Optischer 2x2-Schalter mit zwei variablen optischen Abschwächern und integrierter Pegelmessung

Abstract: The present work focuses on the development of a micromechanical system which integrates the functionalities of switching, attenuating and monitoring into a single device. The wanted system aims at the market of 2x2 Add-Drop-Switches for single-mode telecommunication networks. This thesis provides principles, assessment criterions, general consideration and theoretical background to implement such a system. The gathered fundamentals are demonstrative techniques, which are necessary to understand the arising difficulties, to design the system and to estimate the expected optical losses. The considerations concerning the loss calculation results in a proposed demonstrative way to trace off-axis Gaussian beams through optical systems. A novel switching principle is presented which accomplishes to switch and attenuate two independent light paths with only two actuators. Two mirror sliders are attached as cross-beams to parallelogram lever arms. Both mirror units are introduced into the beam lines. Focusing on this principle a prototype is designed implementing lensed fibers which permit a fabrication by means of enhanced precision engineering technologies. Key features of the developed micromechanical system are: An independence of wavelength and of polarization, a scalable planar flexture hinge layout and a fabrication of all optical parts in a single process step by means of ultra precision milling. A later advancement to implement a latching option is considered. The prototype is easy to assemble and no active alignment steps are required. Low cost piezo benders are utilized as actuators. The system’s performance is predicted. An optical loss lower than 4dB and a switching speed faster than 1/50s are expected form the calculations if a structural accuracy of at least 5µm is achieved and the angular deviations do not exceed 0.1 degree. The conducted calculations do not consider losses caused by mirror surface roughness. Although the optical structure is manufactured in one piece and simple in design, the fabrication of the needed vertical mirror surfaces with a height of 350µm is challenging if a fabrication process suitable for a mass product is considered. By design advancement this height could be reduced to 100µm in future. Beside all fabrication difficulties of the proposed new attenuating switch, it integrates two main components of optical networks into a single device. The new principle saves actuators, the number of beam couplings is divided by two and the fabrication of the whole unit in one piece reduces the assembly and alignment work reasonably