Fabrication of optical-mode converters for efficient fiber-to-silicon-waveguide couplers
Author(s)Barreto, Raúl E
Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
Henry I. Smith.
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Optical-mode converters are needed to efficiently couple light from an optical fiber to a photonic circuit by matching and transforming the propagating modes. This work is based on a horizontally-tapered coupler, in which light from an optical fiber is coupled into a large polymer waveguide and then gradually transferred to a smaller silicon waveguide whose width increases with distance along the guide. Several devices were designed and fabricated to measure the efficiency of the coupler. E-beam exposure doses and writing strategies were optimized to create the tapered silicon waveguides. A fabrication process was developed to form the polymer waveguides without etching the underlying silicon, and a set of marks was created to achieve sub-micron alignment between the two waveguides. Fabrication results showed that the coupler successfully transfers light between the two waveguides and that there is low loss in the polymer. A more accurate characterization of the coupler's efficiency was delayed due to fabrication problems not related to the developed process.
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2007.Includes bibliographical references (leaves 71-73).
DepartmentMassachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
Massachusetts Institute of Technology
Electrical Engineering and Computer Science.