[Show abstract][Hide abstract] ABSTRACT: We demonstrate the fabrication of a novel type of optical fibers with multiple parallel air-suspended cores by the sheet-stacking method. Using this technique we have constructed optical fibers with up to 10 parallel micron-size suspended cores. No extra scattering loss from the fabrication process was observed in a fabricated dual air-suspended core fiber. The sheet-stacking method opens the way towards using a wide range of optical glasses for manufacturing multiple parallel suspended-core specialty optical fibers with novel optical functionalities such as dispersion tunability. Fusion splicing has also been successfully used to connect such a multiple core fiber with a conventional silica fiber.
[Show abstract][Hide abstract] ABSTRACT: We have recently demonstrated a novel type of microstructured nanomechanical optical fibres with optical properties that can be continuously tuned by mechanical actuation, similar to chip-based MEMS optical couplers. We review different options for actuation, such as gas pressure, temperature, and electrostatic forces, and discuss progress in the fabrication and experimental demonstration of these fibres.
2014 16th International Conference on Transparent Optical Networks (ICTON); 07/2014
[Show abstract][Hide abstract] ABSTRACT: We investigate theoretically and experimentally the possibility of electrostatic actuation of nanomechanical optical fibers with integrated electrodes. The fiber has two optically guiding cores suspended in air by thin flexible membranes. This fiber structure allows for control of the optical properties via nanometer-range mechanical core movements. The electrostatic actuation of the fiber is generated by electrically charged electrodes embedded in the fiber cladding. Fiber designs with one to four electrodes are analyzed and, in particular, a quadrupole geometry is shown to allow for all-fiber optical switching in a 10cm fiber with an operating voltage of 25 - 30V. A multi-material fiber draw technique is demonstrated to fabricate a fiber with well-defined dual core structure in the middle and four continuous metal electrodes in the cladding. The fabricated fiber is analyzed and compared with the modeled requirements for electrostatic actuation.
[Show abstract][Hide abstract] ABSTRACT: A dual suspended-core optical fiber with four embedded metal electrodes was fabricated by fiber drawing from a composite preform. Heating the fiber by running watt-level electrical power through the electrodes produced optical switching between cores.
[Show abstract][Hide abstract] ABSTRACT: An optical fiber with nano-electromechanical functionality is presented. The fiber exhibits a suspended dual-core structure that allows for control of the optical properties via nanometer-range mechanical movements. We investigate electrostatic actuation achieved by applying a voltage to specially designed electrodes integrated in the cladding. Numerical and analytical calculations are preformed to optimize the fiber and electrode design. Based on this geometry an all-fiber optical switch is investigated; we find that optical switching of light between the two cores can be achieved in a 10 cm fiber with an operating voltage of 35 V.
[Show abstract][Hide abstract] ABSTRACT: We experimentally investigate white light optical trapping by generating a supercontinuum in a lead silicate fibre pumped by femtosecond pulses from a Ti:Sapphire laser near the zero-dispersion wavelength of 1030 nm, before confining the light using a microfibre half taper with a final tip diameter of 75 nm. Due to the high intensity gradient at the output, robust optical trapping is possible, as demonstrated for individual yeast cells using an average pumping power of 100 mW.
Journal of Lightwave Technology 01/2014; 32(1):40-45. · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We demonstrate using a sheet-stacking method to fabricate nanomechanical optical fibres with long and thin spokes. This approach shows great advantage for manufacturing complex multi-material speciality optical fibres with novel photonic and nanomechanical functionalities.
Workshop on Specialty Optical Fibers and their Applications; 08/2013
[Show abstract][Hide abstract] ABSTRACT: We report the fabrication of new dehydrated halo-tellurite glass fibers with low OH content (1ppm in weight) and low OH-induced attenuation of 10dB/m in 3-4 µm region. It shows halo-tellurite glass fibers a promising candidate for nonlinear applications in 2-5µm region.
[Show abstract][Hide abstract] ABSTRACT: A nanomechanical optical fibre with a mechanically adjustable dual-core structure has been demonstrated recently. The realisation of equivalent systems with an electric actuation would allow for low-loss all-fibre reconfigurable optical networks. Here, the feasibility of nanoelectromechanical actuation of the dual-core fibre is investigated. Such optical systems with mechanically adjustable or controllable components are well known in the form of silicon micro- and nanoelectromechanical systems (MEMS and NEMS) and are widely used in various optoelectronic devices, for example 2-D optical switches and reconfigurable optical add-drop multiplexers.
The European Conference on Lasers and Electro-Optics; 05/2013
[Show abstract][Hide abstract] ABSTRACT: We report the fabrication of a new halo-tellurite glass fiber with low attenuation from 2-4 μm using a dehydration process. It shows a promising candidate for transmission and nonlinear applications in 2-5μm region.
Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC/NFOEC), 2013; 01/2013
[Show abstract][Hide abstract] ABSTRACT: We report experimental results on a dual suspended core nanomechanical optical fibre. Optical switching of light from one core to another is achieved through moving one core by just 8 nm.
Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference (OFC/NFOEC), 2013; 01/2013
[Show abstract][Hide abstract] ABSTRACT: Optical fibers are an excellent transmission medium for light and underpin the infrastructure of the Internet, but generally after fabrication their optical properties cannot be easily modified. Here, we explore the concept of nanomechanical optical fibers where, in addition to the fiber transmission capability, the internal core structure of the fiber can also be controlled through sub-micron mechanical movements. The nanomechanical functionality of such fibers is demonstrated in the form of dual core optical fibers, in which the cores are independently suspended within the fiber. The movement-based optical change is large compared with traditional electro-optical effects and we show that optical switching of light from one core to the other is achieved through moving one core by just 8 nm.
[Show abstract][Hide abstract] ABSTRACT: We report on the first fabrication of a glass fiber based laser-induced crystalline waveguide. The glass and crystal are based on the stoichiometric composition of (La,Yb)BGeO<sub>5</sub>. A laser induced waveguide has been fabricated on the surface of a ribbon glass fiber using milliwatt-level continuous wave UV laser radiation at a fast scanning speed. Evidence of crystallinity in the created structure was observed using micro-Raman spectroscopy and scanning electron microscopy. Preliminary investigations on the waveguiding behavior and the nonlinear performance in the crystalline waveguide are reported.
[Show abstract][Hide abstract] ABSTRACT: We experimentally demonstrate phase regeneration of a 40-Gb/s differential phase shift keying (DPSK) signal in a 1.7-m long highly nonlinear lead silicate W-type fiber using a degenerate two-pump phase-sensitive amplifier (PSA). Results show an improvement in the Error Vector Magnitude (EVM) and a reduction of almost a factor of 2 in the phase noise of the signal after regeneration for various noise levels at the input.
[Show abstract][Hide abstract] ABSTRACT: Direct writing aims to deposit materials onto substrates in localised positions. In this paper, we demonstrate a new method for direct writing of nanoparticles at ambient-air-pressure. An electrical discharge is used to generate gold nanoparticles of the order of 10 nm diameter, which are then transported and ‘focused’ by an electric field in air, through the process of electric field-assisted diffusion, as opposed to normal ballistic focusing since the mean free path in air is very short. This process is novel and allows for practical normal atmospheric-pressure focused deposition of nanoparticles. The focusing mechanism is capable of producing patterned arrays of deposited nanoparticles with widths that are less than 10 % of the diameter of the focusing apparatus; in the present experimental configuration, gold spots with diameters of a few tens of micrometres were achieved, with ultimate size being limited by transverse diffusion and by charged particle mutual repulsion. In this study, the process of generating nanoparticles from bulk material, transporting and focusing these particles takes place in one operation, which is a key advantage in rapid prototyping and manufacturing techniques.
Journal of Nanoparticle Research 11/2012; 14(11). · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Recent years have seen the development of a range of promising optical
fibre technologies emerge, enabled by advances in materials and
fabrication techniques. We describe 3 emerging areas in optical fibre
developments: nanomechanical optical fibres, microstructured hollow core
silica fibres for high peak optical power and/or extended infrared
transmission, and chalcogenide glasses and fibres for mid-IR
Proceedings of SPIE - The International Society for Optical Engineering 09/2012; · 0.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The development of super continuum sources is driven by the requirements of a wide range of emerging applications. This paper points out how non-silica fibers are of benefit not only because their broad mid-IR transparency enables continuum generation in the 2–5 μm region but also since the high intrinsic nonlinearity of the glasses reduces the power-threshold for devices at wavelengths below 2 μm. For these glasses, the material zero-dispersion wavelength is typically shifted to long wavelengths compared to silica so dispersion tailoring is key to creating sources based on practical, near-IR, solid state pump lasers. We show how modeling work has produced fiber designs that provide flattened dispersion profiles with high nonlinearity coefficients and zero-dispersion wavelengths in the near-IR. Building on this flexibility, modeling of the pulse dynamics then demonstrates how coherent mid-IR supercontinuum sources could be developed. We also show the importance of the second zero-dispersion wavelength using bismuth fibers as an example. Nonlinear mode-coupling is shown to be a factor in larger core fibers for high-power applications. Demonstrations of supercontinuum in microstructured tellurite fibers, all-solid lead–silicate (SF57) fibers and in bismuth fibers and tapers are then reported to show what has been achieved experimentally using a range of materials and fiber geometries.
[Show abstract][Hide abstract] ABSTRACT: We demonstrate phase regeneration of a 40-Gb/s DPSK signal in a 1.7m-long lead-silicate fiber using a black-box phase-sensitive amplifier. Results show an improvement in the EVM values of the signal after regeneration for various noise levels.
[Show abstract][Hide abstract] ABSTRACT: We report the experimental realization of glass nanofibers by electrospinning directly from a melt, demonstrating the viability of electrospinning fibers from non-polymer materials with high melting temperatures and higher surface tensions. The nanofiber material (B2O3) is molten on the tip of a gold wire, and voltage applied to the tip causes a jet to form, resulting in solid glass fibers with diameters of ∼100 nm.
[Show abstract][Hide abstract] ABSTRACT: Simple microscopic interactions in non-equilibrium systems give rise to
complex emergent macroscopic phenomena. There has been much theoretical
work to understand dynamics of different systems, and equilibrium
concepts of scaling, criticality and universality have proved useful.
However there is a noted lack of experimental studies. Here we show that
exciton reactions on carbon nanotubes display the rich kinetics of the
prototypical 1D coalescence reaction A+A->A. An Auger-like exciton
interactionootnotetextY.-Z. Maet al, Phys Rev Lett 94, 157402
(2005). and anomalous kineticsootnotetextR. M. Russo et al. Phys
Rev B 74, 041405 (2006). have already been reported. Here we demonstrate
the existence of four distinct dynamical regimes: (1) early dynamics
determined by spatial ordering of excitons due to Pauli repulsion at
high concentrations; (2) a classical mean-field region with exciton
population n decaying as t-1; (3) a self-organized critical
state with anomalous reaction kinetics limited by diffusion and
characterized by n˜t-1/2, which we show to be universal
with respect to the initial population; and (4) an exponential approach
towards an absorbing state corresponding to one exciton per nanotube.
The abrupt crossover between regimes indicates a long-range exciton
interaction, which introduces a non-scaling dimension that breaks
universality at intermediate length-scales.