Text

theses

Silicon photonics is the leading candidate to fulfill the high bandwidth requirement for the future communication networks. Periodic photonic structures, due to their fascinating properties including compact size, high efficiency, and ease of design, play an important role in photonic systems. In this dissertation, SOI-based one-dimensional and two-dimensional periodic photonic structures are studied. Low crosstalk, high density integration of bus waveguides is demonstrated by employing a novel waveguide array structure. Inspired by the low coupling strength shown by initial pair waveguide experiments, novel waveguide array structures are studied by generalizing the nearest-neighbor tight-bonding model. Based on the theory, waveguide arrays have been designed and fabricated. The waveguide arrays have been characterized to demonstrate high density bus waveguides with minimal crosstalk. Two-dimensional photonic crystal waveguide (PCW) structure was then investigated aiming at reducing the propagation loss. A general cross-sectional eigenmode orthogonality relation is first derived for a one dimensional periodic system. Assisted by this orthogonality, analytic formulas are obtained to describe the propagation loss in PCW structures. By introducing the radiation and backscattering loss factors a1 and a2, the total loss coefficient a can be written as a=a1*ng+a2*ng^2 (ng is the group index). It is analytically shown the backscattering loss generally dominates the radiation loss for ng>10. Combined with systematic simulations of loss dependences on key structure parameters, this analytic study helps identify promising strategies to reduce the slow light loss. The influence of the substrate on the performance of a thermo-optic tuning photonic crystal device was studied in the following section. The substrate-induced thermo-optic tuning is obtained as a function of key physical parameters, based on a semi-analytic theory that agrees well with numeric simulations. It is shown that for some devices, the substrate’s contribution to the thermo-optic tuning can exceed 10% for a heater located in the waveguide core and much higher for some other configurations. The slow response of the substrate may also significantly slow down the overall response time of the device. Strategies of minimizing the substrate’s influence are discussed.

ETD_4683

Ph.D.

Includes bibliographical references

Includes vita

by Weiwei Song

http://hdl.rutgers.edu/1782.1/rucore10001600001.ETD.000068972

doi:10.7282/T3RF5SMW

ETD doctoral

The author owns the copyright to this work.