University of Louisville
Fabrication of Sub-Micron Periodic Structures on Glass
Institution
University of Louisville
Faculty Advisor/ Mentor
Sergio Mendes
Abstract
The development of optical waveguide circuits for several applications, e.g., in optical communications, optical computing, and bio-sensors, requires the fabrication of couplers for transferring light beams into- and out of- the device. An important waveguide coupler is based on integrated diffraction grating structures. The fabrication of such optical component involves several processes and requires critical micro-fabrication steps. Diffraction gratings by themselves are very useful tools to the extent of characterizing spectroscopic properties of matter. In this work, the fabrication of integrated diffraction gratings was taken one step further. We investigated if we could use hydrogen plasma or wet chemistry techniques to transfer a periodic modulation, originally holographically written in a photo-sensitive layer, to the surface of a glass substrate. Such substrate with a sub-micron surface-relief grating could then be over-coated with a high refractive index thin-film material to create a waveguide structure. An important challenge here is to develop integrated grating structures that can efficiently couple light into- and out ofsingle-mode optical waveguides.
Fabrication of Sub-Micron Periodic Structures on Glass
The development of optical waveguide circuits for several applications, e.g., in optical communications, optical computing, and bio-sensors, requires the fabrication of couplers for transferring light beams into- and out of- the device. An important waveguide coupler is based on integrated diffraction grating structures. The fabrication of such optical component involves several processes and requires critical micro-fabrication steps. Diffraction gratings by themselves are very useful tools to the extent of characterizing spectroscopic properties of matter. In this work, the fabrication of integrated diffraction gratings was taken one step further. We investigated if we could use hydrogen plasma or wet chemistry techniques to transfer a periodic modulation, originally holographically written in a photo-sensitive layer, to the surface of a glass substrate. Such substrate with a sub-micron surface-relief grating could then be over-coated with a high refractive index thin-film material to create a waveguide structure. An important challenge here is to develop integrated grating structures that can efficiently couple light into- and out ofsingle-mode optical waveguides.