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Lightwave Technology, Journal of

Issue 11 • Date Nov. 1999

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Displaying Results 1 - 25 of 62
  • Localized function method for modeling defect modes in 2-D photonic crystals

    Publication Year: 1999 , Page(s): 2078 - 2081
    Cited by:  Papers (40)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (187 KB)  

    We present a novel, general, and numerically efficient treatment of electromagnetic modes localized at defects in two-dimensional (2-D) photonic crystals. The method represents the fields in terms of orthogonal functions localized at the defect and is a fully vector treatment. View full abstract»

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  • Dipole emission in finite photonic bandgap structures: an exactly solvable one-dimensional model

    Publication Year: 1999 , Page(s): 2142 - 2151
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (669 KB)  

    This paper considers an exact model of atomic spontaneous dipole emission and classical dipole radiation in a finite photonic bandgap (PBG) structure. The full three-dimensional (3-D) or two-dimensional (2-D) problem is reduced to a finite one-dimensional (1-D) model, which then is solved for analytically using algebraic matrix transfer techniques. The results give insight to the electromagnetic emission process in periodic dielectrics, quantitative predictions for emission in 1-D dielectric stacks, and qualitative formulas for the 2-D and 3-D problem. View full abstract»

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  • Guest editorial: Electromagnetic crystal structures, design, synthesis, and applications

    Publication Year: 1999 , Page(s): 1928 - 1930
    Cited by:  Papers (8)  |  Patents (1)
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    Freely Available from IEEE
  • Toward controllable photonic crystals for centimeter- and millimeter-wave devices

    Publication Year: 1999 , Page(s): 2025 - 2031
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (656 KB)  

    In this paper, we present several experimental and theoretical studies showing the feasibility of active photonic crystal controlled either by electrical elements or by light. The controllability of photonic crystals at centimeter wavelengths is proposed with the periodic insertion of diodes along the wires of a two-dimensional (2-D) metallic structure. For only three crystal periods with commercially available devices, more than 30 dB variations of the crystal transmission are predicted over a multigigahertz range by switching the diodes. From calculation models, a tight analogy is shown between these crystals and those consisting of discontinuous metallic rods with dielectric inserts. The numerical models as well as the proposed technology are validated by experimental measurements on 2-D crystals with either continuous or discontinuous metallic rods. The partial control of a 3-D layer-by-layer dielectric structure at millimeter wavelengths is also demonstrated in the second part of the work. A laser light is used to modulate the transmission level of defect modes by photo-induced free carrier absorption. The overall results are expected to contribute to further developments of switchable electromagnetic windows as well as to tunable waveguide structures in the microwave and millimeter wave domains View full abstract»

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  • A novel fiber-optic sensor array based on the Sagnac interferometer

    Publication Year: 1999 , Page(s): 2316 - 2326
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    We propose a novel design for a fiber-optic acoustic sensor array that is based on the Sagnac interferometer. The performance of this Sagnac sensor array (SSA) design is analyzed and compared to acoustic sensor arrays based on the Mach-Zehnder (MZ) interferometer. It is found that the SSA exhibits several decisive advantages, including a stable bias point, a reduced conversion of source phase noise into intensity noise, and a frequency response that matches the ambient ocean noise. It is also shown that the SSA can be easily designed to have a much larger dynamic range than an MZ-based sensor array. Potential noise sources are analyzed and shown to be manageable. A means for eliminating polarization-induced signal fading is presented. The applicability of time-division, frequency-division, and code-division multiplexing schemes for the proposed design is presented View full abstract»

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  • Guiding optical light in air using an all-dielectric structure

    Publication Year: 1999 , Page(s): 2039 - 2041
    Cited by:  Papers (82)  |  Patents (66)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (44 KB)  

    The emergence of a dielectric omnidirectional multilayer structure opens new opportunities for low loss broad-band guiding of light in air. We demonstrate the effectiveness of such an approach by fabricating a broad-band, low-loss hollow waveguide in the 10-μm region and measuring its transmission around a 300 bend. The generality of the solution enables the application of the method to many wavelengths of interest important in telecommunication applications as well as for guiding high-power lasers in medical and other fields of use View full abstract»

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  • Wave propagation through nonuniform gratings with slowly varying parameters

    Publication Year: 1999 , Page(s): 2405 - 2411
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    Light propagation through nonuniform gratings with slowly varying parameters is studied using a Schrodinger-like equation. This treatment is intuitively pleasing when applied to uniform gratings as the results are then expressed in terms of the dispersion of the grating. It is shown here that when applied to nonuniform gratings, this method leads to an additional and potentially significant contribution to the dispersion that is not included in naive treatments. It is found that the magnitude of this dispersion can be larger than the total dispersion of the structure. An approximate expression for the reflectivity is also given View full abstract»

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  • Distribution of spontaneous emission from an Er3+-doped photonic crystal fiber

    Publication Year: 1999 , Page(s): 2138 - 2141
    Cited by:  Papers (8)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    The paper studies the emission of 532-nm light through the photonic crystal cladding of an optically pumped Er3+-doped silica/air photonic crystal fiber. The angular emission pattern is compared with the results of a multiple scattering simulation. Good agreement is obtained View full abstract»

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  • Zero dispersion in step index slab waveguides

    Publication Year: 1999 , Page(s): 2336 - 2341
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (812 KB)  

    Specific features of the dispersion in step index slab waveguides, such as zero waveguide dispersion and zero group delay difference between modes, are shown to be described by normalized expressions involving two normalized structure parameters only. The complete subset of dual-mode waveguide structures exhibiting wavelength independent propagation constant difference is identified, and its importance for sensor applications is emphasized View full abstract»

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  • Resonant coupling of near-infrared radiation to photonic band structure waveguides

    Publication Year: 1999 , Page(s): 2050 - 2057
    Cited by:  Papers (67)  |  Patents (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB)  

    Sharp resonance features are observed in the polarized reflectivity spectra of semiconductor photonic crystals fabricated by deep periodic patterning of AlGaAs surface waveguides. Both one- (1-D) and two-dimensional (2-D) lattices are studied by angular dependent reflectivity. By comparison with theory we show that the sharp features in reflectivity arise from resonant coupling of the external radiation to the folded band structure of the photonic crystal waveguides. Wavevector selective coupling to “heavy photon” states at the edge of the photonic Brillouin zone is demonstrated for the 1-D lattices. In the case of the 2-D lattices we observe polarization mixing of the photonic hands. Theoretical reflectivity spectra were obtained from a numerical solution of Maxwells equations for the patterned waveguide and were found to be in very good agreement with experiment View full abstract»

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  • Synchronous fiber-optic CDMA systems with interference estimators

    Publication Year: 1999 , Page(s): 2268 - 2275
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    Multiple-user interference estimation and cancellation techniques are proposed for synchronous optical code-division multiple-access (CDMA) communication systems. At the receiving end the multiple-user interference is estimated and is used to adapt a threshold level that is placed after an optical correlator. The special properties of the modified prime sequence codes are utilized in the estimation process. Four methods for adapting the threshold are proposed in this paper. The performance of the above system is analyzed and the bit error rates of the four adaptation schemes are compared to each other and to that of the system without cancellation. Our results reveal that the proposed system is very efficient in eliminating the effect of the multiple-user interference. Moreover, it is shown that the error floor which distinguishes the traditional systems is removed under the proposed schemes View full abstract»

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  • Surface-plasmon-enhanced radiation effects in confined photonic systems

    Publication Year: 1999 , Page(s): 2183 - 2190
    Cited by:  Papers (10)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    Combined action of a resonant cavity and metal nanocomposites is shown to result in dramatic enhancement of spontaneous emisson rate in the optical spectral range. The cavity leads to modification of the optical density of states (Parcell effect), whereas the metal nanoparticles lead to giant local-field effects in spontaneous emission occurring because of surface-plasmon-enhanced vacuum field fluctuations. It is also shown that the surface-plasmon resonances may result in a full photonic gap in a metal-dielectric composite, even for a completely random structure of the composite. In our experiments, lasing at extremely low pump intensities, below 1 mW was observed for a novel class of optical materials, microcavities doped with fractal aggregates of metal nanoparticles View full abstract»

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  • Photonic bandgap formation and tunability in certain self-organizing systems

    Publication Year: 1999 , Page(s): 1931 - 1943
    Cited by:  Papers (47)  |  Patents (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    We describe the microfabrication and band structure of large scale three-dimensional (3D) photonic bandgap (PBG) materials based on self-organizing templates. The simplest of these templates is an fcc lattice of close-packed, weakly sintered spheres. Other templates include hcp and hexagonal AB2 self-organizing photonic crystals. These photonic crystals may be converted into PEG materials by partially infiltrating the template with high refractive index semiconductors such as Si, Ge, or GaP and subsequently removing the template. The resulting “inverse opal” structure exhibits both a photonic pseudogap and a complete (3D) PBG in the near visible spectrum, spanning up to 15% of the gap center frequency. The local density of states (LDOS) for photons exhibits considerable variation from point to point in coordinate space and reveals large spectral gaps even in the absence of a PEG in the total density of states. These gaps in the LDOS may lead to novel effects in quantum and nonlinear optics when active atoms or molecules are placed within the PBG material. These effects include anomalous, low threshold nonlinear response, collective atomic switching, and low-threshold all-optical transistor action. When an optically birefringent nematic liquid crystal is infiltrated into the void regions of the “inverse” opal PBG material, the resulting composite material exhibits a completely tunable PBG. In particular, the 3D PBG can be completely opened or closed by applying an electric field which rotates the axis of the nematic molecules relative to the inverse opal backbone View full abstract»

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  • Emission properties of dye-polymer-opal photonic crystals

    Publication Year: 1999 , Page(s): 2121 - 2127
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    The effect of the incomplete photonic bandgap (PEG) provided by the opal template upon the emission properties of the laser dyes (Coumarin G and perylene derivative) dissolved in the solidified polymer has been studied. The bandgap of dye-polymer opal composite is highly anisotropic because of the insufficient refractive index contrast (RIG), moreover, the extent of anisotropy depends on the volume fraction of the polymer. The anisotropic bandgap enforces the corresponding directionality of the emission, but the emission anisotropy is restricted, as compared with the bandgap anisotropy, within the energy range of the Stokes shift between emission and absorption spectra of the dye. The bands of amplified spontaneous emission, which show the same anisotropy as the bandgap, have been observed. Besides, the isotropic amplified spontaneous emission band has been detected at the high intensity excitation, which band was tentatively understood as the result of the weak localization of photons in the gain medium with embedded scatterers View full abstract»

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  • Two-dimensional elastic bandgap crystal to attenuate surface waves

    Publication Year: 1999 , Page(s): 2196 - 2201
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    Experiments on the attenuation of Rayleigh waves in a marble quarry by a periodic array of cylindrical holes, in a honeycomb and in a triangular distribution, are reported. The results are explained in terms of elastic wave crystals (EWC's), and compared to theoretical calculations performed with scalar waves. The scaling property of the underlying theory has led us to explore the possible application of the results obtained to the attenuation of surface waves in seismic movements View full abstract»

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  • Localized surface plasmons in lamellar metallic gratings

    Publication Year: 1999 , Page(s): 2191 - 2195
    Cited by:  Papers (34)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    Surface electromagnetic modes of lamellar metallic gratings made of gold are analyzed both theoretically and experimentally in the 0.21.0 eV spectral range for p-polarized light. For deep enough grooves, we show how waveguide resonances that show no dispersion with parallel momentum appear in the photonic band structure of these surface plasmons. In these resonances the electric field is highly localized inside the grooves and is almost zero in all other regions. We also illustrate the existence of hybrid modes, combination of standing waves with propagating surface plasmon polaritons. Experimental evidence of the excitation of both kind of localized surface plasmons is given for lamellar gratings of period 3.5 μm with grooves 0.5 μm wide and 0.6 μm deep View full abstract»

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  • All-dielectric one-dimensional periodic structures for total omnidirectional reflection and partial spontaneous emission control

    Publication Year: 1999 , Page(s): 2018 - 2024
    Cited by:  Papers (59)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    A remarkable property of one-dimensional (I-D) alldielectric periodic structures has recently been reported, namely, a 1-D structure can totally reflect electromagnetic wave of any polarization at all angles within a prescribed frequency region, Unlike their metallic counterpart, such all-dielectric omnidirectional mirrors are nearly free of loss at optical frequencies. Here we discuss the physics, design criteria and applications of the thin-film all-dielectric omnidirectional mirror. The experimental demonstration of the mirror is presented at optical frequencies View full abstract»

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  • Spontaneous emission of dye molecules, semiconductor nanocrystals, and rare-earth ions in opal-based photonic crystals

    Publication Year: 1999 , Page(s): 2128 - 2137
    Cited by:  Papers (40)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    Photonic crystals based on silica colloidal crystals (artificial opals) exhibit pronounced stopbands for electromagnetic wave propagation and the corresponding modification of the photon density of states in the visible range. These spectrally selective features can be enhanced by impregnating opals with higher refractive materials like, e.g., polymers. Doping of these structures with dye molecules, semiconductor nanoparticles (quantum dots), and rare-earth ions provides a possibility to examine the challenging theoretical predictions of the inhibited spontaneous emission in photonic bandgap (PBG) materials. First experiments are discussed in which pronounced modification of spontaneous emission spectra and noticeable changes in decay kinetics were observed View full abstract»

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  • Optimal phase mask for fiber Bragg grating fabrication

    Publication Year: 1999 , Page(s): 2366 - 2370
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    We show by rigorous coupled-wave analysis and experimental measurements the optimal values of phase retardation and duty cycle of the phase mask to minimize zero and even diffracted orders. The values are more precise than those usually used according to the scalar theory of diffraction. Under an oblique incidence, we optimize the phase mask with three parameters: phase retardation, duty cycle, and refractive index, which result in a perfect sinusoidal interference field with high diffraction efficiency for writing the fiber Bragg grating (FBG) View full abstract»

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  • Asymptotic methods for thin high-contrast two-dimensional PBG materials

    Publication Year: 1999 , Page(s): 1996 - 2007
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    This paper surveys recent analytic and numerical results on asymptotic models of spectra of electromagnetic (EM) waves in two-dimensional (2D) thin high-contrast photonic bandgap (PBG) materials. These models lead to discovery of interesting phenomena, including extremely narrow bands that can be used for spontaneous emission enhancement, gaps in the long wave regions, and asymptotic periodicity of the spectrum. The asymptotic results provide unexpectedly good qualitative (and sometimes quantitative) description of spectral behavior for materials of finite contrast. In some cases, simple ordinary differential models can be derived that yield a good approximation of the spectra. In such situations, one can obtain approximate analytic formulas for the dispersion relations View full abstract»

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  • Spontaneous emission extraction and Purcell enhancement from thin-film 2-D photonic crystals

    Publication Year: 1999 , Page(s): 2096 - 2112
    Cited by:  Papers (101)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    Electromagnetic band structure can produce either an enhancement or a suppression of spontaneous emission from two-dimensional (2-D) photonic crystal thin films. We believe that such effects might be important for light emitting diodes. Our experiments were based on thin-film InGaAs-InP 2-D photonic crystals at ambient temperature, but the concepts would apply equally to InGaN thin films, for example. We show that the magnitude of Purcell enhancement factor, Fp~2, for spatially extended band modes, is similar to that for a tiny mode in a three dimensional (3-D) nanocavity. Nonetheless, light extraction enhancement that arises from Zone folding or Bragg scattering of the photonic bands is probably the more important effect, and an external quantum efficiency >50% is possible. Angle resolved photoluminescence from inside the photonic crystal gives a direct spectral readout of the internal 2-D photonic band dispersion. The tradeoffs for employing various photonic crystal structures in high efficiency light-emitting diodes are analyzed View full abstract»

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  • Basic design for highly stable mechanical optical fiber splice and its development

    Publication Year: 1999 , Page(s): 2297 - 2306
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    In mechanical splice technology, one of the basic problems is the slippage between fibers and fiber-holding substrates. We analyzed the relationship between the dimensions and material constants of a splice in a fiber butt-joint region and the force distributions along fibers, when external tensile forces or thermal stress acted on the fiber joint region. We evaluated factors relating to the slippage and these effects quantitatively. We then designed the joint region largely based on this analysis. We confirmed the joint characteristics using a temperature cycling test in accordance with the relevant Telcordia Technologies (formerly Bellcore) test specification and microscope observations of the damage to the fiber ends after the test. We achieved a highly stable mechanical splice for single fibers and four-fiber ribbons with an insertion loss change of less than ±0.1 dB during the test and with no damage to the fiber ends View full abstract»

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  • Effects of the zeroth-order diffraction of a phase mask on Bragg gratings

    Publication Year: 1999 , Page(s): 2361 - 2365
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    The effects of the zeroth-order diffraction of a phase mask on the creation of Bragg gratings using the mask technique were theoretically and experimentally investigated. Experimental results showed that the zeroth-order diffraction of 1% total power, while in interference with the first-order diffraction of 44% each, dramatically affected the structure of the gratings in a polymer optical preform, including their period. Theoretical analysis by taking the zeroth-order diffraction into account predicted that a very small part of the zeroth-order component (0.1%) would have substantial effects on the gratings, which will be no longer uniform along both the directions of the incident laser beam propagation and the groove array. Theoretical calculation agrees well with the experimental results View full abstract»

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  • Characterization of fiber Bragg gratings by use of optical coherence-domain reflectometry

    Publication Year: 1999 , Page(s): 2371 - 2378
    Cited by:  Papers (9)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    A method based on optical low coherence reflectometry for complete characterization of fiber Bragg gratings (FBG's) is presented. It is shown that the measured signal corresponds to the impulse response of the grating filter, and the measurement therefore yields all information about the device. Experiments have been carried out with a novel dual channel interferometer. The results are in excellent agreement with the theory, demonstrating the versatility of the method for characterization of fiber gratings View full abstract»

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  • One-dimensional photonic bandgap microcavities for strong optical confinement in GaAs and GaAs/AlxOy semiconductor waveguides

    Publication Year: 1999 , Page(s): 2152 - 2160
    Cited by:  Papers (28)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    Photonic bandgap (PBG) waveguide microcavities with tightly confined resonant optical modes have been designed, fabricated using high-dielectric-contrast GaAs/AlxOy III-V compound semiconductor structures, and characterized optically. The photonic crystal lattices are defined by one-dimensional (1-D) arrays of holes in waveguides, and a controlled defect in the spacing between two holes of an array defines a microcavity. Waveguide microcavity resonances have been studied in both monorail and suspended air-bridge geometries. Resonance states with cavity Q's as high as 360 were measured at wavelengths near 1.55 μm, with modal volumes as small as 0.026 μm, which corresponds to only two times (λ/2n)3 View full abstract»

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Aims & Scope

The Journal of Lightwave Technology contains articles on current research, applications and methods used in lightwave technology and fiber optics.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Peter J. Winzer
Alcatel-Lucent Bell Labs