Search results for "Fiber"

White light supercontinuum generation in a Y-shaped microstructured tapered fiber pumped at 1064 nm.

2010

We report the generation of supercontinuum in a Ge-doped Y-shape tapered fiber pumped at 1064 nm in the ns pump regime. The taper was designed to have long taper transitions and a taper waist with a core diameter of 0.9 mum. The large air-filling fraction and diameter of the air-hole microstructure reduces the confinement loss at long wavelengths so, enabling the extension of the spectrum to longer wavelengths. Along the taper transition the zero-dispersion wavelength decreases as the diameter of the taper becomes smaller. The spectral components generated along the taper transition pump the taper waist, enhancing the generation of short wavelengths. A flat spectrum spanning from 420 nm to …

A strike-slip core complex from the Najd fault system, Arabian shield

2014

Metamorphic core complexes are usually thought to be associated with regional crustal extension and crustal thinning, where deep crustal material is exhumed along gently dipping normal shear zones oblique to the regional extension direction. We present a new mechanism whereby metamorphic core complexes can be exhumed along crustal-scale strike-slip fault systems that accommodated crustal shortening. The Qazaz metamorphic dome in Saudi Arabia was exhumed along a gently dipping jog in a crustal-scale vertical strike-slip fault zone that caused more than 25 km of exhumation of lower crustal rocks by 30 km of lateral motion. Subsequently, the complex was transected by a branch of the strike-sli…

Effects of confinement level, cross-section shape and corner radius on the cyclic behavior of CFRCM confined concrete columns

2014

Abstract The main results of an experimental research aiming to investigate the behavior of medium-size low-strength concrete columns wrapped with Carbon Fiber Reinforced Cementitious Matrix (CFRCM) under monotonic and cyclic compressive axial loads are presented. Thirty columns with circular, square and rectangular cross-sections were tested under monotonic and cyclic axial loads to investigate the effect of the confinement level, the cross-section shape and the corner radius on the stiffness, strength, and ductility of CFRCM confined concrete columns under cyclic loads. The results prove that CFRCM confining jackets provide substantial gain in compressive strength, deformability and absor…

2018

We present the design, fabrication and characterization of long-range surface plasmon polariton waveguide arrays with materials, mainly silicones, carefully selected with the aim to be used as mechanically flexible single-mode optical interconnections, the so-called “plasmonic arc” working at 1.55µm. The fabricated plasmonic arcs show a TM/TE polarization ratio of ~25 dB. By using the cut-back method, the straight propagation loss at 1.55µm is estimated to 0.5-1 dB/mm and coupling loss to ~1-2 dB/facet after dicing. In the free-standing S-curved configuration, the bending loss of single cladding plasmonic arc is 2.2-2.8 dB/90° at bending radius 2.5 mm. For double cladding plasmonic arcs, it…

Monitoring the Etching Process in LPFGs towards Development of Highly Sensitive Sensors

2017

Trabajo presentado en la Eurosensors 2017 Conference. París, 3–6 de septiembre de 2017. In this work, the monitoring of the etching process up to a diameter of 30 µm of two LPFG structures has been compared, one of them had initially 125 µm, whereas the second one had 80 µm. By tracking the wavelength shift of the resonance bands during the etching process it is possible to check the quality of etching process (the 80 µm fibre performs better than de 125 µm fibre), and to stop for a specific cladding mode coupling, which permits to obtain an improved sensitivity compared to the initial structure. This work was supported by the Spanish Agencia Estatal de Investigación (AEI) and Fondo Europeo…

Accurate mode characterization of two-mode optical fibers by in-fiber acousto-optics.

2016

Acousto-optic interaction in optical fibers is exploited for the accurate and broadband characterization of two-mode optical fibers. Coupling between LP01 and LP1m modes is produced in a broadband wavelength range. Difference in effective indices, group indices, and chromatic dispersions between the guided modes, are obtained from experimental measurements. Additionally, we show that the technique is suitable to investigate the fine modes structure of LP modes, and some other intriguing features related with modes' cut-off.

All-optical signal processing at ultra-low powers in bottle microresonators using the Kerr effect.

2010

We present experimental results on nonlinear, ultra-low power photonics applications based on a silica whispering-gallery-mode microresonator. Our bottle microresonator combines an ultrahigh quality factor of Q10(8) with a small mode volume V. The resulting Q(2)/V-ratio is among the highest realized for optical microresonators and allows us to observe bistable behavior at very low powers. We report single-wavelength all-optical switching via the Kerr effect at a record-low threshold of 50 microW. Moreover, an advantageous mode geometry enables the coupling of two tapered fiber waveguides to a bottle mode in an add-drop configuration. This allows us to route a CW optical signal between both …

Fiber Sensitivity Characterization near the Turning Point of the Acousto-Optic Interaction

2018

In-fiber acoustic gratings exhibit a turning point in which the sensitivity of the coupling resonances to environment changes is extremely high. The frequency of the acoustic wave enables easy matching of the turning point.

Kerr Optical Frequency Combs With Multi-FSR Mode Spacing in Silica Microspheres

2021

We experimentally demonstrate Kerr optical frequency combs (OFCs) with mode spacing of 1, 2, 3, 5, 6, and 8 free spectral ranges (FSRs) corresponding to 0.4, 0.8, 1.2, 2, 2.4, and 3.2 THz, respectively, in silica microspheres pumped by CW C-band lasers in the anomalous dispersion range. Experimental realizations are based on using standard telecom equipment and components such as SMF-28e fiber for producing microspheres and fiber tapers for pump coupling and OFC outcoupling. Numerical simulation is performed to support the experimental results and explain the observed spectral asymmetry in OFCs by the influence of the 3rd-order dispersion.

Carotenoid bioaccessibility in pulp and fresh juice from carotenoid-rich sweet oranges and mandarins.

2015

Citrus fruits are a good source of carotenoids for the human diet; however, comparative studies of carotenoids in different citrus food matrices are scarce. In this work the concentration and bioaccessibility of carotenoids in sweet oranges and mandarins with marked differences in carotenoid composition were evaluated in pulp and compared to those in fresh juice. The pulp and juice of the red-fleshed Cara Cara sweet orange variety was highly rich in carotenes (mainly lycopene and phytoene) compared to standard Navel orange, while β-cryptoxanthin and phytoene predominated in mandarins. Total carotenoid content in the pulp of the ordinary Navel orange and in the red-fleshed Cara Cara orange, …