The prohibitively large inclusions of micro-ring resonators, interconnected waveguide crossbar arrays, and multi-port multi-mode interferometers components demonstrated in the latest integrated photonic neural network hardware accelerators, pose a significant scaling issue for implementing large number of neural connections required to accurately represent the cognitive functions of a biological brain. In this investigation we utilize phase-change chalcogenide material GST to replicate a non-volatile synaptic weight with built-in memory functionality by employing metamaterial design principles for wavelength-division multiplexing photonic architectures. The transmission response of the optimized GST metamaterial gives rise to contrast ratios of 6dB in both positive and negative weighting values.
Alloys of sulphur, selenium and tellurium, often referred to as chalcogenide semiconductors offer a highly versatile, compositionally-controllable material platform for reconfigurable metamaterial applications. They present various high- and low-index dielectric, low-epsilon and plasmonic properties across ultra-violet (UV), visible and infrared frequencies, in addition to an ultra-fast, non-volatile, electrically-/optically-induced switching capability between phase states with markedly different electromagnetic properties. We show that by integrating chalcogenide metasurfaces on the tip and side of optical fibers as well as silicon photonic waveguide platforms a range of wavelength-tunable modulators for telecommunication networks and synaptic weights for emerging neuromorphic computing applications can be realized.
Recently reconfigurable phase change chalcogenide based metamaterials/metasurfaces have shown great promise in the realization of high speed large contrast all-optical switching and beam-steering devices with built-in memory functionality at a fraction of a wavelength in size across the ultraviolet to infrared frequency range. To incorporate these devices into current telecommunication platforms, integration with photonic waveguide architectures is a must as they present the most mature, widely used commercial photonic device platform today. Here, we present a new class of waveguide-integrated reconfigurable all-dielectric metasurfaces utilizing high refractive index phase change chalcogenides and discuss the unique considerations, design, and physical principles that are essential for integrating such nanostructures into waveguides where illumination is provided through controlled evanescent coupling of guided modes into the metamaterial structure.
Due to their small physical footprint, fibre integrated metamaterials and metadevices made from phase change chalcogenide semiconductors that can be dynamically reconfigured using optical or electrical stimuli present the most promising platform for integration into future telecommunication networks to alleviate the data latency and high power consumption associated with current network configurations. Here, through numerical simulations, we present reconfigurable metadevices that can be integrated onto the tip and side of commercial optical fibres showing tunable behavior across the entire telecommunication band. Such devices can be used for dynamic dispersion control and signal switching.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.