Current crowding of a micro spring pressure contact under high current is studied. The spring conducts >; 250 mA electrical current between chips, has large mechanical compliance (>; 30 μm) compared to other packaging technologies, and fits in a 180 μm pitch 2d array. At 250 mA and 65°C, daisy chains of 134 spring contacts in a silicon package show stable resistances and hot spot temperature rises of less than a degree. At 1 A, failure near the spring tip or body is observed. Finite element modeling is performed to study the current density distribution and provide failure spot insight. A strategy is proposed to avoid current crowding.

Resonant filters in waveguides with vertical gratings have been realized on a silicon-on-insulator wafer. Two identical uniformly distributed Bragg reflectors with vertical gratings are separated by a quarter wavelength phase offset. Experimental studies show a broad stopband and a narrow transmission band which shifts with changing substrate temperature that is also illuminated by an external laser pump beam at 514-nm wavelength. Experimental results on a low-frequency thermal modulation using an external light source are also presented

Summary form only given. GaAsSb/GaAs quantum wells grown on GaAs substrates are a potential active material for the monolithic growth of 1.3 /spl mu/m VCSELs. In this material system we determine a type II band alignment, with a small conduction band offset /spl Delta/E/sub c/ = 100 meV. We measure material gain coefficients comparable to those of type I InGaAs quantum wells, although under flat band conditions the electrons and holes are spatially separated.

We demonstrate a wavelength monitor and a two-wavelength detector based on two single-quantum-well absorbers that sample a standing wave created by a distributed Bragg reflector. As a wavelength monitor, our device is power independent over a 15 dB range. Wavelength discrimination is linear over a 12 nm range.

We present AMOEBA: a single-chip asynchronous multiprocessor optoelectronic bit-sliced arrayed crossbar switch intended to provide switched interconnection between multiple processors in a distributed computing environment. AMOEBA relies on optoelectronic-VLSI integration, free-space optical interconnects, and wavelength-and-space-division multiplexed networking on single-mode fiber. We report the implementation and testing of a first generation, 16-channel prototype of the switch and a compact opto-mechanical transceiver package that accomplishes the free-space-to-fiber interfacing.

We describe the first investigations of hydrogenation on multiple-quantum-well (MQW) optical modulator structures. In particular, we have studied Schottky-barrier modulator structures. We find that hydrogen has a marked beneficial effect on the photocurrent collection efficiency of Schottky-barrier-based MQW modulators. Further, room temperature photoluminescence intensity of our samples was 25 times larger with hydrogen exposure. Both of these results suggest that carrier lifetimes in our samples are increased by hydrogenation, indicating that deep-level non-radiative recombination centers are passivated by hydrogenation. Further, we find that shallow-donor levels are also passivated.

Several authors have demonstrated that quantum well (QW) structures in which the quantum well is graded, stepped, or otherwise modified from the standard square geometry can have an improved quantum-confined Stark effect (QCSE). However, relatively few of these structures have been studied in geometries containing sufficient quantum wells for real modulator use. Here, we report the experimental study of 60-period multiple-quantum well (MQW) structures with photocurrents and in transmission. We have experimentally compared QW geometries containing single- and double-step structures to a standard square QW.

We report the remarkable observation of strong room-temperature excitonic features in the absorption spectra of GaAs-AlxGa1−xAs quantum wells (QWs) for values of x as low as 0.02. This has important implications for high-power modulators, since saturation intensities have been shown to be higher in QW modulators with low barriers. In addition, very shallow QWs have enhanced electroabsorption at small biases because of ease of ionization. In our p-i(multi-QW)-n device with x=0.02, we obtain a transmission change from 29% to 47% for a voltage change from +1 to −3 V.

We have studied excitonic effects in resonantly coupled GaAs/A1GaAs multiple quantum wells. We use photocurrent spectroscopy to deduce the resonant field from the field-dependent exciton energies, and find an unexpected variation of -10% in the resonant field between different excitonic transitions involving the same coupled electron levels. We construct a variational model of the coupled excitons which explains the results in terms of Coulomb mixing of the delocalised electron states.