Cross-talk fiber-optic temperature sensor

The temperature sensitivity of cross talk between closely spaced cores in a common cladding is calculated and compared with measurements. A periodic variation in core contrast is observed when one core is illuminated and the temperature is changed. The variation in light distribution, which is ascribable to a change in coupling between the cores, agrees with theoretical predictions. It is shown that cross talk can be made to be a sensitive, predictable function of temperature or by proper selection of materials, wavelength, and fiber geometry essentially temperature independent.     

Field-Assisted Ion Exchange in Type III Silica

Field-assisted ion exchange of protons in type III silica for Cs or Nu ions from a molten salt was investigated. Although electrolysis occurred, infrared measurements showed no change in hydroxyl content after ion exchange for extended periods. Scanning electron microprobe studies of cesium-exchanged specimens revealed a high-cesium-content layer =2,μm thick; this layer is believed to result from surface reaction with the molten salt.     

Output characteristics of diode pumped fiber ASE sources

High power amplified spontaneous emission (ASE) from multicore Nd:fibers pumped by laser diode arrays is investigated experimentally and theoretically. Particular examination is made of threshold conditions at which lasing occurs. A model is presented which describes output power for arbitrary end reflectors. Experimental measurements of lasing threshold reflectivity versus pump power are made and are shown to deviate from the usual laser threshold condition at high pump powers. It is demonstrated that feedback from Rayleigh backscattering can be sufficient to drive the ASE source above lasing threshold in certain configurations     

Gain characteristics of Pr/sup 3+/-Yb/sup 3+/ codoped fluoride fiber for 1.3 mu m amplification

The authors report on the ability of the Pr/sup 3+/-Yb/sup 3+/ codoped system to move the pumping wavelength to wavelengths shorter than 1.017 mu m. It was demonstrated that, by codoping of Yb/sup 3+/ with Pr/sup 3+/-doped fluoride fiber, amplifiers can be moved to the spectral range where effective pumping can be done with InGaAs laser diodes that have strained-layer quantum-well structures that were developed as a pumping source for Er/sup 3+/-doped fiber amplifiers. The pumping wavelength range was extended down to 0.93 mu m.<>     

Magnification of mask fabricated fibre Bragg gratings

Bragg gratings have been formed in optical fibres by diffraction of a phase mask. This technique is expanded by allowing for the possibility of shifting the Bragg wavelength for a fixed mask periodicity. This method uses a simple lens to introduce a curvature on to the wavefront of the diffracting light that results in a magnification of the original periodicity formed by the mask. The authors show experimentally that the Bragg wavelength is shifted to a shorter wavelength by the addition of a converging lens before the mask.<>     

Some broader issues: Clinical relevance, gender sensitivity, and psychometrics.

Responds to comments by G. B. Spanier (see record 1989-17637-001) and L. Thompson (see record 1989-17646-001) on the present authors' (see record 1989-17603-001) evaluation of the Dyadic Adjustment Scale. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nonlinear refractive index of glass

The general theory of the third-order electronic susceptibility has been specialized to some model systems in order to evaluate the associated nonlinear refractive index of solid materials. The results indicate oppositely signed terms of comparable magnitude, and it is found that the dominant positive contribution involves oscillator strengths connecting excited electronic levels. Some reported values of the nonlinear index n2for various glasses are discussed in relation to the model calculations.     

Sol-Gel Synthesis of High-Quality Heavy-Metal Fluoride Glasses

Fluoride glasses are excellent laser hosts and are very well suited for a broad spectrum of optical applications. However, current fluoride glass synthesis is expensive. The solgel method is an affordable alternative for producing highperformance, optical-quality heavy-metal fluoride glasses. The method involves forming a hydrous oxide gel of the constituent metal alkoxides and salts, polymerizing the solution to form a gel, fluorinating the gel with anhydrous HF, melting the amorphous material in an oxidizing atmosphere of SF₆, and casting the melt into desired shapes. ZBLA (57ZrF₄·36BaF₂·4LaF₃·3AlF₃, in mol%) and Nd-doped (0.3 mol%) ZBLA glass rods were prepared by this process and their properties were measured. The solgel-based glasses had thermal and optical properties similar to those found in the literature for conventionally prepared fluorides.     

The assessment of marital satisfaction: An evaluation of the Dyadic Adjustment Scale.

Investigated 2 critical issues underlying the clinical and research utility of the Dyadic Adjustment Scale (DAS), a widely used self-report instrument for assessing marital satisfaction. A factor analysis of data from 219 female and 190 male parents is presented indicating support for 1 general dimension of satisfaction, rather than the 4 factors frequently used. Separate analyses of men's and women's data indicated that gender is an important variable in this field, and 1 that warrants further theoretical and empirical investigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fabrication of high-concentration rare-earth doped optical fibersusing chelates

A process which uses rare-earth complexes of 2,2,6,6,-tetramethyl-3,5-heptanedione for uniform incorporation of rare earths in the cores of optical fibers is demonstrated. It is a vapor-phase transport process capable of producing fibers having a rare-earth content of at least 11 wt.% and easily lends itself to incorporation of multiple rare-earth dopants. The process gives high rare-earth concentration with low loss and is readily adaptable to multiple rare-earth doping. High-concentration fibers, 1.0 wt.% Nd₂ O₃, necessary for the double-clad fiber laser configuration with low loss, less than 10 dB/km, have been fabricated and shown to have efficiencies approaching quantum limits when pumping well above threshold