EE Devices Seminar - George C. Valley, Aerospace

This talk reviews 3 generations of photonic reservoir computing (RC) work at Aerospace using laser speckle in multimode waveguides for random matrix multiplication. Our first RC used electrical-to-optical-to-electrical conversion at each time step. While this system was inefficient and slow, these experiments showed that RCs with laser speckle perform many standard test problems: Mackey-Glass chaotic waveform prediction and classification, Japanese vowel speaker classification and separation of return-to-zero from non-return-to-zero communications signals. The second RC used optical feedback in a ring geometry to improve efficiency and speed. Simulations again showed that this RC can solve standard test problems, but it had major issues: no obvious optical sigmoidal nonlinearity, the use of a power-hungry array of high speed ADCs (or a camera) and the application of output weights in the digital domain. Our third generation RC, now in the simulation and planning phase, uses the square-law nonlinearity of the photodiodes in place of a sigmoid, uses a single ADC at the information rate of the input signal, and applies the output weights photonically or electronically in the analog domain before the ADC. The 3rd generation RC could be used as an edge computing inference device.

_{Bio: George C. Valley got his AB at Dartmouth College and his PhD at the University of Chicago, both in physics. After 5 years at Cornell Aeronautical Laboratories, he spent 22 years at Hughes Aircraft Co., primarily at Hughes Research Labs. At Hughes, he worked on guide stars for adaptive optics systems, nonlinear optics in photorefractive materials, spatial solitons, beam combining, and visible lasers for displays. He joined Aerospace in 1999 where he has worked on fiber amplifiers, photonic ADCs, photonic compressive sensing systems for GHz-band RF signals, and photonic reservoir computing.}

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