The propagation of pulses through waveguides with subwavelength features, inhomogeneous transverse structure, and high index contrast cannot be described accurately using existing models in the presence nonlinear effects.Here we report development a generalised full vectorial model pulse demonstrate that, unlike standard formulation, z-component guided modes plays key role for these new structures, results definitions coefficient γ, A e f , mode orthognality.While reduce to some limits,...

Several classes of non-planar metallic and dielectric waveguides have been proposed in the literature for guidance terahertz (THz) or T-ray radiation. In this review, we focus on development waveguides, THz regime, with reduced loss dispersion. First, examine different spectroscopy configurations fundamental equations employed characterization waveguides. Then divide into three classes: solid-core, hollow-core, porous-core The guiding mechanism, fabrication steps, measured loss, dispersion...

Porous fibers have been identified as a means of achieving low losses, dispersion and high birefringence among THz polymer fibers.By exploiting optical fiber fabrication techniques, two types porous fibers-spider-web rectangular fibers-with 57% 65% porosity fabricated.The effective refractive index measured by terahertz time domain spectroscopy shows good agreement between the theoretical experimental results indicating lower for compared to microwires.A 0.012 at 0.65 is also reported fiber.

We propose a novel class of optical fiber with porous transverse cross-section that is created by arranging sub-wavelength air-holes within the core fiber.These fibers can offer combination low transmission loss and high mode confinement in THz regime exploiting enhancement guided field occurs these holes.We evaluate properties quantitatively compare their performance relative to solid air cladded (microwire).For similar values, enable improved light reduced distortion broadband pulse...

The dependence of the Brillouin frequency shift on strain in a photonic crystal fiber (PCF) was measured at wavelength 1320 nm for first time to authors' knowledge. Together with measurements temperature PCF, we demonstrate feasibility highly precise simultaneous measurement and by use PCF distributed sensing system spatial resolution 15 cm.

Fabrication of a hybrid diamond-glass material is reported, by embedding diamond nanocrystals containing nitrogen-vacancy (NV) color centers into tellurite soft glass. This allows the fabrication photonic waveguides using well-established glass techniques, such as microstructured optical fiber technology (the figure confocal image that shows center fluorescence in fiber).

We report on the fabrication of novel lead-germanate glasses and fibers.We have characterized these in terms their thermal properties, Raman spectra refractive indices (both linear nonlinear) present them as viable alternatives to tellurite for applications requiring highly nonlinear optical fibers.

Whispering gallery mode lasers are of interest for a wide range applications and especially biological sensing, exploiting the dependence resonance wavelengths on surrounding refractive index. Upon lasing, Q factors resonances greatly improved, enabling measurements wavelength shifts with increased accuracy. A way forward to improve performance index sensing mechanism is reduce size optical resonator, as sensitivity inversely proportional resonator dimensions. However, lasing threshold...

We develop a generic model of excitation and fluorescence recapturing within filled microstructured optical fibres (MOFs) with arbitrary structure demonstrate that the light-matter overlap alone does not determine optimal fibre choice.Fibre designs sub-wavelength features high-index glasses exhibit localised regions high intensity, we show these can lead to approximately two orders magnitude enhancement recapturing.Here how this regime be exploited for sensing experimentally in-fibre filled,...

For the first time, to our knowledge, we demonstrate experimental confirmation of a new vectorially based expression effective nonlinear coefficient gamma in bismuth suspended core fibers with diameters around 500 nm. The predicts significantly higher value than what is expected on standard expression. We confirm that there distinguishable difference between and gamma's, owing high index glass subwavelength dimension this fiber, show result matches within error.

Traditional optical fibers are insensitive to magnetic fields, however many applications would benefit from fiber-based magnetometry devices. In this work, we demonstrate a magnetically sensitive fiber by doping nanodiamonds containing nitrogen vacancy centers into tellurite glass fibers. The fabrication process provides robust and isolated sensing platform as the sensors fixed in matrix. Using optically detected resonance doped nanodiamonds, detection of local fields via side excitation...

The absorption and fluorescence sensing properties of liquidimmersed exposed-core microstructured optical fibers are explored for the regime where these structures act as supported nanowires with direct access to environment.For absorption-based we demonstrate that amount power propagating in region exposedcore fiber can compete traditional MOFs.For fluorescencebased sensing, see addition enhanced capture efficiency already predicted small-core, high refractive index contrast fibers, an...

We present a new approach to the design of optical microstructured fibers that have group velocity dispersion (GVD) and effective nonlinear coefficient (γ) tailored for supercontinuum (SC) generation.This hybrid combines genetic algorithm (GA) with pulse propagation modeling, but without include it into GA loop, allow efficient are capable generating highly coherent large bandwidth SC in mid-infrared (Mid-IR) spectrum.To best our knowledge, this is first use fiber generation.We investigate...

A general model of excitation and fluorescence recapturing by the forward backward modes filled microstructured optical fibers (MOFs) is presented. We also present experimental results for both within a MOF as function fiber length demonstrate good qualitative agreement between numerical results. higher efficiency into in comparison with that modes.

We report fabrication of the lead silicate microstructured fibers (MOFs) with core holes as small 20 nm, smallest fabricated within an optical fiber to date. show that light confinement and average mode intensity such are strongly dependent on hole size. Light 80 nm 250 MOFs has been experimentally characterized using Scanning Near-field Optical Microscopy (SNOM).

We develop a technique based on micromachined photoconductive probe-tip to characterize terahertz (THz) porous fiber. Losses less than 0.08 cm−1 are measured in the frequency range from 0.2 0.35 THz, with minimum of 0.003 at 0.24 THz. Normalized group velocity greater 0.8, which corresponds dispersion values between −1.3 and −0.5 ps/m/μm for 0.2<f<0.35 THz obtained. Moreover, we directly measure evanescent electric field as function frequency. Good agreement curves expected...

A distributed Brillouin scattering sensor has been employed to identify several inner wall cutouts in an end-capped steel pipe by measuring the axial and hoop strain distributions along outer surface of pipe. The locations structural indentations that constitute 50-60% are found distinguished use their corresponding strain-pressure data. These results quantified terms fiber orientation, defect size depth, behavior relative those unperturbed sections.

The significance of full vectorial pulse propagation through emerging waveguides has not been investigated. Here we report the development a generalised model nonlinear due to effects Stimulated Raman Scattering (SRS) in optical waveguides. Unlike standard models, this does use weak guidance approximation, and thus accurately models modal gain strong regime. develop vectorial-based Schrödinger Eq. (VNSE) demonstrate how fails certain regimes, with up factors 2.5 enhancement between VNSE...

A model for the fluorescence sensing properties of small-core high-refractive-index fibers (optical nanowires) is developed and compared quantitatively with experiment.For first time, higher-order modes loss factors relevant to optical nanowires are included, which allows be effectively experiment via use fluorophore filled suspended nanowires.Numerical results show that high-index materials beneficial fluorescence-based sensing.However, both numerical experimental signal relatively...

We fabricated a microstructured optical fiber with dispersion profile that, according to calculations, is near-zero and flat, 3 zero wavelengths in the mid-IR. To best of our knowledge this first report fabrication such fiber. Simulations multimode supercontinuum generation were performed using simplified approach. Strong agreement between experiments simulations observed

The spectral properties of light confined to low-index media by binary layered structures is discussed. A novel phase-based model with a simple analytical form derived for the approximation center arbitrary bandgaps operating at effective indices. An sensitivity bandgap changes in core refractive index thus derived. Experimentally, significant shifting fundamental hollow-core Bragg fiber large cladding layer contrast demonstrated filling liquids various Confirmation these results against...

We resolve the ambiguity in existing definitions of effective area a waveguide mode that have been reported literature by examining which definition leads to an accurate evaluation Kerr nonlinearity.We show nonlinear coefficient can be written as product suitable average coefficients waveguide's constituent materials, mode's group velocity and new suitably defined area.None these parameters on their own completely describe strength effects waveguide.