Seamless Interconnect Networks

Project Term:
07/01/2017 - 04/15/2021

Critical Need:

Datacenters are a critical component of the modern internet, responsible for processing and storing tremendous amounts of data in the “cloud.” Datacenters also provide the computational power needed for handling “big data,” a growing segment of the U.S. economy. Currently, datacenters consume more than 2.5% of U.S. electricity and this figure is projected to double in about eight years due to the expected growth in data traffic. There are many approaches to improving the energy efficiency of datacenters, but these strategies will be limited by the efficiency with which information travels along metal interconnects within the devices in the datacenter—all the way down to the computer chips that process information. Unlike metal interconnects, photonic interconnects do not rely on electrons flowing through metal to transmit information. Instead, these devices send and receive information in the form of photons—light—enabling far greater speed and bandwidth at much lower energy and cost per bit of data. The integration of photonic interconnects will enable new network architectures and photonic network topologies that hold the potential to double overall datacenter efficiency over the next decade.

Project Innovation + Advantages:

The Massachusetts Institute of Technology (MIT) will develop a unified optical communication technology for use in datacenter optical interconnects. Compared to existing interconnect solutions, the proposed approach exhibits high energy efficiency and large bandwidth density, as well as a low-cost packaging design. Specifically, the team aims to develop novel photonic material, device, and heterogeneously integrated interconnection technologies that are scalable across chip-, board-, and rack-interconnect hierarchy levels. The MIT design uses an optical bridge to connect silicon semiconductors to flexible ribbons that carry light waves. The optical bridge scheme employs single-mode optical waveguides with small modal areas to minimize interconnect footprint, increase bandwidth density, and lower power consumption by using active devices with small junction area and capacitance. The architecture builds all the active photonic components (such as semiconductor lasers, modulators, and detectors) on the optical bridge platform to achieve low energy-per-bit connections. After developing the new photonic packaging technologies, and interconnection architectures, the team's final task will be to fabricate and test a prototype interconnect platform to validate the system models and demonstrate high bandwidth, low power, low bit-error-rate data transmission using the platform.

Potential Impact:

If successful, developments from ENLITENED projects will result in an overall doubling in datacenter energy efficiency in the next decade through deployment of new photonic network topologies.


The United States is home to much of the world’s datacenter infrastructure. Photonic networks add resilience that can bolster the energy security of this critical driver of economic activity.


Reducing the overall energy consumption of datacenters cuts energy-related emissions per bit of data processed or stored.


Photonic networks can lower the costs associated with operating datacenters, improving American economic competitiveness in this fast-developing area.


ARPA-E Program Director:
Dr. James Zahler
Project Contact:
Prof. Juejun Hu
Press and General Inquiries Email:
Project Contact Email:


Dartmouth College
LaXense Inc.

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