Search results for "cladding"
showing 10 items of 62 documents
Core-clad phosphate glass fibers for biosensing
2019
Recently, a phosphate glass with composition 20 CaO-20 SrO-10 Na2O-50 P2O5 (mol%) was found to have good potential as a biomaterial and to possess thermal properties suitable for fiber drawing. This study opened the path towards the development of fully bioresorbable fibers promising for biosensing. In the past, this phosphate glass with CeO2 was found to increase the refractive index and the glass stability. Therefore, a new SrO-containing glass was prepared with 1 mol% of CeO2 and core fibers were drawn from it. A core-clad fiber was also processed, where the core was a Ce-doped glass and the clad undoped, to allow for total internal reflection. The mechanical properties of the core and c…
Fabrication of long period fiber gratings of subnanometric bandwidth.
2017
This paper reports on the fabrication of long period fiber gratings having subnanometric bandwidth in the 1500 nm spectral region. Large gratings have been photo-inscribed in a high NA fiber, the grating pitch and the order of the HE cladding mode are optimized to produce gratings with a large number of periods and preventing the coupling to TE, TM or EH modes. Resonances with a FWHM of 0.83 nm and 0.68 nm have been achieved for gratings 15 and 20 cm long respectively, the free spectral range between transmission notches is 125 nm. The polarization effects and the sensitivity of the gratings to temperature and to strain variations are presented as well. © 2015 Optical Society of America Thi…
All-organic electro-optic waveguide modulator comprising SU-8 and nonlinear optical polymer
2017
Institute of Solid State Physics, University of Latvia (SJZ/2016/26); Ministry of Education and Science, Republic of Latvia (MultIfunctional Materials and composItes, photonicS and nanotechnology (IMIS2)). We acknowledge Dr. Anatolijs Sarakovskis at Institute of Solid State Physics for the XPS measurements.
Overview of radiation induced point defects in silica-based optical fibers
2019
International audience; Silica-based optical fibers, fiber-based devices and optical fiber sensors are today integrated in a variety of harsh environments associated with radiation constraints. Under irradiation, the macroscopic properties of the optical fibers are modified through three main basic mechanisms: the radiation induced attenuation, the radiation induced emission and the radiation induced refractive index change. Depending on the fiber profile of use, these phenomena differently contribute to the degradation of the fiber performances and then have to be either mitigated for radiation tolerant systems or exploited to design radiation detectors and dosimeters. Considering the stro…
Etched LPFGs in reflective configuration for sensitivity and attenuation band depth increase
2016
A reflection configuration setup for long-period fiber gratings is presented. It permits to obtain a unique band with attenuation double than that obtained in transmission configuration, which is interesting for applications where this value is reduced (e.g., the mode transition phenomenon). The method is based on the deposition of a silver mirror at the end of the optical fiber, which permits to absorb the power transmitted through cladding modes and to avoid the generation of interferometric bands. The method also solves the requirement of a precise cleave or to polish the end of the grating, a drawback present in other publications. The versatility of the setup has been proved by applica…
Fiber Characterization Using Whispering Gallery Modes(Invited)
2019
Fiber whispering gallery modes (WGMs) are surface waves that propagate azimuthally along the outer surface of the fiber cladding. Those waves that are in phase every turn give rise to narrow resonances defined by the resonant wavelength and a high Q factor. The actual values of the resonant wavelengths depend on the radius and the refractive index of the fiber cladding, enabling the development of several fiber characterization techniques. In addition, the typical high Q factor of these resonances (Q > 106) provides the characterization techniques with a low detection limit. Here, we report the development of a technique for measuring temperature profiles along the optical fiber, which enab…
Experimental analysis of distributed pump absorption and refractive index changes in Yb-doped fibers using acousto-optic interaction.
2015
In-fiber acousto-optic interaction is used to characterize the refractive index changes at the C band in a single-mode ytterbium-doped optical fiber under 980 nm pumping. The transmission notch created by the acoustic-induced coupling between the core mode and a cladding mode shifts to longer wavelengths when the pump is delivered to the fiber. The electronic contribution to the refractive index change is quantified from the wavelength shift. Using a time-resolved acousto-optic method, we investigate the distribution of pump absorption, and the resulting refractive index change profile, along sections of ytterbium-doped fiber exceeding 1 m long under different pump power levels.
Aging resistance of bio-epoxy jute-basalt hybrid composites as novel multilayer structures for cladding
2017
Abstract Aging resistance of jute reinforced laminates is compared with two jute/basalt hybrid laminates prepared with different stacking sequences (i.e., sandwich and intercalated configuration). To this aim, composites are exposed to cyclic conditions comprising hygrothermal stress and UV radiation to promote an accelerated aging, for a period of 84 days. Specimens of each laminate are tested after 14, 28, 56 and 84 days, respectively. Quasi-static flexural tests, Charpy impact tests and dynamic mechanical tests are performed according to international ASTM and ISO standards. Furthermore, scanning electron microscopy and differential scanning calorimetry are used to evaluate the morpholog…
Ultralow chirp photonic crystal fiber Mach-Zehnder interferometer
2018
A photonic crystal fiber Mach-Zehnder interferometer design was optimized to obtain high performance and ultralow chirp. Two long-period gratings were used to excite the cladding modes, and the rich structure of the cladding was tailored to obtain a slightly chirped free spectral range, as required by the Telecommunication Standardization Sector of the International Telecommunication Union (ITU-T) Norm G.694.1. Finally, a fabrication tolerance analysis was performed. The advantages of the proposed device are an ultralow chirp, high bandwidth, and fabrication robustness tolerance.
High-repetition rate acoustic-induced Q-switched all-fiber laser
2005
We report a high repetition rate actively Q switched all fiber laser. The acousto optic interaction controls the cou pling between co propagating core and cladding modes and is used to modulate the optical losses of the cavity, which permits to perform active Q-switching. Using 1.4 m of 300 ppm Er-doped fiber and a maximum pump power of 120 mW, we have obtained up to 1 W peak power pulses, with a pulse repetition rate that can be continuously varied from 1 Hz to 120 kHz and a pulse width that changes from 70 ns to 2.2 μs.