Search results for "Optoelectronics"
showing 10 items of 2306 documents
In-Fiber Acousto-Optics for the Broadband Measurement of the UV-Induced Refractive Index Change in Photosensitive Fibers
2019
In fiber acousto-optics has been demonstrated to be a versatile, highly sensitive technique that allows characterizing different parameters of singlemode or few-mode fibers, such as dispersion curves, radius or core refractive index, in a broadband wavelength range. The working principle of the technique relies in the fact that a variation in a parameter of the fiber leads to a shift in the optical wavelength that fulfills the acousto-optic phase matching condition. Thus, by measuring this wavelength shift it is possible to evaluate the change in the parameter under study. The technique shows a low detection limit: for example, it is as low as 10-8 for the core refractive index, in singlemo…
Shaping the supercontinuum spectral profile
2009
We numerically recognize a procedure for shaping, at least to some extent, the spectral profile of the supercontinuum (SC) generated by soft-glass photonic crystal fibers (PCFs). As example, we identify a PCF geometry that provides an ultrawide (over an octave) and very flat SC when pumped with pulsed light parameters corresponding to a commercially available Er-doped femtosecond fiber laser.
Intensity-Modulated Optical Fiber Sensor for AC Magnetic Field Detection
2015
An erbium-doped (Er3+) fiber optic laser is proposed for sensing alternated magnetic fields by measuring the laser intensity modulation. The sensor is fabricated using two partially overlapped narrow-band fiber Bragg gratings (FBGs) and a section of doped fiber in a Fabry–Perot configuration. Laser power stability and bandwidth are studied while changing the overlap. A bulk rod of TbDyFe, a magnetostrictive material, is glued to both the FBGs and the laser wavelength and power are modulated according to the magnetic field. Acquisition and processing are done using virtual instrumentation. Results have shown the possibility of detecting 11.18 $\mu \text{T}_{\mathrm {{rms}}}/\surd $ Hz for an…
Generation of supercontinuum in erbium-doped microstructured optical fibers
2009
We present experimental results on supercontinuum (SC) generation in Er-doped microstructured optical fibers (MOF) pumped with nanosecond pulses at 1064 nm. The Er doping increases the effective nonlinear refractive index [1]. As a result, nonlinear interactions are enhanced and broad supercontinuum spectra are generated with relatively low pump power. Supercontinuum spectra generated in two fibers with the zero dispersion wavelengths (ZDW) close to the pump wavelength are presented. The first MOF is an endlessly singlemode fiber with normal dispersion at the pump wavelength, while the second fiber is a large air-filling fraction MOF with anomalous dispersion at 1064 nm.
Fiber-pigtailed temperature sensors based on dielectric-loaded plasmonic waveguide-ring resonators.
2012
We demonstrate optical fiber-pigtailed temperature sensors based on dielectric-loaded surface plasmon-polariton waveguide-ring resonators (DLSPP-WRRs), whose transmission depends on the ambient temperature. The DLSPP-WRR-based temperature sensors represent polymer ridge waveguides (~1×1 µm(2) in cross section) forming 5-µm-radius rings coupled to straight waveguides fabricated by UV-lithography on a 50-nm-thick gold layer atop a 2.3-µm-thick CYTOP layer covering a Si wafer. A broadband light source is used to characterize the DLSPP-WRR wavelength-dependent transmission in the range of 1480-1600 nm and to select the DLSPP-WRR component for temperature sensing. In- and out-coupling single-mod…
Tunable Four-wave Mixing Light Source Based on Photonic Crystal Fibers with Variable Chromatic Dispersion
2019
We present a detailed experimental study of fourwave mixing tuning in photonic crystal fibers that were filled either with ethanol or with heavy water. It is demonstrated that wide tuning ranges can be achieved in both cases through the variable chromatic dispersion generated by thermo-optic effect. Tunability of the signal band from 745 nm to 919 nm, and of the idler band from 1260 nm to 1759 nm is demonstrated with a pump at 1064 nm. Numerical calculations were carried out and show good agreement with experimental measurements. We present a detailed experimental study of fourwave mixing tuning in photonic crystal fibers that were filled either with ethanol or with heavy water. It is demon…
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.
<title>Use of AlN ceramics in ultraviolet radiation dosimetry</title>
2003
AlN-Y2O3 ceramics is studied as a material for application in the area of ultraviolet radiation (UVR) dosimetry. The properties of optically stimulated luminescence (OSL) and thermally stimulated luminescence (TL) revealed by AlN ceramics are characterized and considered for practical application. A special attention is devoted to studies of the spectral properties of the material, including stimulated luminescence. Spectral properties of the material make it potentially suitable for dosimetric application both in UV-C region (200-290 nm), where it has the maximum sensitivity, and in UV-B+UV-A (290-350 nm) region, where the spectral behavior of its sensitivity coincides rather well with tha…
Performance data of optically stimulable irradiated materials (doped alkali halides) oriented for imaging and dosimetry purposes
1997
Performance characteristics of a doped alkali halide (KBr:In)-based imaging plate (IP) and dosemeter (D) both the devices utilizing optically stimulated luminescence (OSL) and suitable for UV-light and x-ray energy recording are described. By exploiting (silicon) photodiode array as a photodetector, the detective quantum efficiency of 0.1 for IP (KBr:In) can be achieved. A very wide dynamic range, 1010:1 for UV (6.35 eV) and 1011:1 for x-ray (44 kV tube voltage) OSL recording at the spatial resolution of 1 mm2, is favorable for digital imaging and considerably improves image quality. These possibilities are illustrated by presenting available information capacities, energy consumption per b…
Electric breakdown of dielectric thin films for high-voltage display applications
2016
Smectic A liquid crystal is one of the most promising material for smart glass application due to infinite bistability and low haze at clear state. Voltage is needed to switch from scattering to transparent and it is likely for dielectric breakdown to occur. In order to reduce the probability of dielectric breakdown to occur, a dielectric insulating coating is usually employed. In this work we have compared electrical and optical properties of SiO2 thin films with thickness up to 500 nm coated by flexographic printing and reactive magnetron sputtering. IV characteristics and dielectric breakdown values show sputtered coatings to have higher dielectric strength. For sputtered coatings with t…