Search results for "Fiber optic"
showing 10 items of 193 documents
Experiments with a fiber-based optical dipole trap for cold Cs-Atoms
2011
Pulling a standard optical fiber to a diameter of less than the wavelength of the guided light causes the light field to project slightly over the fiber boundaries in form of an evanescent wave. The latter can be used for light-matter-interactions in the vicinity of the surface of the fiber and therefore allows to perform quantum optic experiments.
Evolution of Photo-induced defects in Ge-doped fiber/preform: influence of the drawing
2011
International audience; We have studied the generation mechanisms of two different radiation-induced point defects, the Ge(1) and Ge(2) centers, in a germanosilicate fiber and in its original preform. The samples have been investigated before and after X-ray irradiation using the confocal microscopy luminescence and the electron paramagnetic resonance techniques. Our experimental results show the higher radiation sensitivity of the fiber as compared to the perform and suggest a relation between Ge(1) and Ge(2) generation. To explain our data we have used different models, finding that the destruction probability of the Ge(1) and Ge(2) defects is larger in fiber than in preform, whereas the …
Influence of Drawing Conditions on the Properties and Radiation Sensitivities of Pure-Silica-Core Optical Fibers
2012
International audience; The structure and radiation sensitivities of three different pure-silica-core fluorine-doped-cladding optical fibers, made from the same original preform, were investigated by several experimental techniques. The fibers were obtained by changing the drawing speed and tension in the typical ranges of values used for the radiation-tolerant waveguides. The Raman spectroscopy revealed no significant difference among the fibers before irradiation. At variance, the comparison between the fibers and their associated preform highlighted an increase in the amplitude of the D2 band that is related to the concentration of 3 member rings. Moreover, in the zones where the D2 incr…
Plastic optical fibers for transmission and sensors
2005
This paper presents state and ways of development of plastic optical fibers (POF) for use in transmission-measuring devices for small area object networks (LAN networks in stationary and dynamic objects). Transmission links (with new fiber optics, simple optical components -- optical transmitters/receivers) allows nowadays transmission speed of a few Gb/s for a distance of hundreds meters. Properties and advantages of solutions based on plastic optical fiber for control, communication and managing are shown. Example practical solutions, regarding entering new standards and technologies, presents technical and economical advantages, compared to difficult and unfortunately expensive technolog…
Raman based distributed fiber optic temperature sensors for structural health monitoring in radiation environment
2015
Raman distributed temperature sensor (RDTS) measurements were performed during γ-radiation on three different classes of standard multimode fibers (pure, Ge-doped and F-doped). The sensor response is affected by the radiation induced attenuation phenomena leading to errors in the temperature measurements. The amplitude of this error strongly depends on the fiber type and the irradiation conditions. These results are promising in view of the integration of these RDTS into the deep geological repository for radioactive waste.
<title>Optical fiber loop sensors</title>
2003
Article presents prepared and tested constructions of loop hybrid fiber optical sensors with light amplitude modulation used for measuring loads and temperature.
Two-wave interferences space-time duality: Young slits, Fresnel biprism and Billet bilens
2017
International audience; Taking advantage of the analogy that can be drawn between the spatial and temporal propagations, we explore two-wave temporal interference in textbook cases such as Young's double slits, Fresnel's biprism and Billet's bilens. We illustrate our approach by numerical simulations for short pulses propagating in dispersive optical fibers with parameters typical of those found in modern optical telecommunications.
Steady state γ-ray radiation effects on Brillouin fiber sensors
2015
International audience; Brillouin optical time-domain analysis (BOTDA) sensors offer remarkable advantages for the surveillance of the planned French deep geological radioactive wastes repository, called Cigéo1,2. In this work we study the performances of Brillouin distributed sensors in harsh environment. We evaluate the radiation tolerance of different sensor classes and their responses evolution during γ-ray exposition with 1kGy/h dose rate (to reach ~0.2MGy) and after 1, 3, 6 and 10 MGy accumulated doses. Measurements on strained Ge-doped SMF are reported to highlight the variation on Brillouin scattering proprieties, both intrinsic frequency position of Brillouin shift and its dependen…
Nonlinear repolarization dynamics in optical fibers: transient polarization attraction
2011
International audience; In this work, we present a theoretical and experimental study of the response of a lossless polarizer to a signal beam with a time-varying state of polarization (SOP). By lossless polarizer, we mean a nonlinear conservative medium (e.g., an optical fiber) that is counterpumped by an intense and fully polarized pump beam. Such a medium transforms input uniform or random distributions of the SOP of an intense signal beam into output distributions that are tightly localized around a well-defined SOP. We introduce and characterize an important parameter of a lossless polarizer--its response time. Whenever the fluctuations of the SOP of the input signal beam are slower th…
High-speed and high-resolution interrogation of FBG sensors using wavelength-to-time mapping and Gaussian filters
2019
In this work we report a novel intensity-based technique for simultaneous high-speed and high-resolution interrogation of fiber Bragg grating (FBG) sensors. The method uses a couple of intensity Gaussian filters and the dispersion-induced wavelength-to-time mapping effect. The Bragg wavelength is retrieved by means of the amplitude comparison between the two filtered grating spectrums, which are mapped into a time-domain waveform. In this way, measurement distortions arising from residual power due to the grating sidelobes are completely avoided, and the wavelength measurement range is considerably extended with respect to the previously proposed schemes. We present the mathematical backgro…