Open AccessFeedback control for microring weight banks
Author(s) -
Alexander N. Tait,
Hasitha Jayatilleka,
Thomas Ferreira de Lima,
Y. Philip,
Mitchell A. Nahmias,
Bhavin J. Shastri,
Sudip Shekhar,
Lukas Chrostowski,
Paul R. Prucnal
Publication year - 2018
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.026422
Subject(s) - feed forward , photonics , transmission (telecommunications) , optical filter , filter (signal processing) , computer science , demodulation , multiplexing , optics , wavelength , wavelength division multiplexing , electronic engineering , materials science , optoelectronics , channel (broadcasting) , telecommunications , physics , engineering , control engineering , computer vision
Microring weight banks present novel opportunities for reconfigurable, high-performance analog signal processing in photonics. Controlling microring filter response is a challenge due to fabrication variations and thermal sensitivity. Prior work showed continuous weight control of multiple wavelength-division multiplexed signals in a bank of microrings based on calibration and feedforward control. Other prior work has shown resonance locking based on feedback control by monitoring photoabsorption-induced changes in resistance across in-ring photoconductive heaters. In this work, we demonstrate continuous, multi-channel control of a microring weight bank with an effective 5.1 bits of accuracy on 2Gbps signals. Unlike resonance locking, the approach relies on an estimate of filter transmission versus photo-induced resistance changes. We introduce an estimate still capable of providing 4.2 bits of accuracy without any direct transmission measurements. Furthermore, we present a detailed characterization of this response for different values of carrier wavelength offset and power. Feedback weight control renders tractable the weight control problem in reconfigurable analog photonic networks.