# Input and output waveguide grating couplers: Theory, fabrication and testing.

http://hdl.handle.net/10150/185250
Title:
Input and output waveguide grating couplers: Theory, fabrication and testing.
Author:
Gong, Qian.
Issue Date:
1990
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
This dissertation investigates the modeling, design, fabrication and testing of the input and output coupling properties of waveguide grating couplers. It is motivated by the application of waveguide gratings to integrated optics. The coupling in both normal incidence and oblique incidence are described, but more attention is paid to the normal incident case. The perturbation transmission line theory is chosen as a theoretical model to design grating couplers in this work. The fundamental coupling parameters were carefully measured by many experiments. The comparison of experimental results to theoretical results is also discussed in this dissertation. For the case of normal incidence, the emphasis is on the optimization of the input coupling efficiency. The maximum input coupling efficiency carried out from our experiment was 75% by means of blazed grating in dielectric waveguide at a wavelength 0.6328 $\mu$m, which is very close to the maximum theoretical value of 80%. This coupling efficiency is significantly larger than that having been reported (40-50%). To achieve this goal, some parameters, such as, output coupling efficiency (branching ratio) and coupling distance (leakage factor), have been measured to test the theoretical model. The effect of the angular divergence and the wavelength dispersion of the incident beam on the input coupling efficiency is taken into account, which was modeled by coupled mode equation and tested by experiment. In addition, the design and fabrication procedure is also discussed in detail. In the case of oblique incidence the emphasis is on the output coupling only, i.e. the coupling from guided wave to radiated wave. In this part of the work the important features of the radiated wave-mode coupling efficiency and mode-conversion efficiencies, the phase difference between TE and TM components and the polarization state--were revealed and compared with the theory. These parameters were measured using one shallow rectangular grating and one deep blazed grating. These measurements were compared with the theoretical model.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Physics
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Degree Grantor:
University of Arizona
Burke, James J.

DC FieldValue Language
dc.language.isoenen_US
dc.titleInput and output waveguide grating couplers: Theory, fabrication and testing.en_US
dc.creatorGong, Qian.en_US
dc.contributor.authorGong, Qian.en_US
dc.date.issued1990en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThis dissertation investigates the modeling, design, fabrication and testing of the input and output coupling properties of waveguide grating couplers. It is motivated by the application of waveguide gratings to integrated optics. The coupling in both normal incidence and oblique incidence are described, but more attention is paid to the normal incident case. The perturbation transmission line theory is chosen as a theoretical model to design grating couplers in this work. The fundamental coupling parameters were carefully measured by many experiments. The comparison of experimental results to theoretical results is also discussed in this dissertation. For the case of normal incidence, the emphasis is on the optimization of the input coupling efficiency. The maximum input coupling efficiency carried out from our experiment was 75% by means of blazed grating in dielectric waveguide at a wavelength 0.6328 $\mu$m, which is very close to the maximum theoretical value of 80%. This coupling efficiency is significantly larger than that having been reported (40-50%). To achieve this goal, some parameters, such as, output coupling efficiency (branching ratio) and coupling distance (leakage factor), have been measured to test the theoretical model. The effect of the angular divergence and the wavelength dispersion of the incident beam on the input coupling efficiency is taken into account, which was modeled by coupled mode equation and tested by experiment. In addition, the design and fabrication procedure is also discussed in detail. In the case of oblique incidence the emphasis is on the output coupling only, i.e. the coupling from guided wave to radiated wave. In this part of the work the important features of the radiated wave-mode coupling efficiency and mode-conversion efficiencies, the phase difference between TE and TM components and the polarization state--were revealed and compared with the theory. These parameters were measured using one shallow rectangular grating and one deep blazed grating. These measurements were compared with the theoretical model.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPhysicsen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineOptical Sciencesen_US