5 Zusammenfassung 7 1 Introduction 9 1.1 High frequency requirements of modern electronic systems 10 1.2 State-of-the-art MEMS micromachining 12 1.3 State-of-the-art transmission lines and waveguides 15 1.4 Organization of the thesis 21

Two-channel imbedded directional couplers were fabricated with proton implantation, yielding complete light transfer in 2 mm. Ridged channel guides were fabricated by ion-micromachining epitaxial layers, and a method of directional coupling was demonstrated.

Liquid-immersion nanosecond-pulsed laser micromachining is introduced as an efficient way for device isolation and rapid prototyping on GaN-on-sapphire wafer. Using deionized water as an ambient medium for laser micromachining, smooth trenches that are free from redeposition can be formed in the GaN layer. Coupled with the large difference between the ablation thresholds and ultraviolet absorpt...

This thesis describes the development of advanced laser resonators and applications of laserinduced micromachining for photonic circuit fabrication. Two major advantages of laserinduced micromachining are direct patterning and writing on large areas of substrates at high speed following the exposure of laser light, without using complicated photomask steps. For passive photonic devices fabricat...

MEMS components by their very nature have different and unique failure mechanisms than their macroscopic counterparts. This paper discusses failure mechanisms observed in various MEMS components and technologies. MEMS devices fabricated using bulk and surface micromachining process technologies are emphasized.