Studies of advanced integrated nano-photonic devices in silicon

Abstract

Electronic-photonic integrated circuits (EPICs) are a promising technology for overcoming bandwidth and power-consumption bottlenecks of traditional integrated circuits. Silicon is a good candidate for building such devices, due to its high-index contrast and low propagation loss at telecom wavelengths. The current thesis presents recent advances in demonstrating discrete components built in silicon-on-insulator (SOI) platforms, around 1550 nm, that can be used as building blocks for future EPIC systems. The first part of this thesis investigates electro-optic modulators based on one-dimensional photonic crystal microcavities, with femtojoule switching energies, as well as on-chip optical interconnects using the super-collimation effect in two-dimensional photonic crystals, both in hole- and rod-based configurations. The second part focuses on microring-based structures, demonstrating wide thermal tunability and hitless operation of single-ring filters, as well as three more advanced categories of devices suitable for wavelength-division multiplexing (WDM) applications. These are twenty-channel second-order tunable filterbanks (both in dual- and counter-propagating configurations), reconfigurable optical add-drop multiplexers (ROADMs) with telecom-grade specifications, and a dynamical slow light cell for delay lines and optical memory elements. All the devices demonstrated in this thesis can be integrated on the same chip. The small device footprints and the use of the SOI platform are ideal for integration with a standard CMOS process, enabling the fabrication of novel electronic-photonic integrated circuits. These new EPIC systems may one day play an important role in the scaling of current computing systems and taking advantage of the WDM capability to increase operational bandwidth, while keeping the power consumption at low levels.