Quantum effectively (QW) and quantum dot (QD) semiconductor materials-based laser diodes built-in with SiN microresonators present promising potential as a consequence of their excessive energy effectivity and compact measurement. A research led by Professor Yating Wan explored these composite cavity lasers’ design and performance, providing precious insights for future laser diode know-how improvement.
Quantum Dot and Quantum Properly Laser Diodes: The Way forward for Microresonators
Quantum effectively (QW) and quantum dot (QD) semiconductor materials-based on-chip laser diodes at the moment are major candidates in varied functions. Their engaging options embody excessive energy effectivity, the flexibility to function at excessive temperatures, and compact measurement. Whereas QWs have been extensively applied in industrial merchandise, QDs, with their distinctive zero-dimensional density of states and atom-like degeneracy, are a promising alternative.
The heterogeneous integration of III-V lasers with silicon nitride (SiN) microresonators, facilitated by self-injection locking, adds intrinsic benefits. These include compactness, high-volume production potential, and enhanced stability. This technology allows for superior linewidth narrowing performance compared to III-V lasers grown on native platforms.
New Study Explores Quantum Well and Quantum Dot Devices
A study recently published in the journal Light Science & Application dove into a parametric investigation of the design of the active medium of composite cavity lasers. This research was headed by Professor Yating Wan from the Integrated Photonics Lab at King Abdullah University of Science and Technology (KAUST), Saudi Arabia, Dr. Weng W. Chow from Sandia National Laboratories, Albuquerque, USA, Prof. Frédéric Grillot from LTCI, Télécom Paris, Institut Polytechnique de Paris, France, and Prof. John Bowers from the University of California Santa Barbara, USA.
The team focused on the impact of carrier quantum confinement on the dynamic and spectral characteristics of the locked composite cavity device. Their specific emphasis was on emission spectral refinement, or linewidth narrowing, when integrating III-V QW or QD distributed feedback (DFB) lasers with SiN microring resonators. Emad Alkhazraji, the research paper’s first author, clarified the principle behind the improvement. “When properly tuned and locked to one or more of the microring’s whispering gallery modes, optical feedback in the form of Rayleigh backscattering can enable drastic reductions in the lasing linewidth of a laser diode to the Hz-level,” Alkhazraji explained.
Findings and Implications for Future Design
The parametric investigation was concluded with a multi-objective design-operation optimization analysis of both QW and QD devices via a genetic algorithm. A multi-decision algorithm was then employed to determine the optimal design-operation points for each optimization variable.
“These findings provide guidance for more comprehensive parametric studies that can produce timely results for engineering design,” Professor Yating Wan concluded. The study highlights the potential for improvement and further developments in the field of laser diode technology.
Reference: “Linewidth narrowing in self-injection-locked on-chip lasers” by Emad Alkhazraji, Weng W. Chow, Frédéric Grillot, John E. Bowers and Yating Wan, 28 June 2023, Light Science & Applications.
Funding: Advanced Research Projects Agency-Energy (ARPA-E), the U.S. Department of Energy, the American Institute for Manufacturing (AIM) Integrated Photonics.