Showing papers on "Photonic-crystal fiber published in 1999"
TL;DR: The confinement of light within a hollow core (a large air hole) in a silica-air photonic crystal fiber is demonstrated and certain wavelength bands are confined and guided down the fiber.
Abstract: The confinement of light within a hollow core (a large air hole) in a silica-air photonic crystal fiber is demonstrated Only certain wavelength bands are confined and guided down the fiber, each band corresponding to the presence of a full two-dimensional band gap in the photonic crystal cladding Single-mode vacuum waveguides have a multitude of potential applications from ultrahigh-power transmission to the guiding of cold atoms
1,935 citations
Book•
15 Mar 1999
TL;DR: The history of Erbium-doped fiber amplifiers can be found in this article, where the authors present a survey of the development of fiber-based Amplifiers in FIBER networks.
Abstract: INTRODUCTION 1.1 Long Haul Fiber Networks 1.2 Historical Development of Erbium-Doped Fiber Amplifiers 1.3 From Glass to Systems 2 OPTICAL FIBER FABRICATION 2.1 Introduction 2.2 Conventional Communication Fiber 2.3 Rare Earth Doped Fibers 2.4 Pump-Signal Interaction Methods 2.5 Compositions 2.6 Physical Properties 3 COMPONENTS AND INTEGRATION 3.1 Introduction 3.2 Fiber Connectors 3.3 Fusion Splicing 3.4 Pump and Signal Combiners 3.5 Isolators 3.6 Circulators 3.7 Filters 3.8 Fiber Gratings 3.9 Signal Multiplexers and Demultiplexers 3.10 Signal Add/Drop Components 3.11 Dispersion Compensation Components 3.12 Integrated Components 3.13 Pump Lasers 4 RARE EARTH IONS--INTRODUCTORY SURVEY 4.1 Introduction 4.2 Atomic Physics of the Rare Earths 4.3 Optical Spectra of Rare Earth Ions 4.4 Fundamental Properties 4.5 Spectroscopy of the Er3 Ion 4.6 Er3 -Er3 Interaction Effects 5 ERBIUM-DOPED FIBER AMPLIFIERS--AMPLIFIER BASICS 5.1 Introduction 5.2 Amplification in Three-Level Systems 5.3 Reduction of the Three-Level System to the Two-Level System 5.4 Amplified Spontaneous Emission 5.5 Analytical Solutions to the Two-Level System 6 ERBIUM-DOPED FIBER AMPLIFIERS--MODELING AND COMPLEX EFFECTS 6.1 Introduction 6.2 Absorption and Emission Cross Sections 6.3 Gain and ASE Modeling 6.4 Amplifier Simulations 6.5 Transverse Mode Models--Erbium Confinement Effect 6.6 Excited State Absorption Effects 6.7 Er3 -Er3 Interaction Effects 7 OPTICAL AMPLIFIERS IN FIBER OPTIC COMMUNICATION SYSTEMS--THEORY 7.1 Introduction 7.2 Optical Noise: Device Aspects 7.3 Optical Noise: System Aspects 8 AMPLIFIER CHARACTERIZATION AND DESIGN ISSUES 8.1 Introduction 8.2 Basic Amplifier Measurement Techniques 8.3 Amplifier Design Issues 9 SYSTEM IMPLEMENTATIONS OF AMPLIFIERS 9.1 Introduction 9.2 System Demonstrations and Issues 9.3 Soliton Systems 10 FOUR LEVEL FIBER AMPLIFIERS FOR 13 MM AMPLIFICATION 10.1 Introduction 10.2 Pr3 -doped Fiber Amplifiers 10.3 Nd3 -doped Fiber Amplifiers Appendix Subject Index
726 citations
TL;DR: In this paper, a novel type of optical waveguide, operating truly by the photonic bandgap effect, has been demonstrated, which has an improved photonic crystal cladding and a central low-index structural defect along which light is guided.
587 citations
TL;DR: The fiber gratings that were fabricated by this technique have a high resistance to thermal decay and the values of the loss peak wavelength and the transmittance after heat treatment below 500 degrees C are the same as initial values before heat treatment.
Abstract: We have fabricated long-period fiber gratings by use of a novel technique using focused irradiation of infrared femtosecond laser pulses. We investigate the thermal stability of the fabricated fiber gratings. The values of the loss peak wavelength and the transmittance of the fiber gratings after heat treatment below 500°C are the same as initial values before heat treatment. The fiber gratings that were fabricated by this technique have a high resistance to thermal decay. We propose that this technique mill be useful for fabrication of fiber gratings with a superior aging characteristic.
439 citations
TL;DR: The properties of photonic crystal fibers with large air holes can be modeled by a silica rod in air as mentioned in this paper, and it has been shown that the dispersion of such fibers could exceed -2000 ps/mm/km, or they could compensate (to within /spl plusmn/0.2%) the length of standard fiber over a 100nm range.
Abstract: The properties of photonic crystal fibers with large air holes can be modeled by a silica rod in air. Such approximate calculations show that the dispersion of photonic crystal fibers could exceed -2000 ps/mm/km, or they could compensate (to within /spl plusmn/0.2%) the dispersion of 35 times their length of standard fiber over a 100-nm range.
337 citations
TL;DR: The small effective area that is possible in this type of fiber significantly enhances its effective nonlinearity relative to standard fiber.
Abstract: Holey fibers combine two-dimensional microstructuring with one-dimensional longitudinal propagation, resulting in fibers with tailorable dispersive and nonlinear properties. We measure the effective nonlinearity of a typical holey fiber. The small effective area that is possible in this type of fiber significantly enhances its effective nonlinearity relative to standard fiber.
319 citations
TL;DR: A simple pigtailing method for microspheres permits their wider use in fiber optics and photonics devices and in the experimental setup, the total fiber-to-fiber transmission at resonance reached 23%.
Abstract: We demonstrate a simple method for efficient coupling of standard single-mode optical fibers to a high- Q optical microsphere cavity. Phase-matched excitation of whispering-gallery modes is provided by an angle-polished fiber tip in which the core-guided wave undergoes total internal reflection. In the experimental setup, which included a microsphere with both an input and an output coupler, the total fiber-to-fiber transmission at resonance reached 23% (total insertion loss, 6.3 dB), with loaded quality factor Q> or =3 x 10(7) and unloaded Q approximately 1.2 x 10(8) at 1550 nm. A simple pigtailing method for microspheres permits their wider use in fiber optics and photonics devices.
303 citations
TL;DR: In this article, a Bragg grating in a single-mode polymer optical fiber (POF) has been created, which has a length of 1 cm with a reflectivity of 80% and a linewidth of about 0.5 nm.
Abstract: A Bragg grating in a single-mode polymer optical fiber (POF) has been created. The novel grating has a length of 1 cm with a reflectivity of 80% and a linewidth of about 0.5 nm. The wavelength tunability of the POF grating by stretching was investigated and a wavelength tunable range of 20 nm has been achieved. Based on the properties of the polymer, we believe that this kind of grating has a wavelength tuning potential of more than 100 nm.
303 citations
TL;DR: It is shown that the spatial distribution and the effective index of these modes are determined largely by the design of the lattice and that the grating spectra are unaffected by the refractive index surrounding the fiber.
Abstract: We report what is believed to be the first demonstration of optical fiber gratings written in photonic crystal fibers. The fiber consists of a germanium-doped photosensitive core surrounded by a hexagonal periodic air-hole lattice in a silica matrix. The spectra of these gratings allow for a detailed characterization of the fiber. In particular, the gratings facilitate coupling to higher-order leaky modes. We show that the spatial distribution and the effective index of these modes are determined largely by the design of the lattice and that the grating spectra are unaffected by the refractive index surrounding the fiber. We describe these measurements and corresponding simulations and discuss their implications for the understanding of such air-hole structures.
261 citations
TL;DR: In this paper, a new type of optical hydrogen sensor with a fiber optic Bragg grating (FBG) coated with palladium thin film is reported, which is based on mechanical stress induced in the palladium coating when it absorbs hydrogen.
Abstract: We report a new type of optical hydrogen sensor with a fiber optic Bragg grating (FBG) coated with palladium thin film. The sensing mechanism in this device is based on mechanical stress that is induced in the palladium coating when it absorbs hydrogen. The stress in the palladium coating stretches and shifts the Bragg wavelength of the FBG. Using FBGs with different wavelengths many such hydrogen sensors can be multiplexed on a single optical fiber. Here multiplexing two sensors is demonstrated. Moreover, hydrogen and thermal sensitivities of the sensors were calculated using a simple elastic model. Additionally, to quantify the amount of stress in the palladium film as a function of hydrogen concentration, a novel and very sensitive method was devised and used to detect deflections in a Pd-coated cantilever using an evanescent microwave probe. This stress was in the range of 5.26–8.59×10−7 Pa for H2 concentrations of 0.5–1.4% at room temperature, which is about three times larger than that found in the bulk palladium for the same range of H2 concentrations.
253 citations
TL;DR: This work analyzes the guiding problem in a realistic photonic crystal fiber, using a novel full-vector modal technique based on the non-self-adjoint character of the electromagnetic propagation in a fiber, which matches those achieved in recent experiments.
Abstract: We analyze the guiding problem in a realistic photonic crystal fiber, using a novel full-vector modal technique. This is a biorthogonal modal method based on the non-self-adjoint character of the electromagnetic propagation in a fiber. Dispersion curves of guided modes for different fiber structural paremeters are calculated, along with the two-dimensional transverse intensity distribution of the fundamental mode. Our results match those achieved in recent experiments in which the feasibility of this type of fiber was shown.
TL;DR: In this article, a novel fiber optic hydrogen sensor was constructed by depositing palladium over an exposed core region of a multimode fiber, which is based on evanescent field interaction with the palladium coating.
Abstract: A novel fiber optic hydrogen sensor which is constructed by depositing palladium over an exposed core region of a multimode fiber is reported. The sensing mechanism is based on evanescent field interaction with the palladium coating. Since the length, thickness, and composition of the palladium patch can be controlled independently of each other, it is possible to increase the speed of our sensor at lower temperatures while maintaining its sensitivity. In micromirror sensors such an optimization is not possible due to a restriction imposed on their active area of interaction by the fiber optic cross-section. Micromirror fiber optic sensors, studied in the past, take advantage of the reflection/absorption of a palladium film deposited at the end of a fiber resulting in one sensor per fiber optic strand. On the other hand, many evanescent field-based sensors can be deposited over a single fiber optic strand. Using a 100 A thick palladium with 1.5 cm interaction length, we could detect hydrogen in the 0.2–0.6% range with corresponding response times of 30–20 s at room temperature. At −10°C, these response times increased by a factor of only 2.
TL;DR: This work reports the fabrication of long lengths of mechanically robust holey fiber and what is believed to be the first demonstration of their splicing and compares dispersion measurements with numerical predictions and confirms that the model can be used to predict accurately holey Fiber properties.
Abstract: We report the fabrication of long lengths of mechanically robust holey fiber and what is believed to be the first demonstration of their splicing. These practical advances have permitted what is to our knowledge the first detailed characterization of a holey fiber near 1.5mum . We compare dispersion measurements with our numerical predictions and confirm that our model can be used to predict accurately holey fiber properties.
TL;DR: A new type of high-performance long-period fiber grating based on arc-induced periodic microbends that makes it possible to produce arbitrary filter profiles by use of a simple apodization technique, which is difficult to do with conventional long- period gratings.
Abstract: We demonstrate a new type of high-performance long-period fiber grating based on arc-induced periodic microbends. The fabrication method is simple and does not require special fibers. Flexibility in controlling the filter parameters makes it possible to produce arbitrary filter profiles by use of a simple apodization technique, which is difficult to do with conventional long-period gratings.
TL;DR: In this paper, a fiber optic surface plasmon resonance (SPR) sensor utilizing the resonant interaction between a guided mode of a singlemode optical fiber and a surface plasma wave supported by a thin metal film is described.
Abstract: A fiber optic surface plasmon resonance (SPR) sensor utilizing the resonant interaction between a guided mode of a single-mode optical fiber and a surface plasma wave supported by a thin metal film is described. Theoretical analysis of the SPR sensing structure based on the equivalent planar waveguide approach and the mode expansion and propagation method is presented. A detailed analysis of the effect of the major parameters of the SPR sensing structure on the sensor performance is carried out. Experimental results obtained with fabricated laboratory prototypes of the SPR sensing device for measurement of the refractive index of analyte are reported. It has been demonstrated that the fiber optic SPR sensing device may be used as a spectral as well as an amplitude sensor.
Patent•
30 Nov 1999TL;DR: In this article, an optical waveguide fiber preform is described, which is an assembly of one or more core rods (14) surrounded by a plurality of clad rods (10), in which the clad rods have a central portion (12) and a surrounding layer (22), and the refractive index of the central portion is lower than that of the surrounding layer.
Abstract: Disclosed is an optical waveguide fiber preform which is an assembly of one or more core rods (14) surrounded by a plurality of clad rods (10). The clad rods (10) have a central portion (12) and a surrounding layer (22), in which the refractive index of the central portion is lower than that of the surrounding layer. The preform is drawn into an optical waveguide fiber that has a two component clad layer. Proper choice of the central portion (12) and surrounding layer provide a waveguide fiber that is endlessly single mode. Alternative embodiments include fibers containing dopants that enhance fiber photosensitivity or which provide stress-induced or asymmetric-refractive-index-induced birefringence in the waveguide fiber.
TL;DR: In this paper, a very compact wavelength converter module has been demonstrated by using the fiber, and highly nonlinear dispersion-shifted fibers have been developed, and Dispersion-flattened and dispersiondecreasing fibers have also been proved to be highly effective for supercontinuum generation.
Abstract: Silica-based optical fibers are now being used in various applications which utilize nonlinear effects in fiber. In addition to enhancing nonlinearity of optical fibers, tailoring chromatic dispersion is one of the important design issues in such applications. Highly nonlinear dispersion-shifted fibers have been developed, and a very compact wavelength converter module has been demonstrated by using the fiber. Dispersion-flattened and dispersion-decreasing fibers have also been proved to be highly effective for supercontinuum generation.
TL;DR: A fiber Bragg grating sensor with controllable sensitivity is demonstrated by connecting two metal strips that have different temperature-expansion coefficients by changing the lengths of the metal strips.
Abstract: We demonstrate a fiber Bragg grating (FBG) sensor with controllable sensitivity by connecting two metal strips that have different temperature-expansion coefficients. By changing the lengths of the metal strips we successfully controlled and improved the temperature sensitivity to 3.3 times of that of bare FBG.
21 May 1999
TL;DR: In this article, a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect, is presented.
Abstract: The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibres, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures, which are easy to manufacture. Finally, the present invention relates to a new fabrication technique, which allows easy manufacturing of preforms for photonic crystal fibers with large void filling fractions, as well as it allows a high flexibility in the design of the cladding and core structures.
Patent•
16 Nov 1999
TL;DR: A fiber optic illumination system includes a light source, a waveguide, and an optical fiber as discussed by the authors, which conveys light from the light source to the optical fiber by transmission and/or internal reflection.
Abstract: A fiber optic illumination system includes a light source, a waveguide, and an optical fiber. One or more lamps and/or solid-state devices may be employed as the light source. The waveguide includes a straight collecting segment, a tapered condensing segment, and a straight homogenizing segment, may be fabricated from fused silica as a single monolithic component, conveys light from the light source to the optical fiber by transmission and/or internal reflection, and may be provided with UV and/or IR blocking filter coating(s). The optical fiber may be colorless or fluorescent optical fiber. Light transmitted by the optical fiber may be delivered to any one or more of a variety of light output devices, including diffusive flat panels, diffusive rods or wands, fluorescent light emitting converters, projectors, spectrum generators, and so on.
TL;DR: A theoretical investigation of a novel type of optical fiber that relies entirely on wave guidance through the photonic bandgap effect and not on total internal reflection, thereby distinguishing that fiber from all other known fibers, including recently studied photonic crystal fibers.
Abstract: A theoretical investigation of a novel type of optical fiber is presented. The operation of the fiber relies entirely on wave guidance through the photonic bandgap effect and not on total internal reflection, thereby distinguishing that fiber from all other known fibers, including recently studied photonic crystal fibers. The novel fiber has a central low-index core region and a cladding consisting of a silica background material with air holes situated within a honeycomb lattice structure. We show the existence of photonic bandgaps for the silica-air cladding structure and demonstrate how light can be guided at the central low-index core region for a well-defined frequency that falls inside the photonic bandgap region of the cladding structure.
TL;DR: In this article, a dye-doped polymer optical fiber has two identical cores each doped with fluorescein, and the pump beam is launched axially into one of the cores.
TL;DR: In this article, the authors proposed a novel design for a compact dispersion slope compensator based on sampled fiber Bragg gratings, which can be controlled by chirping the sample function in a sampled grating to match that of current transmission fibers.
Abstract: We propose a novel design for a compact dispersion slope compensator based on sampled fiber Bragg gratings. By chirping the sample function in a sampled grating, we show that the dispersion slope can be controlled to match that of current transmission fibers. Interleaving several sampled gratings provides an effective technique to reduce UV-induced refractive index requirements to readily achievable levels.
Patent•
JDSU1
TL;DR: In this article, the power distribution uniformity of a multimode fiber bundled region taper converges down to a minimum waist having a diameter, where the input light from the multimode input fibers substantially fills the entire numerical aperture (NA) of an air-cladding region of the couple.
Abstract: Optical couplers (48) functioning, for example, as fiber optic combiners or fiber optic splitters for multimode fibers are disclosed for coupling, for example, the light output of a plurality of multimode laser (44) sources into a multimode output fiber or fibers (30). Coupling combinations include multimode fibers to multimode fiber or fibers (MMFs/MMF(s)) or multimode fibers/single mode fiber to double clad fiber (MMFs/SMF/DCF). Improvements are disclosed in coupling efficiency and the power distribution uniformity of optical power into an output fiber, such as double clad fiber (20) inner cladding or multimode fiber core, from multiple multimode input fibers (30). Power distribution uniformity can be significantly improved by having the multimode fiber bundled region taper converging down to a minimum waist having a diameter, D0 (43), where the input light from the multimode input fibers (30) substantially fills the entire numerical aperture (NA) of an air-clad region of the couple, where NA ≈ 1, followed by an adiabatic diverging taper up to the nominal cladding or core diameter, Doutput (33), of the output fiber (20) or combined fibers.
TL;DR: A novel sensor by using a single-fiber Bragg grating that can simultaneously measure strain and temperature with the aid of an erbium-doped fiber amplifier is proposed and demonstrated.
Abstract: We propose and demonstrate a novel sensor by using a single-fiber Bragg grating that can simultaneously measure strain and temperature with the aid of an erbium-doped fiber amplifier. By using a linear variation in the amplified spontaneous emission power of the erbium-doped fiber amplifier with temperature, we determine the temperature. By subtracting the temperature effect from the fiber Bragg grating Bragg wavelength shift, we determine the strain. Experiments show rms deviations of 18.2 µe and 0.7 °C for strain and temperature, respectively.
TL;DR: One half of a 2x2 fused taper single-mode fiber coupler is used for the all-fiber spatial and spectral beam combining of two fiber lasers.
Abstract: One half of a 2×2 fused taper single-mode fiber coupler is used for the all-fiber spatial and spectral beam combining of two fiber lasers.
TL;DR: In this paper, the power density in the vicinity of a tapered fiber is calculated, with the vectorial model of step-index circular waveguides, for the fundamental HE11 mode carrying a power of 1 Watt, and it is possible to obtain theoretical densities in the range of 108 W/cm2 at the fiber surface.
Abstract: The power density in the vicinity of a tapered fiber is calculated, with the vectorial model of step-index circular waveguides. For the fundamental HE11 mode carrying a power of 1 Watt, we show that it is possible to obtain theoretical densities in the range of 108 W/cm2 at the fiber surface. The promising use of such intense evanescent fields as “atomic mirrors” is considered, and the feasibility of these guides is investigated.
TL;DR: Theoretical and experimental aspects of the nanometer-scale Fabry-Perot cavity are described, and both theoretical and experimental results show good agreement.
Abstract: The ionic self-assembly monolayer process is a novel technique that has already been used to deposit ultrathin films on glass, polymer, and silicon substrates of different sizes and shapes. This technique is presented as a new tool with which to apply coatings on optical fibers. A nanometer-scale interferometric cavity was built up at the end of an optical fiber with discrete thickness increments of 4.75??nm for a total thickness of 1 ?m. Theoretical and experimental aspects of the nanometer-scale Fabry–Perot cavity are described, and both theoretical and experimental results show good agreement.
Patent•
02 Aug 1999
TL;DR: In this paper, an optical amplifier system includes a fiber amplifier doped with rare earth dopant provided in its fiber core, and a reflector is provided in each of the coupling fibers for reflecting a portion of the respective light outputs back into the fiber lasers to control their wavelength of operation.
Abstract: An optical amplifier system includes a fiber amplifier doped with rare earth dopant provided in its fiber core. A plurality of fiber lasers have their light outputs optically coupled together for launching into the fiber amplifier for optically pumping the amplifier. Each of the fiber lasers have a rare earth dopant provided in its fiber core for stimulated lasing emission with the rare earth dopant of the fiber amplifier being different from the rear earth dopant of the fiber lasers. A reflector may be provided in each of the coupling fibers for reflecting a portion of the respective light outputs back into the fiber lasers to control their wavelength of operation, the wavelength of operation of the reflectors chosen to be within a high absorption region of the absorption band of the fiber amplifier. Where the pump source is a semiconductor laser source, the source may include a flared gain section to increase the output intensity of the light output of the source.
TL;DR: In this article, fiber Bragg gratings (FBGs) written in a 10 mol.% Ge-doped core silica fiber using a phase mask were exposed to /spl gamma/radiation.
Abstract: Fiber Bragg gratings (FBGs) written in a 10 mol.% Ge-doped core silica fiber using a phase mask were exposed to /spl gamma/-radiation. The transmission and reflection spectra were recorded during irradiation up to doses in excess of 1 MGy. There was no detectable change of the Bragg peak amplitude and the grating temperature sensitivity. The radiation-induced shift of the Bragg wavelength saturated at a dose of 0.1 MGy at a level less than 25 pm, which could still be decreased by optimization of the grating parameters. Our results confirm that FBGs are good candidates for sensing applications in radiation environments.