Superconducting Technology Assessment - nitrd

For further discussions of the options considered, see Appendix K: Data Signal Transmission. (The full text of this
appendix can be found on the CD accompanying this report.)
Figure 5-1. A 64-fiber, 4-wavelength, 25-Gbps CWDM System for bi-directional transmission totaling 6.4 Tbps between a superconducting
processor at 4 K and high speed mass memory at 300 K. Optical connections are shown in red, electrical in black. This technology should be
commercially available for 300 K operation by 2010.
5.1.1 OPTICAL INTERCONNECT TECHNOLOGY – STATUS
The need to move optical interconnects closer to the I/O pin electronics requires advances in packaging, thermal
management, and waveguide technology, all of which will reduce size and costs. The research is ongoing with
some efforts funded by industry, and others by governmental entities such as Defense Advanced Research Projects
Agency (DARPA). For example, using Vertical Cavity Surface Emitting Lasers (VCSELs) and Coarse WDM, the joint
IBM/Agilent effort has achieved 240 Gbps aggregate over 12 fibers, each carrying four wavelengths at 5 Gbps
each (Figure 5-1). The next step is planned to be 480 Gbps, with each channel at 10 Gbps. Optical interconnects
were already used in some large scale commercial high-performance data routers to connect backplanes and line
cards together.
100
CPU
DETECTOR
ARRAY
OUTPUT
LINE
DRIVERS
128 x 25
DEMU 4λ DEMUX
ELECTRICAL
RIBBON
CABLE
DATA TRANSMISSION CONCEPT
32 X 4λ x 25 Gbps
4
WAVELENGTH
VCSEL ARRAY
@ 25 Gbps
4λ MUX
32 X 4λ x 25 Gbps
4λ MUX
128 x 25 Gbps
128 x 25 Gbps
4λ DEMUX
4 K 40 K 300 K
4
WAVELENGTH
VCSEL ARRAY
@ 25 Gbps
FROM MEMORY
DETECTOR
ARRAY
TO MEMORY