Search

Ray-tracing calculations are employed to identify basic design rules for the configuration of microstructured daylighting systems. The results show the advantage of combinations of lenslike geometries in comparison to conventional microprism arrays regarding the overall light redirection efficiency as well as the producibility and cost efficiency. Measurements at silicone prototypes and large scale industrially produced acrylic panels confirmed the simulation results. Optimization leads to free-form geometries which can further be improved by selective roughening of specific microsurfaces.

Based on the standards for optical components in telecommunications (Telcordia) and general printed circuit boards (Institute of Printed Circuits and International Electro Technical Commission), three environmental stability verification tests are concluded for polysiloxane-based electrical-optical circuit boards (EOCBs). In terms of defined test models, the respective acceleration factors are determined. Combining the acceleration factors and proposed reliability objective of 400 failures in time (FITs) (one FIT is equal to one device failure in 10(9) device hours of operation) at the 90% confidence level, EOCB test sample size to each acceleration test are deduced, and a corresponding amount of samples are prepared for mechanical and optical stabilities verification. In addition to the good mechanical stability the results exhibit, the packaged EOCBs have low and stable optical loss values (0.1 dB/cm) and numerical aperture even at extreme environmental conditions. Furthermore, a total failure rate of 400 FITs is predicted for 14.4 yr of operation at 25 degrees C and moderate humidity conditions (20% relative humidity).

The refractive index profiles of titanium-diffused LiNbO(3) planar and channel waveguides are determined directly by measuring the reflectivity of angular polished surfaces. Three measurement techniques are described and compared: (1) large area illumination of the angular polished waveguide and imaging of the reflected light to a vidicon, (2) scanning of a focused beam across the sample, and (3) scanning of the sample under a focused beam. Preference is given to the last method which provides an accuracy of Deltan/n = 10(-4) with a local resolution of the index profile of