Showing papers on "Optical fiber published in 2003"
TL;DR: In this article, a periodic array of microscopic air holes that run along the entire fiber length are used to guide light by corralling it within a periodic arrays of microscopic holes.
Abstract: Photonic crystal fibers guide light by corralling it within a periodic array of microscopic air holes that run along the entire fiber length Largely through their ability to overcome the limitations of conventional fiber optics—for example, by permitting low-loss guidance of light in a hollow core—these fibers are proving to have a multitude of important technological and scientific applications spanning many disciplines The result has been a renaissance of interest in optical fibers and their uses
3,918 citations
Journal Article•
TL;DR: Optical microcavities confine light to small volumes by resonant recirculation as discussed by the authors, and are indispensable for a wide range of applications and studies, such as long-distance transmission of data over optical fibres; they also ensure narrow spot-size laser read/write beams in CD and DVD players.
Abstract: Optical microcavities confine light to small volumes by resonant recirculation. Devices trased on optical microcavities are already indispensable for a wide range of applications and studies, For example, microcavities made of active III-V semiconductor materials control laser emission spectra to enable long-distance transmission of data over optical fibres; they also ensure narrow spot-size laser read/write beams in CD and DVD players. In quantum optical devices, mocrocavities can coax atoms or quantum dots to emit spontaneous photons In a desired direction or can provide an environment where dissipative mechanhms such as spontaneous emission are overcome so that quantum entanglement of radiation and matter is possible. Applications of these remarkable devices are as diverse as their geometrical and resonant properties.
1,855 citations
TL;DR: Among the various fiber-optic sensor technologies, especially, technologies such as fiber grating sensors, fiber- Optic gyroscopes, and fiber-Optic current sensors are discussed with emphasis on the principles and current status.
1,610 citations
TL;DR: In this paper, the temperature dependence of the fluorescence intensity ratio has been studied using thermally coupled energy levels in seven different rare earth ions doped into a variety of glasses and crystals.
Abstract: The fluorescence intensity ratio technique for optical fiber-based point temperature sensing is reviewed, including the materials suitable for this technique. The temperature dependence of the fluorescence intensity ratio has been studied using thermally coupled energy levels in seven different rare earth ions doped into a variety of glasses and crystals. Sensor prototypes developed using Pr3+:ZBLANP, Nd3+-doped silica fiber and Yb3+-doped silica fiber as the sensing material have been used to measure temperatures covering the range of approximately −50 to 600 °C with a resolution of the order of 1 °C.
1,033 citations
TL;DR: It is shown that the micrometer-long silicon-on-insulator-based nanotaper coupler is able to efficiently convert both the mode field profile and the effective index, with a total length as short as 40 microm, during compact mode conversion between a fiber and a submicrometer waveguide.
Abstract: We propose and demonstrate an efficient coupler for compact mode conversion between a fiber and a submicrometer waveguide. The coupler is composed of high-index-contrast materials and is based on a short taper with a nanometer-sized tip. We show that the micrometer-long silicon-on-insulator-based nanotaper coupler is able to efficiently convert both the mode field profile and the effective index, with a total length as short as 40 microm. We measure an enhancement of the coupling efficiency between an optical fiber and a waveguide by 1 order of magnitude due to the coupler.
994 citations
TL;DR: The results demonstrate a unique capability to deliver high-power pulses in a single spatial mode over distances exceeding 200 meters, and represent an increase in the power that can be propagated in an optical fiber of two orders of magnitude.
Abstract: The measured dispersion of a low-loss, hollow-core photonic band-gap fiber is anomalous throughout most of the transmission band, and its variation with wavelength is large compared with that of a conventional step-index fiber. For an air-filled fiber, femtosecond self-frequency--shifted fundamental solitons with peak powers greater than 2megawatts can be supported. For Xe-filled fibers, nonfrequency-shifted temporal solitons with peak powers greater than 5.5 megawatts can be generated, representing an increase in the power that can be propagated in an optical fiber of two orders of magnitude. The results demonstrate a unique capability to deliver high-power pulses in a single spatial mode over distances exceeding 200 meters.
509 citations
23 Mar 2003
TL;DR: In this article, the fundamental properties of gain from stimulated Raman scattering are discussed, and the merits of distributing Raman gain along a transmission fiber are explained, and other sources of noise that are particularly relevant for Raman amplifiers are summarized.
Abstract: Raman amplification has enabled dramatic increases in the reach and capacity of lightwave systems. This tutorial explains why, starting with the fundamental properties of gain from stimulated Raman scattering. Next, noise accumulation from amplified spontaneous emission is reviewed, and the merits of distributing Raman gain along a transmission fiber are explained. Other sources of noise that are particularly relevant for Raman amplifiers are summarized. Finally, novel Raman pumping schemes that have recently been developed are highlighted.
504 citations
TL;DR: The fabrication and characterization of long lengths of low attenuation photonic bandgap fibre are reported here, and Coupling between surface and core modes of the structure is identified as an important contributor to transmission loss in hollow-core photonicBandgap fibres.
Abstract: Photonic bandgap structures use the principle of interference to reflect radiation. Reflection from photonic bandgap structures has been demonstrated in one, two and three dimensions and various applications have been proposed1,2,3,4. Early work in hollow-core photonic bandgap fibre technology5 used a hexagonal structure surrounding the air core; this fibre was the first demonstration of light guided inside an air core of a photonic bandgap fibre. The potential benefits of guiding light in air derive from lower Rayleigh scattering, lower nonlinearity and lower transmission loss compared to conventional waveguides. In addition, these fibres offer a new platform for studying nonlinear optics in gases6. Owing largely to challenges in fabrication, the early air-core fibres were only available in short lengths, and so systematic studies of loss were not possible. More recently, longer lengths of fibre have become available7,8 with reported losses of 1,000 dB km-1. We report here the fabrication and characterization of long lengths of low attenuation photonic bandgap fibre. Attenuation of less than 30 dB km-1 over a wide transmission window is observed with minimum loss of 13 dB km-1 at 1,500 nm, measured on 100 m of fibre. Coupling between surface and core modes of the structure is identified as an important contributor to transmission loss in hollow-core photonic bandgap fibres.
475 citations
TL;DR: This work reviews the use of fiber optic probes for optical spectroscopy, focusing on applications in turbid media, such as tissue, and covers universal design principles as well as technologies for beam deflecting and reshaping.
Abstract: Fiber optic probes are a key element for biomedical spectroscopic sensing. We review the use of fiber optic probes for optical spectroscopy, focusing on applications in turbid media, such as tissue. The design of probes for reflectance, polarized reflectance, fluorescence, and Raman spectroscopy is illustrated. We cover universal design principles as well as technologies for beam deflecting and reshaping.
464 citations
TL;DR: The cancellation of the soliton self-frequency shift in a silica-core photonic crystal fiber with a negative dispersion slope is reported and may find applications in the development of a family of optical parametric amplifiers.
Abstract: We report the cancellation of the soliton self-frequency shift in a silica-core photonic crystal fiber with a negative dispersion slope. Numerical and experimental results show that stabilization of the soliton wavelength is accompanied by exponential amplification of the red-shifted Cherenkov radiation emitted by the soliton. The spectral recoil from the radiation acts on the soliton to compensate for the Raman frequency shift. This phenomenon may find applications in the development of a family of optical parametric amplifiers.
450 citations
TL;DR: In this paper, a multipole method for calculating the modes of microstructured optical fibers is described, which uses a multi-hole expansion centered on each hole to enforce boundary conditions accurately and matches expansions with different origins by use of addition theorems.
Abstract: We describe a multipole method for calculating the modes of microstructured optical fibers. The method uses a multipole expansion centered on each hole to enforce boundary conditions accurately and matches expansions with different origins by use of addition theorems. We also validate the method and give representative results.
TL;DR: In this article, a two-dimensional grating etched in a silicon-on-insulator waveguide was used to couple orthogonal modes from a singlemode optical fiber into identical modes of two planar ridge waveguides.
Abstract: We demonstrate a novel polarization splitter based on a two-dimensional grating etched in a silicon-on-insulator waveguide. The device couples orthogonal modes from a single-mode optical fiber into identical modes of two planar ridge waveguides. The extinction ratio is better than 18 dB in the wavelength range of 1530-1560 nm and the coupling efficiency is approximately 20%. The device is very compact and couples light only to transverse-electric modes of the planar waveguides. Therefore, it may be used in a polarization diversity configuration to implement a polarization insensitive photonic integrated circuit based on photonic crystal waveguides.
17 Nov 2003
TL;DR: In this paper, a review of the different types and applications of photonic crystal fibers with particular emphasis on recent advances in the field is presented, with a focus on the photonic bandgap effect.
Abstract: Photonic crystal fibers having a complex microstructure in the transverse plane constitute a new and promising class of optical fibers. Such fibers can either guide light through total internal reflection or the photonic bandgap effect, In this paper, we review the different types and applications of photonic crystal fibers with particular emphasis on recent advances in the field.
TL;DR: Broadband noise on supercontinuum spectra generated in microstructure fiber is shown to lead to amplitude fluctuations as large as 50% for certain input laser pulse parameters, finding good quantitative agreement over a range of input-pulse energies and chirp values.
Abstract: Broadband noise on supercontinuum spectra generated in microstructure fiber is shown to lead to amplitude fluctuations as large as 50% for certain input laser pulse parameters. We study this noise using both experimental measurements and numerical simulations with a generalized stochastic nonlinear Schrodinger equation, finding good quantitative agreement over a range of input-pulse energies and chirp values. This noise is shown to arise from nonlinear amplification of two quantum noise inputs: the input-pulse shot noise and the spontaneous Raman scattering down the fiber.
TL;DR: No thermo-optical limitations are observed at the extracted /spl sim/35 W/m, therefore such fibers allow scaling to even higher powers, and single transverse mode operation is achieved with a mode-field area of 350 /spl mu/m/sup 2/.
Abstract: We report on a 2.3 m long air-clad ytterbium-doped large-mode-area photonic crystal fiber laser generating up to 80 W output power with a slope efficiency of 78%. Single transverse mode operation is achieved with a mode-field area of 350 µm2. No thermo-optical limitations are observed at the extracted ~35W/m, therefore such fibers allow scaling to even higher powers.
Proceedings Article•
06 Jun 2003TL;DR: In this paper, the authors demonstrate evanescent-wave sensing of Cy5-DNA-molecules in an aqueous solution using a photonic crystal fiber and demonstrate that less than 0.8µL sample volume placed in the holes of the fiber is sufficient for reliable detection.
Abstract: We demonstrate evanescent-wave sensing of Cy5-DNA-molecules in an aqueous solution using a photonic crystal fiber. Less than 0.8µL sample volume placed in the holes of the fiber is sufficient for reliable detection.
TL;DR: An ultrahigh-resolution optical coherence tomographic system in which broadband continuum generation from a photonic crystal fiber is used to produce high longitudinal resolution is developed and subcellular imaging is demonstrated.
Abstract: We have developed an ultrahigh-resolution optical coherence tomographic system in which broadband continuum generation from a photonic crystal fiber is used to produce high longitudinal resolution. Longitudinal resolution of 1.3-microm has been achieved in a biological tissue by use of continuum light from 800 to 1400 nm. The system employed a dynamic-focusing tracking method to maintain high lateral resolution over a large imaging depth. Subcellular imaging is demonstrated.
TL;DR: A novel class of fiber-optic evanescent-wave sensor that is sensitive to the refractive index of the environment near the colloidal gold surface and is suitable for label-free detection of molecular or biomolecular binding at the surface of gold colloids is demonstrated.
Abstract: A novel class of fiber-optic evanescent-wave sensor was constructed on the basis of modification of the unclad portion of an optical fiber with self-assembled gold colloids. The optical properties and, hence, the attenuated total reflection spectrum of self-assembled gold colloids on the optical fiber changes with different refractive index of the environment near the colloidal gold surface. With sucrose solutions of increasing refractive index, the sensor response decreases linearly. The colloidal gold surface was also functionalized with glycine, succinic acid, or biotin to enhance the selectivity of the sensor. Results show that the sensor response decreases linearly with increasing concentration of each analyte. When the colloidal gold surface was functionalized with biotin, the detection limit of the sensor for streptavidin was 9.8 × 10-11 M. Using this approach, we demonstrate proof-of-concept of a class of refractive index sensor that is sensitive to the refractive index of the environment near the...
TL;DR: It is argued that the multimode cutoff occurs at a wavelength lambda* that satisfies VPCF(lambda*) = pi, and by comparing this approach with numerics and recent cutoff calculations, this result is confirmed.
Abstract: We address the long-standing unresolved problem concerning the V parameter in a photonic crystal fiber. In formulating the parameter appropriate for a core defect in a periodic structure, we argue that the multimode cutoff occurs at a wavelength lambda* that satisfies VPCF(lambda*) = pi. By comparing this approach with numerics and recent cutoff calculations we confirm this result.
01 Jul 2003
TL;DR: In this paper, a coherent anti-Stokes Raman scattering (CARS) microscopy was demonstrated using a light source consisting of the output from a photonic crystal fiber pumped by a standard Ti:sapphire oscillator and the fundamental oscillator beam.
Abstract: Coherent anti-Stokes Raman scattering (CARS) microscopy is demonstrated using a light source consisting of the output from a photonic crystal fiber pumped by a standard Ti:sapphire oscillator and the fundamental oscillator beam.
TL;DR: The wavelength dependence and the structural dependence of leakage loss and group velocity dispersion (GVD) in air-core photonic bandgap fibers (PBGFs) are numerically investigated by using a full-vector finite element method.
Abstract: The wavelength dependence and the structural dependence of leakage loss and group velocity dispersion (GVD) in air-core photonic bandgap fibers (PBGFs) are numerically investigated by using a full-vector finite element method. It is shown that at least seventeen rings of arrays of air holes are required in the cladding region to reduce the leakage losses to a level of 0.1 dB/km in 1.55-microm wavelength range even if using large air holes of the diameter to pitch ratio of 0.9 and that the leakage losses in air-core PBGFs decrease drastically with increasing the hole diameter to pitch ratio. Moreover, it is shown that the waveguide GVD and dispersion slope of air-core PBGFs are much larger than those of conventional silica fibers and that the shape of air-core region greatly affects the leakage losses and the dispersion properties.
TL;DR: It is shown from numerical results that it is possible to realize significantly shorter MUX-DEMUX PCFs, compared to conventional optical fiber couplers.
Abstract: Coupling characteristics of dual-core photonic crystal fiber (PCF) couplers are evaluated by using a vector finite element method and their application to a multiplexer-demultiplexer (MUX-DEMUX) based on PCF is investigated. The PCF couplers for 1.48/1.55-m, 1.3/1.55-m, 0.98/1.55-m, and 0.85/1.55-m wavelength MUX-DEMUX are designed and the beam propagation analysis of the proposed PCF couplers is performed. It is shown from numerical results that it is possible to realize significantly shorter MUX-DEMUX PCFs, compared to conventional optical fiber couplers.
15 Nov 2003
TL;DR: An interferometer topology based on 3 x 3 fiber couplers that gives instantaneous access to the magnitude and phase of die interferometric signal is presented and its performance in heterodyne and homodyne detection with a broadband light source is demonstrated.
Abstract: We present an interferometer topology based on 3 x 3 fiber couplers that gives instantaneous access to the magnitude and phase of die interferometric signal. We demonstrate its performance in heterodyne and homodyne detection with a broadband light source.
TL;DR: A new fiber design comprising a hybrid core-region with three-fold symmetry that enables unprecedented dispersion control while maintaining low loss and a high nonlinear coefficient is proposed.
Abstract: Photonic crystal fibers are highly attractive as nonlinear media as they combine a large nonlinear coefficient and a highly customizable zero dispersion wavelength - flexibility not found in any other medium. However, the high dispersion slope at the zero-dispersion wavelength demonstrated so far is very limiting to the useful bandwidth. We propose a new fiber design comprising a hybrid core-region with three-fold symmetry that enables unprecedented dispersion control while maintaining low loss and a high nonlinear coefficient. The lowest dispersion slope obtained is 1·10-3ps/(km·nm2) or one order of magnitude lower than for conventional slope reduced nonlinear fibers. The nonlinear coefficient is more than 11 (W·km)-1 and loss below 7.9 dB/km at 1.55 µm has been achieved.
Patent•
04 Apr 2003TL;DR: In this paper, a system for measuring tissue including a fiber optic probe having a proximal end, a distal end, and a diameter of 2 mm or less is described, which can be used for the diagnosis of coronary artery disease or other small lumens or soft tissue with minimal trauma.
Abstract: The system and method of the present invention relates to using spectroscopy, for example, Raman spectroscopic methods for diagnosis of tissue conditions such as vascular disease or cancer. In accordance with a preferred embodiment of the present invention, a system for measuring tissue includes a fiber optic probe having a proximal end, a distal end, and a diameter of 2 mm or less. This small diameter allows the system to be used for the diagnosis of coronary artery disease or other small lumens or soft tissue with minimal trauma. A delivery optical fiber is included in the probe coupled at the proximal end to a light source. A filter for the delivery fibers is included at the distal end. The system includes a collection optical fiber (or fibers) in the probe that collects Raman scattered radiation from tissue, the collection optical fiber is coupled at the proximal end to a detector. A second filter is disposed at the distal end of the collection fibers. An optical lens system is disposed at the distal end of the probe including a delivery waveguide coupled to the delivery fiber, a collection waveguide coupled to the collection fiber and a lens.
TL;DR: In this article, a fiber-optic surface plasmon resonance (SPR) sensor was proposed which utilizes both polarization separation and broad band radiation depolarization in polarization-maintaining fibers to enhance sensor stability.
Abstract: A novel wavelength modulation-based fiber-optic surface plasmon resonance (SPR) sensor is reported which utilizes both polarization separation and broad band radiation depolarization in polarization-maintaining fibers to enhance sensor stability. Theoretical analysis of the sensing structure with ideally separated polarizations based on the mode of expansion and propagation method is presented. The effect of polarization cross-coupling was also analyzed in the approximation of an equivalent bulk optic structure. A laboratory prototype of the fiber-optic SPR sensor was characterized in terms of sensitivity and resolution. Experimental results indicate that this fiber-optic SPR sensor is able to resolve refractive index changes as low as 4×10−6 under moderate fiber deformations.
TL;DR: In this paper, the authors demonstrated an amplification phenomenon in a bismuth-doped silica glass at 1.3 μm with 0.8-μm excitation.
Abstract: We demonstrated an amplification phenomenon in a bismuth-doped silica glass at 1.3 μm with 0.8-μm excitation. This luminescent material is a promising candidate for use as the core-fiber material of an optical amplifier at the natural zero-dispersion wavelength (1.3 μm) of silica glass fiber.
Patent•
26 Feb 2003
TL;DR: In this paper, the authors proposed a flexible "smart cable" which enables accurate measurement of local curvature and torsion along its length, which is then used to infer the position and attitude of one end of the cable relative to the other.
Abstract: The central system component of the present invention is a flexible “smart cable” which enables accurate measurement of local curvature and torsion along its length. These quantities are then used to infer the position and attitude of one end of the cable relative to the other. Sufficiently accurate measurements of the local curvature and torsion along the cable allow reconstruction of the entire cable shape, including the relative position and orientation of the end points. The smart cable for making these measurements comprises a multicore optical fiber, with individual fiber cores constructed to operate in the single mode regime, but positioned close enough to cause cross-talk (mode coupling) between cores over the length of the fiber. This cross-talk is very sensitive to the distribution of strains (curvature and torsion) along the cable.
TL;DR: Generation of 3.8-fs pulses with energies of up to 15 microJ from a supercontinuum produced in two cascaded hollow fibers is demonstrated through a closed-loop combination of a spatial light modulator for adaptive pulse compression and spectral-phase interferometry for direct electric-field reconstruction (SPIDER) measurements as feedback signal.
Abstract: We demonstrate generation of 3.8-fs pulses with energies of up to 15 μJ from a supercontinuum produced in two cascaded hollow fibers. Ultrabroadband dispersion compensation was achieved through a closed-loop combination of a spatial light modulator for adaptive pulse compression and spectral-phase interferometry for direct electric-field reconstruction (SPIDER) measurements as feedback signal.
TL;DR: The efficient generation of 100-W single-frequency radiation with diffraction-limited beam quality at the 1064-nm wavelength by use of a master-oscillator fiber power-amplifier system, consisting of a diode-pumped monolithic nonplanar ring laser as the master oscillator and an Yb-doped large-mode-area fiber as the power amplifier is reported.
Abstract: We report the efficient generation of 100-W single-frequency radiation with diffraction-limited beam quality at the 1064-nm wavelength by use of a master-oscillator fiber power-amplifier system, consisting of a diode-pumped monolithic nonplanar ring laser as the master oscillator and an Yb-doped large-mode-area fiber as the power amplifier. The emission spectrum, the intensity noise behavior, and further power-scaling possibilities to the >200-W level, which are determined by the threshold of stimulated Brillouin scattering in the fiber amplifier, are discussed.