Search results for "Photonic-crystal fiber"

Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber

2009

Nonlinear femtosecond pulse propagation in an all-solid photonic bandgap fiber is experimentally and numerically investigated. Guiding light in such fiber occurs via two mechanisms: photonic bandgap in the central silica core or total internal reflection in the germanium doped inclusions. By properly combining spectral filtering, dispersion tailoring and pump coupling into the fiber modes, we experimentally demonstrate efficient supercontinuum generation with controllable spectral bandwidth.

Waveguiding properties of a photonic crystal fiber with a solid core surrounded by four large air holes

2009

The polarization-dependent guiding properties of a hexagonal-lattice photonic crystal fiber with a solid-core surrounded by four large air holes are investigated. The appearance of a polarization dependent cutoff frequency, together with several parameters as the birefringence, the modal effective area, the group velocity dispersion and the polarization dependent loss are analyzed. A collection of fibers with different structural parameters were fabricated and characterized. An effective anti-guide structure from at least 450 nm to 1750 nm, a polarizing fiber with a polarization dependent loss of 16 dB/m at 1550 nm, and an endlessly singlemode polarization-maintaining fiber with group biref…

2017

Tailored tellurite-glasses possess excellent thermo-viscous ability and linear/nonlinear optical properties. Here, bringing together the merits of these materials with fiber optic technology, we report on the first tellurite-based core-clad dual-electrode composite fiber made by direct, homothetic preform-to-fiber thermal co-drawing. The rheological and optical properties of the selected glasses allow both to regulate the metallic melting flow and to manage the refractive index core/clad waveguide profile. We demonstrate the electrical continuity of the electrodes over meters of fiber. We believe the drawing of architectures merging electrical and optical features in a unique elongated wave…

Application prospects of silica core side-glowing optical fibers

2005

The side-emitting optical fibers are specially designed to stimulate leakage of the core-transmitted radiation via their side surfaces, so creating the effect of glowing tiny wires. The basic design concepts for this kind of optical fibers are discussed, as well as some of the present and potential future applications.

A Refractive Index Sensor Based on the Resonant Coupling to Cladding Modes in a Fiber Loop

2013

We report an easy-to-build, compact, and low-cost optical fiber refractive index sensor. It consists of a single fiber loop whose transmission spectra exhibit a series of notches produced by the resonant coupling between the fundamental mode and the cladding modes in a uniformly bent fiber. The wavelength of the notches, distributed in a wavelength span from 1,400 to 1,700 nm, can be tuned by adjusting the diameter of the fiber loop and are sensitive to refractive index changes of the external medium. Sensitivities of 170 and 800 nm per refractive index unit for water solutions and for the refractive index interval 1.40-1.442, respectively, are demonstrated. We estimate a long range resolut…

Management of OH absorption in tellurite optical fibers and related supercontinuum generation

2013

Abstract We report the fabrication and the characterization of low OH content and low loss tellurite optical fibers. The influence of different methods of glass fabrication on fiber losses has been investigated. The use of the purest commercial raw materials can reduce the losses below 0.1 dB/m at 1.55 μm. Incorporation of fluoride ions into the tellurite glass matrix makes the optical fibers transparent up to 4 μm. A suspended core microstructured fiber has been fabricated and pumped by nanojoule-level femtosecond pulses, thus resulting in more than 2000-nm bandwidth supercontinuum after a few centimeters of propagation.

Visible Light Generation and its Influence on Supercontinuum in Chalcogenide As2S3 Microstructured Optical Fiber

2011

We demonstrate visible light generation in chalcogenide As2S3 microstructured optical fiber. The generated visible light causes irreversible damage to the fiber core because of the high absorption coefficient of chalcogenide glasses in the visible band. The SCs (supercontinua) are measured in both untapered and tapered As2S3 fibers, no wider SC is obtained in the tapered one. The SC growth is prevented by the visible light generation since the damage to the fiber core decreases the fiber transmission substantially. This effect can be avoided by designing the fiber to enable the pump source to work in single-mode operation.

Resonant and thermal changes of refractive index in a heavily doped erbium fiber pumped at wavelength 980 nm

2004

We report a theoretical and experimental study of the refractive index variation in a heavily doped erbium silica fiber within the spectral range 1500-1580 nm under the pumping at the wavelength 980 nm. The two main contributions in the refractive index change are addressed the resonant part determined by the saturation effect in the fiber and the thermal part stemming from the fiber heating due to the excited-state absorption and Stokes losses. We demonstrate that the thermal contribution in the resultant refractive index change is a notable value, which is the feature of erbium fibers with a high concentration of erbium ions.

Fundamental-mode cutoff in liquid-filled Y-shaped microstructured fibers with Ge-doped core

2008

We report on the cutoff characteristics of a Ge-doped Y-shaped microstructured fiber in which the holes are filled with a liquid of refractive index higher than silica but lower than the Ge-doped core. It is found that the cutoff wavelength was very sensitive to temperature variations as a result of the refractive index changes of the liquid. The basic properties of such a fiber permit the fabrication of wideband tunable short-pass filters, as well as temperature sensors with high sensitivity. A temperature sensitivity of 25 nm/degrees C is reported.

Multioctave midinfrared supercontinuum generation in suspended-core chalcogenide fibers

2014

An As2S3 fiber-based supercontinuum source that covers 3500 nm, extending from near visible to the midinfrared, is successfully reported by using a 200-fs-pulsed pump with nJ-level energy at 2.5 μm. The main features of our fiber-based source are two-fold. On the one hand, a low-loss As2S3 microstructured optical fiber has been fabricated, with typical attenuation below 2 dB/m in the 1-4 μm wavelength range. On the other hand, a 20-mm-long microstructured fiber sample is sufficient to enable a spectral broadening, spreading from 0.6 to 4.1 μm in a 40 dB dynamic range.