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Narrow-Linewidth Si/III-V Lasers: a Study of Laser Dynamics and Nonlinear Effects


Vilenchik, Yaakov (2015) Narrow-Linewidth Si/III-V Lasers: a Study of Laser Dynamics and Nonlinear Effects. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9513W57.


Narrow-linewidth lasers play an important role in a wide variety of applications, from sensing and spectroscopy to optical communication and on-chip clocks. Current narrow-linewidth systems are usually implemented in doped fibers and are big, expensive, and power-hungry. Semiconductor lasers compete favorably in size, cost, and power consumption, but their linewidth is historically limited to the sub-MHz regime. However, it has been recently demonstrated that a new design paradigm, in which the optical energy is stored away from the active region in a composite high-Q resonator, has the potential to dramatically improve the coherence of the laser.

This work explores this design paradigm, as applied on the hybrid Si/III-V platform. It demonstrates a record sub-KHz white-noise-floor linewidth. It further shows, both theoretically and experimentally, that this strategy practically eliminates Henry’s linewidth enhancement by positioning a damped relaxation resonance at frequencies as low as 70 MHz, yielding truly quantum limited devices at frequencies of interest.

In addition to this empirical contribution, this work explores the limits of performance of this platform. Here, the effect of two-photon-absorption and free-carrier-absorption are analyzed, using modified rate equations and Langevin force approach. The analysis predicts that as the intra-cavity field intensity builds up in the high-Q resonator, non-linear effects cause a new domain of performance-limiting factors. Steady-state behavior, laser dynamics, and frequency noise performance are examined in the context of this unique platform, pointing at the importance of nonlinear effects.

This work offers a theoretical model predicting laser performance in light of nonlinear effects, obtaining a good agreement with experimental results from fabricated high-Q Si/III-V lasers. In addition to demonstrating unprecedented semiconductor laser performance, this work establishes a first attempt to predict and demonstrate the key impact of nonlinear effects on silicon-based lasers.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:nonlinear effect; Si/III-V; Narrow-linewidth lasers; TPA; Narrow-linewidth; Two-photon-absorption Free-carrier-absorption; FCA;
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:
  • Vahala, Kerry J. (chair)
  • Yariv, Amnon
  • Painter, Oskar J.
  • Faraon, Andrei
Defense Date:4 June 2015
Record Number:CaltechTHESIS:06042015-232226135
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8991
Deposited By: Yaakov Vilenchik
Deposited On:14 Nov 2016 23:04
Last Modified:04 Oct 2019 00:08

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