| PhD Seminar

Name of the Speaker: Mr. Anirban Mukhopadhyay (EE19D022)
Guide: Prof. Anil Prabhakar
Venue: ESB-244 (Seminar Hall)
Date/Time: 29th October 2024 (Tuesday), 4:00 PM
Title: Study of Spin Wave Active Ring Oscillators (SWAROs): Towards Temporal Pattern Classification

Abstract :

Nonlinear oscillators with delayed feedback have gained significant attention for their ability to demonstrate various nonlinear behaviours, such as soliton excitation, period doubling, and chaotic signal generation. Spin waves, small signal excitations propagating through magnetically saturated films, are promising candidates for developing nonlinear RF devices due to their highly tunable dispersive properties. In the initial stages of our work, we excited surface spin waves in a micrometre-thick yttrium iron garnet (YIG) film. We identified a few hundred MHz wide spin-wave passband. We then built a Spin Wave Active Ring Oscillator (SWARO) using the YIG film as a delay line. The interaction between the external RF drive and oscillator modes was investigated under different oscillator gain settings, drive frequencies, and strengths, leading to the observation of phenomena such as sideband generation, injection pulling, and injection locking in the spectral output of the driven oscillator [1].

Recent efforts have been directed towards leveraging the nonlinear dynamics of delay-line oscillators to process complex temporal information [2]. Our current focus is on developing a temporal pattern classifier using the SWARO. We modulate the amplitude of a GHz drive with a temporal pattern, inject it into the SWARO, and analyze the output envelope signal to perform the classification task.