Fabrication of visible range hollow Bragg waveguides

• Author / Creator

  Melnyk, Aaron D

• This thesis describes the fabrication and characterization of visible-range hollow Bragg waveguides. A wafer bonding method was first utilized to fabricate tapered hollow Bragg waveguides, which can function as the dispersive element of an integrated spectrometer. Etched channels coated with Bragg reflector claddings enabled three-dimensional guiding. These prototypes were used to assess the spectroscopic sensing capability of the waveguides, and in particular their potential for integration into microfluidic sensing systems. The emission spectra of fluorescent microspheres were extracted, with an experimentally determined resolution as low as 0.9nm, and the results were shown to be in good agreement with measurements made by a commercial spectrometer. Hollow waveguides were subsequently fabricated by controlled thin film buckling. Lithographically patterned areas of a low-adhesion material were embedded between matching Bragg reflectors. Heating the samples induced the buckling of the compressively stressed upper cladding over the regions defined by the low-adhesion layer. Ta2O5/SiO2 multilayers combined with a fluorocarbon-based low-adhesion layer were found to produce buckle features consistent with the morphology predicted by elastic buckling theory. Device yield was as high as 60% and waveguide loss was as low as 2.6dB/cm at 543nm wavelength. These devices have potential applications in optofluidic microsystems as well as in fundamental physics studies.

• Subjects / Keywords

  • Waveguides
  • Bragg reflectors
  • Integrated optics

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3X34N071

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.