1 Department of Photonics Engineering, Technical University of Denmark2 Department of Micro- and Nanotechnology, Technical University of Denmark
This thesis is a part of the ph.d. work: packaging of integrated optical components carried out in collaboration between IONAS A/S and COM at the Technical University of Denmark. The work has mainly been concentrated on developing a new passive alignment method of planar waveguide components, but also a silicon motherboard for laser diode pigtailing and a Variable Optical Attenuator have been realized. The pigtailing method consists of three major parts: a waveguide chip with alignment trenches, a fiber array with alignment trenches, and a top plate with alignment rails. The top plate aligns the waveguide chip and the fiber array with respect to each other. A process sequence for each of the three parts has been developed. It has been shown that the additional processing steps to fabricate the alignment trenches on the waveguide chip can be applied without altering the performance of the waveguides. The fiber array carrier and the top plate are fabricated by potassium hydroxide (KOH) etching. A method to align the mask pattern to the crystal orientation of the silicon substrate has been implemented. The impact of the etch of the nitride layer, used as an etch mask in KOH, on the line widths of the critical structures has been studied. The influence of the process parameters of a RIE etch process has been investigated with respect to the etch rate uniformity. After processing the variation of the line widths of the critical structures on the fiber array carrier and the top plate is determined. The quality of the facet of the wavguide chip has been investigated. The dicing process has been optimized to obtain a smooth facet. Furthermore, a polishing setup and procedure have been implemented. Finally, the assembly of the pigtailing parts has been implemented and evaluated. The parts are attached by applying an adhesive. The influence of the viscosity of the adhesive has been investigated.