigation of optical response from rolled-up microtube resonator and its application

    Page(s): 45
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    Summary form only given. We preformed a numerical investigation of the optical mode in rolled-up microtube resonators. The optical responses of the self-rolling semiconductor-based resonators are calculated by solving Maxwellpsilas equations using the finite-difference time-domain (FDTD) method. Observed mode patterns characterized by whispering-gallery-mode-like profile are presented with various sets of structural parameters (tube diameter, tube wall thickness, and the number of rotation). The degeneracy breaking results in splitting of the mode peaks with the same azimuthal mode index is observed and we confirmed that it causes by structural asymmetry of the rolled-up structure. For the rolled-up tube with thick tube wall, the quasi-whispering gallery mode pattern due to very high degree of structural asymmetry is shown. In this presentation, we also propose an application of the rolled-up microtube as a refractometric sensor. For this proposal, we experimentally fill the rolled-up tube with liquid and measure the mode peaks shift due to the change of refractive index inside the tube. A FDTD simulation with realistic structural parameters fits well with the experimental spectra. The field shows more leaky to the inner part of the tube due to the increase of the refractive index. High spectral sensitivity is obtained from the tube with thin-wall structure at the long wavelength peak with low azimuthal mode index. This is due to the large overlap between the leakage field and the liquid for the lower mode index. However, the quality factor considerably drops when the wall is very thin. Rolled-up tube with larger number of rotation has lower sensitivity as effectively similar to the tube with thicker wall. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Features of propagation of light in the linear array of dielectric spheres

    Page(s): 46 - 49
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    A finite length linear chain of dielectric loss-less identical spheres is considered. A propagation of dipole radiation in the chain of particles induced by the point dipole source placed near one end of the chain is investigated. It is found that at sufficiently large refractive index there exist frequency pass bands around every low frequency Mie resonance. In particular, if the dipole oscillates across the chain axis, one can reveal a longitudinal mode frequency pass band if refractive index nr of the spheres exceeds 1.9. Then, if the dipole oscillates transversely to the chain axis, the transverse frequencies pass bands show up depending on the chain length. In this case, the pass band is formed if the length chain is large enough. Three dielectric materials with nr = 1.9, nr = 2.7, nr = 3.5 are considered what corresponds to ZnO, TiO2, GaAs. It is found that the top of the frequency pass band corresponds to the top of the Brillouin band edge in the quasi-momentum space. On the order hand, the bottom of the frequency pass band corresponds to the guiding wave criterion [2, 3]. This explains the remarkable feature of the band picture established for infinite chain in Ref. [1]: the band structure breaks down as the wavevector becomes small enough. The multisphere Mie scattering formalism is used to calculate how the amplitude of the radiation changes along the chain. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of general optical resonator structures coupled by straight waveguides

    Page(s): 50 - 53
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (779 KB) |  | HTML iconHTML  

    In this contribution will be shown how optical resonators can be analyzed in an efficient way. The structure should be symmetric with two symmetry planes S1 - S1 and S2 - S2. Therefore only a quarter of it with different walls at the symmetry planes must be analysed. The quarter is subdivided into different parts. In homogeneous parts the MoL is used and in the inhomogeneous ones an adequate FD-algorithm based on the GTL-equations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Numerical simulations of 3D micro-resonators

    Page(s): 54 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (438 KB) |  | HTML iconHTML  

    Micro-resonators are critical optical components that have many exciting applications in fields such as telecommunications, quantum cryptography and optical signal processing. Fabrication techniques allow many different designs of micro-resonator to be realised, but at present their optimisation and simulation remain firmly entrenched in 2D. The geometrical complexity of many micro-resonators mitigates against analytic study. Thus there is a strong demand for comprehensive 3D numerical simulations. We discuss some of the difficulties and challenges when modelling micro-resonators and recent progress towards their 3D modelling using time-domain codes. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Demonstration of novel high-Q fibre WGM “Bottle” microresonators

    Page(s): 58 - 60
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    We demonstrate a novel and simple technique, involving a standard fibre fusion splicer, to fabricate robust fibre whispering-gallery-mode bottle microresonators with loaded Q factors in excess of 3-107 (limited by the source tuning resolution). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Spectra and periodic orbits in a square shaped organic micro-lasers

    Page(s): 61 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    There is currently a great deal of interest in dielectric micro-cavities due to their numerous practical applications and their use to test fundamental physics issues. A systematic way of identifying dominating periodic orbits is presented including a comparison of cavities with singular or smooth edges. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.