Nonreciprocal Photonics for Suppression of Disorder Induced Scattering
Abstract
The ultimate limits of performance for any classical optical system are set by sub wavelength fluctuations within the host material, that may be frozen in (e.g. radiation damage) or even dynamically induced (e.g. thermally). The most common manifestation of sub wavelength disorder is Rayleigh light scattering, which is observed in nearly all wave guiding technologies and can lead to both irreversible radiative losses and undesirable intermodal coupling. An elegant solution to suppress optical backscattering is to break timereversal symmetry in the medium. While this idea has been demonstrated magneto optic and topological insulator materials, common optical dielectrics possess neither of these properties. We propose a new solution to this challenge, using light sound coupling, that relies on the Brillouin acousto optic scattering nonlinearity that is available in all dielectrics. We describe in our technical approach a series of methods relying on Brillouin scattering that break timereversal symmetry for light propagation in waveguides. Our research goal is to experimentally demonstrate suppression of commonly encountered deleterious phenomena, specifically Rayleigh backscattering and Anderson localization, even in the presence of sub wavelength defects. Our preliminary data show enormous potential in resonators, and extensibility to linear systems. We will achieve our goals using integrated photonic components and commercial optical fiber in which time reversal symmetry is broken using both optical and acoustic pumping. We will also explore if these approaches can mitigate undesirable reflections from grating couplers and edge emission facets. The anticipated outcome is transformative improvement to fundamental performance metrics, specifically intrinsic loss and defect tolerance, for a wide range of photonic components. The physical principles we will develop can have major impact to lasers, sensors, and signal processing devices.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501910256
Entities
People
- Gaurav Bahl
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Illinois Urbana–Champaign