Controlling the Polarization Dependence of SOI Waveguides by Using Slot Waveguide Structure
Date Issued
2011
Date
2011
Author(s)
Ma, Yao-Feng
Abstract
In this dissertation, slot waveguide structures are successfully employed to overcome the problem of polarization dependence in designing fundamental silicon-on-insulator waveguide-based components. Through controlling of the polarization dependence of the slot waveguide, a polarization-independent dual channel directional coupler formed by slot waveguides is proposed. For vertical slot, the length of the coupling region of the device is 23.13 μm while delivering the good performance with the extinction ratio of more than 22 dB and 1-dB bandwidth of larger than 100 nm. For horizontal slot, the length of the coupling region of the device is 27.33 μm while delivering the good performance with the extinction ratio of more than 27 dB and 1-dB bandwidth of around 200 nm. The tolerance of the fabrication error on the practical device is also discussed.
Furthermore, the polarization-independent coupler proposed previously is employed to realize a polarization-independent racetrack type micro-ring resonator formed by silicon-on-insulator slot waveguides as well, in which the polarization-mode dispersion-free operation can be perfectly maintained over a wide spectral range by optimizing the slot waveguide geometry. The spectral responses for both polarization modes are nearly identical not only around the designed operating wavelength but also over C- and L-band with a resonance wavelength mismatch between the two orthogonal polarization modes less than 0.1 nm for vertical slot, and less than 0.25 nm for horizontal slot waveguide structures. The free spectral range of more than 10 nm can be achieved as well as a compact device size of less than 30 μm. To the knowledge it is the first micro-ring resonator that achieves such an excellent polarization-mode dispersion-free operation.
Subjects
slot waveguide
silicon-on-insulator
polarization dependence
polarization-mode dispersion
directional coupler
micro-ring resonator
Type
thesis
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