The U.S. Army Research Office (ARO) in partnership with the Intelligence Advanced Research Projects Activity (IARPA) seeks research and development of technology and techniques for energy-efficient, high data rate transmission of digital signals between computing systems operating at room and cryogenic temperatures. The focus in the SuperCables program is research and demonstration of components to convert from low level electrical signals in circuits operating at a temperature of approximately 4 kelvins to conventional optical signals at room temperature and to move the information therein from one environment to the other. Pending results of this program, IARPA may support a follow-on program to develop the complete system for bidirectional data transmission between room temperature and 4 kelvins.
The SuperCables program is 24-month effort to research the challenges and develop components for the data egress system. A follow-on BAA may address data ingress or system integration.
The SuperCables program intends to address only the sub-system presently considered most limiting: electrical to optical (EO) signal conversion and transmission from the cryogenic to the room temperature environment. The BAA will consider any approach that could meet the program goals.
Proposals submitted in response to this BAA should be to research and develop a device to convert and transmit digital electronic information at ~4 K to digital optical information at ~300 K.
Digital data at ~4 K is encoded using single flux quantum (SFQ) signals in superconducting circuits based on Josephson junctions. For example, digital ‘1’ or ‘0’ can be represented by the presence or absence of a flux quantum in a given timing window. The switching energy depends on the critical current Ic of a Josephson junction. In present technology , switching a Josephson junction dissipates ~2.1e-19 J and produces an electrical signal about 1 mV high and 2 ps wide. For comparison, the energy of a 1550 nm wavelength photon used in conventional fiber-optic communications is 1.28e-19 J.
Additional considerations and details:
1. The proposed solution may include multiple components along the path, located at various temperature stages. Note that the operating temperature of a mounted device will depend on power dissipation and that thermal properties of materials can be very different at cryogenic temperatures. Also keep in mind that the focus of this program is on development of energy-efficient cryogenic electro-optic devices, and not on cryogenic cable or high frequency amplifier development.
2. The proposed solution may assume an input bit stream consisting of a random sequence of 1s and 0s.
3. A cryogenic testbed will be provided as Government furnished equipment (GFE).
4. The Stimulus Module will be developed by the Government T&E team. Until the Stimulus Module is available, performers must test their devices using signals from some other source, which may originate at room temperature.
5. At the output, the room temperature optical data must be compatible with conventional optical communications technology.
Details are at: