Biasing

About: Biasing is a research topic. Over the lifetime, 29422 publications have been published within this topic receiving 301035 citations.

Fiberoptic transmitter using thermistor to maintain stable operating conditions over a range of temperature

Abstract: Techniques for controlling the operation of a laser diode to maintain optimum operating characteristics (i.e., fairly constant output power and extinction ratio) despite the fact that the threshold current and slope efficiency vary greatly over a the desired range of operating temperature. A laser driving circuit includes a bias current generator, a temperature-dependent modulation current generator, and a switching element for switching the modulation current on and off in accordance with a desired input pattern. The modulation current is caused to vary with temperature in a manner that compensates for the fact that the laser diode's slope efficiency varies with temperature.

Current–voltage instabilities in GaN/AlGaN resonant tunnelling structures

Abstract: GaN/AlGaN double barrier resonant tunnelling structures grown by molecular beam epitaxy on GaN templates have been studied. Peaks in the I(V) characteristics are observed, which are similar to resonant peaks seen in conventional III–V based devices. However, the behaviour of the peaks in I(V) depend upon the previous charge-state of the device produced by electrical bias. Current instabilities are also observed at low voltages. The possible origin of the peaks in the I(V) at room temperature and 4 K is discussed. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Cathodic arc evaporation of (Ti,Al)N coatings and (Ti,Al)N/TiN multilayer-coatings—correlation between lifetime of coated cutting tools, structural and mechanical film properties

Abstract: (Ti,Al)N and (Ti,Al)N/TiN multi-layer coatings were deposited by cathodic arc evaporation with a large area TiAl and/or Ti cathode. The ratio of Ti/Al varied between 50/50, 40/60 and 33/67. The goal was to determine the influence of the bias voltage, which varied between −30 and −125 V, on the lifetime of coated cutting tools under drilling conditions. Film orientation and compressive stress were determined by X-ray diffraction. The chemical composition of the coatings was investigated by secondary-neutral-mass spectrometry (SNMS). It was found, that in the multi-layer coatings, there is a transition in the texture from 〈2 0 0〉 to 〈1 0 0〉 with increasing negative bias voltage, beginning at approximately −75 V, while the monolayer retained 〈2 0 0〉 orientation. The stress in the monolayers reached a maximum at a bias voltage approximately −100 V. Rockwell and Scratch tests show excellent adhesion on carbide and steel materials. Multilayer tool lifetime reached a maximum at −100 V, while the monolayer coated tool life increased monotonically with negative bias.