Event
Ph.D. Research Proposal Exam
Thursday, March 30, 2023
2:00 a.m.
ERF 1207
Maria Hoo
301 405 3681
mch@umd.edu
ANNOUNCEMENT: Ph.D. Research Proposal Exam
Name: Meenwook Ha
Committee:
Professor Yanne K. Chembo (Chair)
Professor Thomas E. Murphy
Professor Kevin M. Daniels
Date/time: Thursday, March 30, 2023 from 2-3 PM
Location: ERF 1207
Title: The optoelectronic oscillator based on stimulated Brillouin scattering
Abstract: Optoelectronic oscillators (OEOs) are time-delayed microwave photonic systems able to generate pure RF signals by utilizing their half-optical and half-electronic structure. The conceptual breakthrough of the oscillators is storing optical energy for electronic signal generation so that it is possible to achieve a very high Q-factor, leading the oscillators to be considered as one of the most promising millimeter-wave sources. However, a number of OEOs have a primary concern that their frequency selection highly depends on electronic components, thereby becoming progressively less effective in response to increase of frequency. The proposed concerns are addressed by OEOs based on stimulated Brillouin scattering (SBS). In the model, a pump laser is used to generate a Brillouin gain which selectively amplifies a phase-modulated and contra-propagating laser signal. The model has been successfully demonstrated at the experimental level, and they feature competitive phase noise performances along with continuous tunability for the output RF signal, up to the millimeter-wave band. However, in spite of the high potential, no dynamical model has ever been introduced to describe their nonlinear behavior. We introduce a time-domain delay differential envelope equation that can describe the dynamics of the SBS-based OEOs allowing us to track the dynamics of the amplitude and phase of the RF signal. We first deeply analyze Brillouin amplification at a high nonlinear fiber spool and derive time-domain envelope equations describing the amplification process of optical fields. Based on the field relation, we derive the microwave envelope equation and explore the dynamics of the system in depth. The stability analysis of the stationary-state solutions corresponds to results of numerical simulations, and in agreement is shown that as the loop gain is increased, the system undergoes a primary Hopf bifurcation as the stability of the two solutions are switched, and then a Neimark-Sacker bifurcation is observed as every solution becomes unstable.
