Ultrabroadband Polarization Insensitive Hybrid using Multiplane Light Conversion

We designed, fabricated and tested an optical hybrid that supports an octave of bandwidth (900-1800 nm) and below 4-dB insertion loss using multiplane light conversion. Measured phase errors are below 3-degree across a measurement bandwidth of 390 nm.Comment: 3 pages, 4 figures, accepted by OFC 202

Efecto de los arados rotativos sobre algunas propiedades físicas de un suelo franco arcilloso

The effect of rotating plows (rotavator, power harrows and motorhoes) on some of the main physical properties in a clay loam soil Vertic Haplustalf, with alluvial parent material and slope less than 3%, was studied. Twelve experimental parcels were stablished and three different treatments and a control were applied to the soil. Values of soil bulk density, total porosity, gravimetric moisture content, penetration resistance, distribution and structural stability of aggregates were determined for treated parcels. Only significant difference was found (p<0,05) in the penetration resistance between control soil and treated with rotavator and power harrows. The remaining soil physical properties evaluated showed some variation, but were not statistically significant, so we conclude that these (rotary plows) did not alter or affect the properties in question representatively.Se estudió el efecto de diferentes arados rotativos (rotavator, grada rotativa y motoazada) sobre algunas de las principales propiedades físicas de un suelo Vertic Haplustalf, franco arcilloso, con material parental aluvión y pendiente <3%. Se establecieron 12 parcelas experimentales, en tres diferentes tratamientos y un tratamiento control. Se determinaron valores de densidad aparente, porosidad total, contenido de humedad gravimétrica, resistencia a la penetración, distribución y estabilidad estructural de agregados por parcelas tratadas. Sólo se encontró diferencia significativa (p<0,05) en la resistencia a la penetración entre el suelo testigo y los tratados con rotavator y grada rotativa. Las restantes propiedades físicas del suelo evaluadas presentaron algunas variaciones, pero no fueron estadísticamente significativas, por lo que se concluye los arados rotativos no alteraron, ni afectaron representativamente las propiedades en cuestión

Distributed Effects in High Power RF LDMOS Transistors

Abstract -This paper focuses on the effects of distributed RF transmission lines on performance aspects, such as, gain, output power, efficiency etc. in high power RF LDMOS amplifiers. The methodology to model and capture the distributed effects will be discussed. Suitable alternatives to mitigate power loss due to distributive effects in large transistors will be presented. Also, the contributions of the package to the overall device performance will be addressed

Bulk Phase Transition in YBa2Cu3O7- Single Crystals

Precise magnetization measurements of YBa2Cu3O7- single crystals have found evidence for a bulk phase transition a few degrees below the superconducting critical temperature. The phase transition is indicated by a sudden drop of the lower critical field, Hc1(T), separating a full coherent state at low fields and temperatures, the Meissner state, from a region at higher temperatures where magnetic excitations are induced at H=0

Observation of Two-Dimensional Vortices in Bi2Sr2CaCu2Ox

We report transport measurements in the mixed state of single crystals of Bi2Sr2CaCu2Ox using a modified version of the dc flux transformer geometry pioneered by Giaever in low-Tc materials. We find that over a wide range of the phase diagram the vortices are effectively two dimensional in character. Our results suggest that vortex cutting is an efficient process and that it is unlikely that the vortices are strongly entangled in this region of the phase diagram

López Et Al. Reply

A Reply to the Comment by Yu. Eltsev and O. Rapp

Observation of a Nonlocal Conductivity in the Mixed State of YBa2Cu3O7-Δexperimental Evidence for a Vortex Line Liquid

We report on transport measurements in the mixed state of YBa2Cu3O7 single crystals using the dc flux transformer geometry. In the vortex fluid regime we have observed the onset of a nonlocal conductivity. At lower temperatures, close to but above the phase transition temperature the vortices become effectively three dimensional in character. This is in sharp contrast to recent flux transformer experiments on Bi2Sr2CaCu2O which have failed to see a nonlocal conductivity, confirming the two-dimensional character at high temperatures of the vortices in that system. These observations suggest that in a finite temperature interval, the vortex state in YBa2Cu3O7 is a line liquid

Logarithmic-to-Nonlogarithmic Flux-Creep Transition and Magnetic-Flux Hardening in Bi-Sr-Ca-Cu-O Superconducting Ceramics

A sharp temperature- and field-dependent transition from a logarithmic to a nonlogarithmic flux-creep behavior has been found in Bi-Sr-Ca-Cu-O superconductors. The transition is not followed by any noticeable change in the magnetization. However, vibrating-reed measurements show that it coincides with a strong hardening of the magnetic structure. The transition occurs at fields and temperatures well below the reversibility line. The possible relation to the recently proposed flux lattice melting is discussed

Experimental Evidence of a Non-Local Resistivity in a Vortex Line Liquid

We present transport measurements on YBCO single crystals in the vortex liquid regime using the DC flux transformer geometry. We show that the data are inconsistent with the material being an anisotropic, local conductor. The results provided evidence for non-local transport which indicate that there can be correlated vortex motion over macroscopic distances in this system. We have shown that this correlated vortex motion can be destroyed by either thermal fluctuations or the applications of large driving forces