Superconducting Technology Assessment - nitrd
Superconducting Technology Assessment - nitrd
Superconducting Technology Assessment - nitrd
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Optical interconnects may require the use of elements such as prisms or gratings. These elements can be relatively<br />
large and may not fit within the planned size of the cryostat. The power required for the optical receivers—or<br />
the thermal energy delivered by the photons themselves—may offset any gains from using the low thermal<br />
conductance glass fibers. A detailed design is needed to establish these trade-offs.<br />
The use of HTS wires would include two significant technical risks:<br />
■ Currently, the best HTS films are deposited epitaxially onto substrates such as lanthanum-aluminate<br />
or magnesium oxide. These substrates are brittle, and have relatively large thermal conductance<br />
which offset the “zero” thermal conductivity of the HTS conductors.<br />
■ Any HTS cable would need to have at least two superconductor layers<br />
(a ground plane and a signal line layer) in order to carry multi-Gbps data.<br />
Presently, multi-layer HTS circuits can only be made on a relatively small scale due to pin-holes and other such<br />
defects that short circuit the two layers together.<br />
6.5.5 POWER DISTRIBUTION AND CABLES – ROADMAP AND FUNDING<br />
A roadmap for the development of cables for an SCE-based, large-scale computer is shown below. The funding profile<br />
needed to maintain development pace is listed in Table 6-8. More details are presented in Appendix L: Multi-Chip<br />
Modules and Boards. (The full text of this appendix can be found on the CD accompanying this report.)<br />
130<br />
I.<br />
Trade -<br />
offs<br />
1.<br />
Power<br />
and<br />
Cable<br />
Req<br />
docum<br />
ent<br />
2. Power &<br />
Cable<br />
Test Vehicle<br />
Design<br />
2.<br />
Power<br />
&<br />
Cables<br />
Test<br />
Vehicle<br />
3. Power &<br />
Cable Test<br />
Vehicle<br />
Fabrication<br />
and Qual<br />
3.<br />
Power<br />
and<br />
Cable<br />
Demo ’<br />
ed<br />
and<br />
qualified<br />
4. Prototype<br />
Design<br />
4.<br />
Prototype<br />
Cables and<br />
Power<br />
Distribution<br />
5 .Prototype<br />
Fab and Test<br />
MILESTONES<br />
5.<br />
Prototype<br />
qualified<br />
2006 2007 2008 2009 2010<br />
TABLE 6-8. CABLES AND POWER DISTRIBUTION DEVELOPMENT COSTS ($M)<br />
Year 2006 2007 2008 2009 2010 Total<br />
Cables and Power<br />
Distribution Development 2.0 2.3 3.3 3.5 3.6 14.7<br />
Total Investment 2.0 2.3 3.3 3.5 3.6 14.7
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