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Frequency Noise Control of Heterogeneous Si/III-V Lasers


Kim, Dongwan (2018) Frequency Noise Control of Heterogeneous Si/III-V Lasers. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z90Z71G6.


Narrow-linewidth lasers have many applications including optical telecommunication, laser spectroscopy, atomic clocks, and light detection and ranging. Conventionally, narrow linewidth lasers have been realized in the form of fiber-based or solid-state lasers. These lasers are bulky and relatively expensive, limiting their usage as bench-top systems in laboratory environments. Historically, semiconductor lasers, also known as laser diodes, have served applications where size and cost are important factors, including fiber optic communications. The linewidth of the semiconductor lasers, however, has been limited to the MHz-level, due to high loss in laser cavities and small size.

Recently, reduction of the frequency fluctuations in the semiconductor lasers has been achieved, obtaining tens of kHz linewidth, using the heterogeneous Silicon/III-V platform with a new design strategy. In this design, the majority of the optical energy is stored in the low-loss high-Q silicon resonator away from the high-loss III-V active region, requiring the minimal gain from the active region to overcome the reduced modal loss.

This work explores the new design strategy further, and demonstrates theoretically and experimentally that the strategy eliminates the frequency fluctuations arising from the amplitude-phase coupling by placing a relaxation resonance frequency at frequencies of a few hundred MHz. Consequently, it becomes possible to obtain a semiconductor laser device possessing sub-kHz quantum-limited linewidths at frequencies of a few GHz (the frequencies of interest in optical telecommunication).

In addition to the frequency noise reduction, the strategy turns out to have the additional benefit of accomplishing a coherent and stable lasing operation, even under external reflections. Thus, the new design strategy has the potential to replace the costly, but currently indispensable external optical isolators, which have been traditionally used to maintain the consistent performance of semiconductor lasers in the presence of external reflection.

This work paves the way for the design of narrow-linewidth and stable semiconductor lasers that can function without the use of the bulky and costly external components, such as external cavities or optical isolators.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Semiconductor lasers, linewidth, coherence, phase noise, DFB lasers
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Applied Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Yariv, Amnon
Group:Kavli Nanoscience Institute
Thesis Committee:
  • Painter, Oskar J. (chair)
  • Faraon, Andrei
  • Schwab, Keith C.
  • Yariv, Amnon
Defense Date:17 October 2017
Funding AgencyGrant Number
US Army Research OfficeW911NF-16-C-0026
US Army Research OfficeW911NF-15-1-0584
US Army Research OfficeW911NF-14-P-0020
Defense Advanced Research Projects AgencyN66001-14-1-4062
Record Number:CaltechTHESIS:10262017-003847721
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter IV. adapted for Chapter III. adapted for Chapter V. adapted for Appendix B. adapted for Appendix B.
Kim, Dongwan0000-0002-5661-2503
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10540
Deposited By: Dongwan Kim
Deposited On:30 Oct 2017 22:02
Last Modified:04 Oct 2019 00:18

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