Sun Microsystems to Develop On-Chip Optical Networks

Caren B. Les

The US Department of Defense has awarded Sun Microsystems Inc. of Santa Clara, Calif., $44.29 million to develop computer microchip interconnectivity through on-chip optical networks enabled by silicon photonics and by the company’s proximity communications technology.

Based on laser transmission, this interconnection system could result in the creation of supercomputing capabilities for applications with high computation and communications requirements, such as biotechnology, weather modeling, energy exploration, image processing, autonomous operations and synthetic aperture radar.

Part of the DARPA Ultraperformance Nanophotonic Intrachip Communication (UNIC) program, the project has been launched with funding of $8.1 million to Sun Microsystems’ Microelectronics and Laboratories divisions. The UNIC program is expected to demonstrate photonics technology for high bandwidth, on-chip photonics communications for advanced microprocessors.

Under a 51/2-year contract, Sun seeks to combine a new form of optical proximity communications signaling with capacitive proximity communication — its electrical chip-to-chip input/output technology — to construct arrays of low-cost chips into a single virtual “macrochip.” This assemblage would perform as one very large chip and would eliminate the conventional soldered-chip interconnections. Long connections across the macrochip would leverage the low latency, high bandwidth and low power of silicon optics. Through the program, Sun and DARPA will research technologies to further increase the efficiency of these optical connections.

Optical transmission in and between microchips has been considered superior to the traditional electrical transmission technology, which can be slower and which has a power cost that rises with the distance traveled. In contrast, optical transmission can be faster and has a fixed power cost to connect to any point within the system.