Current Research

1. Quantum and Nonlinear Photonics Group, Columbia University

I joined Prof. Alex Gaeta’s group at Columbia University as a Postdoctoral Research Scientist in the Fall of 2022. My current research focuses on exploring Kerr nonlinear and thermo-optical effects occurring in silicon nitride ring resonators (fabricated by Prof. Michal Lipson’s group). At CLEO 2023, I presented our work on demonstrating photodiode-free locking of a laser to a silicon nitride micro-cavity. The locking technique that I developed at Alex’s group makes use of optical heating that occurs in the resonator waveguide and the subsequent change in electrical resistance of an integrated microheater. This simple but effective approach has the potential to jumpstart new research in effective thermal management in high-Q low-mode-volume microresonators. See our CLEO 2023 extended abstract here.

2. Institute for Research in Electronics and Applied Physics, University of Maryland

At the University of Maryland, I work with Prof. Thomas E. Murphy on experimentally investigating nonlinear optical effects in few- and multi-mode optical fibers (FMFs and MMFs). We are interested in measuring the fundamental nonlinear interactions between individual spatial modes. To this end, we develop and implement novel mode excitation mechanisms as well as unique spatiotemporal characterization techniques to study intermodal nonlinear interactions in a variety of FMFs/MMFs.

This research is of interest not only for space division multiplexing (SDM) applications, but also in the context of recently uncovered complex spatiotemporal nonlinear phenomeona occurring in MMFs that support hundreds of co-propagating spatial modes, such as Kerr-induced beam “self-cleaning”, spatiotemporal modulation instability and spatiotemporal mode-locking.

Representative publications:

Sai Kanth Dacha, Wenqi Zhu, Amit Agrawal, Kenneth J. Ritter and Thomas E. Murphy, "Nonlinear rotation of spin-orbit coupled states in hollow ring-core fibers" Opt. Express 30, 18481-18495 (2022) (Link to paper)Sai Kanth Dacha and Thomas E. Murphy, "Spatiotemporal characterization of nonlinear intermodal interference between selectively excited modes of a few-mode fiber," Optica 7, 1796-1803 (2020) (Link to paper)

3. Nokia Bell Labs, Murray Hill

As a graduate research intern (June - December 2021) at Bell Labs, I worked with Dr. René-Jean Essiambre on semi-classical/quantum optical communication experiments using attenuated pulsed laser sources and superconducting nanowire single-photon detectors (SNSPDs). The details of this project are currently confidential as publications and/or patents are being drafted, but further details are available upon request.