Showing papers on "Optical fiber published in 2013"
TL;DR: In this paper, the authors summarized the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications, and showed that the results achieved in both multicore and multimode optical fibers are documented.
Abstract: This Review summarizes the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications. Recent results achieved in both multicore and multimode optical fibres are documented.
2,629 citations
TL;DR: The viability of using the orbital angular momentum (OAM) of light to create orthogonal, spatially distinct streams of data-transmitting channels that are multiplexed in a single fiber is demonstrated and suggest that OAM could provide an additional degree of freedom for data multiplexing in future fiber networks.
Abstract: Internet data traffic capacity is rapidly reaching limits imposed by optical fiber nonlinear effects Having almost exhausted available degrees of freedom to orthogonally multiplex data, the possibility is now being explored of using spatial modes of fibers to enhance data capacity We demonstrate the viability of using the orbital angular momentum (OAM) of light to create orthogonal, spatially distinct streams of data-transmitting channels that are multiplexed in a single fiber Over 11 kilometers of a specially designed optical fiber that minimizes mode coupling, we achieved 400-gigabits-per-second data transmission using four angular momentum modes at a single wavelength, and 16 terabits per second using two OAM modes over 10 wavelengths These demonstrations suggest that OAM could provide an additional degree of freedom for data multiplexing in future fiber networks
2,343 citations
TL;DR: This paper presents a meta-anatomy of the response of the immune system to PNA-Based Biosensors (DNA, Aptamers) and some of the mechanisms leading to cell reprograming and apoptosis.
Abstract: ■ CONTENTS Books, Reviews, and Articles of General Interest 488 Sensors for (Dissolved) Gases and Vapors 489 Hydrogen 489 Hydrocarbons 490 Oxygen 491 Ammonia 493 Carbon Dioxide 494 Nitrogen Oxides 494 Vapors of Organic Solvents 495 Sensors for Humidity, Water Fractions, Hydrogen Peroxide, and Hydrazine 495 Humidity 495 Water Fractions 496 Hydrogen Peroxide and Hydrazine 496 Sensors for pH Values, Ions, and Salinity 496 pH Values 496 Ions 497 Salinity and Ionic Strength 499 Sensors for Organic Species 499 Biosensors 500 Immunosensors 500 PNA-Based Biosensors (DNA, Aptamers) 501 Other Affinity Sensors 501 Enzymatic Biosensors 502 Whole Cell Sensors 502 Advanced Optical Sensing Schemes and Materials 503 Author Information 505 Corresponding Author 505 Notes 505 Biographies 505 Acknowledgments 505 References 505
419 citations
TL;DR: In this article, the effects of radiation on silica-based optical fibers are discussed and the main results regarding the fiber vulnerability and hardening to radiative constraints associated with several facilities such as Megajoule class lasers, ITER, LHC, nuclear power plants or with space applications.
Abstract: In this review paper, we present radiation effects on silica-based optical fibers. We first describe the mechanisms inducing microscopic and macroscopic changes under irradiation: radiation-induced attenuation, radiation-induced emission and compaction. We then discuss the influence of various parameters related to the optical fiber, to the harsh environments and to the fiber-based applications on the amplitudes and kinetics of these changes. Then, we focus on advances obtained over the last years. We summarize the main results regarding the fiber vulnerability and hardening to radiative constraints associated with several facilities such as Megajoule class lasers, ITER, LHC, nuclear power plants or with space applications. Based on the experience gained during these projects, we suggest some of the challenges that will have to be overcome in the near future to allow a deeper integration of fibers and fiber-based sensors in radiative environments.
365 citations
TL;DR: In this article, the authors discuss the means by which optical fibers, hitherto considered unsuitable for stably supporting optical vortices, may be used to generate and propagate such exotic beams.
Abstract: Optical vortex beams, possessing spatial polarization or phase singularities, have intriguing properties such as the ability to yield super-resolved spots under focussing, and the ability to carry orbital angular momentum that can impart torque to objects. In this review, we discuss the means by which optical fibers, hitherto considered unsuitable for stably supporting optical vortices, may be used to generate and propagate such exotic beams. We discuss the multitude of applications in which a new class of fibers that stably supports vortices may be used, and review recent experiments and demonstration conducted with such fibers.
341 citations
TL;DR: The small diameter of the proposed endoscope, along with its high quality images offer an opportunity for minimally invasive medical endoscopic imaging and diagnosis based on cellular phenotype via direct tissue penetration.
Abstract: We propose and experimentally demonstrate an ultra-thin rigid endoscope (450 μm diameter) based on a passive multimode optical fiber. We use digital phase conjugation to overcome the modal scrambling of the fiber to tightly focus and scan the laser light at its distal end. By exploiting the maximum number of modes available, sub-micron resolution, high quality fluorescence images of neuronal cells were acquired. The imaging system is evaluated in terms of fluorescence collection efficiency, resolution and field of view. The small diameter of the proposed endoscope, along with its high quality images offer an opportunity for minimally invasive medical endoscopic imaging and diagnosis based on cellular phenotype via direct tissue penetration.
293 citations
22 Apr 2013
TL;DR: A thulium doped fiber amplifier designed for optical communications providing high gain and low noise figure over 1910nm-2020nm with a maximum saturated output power of more than 1W is reported.
Abstract: We report the realization of a thulium doped fiber amplifier designed for optical communications providing high gain (>35dB) and low noise figure (<;6dB) over 1910nm-2020nm with a maximum saturated output power of more than 1W.
271 citations
TL;DR: In this paper, the authors demonstrate optical-frequency transfer over a 1840-km underground optical fiber link using a single-span stabilization, and find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about $3.
Abstract: To compare the increasing number of optical frequency standards, highly stable optical signals have to be transferred over continental distances. We demonstrate optical-frequency transfer over a 1840-km underground optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}15}$ for a gate time $\ensuremath{\tau}$ of 1 s reaching $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$ in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about $3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}$. The spectral noise distribution of our fiber link at low Fourier frequencies leads to a ${\ensuremath{\tau}}^{\ensuremath{-}2}$ slope in the modified Allan deviation, which is also derived theoretically.
270 citations
TL;DR: In this paper, a review of recent progress in the optical fiber field for the measurement of humidity and moisture and examine, as a result, the breadth of applications that now are being discussed.
213 citations
TL;DR: In this article, the effect of the fiber geometry on the spectral resolution and bandwidth was investigated, and the additional limitation on the bandwidth imposed by speckle contrast reduction when measuring dense spectra.
Abstract: A standard multimode optical fiber can be used as a general purpose spectrometer after calibrating the wavelength dependent speckle patterns produced by interference between the guided modes of the fiber. A transmission matrix was used to store the calibration data and a robust algorithm was developed to reconstruct an arbitrary input spectrum in the presence of experimental noise. We demonstrate that a 20 meter long fiber can resolve two laser lines separated by only 8 pm. At the other extreme, we show that a 2 centimeter long fiber can measure a broadband continuous spectrum generated from a supercontinuum source. We investigate the effect of the fiber geometry on the spectral resolution and bandwidth, and also discuss the additional limitation on the bandwidth imposed by speckle contrast reduction when measuring dense spectra. Finally, we demonstrate a method to reduce the spectrum reconstruction error and increase the bandwidth by separately imaging the speckle patterns of orthogonal polarizations. The multimode fiber spectrometer is compact, lightweight, low cost, and provides high resolution with low loss.
203 citations
TL;DR: Coating the membrane onto the surface of an optical fiber resulted in a device with high pH-sensing performance in terms of the response rate and the sensitivity, due to the charge and porous nature of the membrane layer.
Abstract: Nanoporous polyelectrolyte membranes with hierarchical and unique pore architectures can be readily made via electrostatic complexation between imidazolium-based poly(ionic liquid)s and poly(acrylic acid) in a variety of morphologies. Coating the membrane onto the surface of an optical fiber resulted in a device with high pH-sensing performance in terms of the response rate and the sensitivity, due to the charge and porous nature of the membrane layer.
TL;DR: This work investigates the effect of the fiber geometry on the spectral resolution and bandwidth, and discusses the additional limitation on the bandwidth imposed by speckle contrast reduction when measuring dense spectra.
Abstract: A standard multimode optical fiber can be used as a general purpose spectrometer after calibrating the wavelength dependent speckle patterns produced by interference between the guided modes of the fiber. A transmission matrix was used to store the calibration data and a robust algorithm was developed to reconstruct an arbitrary input spectrum in the presence of experimental noise. We demonstrate that a 20 meter long fiber can resolve two laser lines separated by only 8 pm. At the other extreme, we show that a 2 centimeter long fiber can measure a broadband continuous spectrum generated from a supercontinuum source. We investigate the effect of the fiber geometry on the spectral resolution and bandwidth, and also discuss the additional limitation on the bandwidth imposed by speckle contrast reduction when measuring dense spectra. Finally, we demonstrate a method to reduce the spectrum reconstruction error and increase the bandwidth by separately imaging the speckle patterns of orthogonal polarizations. The multimode fiber spectrometer is compact, lightweight, low cost, and provides high resolution with low loss.
TL;DR: In this work, a quasi-closed-form solution for the nonlinear coupling coefficient is found for stimulated thermal Rayleigh scattering in optical fibers, which helps to significantly improve understanding of mode instability.
Abstract: Recently, mode instability was observed in optical fiber lasers at high powers, severely limiting power scaling for single-mode outputs. Some progress has been made towards understanding the underlying physics. A thorough understanding of the effect is critical for continued progress of this very important technology area. Mode instability in optical fibers is, in fact, a manifestation of stimulated thermal Rayleigh scattering. In this work, a quasi-closed-form solution for the nonlinear coupling coefficient is found for stimulated thermal Rayleigh scattering in optical fibers. The results help to significantly improve understanding of mode instability.
TL;DR: The concentrically-layered photonic structure found in the tropical fruit Margaritaria nobilis serves as inspiration for photonic fibers with mechanically tunable band-gap that show the spectral filtering capabilities of a planar Bragg stack while the microscopic curvature decreases the strong directional chromaticity associated with flat multilayers.
Abstract: The concentrically-layered photonic structure found in the tropical fruit Margaritaria nobilis serves as inspiration for photonic fibers with mechanically tunable band-gap. The fibers show the spectral filtering capabilities of a planar Bragg stack while the microscopic curvature decreases the strong directional chromaticity associated with flat multilayers. Elongation of the elastic fibers results in a shift of the reflection of over 200 nm.
TL;DR: The working principles of the most promising MR-compatible FOS are reviewed in terms of their relevant advantages and disadvantages, together with their applications in medicine.
Abstract: During last decades, Magnetic Resonance (MR)—compatible sensors based on different techniques have been developed due to growing demand for application in medicine. There are several technological solutions to design MR-compatible sensors, among them, the one based on optical fibers presents several attractive features. The high elasticity and small size allow designing miniaturized fiber optic sensors (FOS) with metrological characteristics (e.g., accuracy, sensitivity, zero drift, and frequency response) adequate for most common medical applications; the immunity from electromagnetic interference and the absence of electrical connection to the patient make FOS suitable to be used in high electromagnetic field and intrinsically safer than conventional technologies. These two features further heightened the potential role of FOS in medicine making them especially attractive for application in MRI. This paper provides an overview of MR-compatible FOS, focusing on the sensors employed for measuring physical parameters in medicine (i.e., temperature, force, torque, strain, and position). The working principles of the most promising FOS are reviewed in terms of their relevant advantages and disadvantages, together with their applications in medicine.
TL;DR: The evanescent wave interaction is found to be better than the traditional approach which confines the graphene nano-particles at the interface of two SMF patchcords.
Abstract: A photonic crystal fiber (PCF) with high-quality graphene nano-particles uniformly dispersed in the hole cladding are demonstrated to passively mode-lock the erbium-doped fiber laser (EDFL) by evanescent-wave interaction. The few-layer graphene nano-particles are obtained by a stabilized electrochemical exfoliation at a threshold bias. These slowly and softly exfoliated graphene nano-particle exhibits an intense 2D band and an almost disappeared D band in the Raman scattering spectrum. The saturable phenomena of the extinction coefficient β in the cladding provides a loss modulation for the intracavity photon intensity by the evanescent-wave interaction. The evanescent-wave mode-locking scheme effectively enlarges the interaction length of saturable absorption with graphene nano-particle to provide an increasing transmittance ΔT of 5% and modulation depth of 13%. By comparing the core-wave and evanescent-wave mode-locking under the same linear transmittance, the transmittance of the graphene nano-particles on the end-face of SMF only enlarges from 0.54 to 0.578 with ΔT = 3.8% and the modulation depth of 10.8%. The evanescent wave interaction is found to be better than the traditional approach which confines the graphene nano-particles at the interface of two SMF patchcords. When enlarging the intra-cavity gain by simultaneously increasing the pumping current of 980-nm and 1480-nm pumping laser diodes (LDs) to 900 mA, the passively mode-locked EDFL shortens its pulsewidth to 650 fs and broadens its spectral linewidth to 3.92 nm. An extremely low carrier amplitude jitter (CAJ) of 1.2-1.6% is observed to confirm the stable EDFL pulse-train with the cladding graphene nano-particle based evanescent-wave mode-locking.
TL;DR: A whispering-gallery-mode bottle microresonator coupled to a single atom and interfaced by two tapered fiber couplers reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum.
Abstract: We demonstrate highly efficient switching of optical signals between two optical fibers controlled by a single atom. The key element of our experiment is a whispering-gallery-mode bottle microresonator, which is coupled to a single atom and interfaced by two tapered fiber couplers. This system reaches the strong coupling regime of cavity quantum electrodynamics, leading to a vacuum Rabi splitting in the excitation spectrum. We systematically investigate the switching efficiency of our system, i.e., the probability that the fiber-optical switch redirects the light into the desired output. We obtain a large redirection efficiency reaching a raw fidelity of more than 60% without postselection. Moreover, by measuring the second-order correlation functions of the output fields, we show that our switch exhibits a photon-number-dependent routing capability.
TL;DR: In this article, the distribution of time-bin entangled photon pairs over 300 km of optical fiber was reported, and the observed two-photon interference fringes exhibited a visibility of 84%.
Abstract: We report the distribution of time-bin entangled photon pairs over 300 km of optical fiber. We realized this by using a high-speed and high signal-to-noise ratio entanglement generation/evaluation setup that consists of periodically poled lithium niobate waveguides and superconducting single photon detectors. The observed two-photon interference fringes exhibited a visibility of 84%. We confirmed the violation of Bell’s inequality by 2.9 standard deviations.
TL;DR: In this article, a method for conducting fast Brillouin optical time domain analysis for dynamic sensing of optical fibers is presented, which includes the following stages: injecting a pump pulse signal into the first end of an optical fiber and a probe signal into a second end of the optical fiber, wherein the probe and the pump pulse signals exhibit a frequency difference between them that is appropriate for an occurrence of a Brillourin effect; alternating the frequency of either the probe or the pulse signals, so as the alternated signal exhibits a series of signal sections, each signal section having a pred
Abstract: A method for conducting fast Brillouin optical time domain analysis for dynamic sensing of optical fibers is provided herein The method includes the following stages: injecting a pump pulse signal into a first end of an optical fiber and a probe signal into a second end of the optical fiber, wherein the probe and the pump pulse signals exhibit a frequency difference between them that is appropriate for an occurrence of a Brillouin effect; alternating the frequency of either the probe or the pulse signals, so as the alternated signal exhibits a series of signal sections, each signal section having a predefined common duration and a different frequency; measuring the Brillouin probe gain for each one of the alternating frequencies; and extracting physical properties of the optical fiber throughout its length at sample points associated with the sampled time and the frequencies, based on the measured Brillouin probe gain
TL;DR: The results prove that with such a design the optical performances are strongly driven by the contour negative curvature of the core-cladding interface, including a modal content approaching true single-mode guidance.
Abstract: We report on numerical and experimental studies showing the influence of arc curvature on the confinement loss in hypocycloid-core Kagome hollow-core photonic crystal fiber. The results prove that with such a design the optical performances are strongly driven by the contour negative curvature of the core-cladding interface. They show that the increase in arc curvature results in a strong decrease in both the confinement loss and the optical power overlap between the core mode and the silica core-surround, including a modal content approaching true single-mode guidance. Fibers with enhanced negative curvature were then fabricated with a record loss-level of 17 dB/km at 1064 nm.
TL;DR: The model shows that efficient power transfer between the fundamental and higher-order modes of the fiber can be induced by a nonlinear interaction mediated through the thermo-optic effect, leading to transverse mode instability in high-power rare-earth doped fiber amplifiers.
Abstract: We present a simple theoretical model of transverse mode instability in high-power rare-earth doped fiber amplifiers. The model shows that efficient power transfer between the fundamental and higher-order modes of the fiber can be induced by a nonlinear interaction mediated through the thermo-optic effect, leading to transverse mode instability. The temporal and spectral characteristics of the instability dynamics are investigated, and it is shown that the instability can be seeded by both quantum noise and signal intensity noise, while pure phase noise of the signal does not induce instability. It is also shown that the presence of a small harmonic amplitude modulation of the signal can lead to generation of higher harmonics in the output intensity when operating near the instability threshold.
TL;DR: It is demonstrated that this depletion effect can be precisely modelled and strict guidelines can be enunciated from the model to make the impact of depletion negligible, for any type and any length of fiber.
Abstract: Energy transfer between the interacting waves in a distributed Brillouin sensor can result in a distorted measurement of the local Brillouin gain spectrum, leading to systematic errors It is demonstrated that this depletion effect can be precisely modelled This has been validated by experimental tests in an excellent quantitative agreement Strict guidelines can be enunciated from the model to make the impact of depletion negligible, for any type and any length of fiber
Patent•
13 Sep 2013TL;DR: In this paper, a tapered core waveguide with cladding disposed thereabout, the core having an aperture at the wider end of the taper, at least one transducer is disposed about the cladding.
Abstract: An optical fiber interface devices and repeaters are provided. The devices utilized a tapered core waveguide with cladding disposed thereabout, the core having an aperture at the wider end of the taper. At least one transducer is disposed about the cladding. Energy coupled from the transducer into the cladding is coupled into the fiber in transmitting embodiment, and energy coming from the fiber is coupled to the transducer in receiving embodiment. The interface may act as a multiplexer and/or demultiplexer. A repeater comprises a receiving and a transmitting embodiment. Optionally the devices are able to harvest energy transmitted via the fiber.
TL;DR: A distributed optical fiber sensing system merged Mach-Zehnder interferometer and phase sensitive optical time domain reflectometer system for vibration measurement with high-frequency response and high spatial resolution is demonstrated, where modulated pulses are proposed to be used as sensing source.
Abstract: A distributed optical fiber sensing system merged Mach-Zehnder interferometer and phase sensitive optical time domain reflectometer (φ-OTDR) system for vibration measurement with high-frequency response and high spatial resolution is demonstrated, where modulated pulses are proposed to be used as sensing source. Frequency response and location information are obtained by Mach-Zehnder interferometer and φ-OTDR technology, respectively. In order to simulate high-frequency vibration of crack of cable and civil structure, experiments on detection of piezoelectric transducer and pencil-break are carried out. Spatial resolution of 5 m and the maximum frequency response of ~3 MHz are achieved in 1064 m fiber link when the narrow pulse width is 50 ns.
TL;DR: In this paper, a large number of papers devoted to the development of Bi-doped fiber lasers and optical amplifiers have been published, and it has been shown that Bi-Doped fibers are a new breakthrough in active laser materials.
Abstract: Bismuth-doped optical glasses emit NIR luminescence in an ultrabroad spectral region of 1000-2000 nm. It makes Bi-doped glasses and glass optical fibers a promising active medium for the creation of Bi-doped fiber lasers and broadband optical amplifiers for this spectral region. Since the first fabrication of Bi-doped fibers in 2005 a large number of papers devoted to the development of Bi-doped fiber lasers and optical amplifiers have been published. It has been shown that Bi-doped fibers are a new breakthrough in active laser materials.
TL;DR: In this paper, a detailed investigation of the nonlinear multimodal interference in a short graded-index multimode optical fiber is presented, where the light is coupled in and out of the multimode fiber via single-mode fibers.
Abstract: A detailed investigation of the nonlinear multimodal interference in a short graded-index multimode optical fiber is presented. The analysis is performed for a specific device geometry, where the light is coupled in and out of the multimode fiber via single-mode fibers. The same device geometry was recently used to obtain ultra-low-loss coupling between two single-mode optical fibers with very different mode-field diameters. Our results indicate the potential application of this simple geometry for nonlinear devices, such as in nonlinear switching, optical signal processing, or as saturable absorbers in mode-locked fiber lasers. Saturable absorption in this all-fiber configuration is discussed and it is shown that it provides attractive properties that can potentially be used in high pulse energy mode-locked fiber lasers.
TL;DR: It is shown that bright, high quality, localized bands of UV light can be generated at all wavelengths across this range, and the coherence of the deep-UV dispersive wave radiation numerically investigated.
Abstract: An efficient and tunable 176-550 nm source based on the emission of resonant dispersive radiation from ultrafast solitons at 800 nm is demonstrated in a gas-filled hollow-core photonic crystal fiber (PCF). By careful optimization and appropriate choice of gas, informed by detailed numerical simulations, we show that bright, high quality, localized bands of UV light (relative widths of a few percent) can be generated at all wavelengths across this range. Pulse energies of more than 75 nJ in the deep-UV, with relative bandwidths of ~3%, are generated from pump pulses of a few μJ. Excellent agreement is obtained between numerical and experimental results. The effects of positive and negative axial pressure gradients are also experimentally studied, and the coherence of the deep-UV dispersive wave radiation numerically investigated.
TL;DR: The first in-band diode-pumped TDFAs operating in the 2 µm wavelength region are presented and their suitability as high performance amplifiers in potential future telecommunication networks is tested.
Abstract: We present the first in-band diode-pumped TDFAs operating in the 2µm wavelength region and test their suitability as high performance amplifiers in potential future telecommunication networks. We demonstrate amplification over a 240nm wide window in the range 1810 - 2050nm with up to 36dB gain and noise figure as low as 4.5dB.
TL;DR: In this paper, the authors focus on Rayleigh-based distributed optical fiber sensors, which are based on the scattering processes that originate from the interaction between light and matter, and provide unprecedented features, such as the ability of monitoring varia- tions of the observed physical field with spatial continuity along the fiber.
Abstract: Optical fiber sensors offer unprecedented features, the most unique of which is the ability of monitoring varia- tions of the observed physical field with spatial continuity along the fiber. These distributed optical fiber sensors are based on the scattering processes that originate from the interaction between light and matter. Among the three different scatter- ing processes that may take place in a fiber—namely Rayleigh, Raman and Brillouin scattering, this paper focuses on Rayleigh-based distributed optical fiber sensors. For a given optical frequency, Rayleigh-based sensors exploit the three main properties of light: intensity, phase and polarization. All these sensing mechanisms are reviewed, along with basic principles, main acquisition techniques and fields of application. Emphasis, however, will be put on polarization-based distributed optical fiber sensors. While they currently represent a niche, they offer promising unique features worth being considered in greater detail.
TL;DR: A fiber-optic Fabry-Perot interferometric pressure sensor with its external diaphragm surface thinned and roughened by a femtosecond laser, which makes the sensor immune to variations in the ambient refractive index.
Abstract: In this Letter, we report on a fiber-optic Fabry-Perot interferometric pressure sensor with its external diaphragm surface thinned and roughened by a femtosecond laser. The laser-roughened surface helps to eliminate outer reflections from the external diaphragm surface and makes the sensor immune to variations in the ambient refractive index. The sensor is demonstrated to measure pressure in a high-temperature environment with low-temperature dependence.