David Borlaug

Rogue events and noise shaping in nonlinear silicon photonics

We revisit recent work on the generation of extreme optical events via nonlinear dynamics in silicon waveguides. The underlying processes, modulation instability and stimulated Raman scattering, are able to reshape normally distributed initial conditions into skewed output statistics whose properties can be tailored by controlling experimental variables. While these are both gain processes, they bear fundamental differences: modulation instability is a broadband parametric process, whereas stimulated Raman scattering is a narrowband inelastic process. As a result, they respond to different forms of input noise. Specifically, the extreme events generated spontaneously by modulation instability evidence a strong sensitivity to a particular input noise component. This sensitivity can be controllably seeded to generate coherent supercontinuum radiation, which also offers a means to alleviate conventional free-carrier limitations to chip-scale spectral broadening.

Extreme value statistics in silicon photonics

L-shape probability distributions are extremely non-Gaussian functions that have been surprisingly successful in describing the occurrence of extreme events ranging from stock market crashes, natural disasters, structure of biological systems, fractals, and optical rogue waves. We show that fluctuations in stimulated Raman scattering, as well as in coherent anti-Stokes Raman scattering, in silicon can follow extreme value statistics and provide mathematical insight into the origin of this behavior.

Demonstration of Vpi Reduction in Electrooptic Modulators Using Modulation Instability

We show a 10 fold reduction in an electro optic modulators half-wave voltage by employing modulation instability. Experimental results are reported up to 50 GHz.

Raman beam cleanup in silicon in the mid-infrared.

We report evidence of beam cleanup during stimulated Raman scattering in silicon. An amplified near-diffraction-limited Stokes beam is obtained from a severely aberrated pump beam.

Engineering strain in silicon using SIMOX 3D sculpting

SIMOX 3D sculpting is considered as a new method for 3D strain engineering in buried silicon waveguides. A model capable of analyzing the stress distribution and strain gradient of buried silicon waveguides is developed.

Engineering Strain in Silicon Using SIMOX 3-D Sculpting

Separation by IMplantation of OXygen (SIMOX) 3-D sculpting is considered as a new method for 3-D strain engineering in buried silicon waveguides. A model capable of analyzing the stress distribution and strain gradient of buried silicon waveguides is developed. The modeled stress shows agreement with experimental measurements obtained using Raman spectroscopy. Our method not only provides a new way to engineer strain in silicon but allows for the integration of strained-silicon-based devices with other optical and/or electronic devices on the same substrate as well, improving the device density and enhancing the functionality of the optical chip.

V-pi reduction by using modulation index booster (MiBo) in RF links

The spur-free dynamic range (SFDR) of a modulation index booster (MiBo) link is experimentally and numerically demonstrated. 14.2dB RF gain is demonstrated for 5-fold V_π reduction at 10GHz with an SFDR₃ better than 90dB/Hz.

Experimental Demonstration of Vpi Reduction in EO Modulators using Modulation Instability

An electrooptic modulators half-wave voltage is experimentally lowered by 10-fold for intensity modulated waveforms using modulation instability. Results are reported up to 50 GHz.

Enhancing the Electrooptic Effect using Optical Sideband-only Amplification

The high-frequency increase in modulator half-wave voltage contradicts the reduction in voltage swing of electronics. We show a solution whereby modulation side-bands are amplified, at the expense of the carrier, using controlled modulation instability.