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Open Access Publications from the University of California

Scholarly Works (3 results)

  • Thesis
  • Peer Reviewed
UC Berkeley Electronic Theses and Dissertations (2017)

Vertical-cavity surface-emitting lasers (VCSELs) have emerged as one of the most numerous and diverse categories of semiconductor laser, serving applications in telecommunications, imaging, ranging, and sensing. Improving the behavior of these devices, while extending them into new application spaces, is currently one of the most active fields of optoelectronics research. Concurrently, improvements in micro-optics, micro-mechanics, and low-noise experimentation have produced a field of cavity optomechanics studying the forces of confined light to excite or cool mechanical systems. This thesis explores the interaction of those fields by observing optomechanical forces acting on the MEMS-supported high-contrast grating (HCG) reflector in VCSELs. The unique properties of the HCG as a lightweight, ultra-high-reflectivity mirror enable optomechanical forces to be more salient in these devices than in typical distributed Bragg reflector (DBR) VCSELs. Through optical, electrical, and microscopy characterization methods, we demonstrate the use of radiation pressure to drive the mirror through current modulation and self-oscillation, notably producing a large amplitude oscillation resulting in broad-spectrum self-swept light. By demonstrating optomechanical effects in a single device, we simplify the traditional cavity optomechanics experiment and open a new design space in which to obtain the ingredients necessary for feedback-based optomechanical damping. Looking to both the applications of passive cavity optomechanics and those of wavelength-swept VCSELs, we highlight applications for these phenomena and design and fabrication changes to further explore and harness optomechanical forces in VCSELs. Additionally, we show the development of the first physics-based compact model of VCSELs, which enables simultaneous design of VCSELs and circuits to enhance VCSELs’ performance in communications, ranging, and optomechanics.

    Cover page: Optomechanical Dynamics in Vertical-Cavity Surface-Emitting Lasers
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2015)
    Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors.
      Cover page: Laser optomechanics.
      • Article
      • Peer Reviewed
      UC Berkeley Previously Published Works (2015)
      Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors.
        Cover page: Laser optomechanics.Creative Commons 'BY' version 4.0 license
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