Mesa-structuring of InGaAs/InAlAs photoconductive layers is performed employing a chemical assisted ion beam etching (CAIBE) process. Terahertz photoconductive antennas for 1.5 microm operation are fabricated and evaluated in a time domain spectrometer. Order-of-magnitude improvements versus planar antennas are demonstrated in terms of emitter power, dark current and receiver sensitivity.

A device concept for laterally extracting selected wavelength from an optical signal travelling along a waveguide, for operation in metropolitan area networks, is presented. The signal on the fundamental mode of a multimode photonic crystal waveguide is coupled to a higher-order mode, at a center frequency that spatially depends on the slowly varying guide parameters. The device is compact, intrinsically fault-tolerant, and can split any desired fraction of the signal for monitoring purpose. Characterizations by the internal light source technique validate the optical concept while an integrated device with four photodiodes qualifies its potential with respect to real-world applications

Electrical bandwidth of 60 GHz and optical bandwidth exceeding 35 GHz, limited by the photodetector response, are demonstrated for an electrooptically-modulated VCSEL. The maximum single mode power approaches 3mW continuous wave. Modulation voltage efficiency factor is 3-10 dB/V.

The optical properties of molecules adsorbed on a metal/electrolyte interface depend on the electric field across the double layer. The changes with the electrode potential can be measured by modulation reflection spectroscopy. This provides a method for measuring specifically optical properties of the adsorption layer.

The self-aligned flip-chip (FC) bonding technique is a very attractive means for the assembly of photonic devices containing multiple optical as well as electrical waveguide interconnects. In this article we propose a fluxless FC-bonding technology which nevertheless ensures efficient solder oxide reduction by applying molecular hydrogen (H2) under vacuum conditions. Bonding experiments were carried out in a newly developed FC-bonder of which some interesting details are reported. Reproducable bonding accuracies below the required tolerances for fiber to tapered waveguide coupling of