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Open Access Publications from the University of California

Scholarly Works (2 results)

  • Thesis
  • Peer Reviewed
UC Santa Barbara Electronic Theses and Dissertations (2024)

Rapid development of the Si photonics industry and its applications in data communication calls for the making of on-chip light sources integrated on the Silicon-on-Insulator (SOI) platform for mass production. Monolithic integration of III-V lasers, especially quantum dot (QD) lasers has gained increasing attention as a key technology to realize efficient, cost-effective, industrial-scale integration of light sources for Si photonics.

In this thesis, we demonstrate for the first time, QD lasers grown and fabricated for electrically pumped lasing both on a planar template and in-pocket-template on 300 mm Si wafers. O-band edge-emitting in-pocket lasers are fabricated on Si with robust performance of continuous wave lasing up to 60 \textdegree C, a maximum double-sided output power of 124.8 mW at 20 °C and high fabrication yield. We also demonstrate for the first time, on-chip etched-facet lasers directly butt-coupled to SiN waveguides made on a 300-mm scale foundry-processed Si photonics wafer, characterized with fiber-coupling from on-chip edge couplers at waveguide output. Process developments addressing issues such as polycrystal deposition on surface, high aspect-ratio pocket geometry, and complications on growth interface affecting coupling are established.

Perspectives on scaling this QD laser process on a 300 mm scale in a Si photonics foundry is also discussed, including remaining challenges of improving laser performance and yield, and prospects on the implementation of fully monolithic integration with a III-V/Si co-processing foundry.

    • Article
    • Peer Reviewed
    UC Santa Barbara Previously Published Works (2022)
    Monolithic integration of quantum dot (QD) gain materials onto Si photonic platforms via direct epitaxial growth is a promising solution for on-chip light sources. Recent developments have demonstrated superior device reliability in blanket hetero-epitaxy of III-V devices on Si at elevated temperatures. Yet, thick, defect management epi designs prevent vertical light coupling from the gain region to the Si-on-Insulator waveguides. Here, we demonstrate the first electrically pumped QD lasers grown by molecular beam epitaxy on a 300 mm patterned (001) Si wafer with a butt-coupled configuration. Unique growth and fabrication challenges imposed by the template architecture have been resolved, contributing to continuous wave lasing to 60 °C and a maximum double-side output power of 126.6 mW at 20 °C with a double-side wall-plug efficiency of 8.6%. The potential for robust on-chip laser operation and efficient low-loss light coupling to Si photonic circuits makes this heteroepitaxial integration platform on Si promising for scalable and low-cost mass production.
      Cover page: Electrically pumped quantum-dot lasers grown on 300 mm patterned Si photonic wafers
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