Flexible Silicon Photonic Integrated Circuits for Optical Interconnects and WDM Networks

• Author / Creator

  Ren, Yang

• In response to the continuous growth in the demand for higher speed and volume of data transmission, optical networks are evolving to become more elastic to maximize spectrum utility. This in turn is driving the development of flexible optical devices
  and circuits that can be reconfigured to adapt to fast changes in network conditions. Over the past decade, silicon photonics has gained widespread industry acceptance as a platform for photonic integrated circuits for optical communication, due to its low cost, potential for dense integration and compatibility with the CMOS fabrication process. In spite of its promising benefits, several important challenges remain in the development of flexible silicon photonic circuits, namely, broadband wavelength tunability, fast reconfigurability, and scalability.

  This thesis addresses these issues through the development of
  flexible and scalable silicon photonic components for elastic optical networks, including a widely tunable reconfigurable optical add-drop multiplexing (ROADM) circuit, a universal variable bandwidth optical filter, and a fast wavelength selection circuit. The ROADM circuit can provide wavelength reconfigurability over more than 4 Tb/s data transmission bandwidth. The variable bandwidth filter is based on a novel microring-loaded Mach-Zehnder interferometer that can provide insertion loss-free bandwidth tuning by only tuning the microring resonant frequencies. The wavelength selection circuit combines the wide band tunability of thermo-optic microring filters with fast switching by free carrier injection to achieve best-case wavelength selection time of a few nanoseconds over a 32 nm wavelength range.

  As silicon photonic circuits grow in functionality and complexity, it also becomes necessary to monitor their performance and optical signal quality throughout the system. To address this issue, we proposed and investigated two novel methods for on-chip optical monitoring. The first method is the use of on-chip thermistors for tracking the centre wavelength and bandwidth of microring add/drop filters. The second method is the use of silicon photodetectors based on two-photon absorption for on-chip signal detection. These devices and methods can be seamlessly integrated into silicon photonic circuits for real-time monitoring of their performance.

• Subjects / Keywords

  • Thermal Tuning
  • Photonic Filters
  • Photodetections
  • Silicon Photonics
  • Integrated Optics

• Graduation date

  Fall 2020

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-h8z2-5441

• License

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