Search results for "cladding"
showing 10 items of 62 documents
Self-Trapped Localized Modes in Photonic Crystal Fibers
2002
We demonstrate the existence of self-trapped localized modes in photonic crystal fibers. We analyze these solutions in terms of the parameters of the photonic crystal cladding and the nonlinear coupling.
Lattice-Matched GaN–InAlN Waveguides at $\lambda=1.55\ \mu$m Grown by Metal–Organic Vapor Phase Epitaxy
2008
We report on the demonstration of low-loss, single-mode GaN-InAlN ridge waveguides (WGs) at fiber-optics telecommunication wavelengths. The structure grown by metal-organic vapor phase epitaxy contains AlInN cladding layers lattice-matched to GaN. For slab-like WGs propagation losses are below 3 dB/mm and independent of light polarization. For 2.6-mum-wide WGs the propagation losses in the 1.5- to 1.58-mum spectral region are as low as 1.8 and 4.9 dB/mm for transverse-electric- and transverse-magnetic-polarization, respectively. The losses are attributed to the sidewall roughness and can be further reduced by the optimization of the etching process.
Asymmetrical all-organic waveguide gas sensor
2019
An all-organic waveguide sensor for volatile solver detecting was presented. Device consists of SU-8 waveguide with novel organic material used as sensitive cladding. Created device was tested in isopropanol and N2 vapor mixture.
Modulation of coaxial modal interferometers based on long period gratings in double cladding fibers
2009
This paper reports on the dynamic modulation of coaxial interferometers based on two cascaded long period gratings written in double cladding fibers. The interferometer is modulated by a piezoelectric ceramic which stretches one the gratings at tens of kHz, the output light is intensity modulated with an efficiency of 97 %. The device operates at 1530nm, has more than 50nm bandwidth, insertion loss of 0.4 dB and a temperature drift of 0.11 nm/ degrees C.
Endlessly single-mode heat-sink waveguide
1998
Recently, a new form of optical fiber, the photonic crystal fiber, has been reported. This fiber has a hexagonal array of submicrometer air holes running along its length and a lattice site without a hole (a line defect) in its center. The defect acts as a core, confining light that travels along the fiber as a guided mode. This structure can be endlessly single mode, never supporting more than one confined mode no matter what the diameter of the core or the wavelength of the light. Having discovered this effect experimentally and provided a qualitative explanation for the observed behavior, we present here a planar version of this fiber. Periodic arrays of parallel planar fins are placed o…
Multicore optical fibres for astrophotonics
2011
We report progress towards multimode (MM) fibre filters for suppressing the OH emission that hinders ground-based observation of the early Universe. Fibre Bragg gratings (FBGs) can filter these narrow spectral lines in single-mode (SM) fibres [1]. Implementing them in MM fibres well-matched to astronomical instruments requires transitions between the MM fibre and several SM fibres [2]. Such hand-crafted “photonic lanterns” require many identical FBGs to be made and spliced in place. Instead we are pursuing the idea in multicore (MC) fibres, Fig. 1(a). The FBG is written at once in all the SM cores. The fibre is jacketed with low-index glass and tapered to form the core and cladding of a MM …
Improving the Design of Ion Track-Based Biosensors
2018
In the last decade we had developed new types of biosensors, by cladding the inner walls of transparent etched swift heavy ion tracks in thin polymer foils with enzymes. The enzymatic reaction products of appropriate analytes penetrating into narrow tracks are enriched in the track’s confinement, and they change the electrical track properties if their charge states differ from those of the analytes. It was yet unknown how to design these sensors so that their best efficiency and highest possible sensitivity is achieved. This requires the accurate knowledge of the optimum track radius and the degree of product enrichment within the tracks. These questions were answered by appropriate experi…
Radiation Characterization of Optical Frequency Domain Reflectometry Fiber-Based Distributed Sensors
2016
International audience; We studied the responses of fiber-basedtemperature and strain sensors related to Optical FrequencyDomain Reflectometry (OFDR) and exposed to high γ-ray dosesup to 10 MGy. Three different commercial fiber classes areused to investigate the evolution of OFDR parameters withdose, thermal treatment and fiber core/cladding composition.We find that the fiber coating is affected by both thermal andradiation treatments and this modification results in anevolution of the internal stress distribution inside the fiber that influences its temperature and strain Rayleigh coefficients. These two environmental parameters introduce a relative error up to 5% on temperature and strain…
Micro-Raman analysis of the fuel-cladding interface in a high burnup PWR fuel rod
2017
International audience; New insights on the fuel-cladding bonding layer in high burnup nuclear fuel were obtained using micro-Raman spectroscopy. A specimen was specifically prepared from a fuel rod which had been irradiated to an average burnup of 56 GWd.tU-1 in a pressurized water reactor (PWR). Both inner and outer corrosion scale regions were investigated. A 10-15 et956;m thick zirconia bonding layer between fuel and cladding materials which consisted of three distinct regions was observed. Close to the fuel, tetragonal, then monoclinic zirconia was identified as the main phases. Close to the bonding layer-cladding interface, peculiar Raman signals were observed. Similar signals were ob…
Recent Developments in Cladding-Pumped Doped Fiber Amplifiers for Telecommunications Systems
2020
This paper aims to review recent developments in the field of doped fiber-based optical amplifiers and serve as a reference for promising optical signal amplification techniques that may be useful for practical implementation in high-capacity and cost-efficient telecommunications systems. The main focus is put on different rare-earth dopant elements, double-clad fibers, and optical couplers for cladding-pumping technique. It is found that codoped double-clad fiber-based amplifiers currently have attained the main research interest and show possible application also in multichannel fiber optical transmission systems. Additionally, we have compared different free space and waveguide construct…