Washington University

Tarek El-Ghazawi

Volker J Sorger

Shuai Sun

Vikram K Narayana

Armin Mehrabian

Abdel-Hameed A Badawy

Mario Miscuglio

Jiaxin Peng

An integrated photonics computing system implements a residue number system (RNS) to achieve orders of magnitude improvements in computational speed per watt over the current state-of-the-art. RNS and nanophotonics have a natural affinity where most operations can be achieved as spatial routing using electrically controlled directional coupler switches, thereby giving rise to an innovative processing-in-network (PIN) paradigm. The system provides a path for attojoule-per-bit efficient and fast electro-optic switching devices, and uses them to develop optical compute engines based on residue arithmetic leading to multi-purpose nanophotonic computing.

Residue arithmetic nanophotonic system

An accelerator for modern convolutional neural networks applies the Winograd filtering algorithm in a wavelength division multiplexing integrated photonics circuit modulated by a memristor-based analog memory unit.

Optical convolutional neural network accelerator

Photonic data routing in optical networks is expected overcome the limitations of electronic routers with respect to data rate, latency, and energy consumption. However photonics-based routers suffer from dynamic power consumption, and non-simultaneous usage of multiple wavelength channels when microrings are deployed and are sizable in footprint. Here we show a design for the first hybrid photonic-plasmonic, non-blocking, broadband 5&#xd7;5 router based on 3-waveguide silicon photonic-plasmonic 2&#xd7;2 switches. The compactness of the router (footprint &#x3c;200 &#x3bc;m) results in a short optical propagation delay (0.4 ps) enabling high data capacity up to 2 Tbps. The router has an average energy consumption ranging from 0.1&#x2dc;1.0 fJ/bit depending on either DWDM or CDWM operation, enabled by the low electrical capacitance of the switch. The total average routing insertion loss of 2.5 dB is supported via an optical mode hybridization deployed inside the 2&#xd7;2 switches, which minimizes the coupling losses between the photonic and plasmonic sections of the router. The router's spectral bandwidth resides in the S, C and L bands and exceeds 100 nm supporting WDM applications since no resonance feature are required. Moreover, this hybrid photonic-plasmonic switch design is also suitable for 3 up to a few dozens of routing ports by simply cascading our 2&#xd7;2 switch with a specific pattern. Taken together this novel optical router combines multiple design features, all required in next generation high data-throughput optical networks and computing systems.

Hybrid photonic non-blocking wide spectrum WDM on-chip router

An optical-electronic device can be controlled by a bias voltage to simulate an electronic component such as a resistor, capacitor, inductor with resistor, or capacitor with resistor. The optical-electronic device can be connected in a network to perform computations, model problems, simulate properties such as physical properties (for instance heat transfer), and achieve circuit performances to carry out computations in the analog domain, all at faster speed with smaller size and at less energy.

Reconfigurable optical computer

The Hybrid Photonic Plasmonic Interconnect (HyPPI) combines both low loss photonic signal propagation and passive routing with ultra-compact plasmonic devices. These optical interconnects therefore uniquely combine fast operational data-bandwidths (in hundreds of Gbps) for light manipulation with low optical attenuation losses by hybridizing low loss photonics with strong light-matter-interaction plasmonics to create, modulate, switch and detect light efficiently at the same time. Initial implementations were considered for on-chip photonic integration, but also promising for free space or fiber-based systems. In general two technical options exist, which distinguished by the method the electric-optic conversion is executed: the extrinsic modulation method consists of an continuous wave source such as an LED or laser operating at steady power output, and signal encoding is done via an electro-optic modulator downstream of the source in the interconnect. In contrast, in the intrinsic method, the optical source is directly amplitude modulated.

Growing community of inventors

Vienna, VA, United States of America

Tarek El-Ghazawi