Gain-coupled DFB lasers with a titanium surface Bragg grating

The improved performance of gain-coupled DFB lasers incorporating a titanium surface Bragg grating and a strained layer multiquantum well active region for operation at 1.55 μm is presented. Besides the essentially simplified fabrication process, the incorporation of the metallic, absorptive grating yields stable singlemode operation with a high sidemode suppression     

Gain-coupled strained layer MQW-DFB lasers with an essentiallysimplified fabrication process for λ=1.55 μm

A gain-coupled (GC) strained-layer (SL) multi-quantum-well (MQW) distributed-feedback (DFB) laser with a metallized surface grating and a substantially simplified fabrication process made by single-step epitaxy without corrugation overgrowth is described. The complex coupling coefficient can be adjusted by the contact metallization. Room-temperature single-mode continuous-wave (CW) operation with a threshold current of 22 mA, an output power of 20 mW, and a linewidth of 2.5 MHz is demonstrated     

A Modelling Approach to Tire-Obstacle Interaction

In order to improve the behavior of heavy off-road vehicles,the use of numerical simulation has become an absolutely necessarystage. The main difficulty resides in the validity of the tire-groundinteraction model, for a large range of obstacles and test courses, andat all acceptable speeds. In this paper, a new obstacle-tireinteraction model has been presented. Starting from the simple fact thatvertical tire behavior depends essentially on the air contained in thetire, this approach is based on the tire air volume optimisation. Thismodel has been investigated in the case of tire statical deflection, andgood correlation has been obtained with experimental results.     

Fine mapping of the Darier's disease locus on chromosome 12q

Darier's disease (DD) is an autosomal dominant genodermatosis characterized by epidermal acantholysis and dyskeratosis. We have performed genetic linkage studies in 10 families with DD (34 affected) by analyzing 14 polymorphic microsatellite markers. Our results confirm recent reports mapping the DD gene to chromosome 12q23-q24.1. Haplotype analysis of recombinant chromosomes in our families, along with previously reported data, narrow the location of the DD gene to a 5 cM interval flanked by the loci D12S354 and D12S84/D12S105. This localization allowed exclusion of two known genes, PLA2A and PAH, as candidate loci for DD. Three other gene loci (PPP1C, PMCH, PMCA1), mapping in 12q21-q24, remain potential candidates.     

Modulation characteristics of double-heterostructure superluminescent diodes

High-speed double-heterostructure GaAs superluminescent diodes have been fabricated. Risetimes of 2 ns at optical linewidths of 10 nm have been achieved.     

FM noise and power-dependent linewidth of GaAs/AlGaAsGRINSCH-SQW-MCRW flared waveguide lasers

The power-dependent part of the linewidth of GaAs/AlGaAs GRINSCH-SQW flared waveguide lasers has been determined from FM noise measurements. For the linewidth-power product a low value of 4 MHz mW has been found, which can be related to the small spontaneous emission coefficient β_sp≃(3.7±1)×10^-6 and a linewidth enhancement factor α≃1.2±0.5