FORLAS

RESEARCH ASSOCIATION LASER TECHNOLOGY

II/1 Laser Assisted Assembly of Microoptical Components

Field of work:

For the coupling of optical fibers to optical chips or electro-optical components, laser assisted methods of joining should replace gluing. Alternative joining methods are relevant, because adhesive bonds tend towards degradation under the influence of temperature and moisture. Aim of this project is the laser assisted fixation of optical fibers in anisotropically etched V-grooves of silicon submounts. Because of the anomaly of silicon during phase transformation, a positive joining can be realized by laser beam welding. A melt pool is created through the energy of a Nd:YAG-laser pulse. During solidification, the volume of silicon expands and a bump is formed in the center. Experiments have shown that this phenomenon can be used for joining optical fibers in silicon-V-grooves. With suitable parameters the silicon flows half around the fiber during solidification. For each fiber, several welding points are necessary. For laser soldering it is necessary to metallize both, the V-grooved silicon submount and the silicon or silica cover plate. After the deposition of solder, the silicon parts and the optical fibers are soldered with a Nd:YAG-laser. In comparison with adhesive bonds, a rise in reliability of the soldered joint is expected.

Application:
The results of this project are important for the coupling of optical fibers to optical chips or electro-optical components. Examples for optical components are power splitter, attenuators and arrayed waveguide multiplexer.