The current ready-to-go version of Light Peak uses copper, not fiber optics.

Intel's Light Peak is now ready. Friday during CES 2011, an Intel executive told Computerworld that its Light Peak interconnect technology is ready for implementation. The only thing is that the new tech--which connects PC's to displays, external storage and more--is currently using copper instead of the promised fiber optics. Intel is turning on the lights, but without light. The chip maker will use copper instead of fiber in its new Light Peak optical interconnection technology, reaching speeds surprisingly better than the company expected.

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Light Peak Ready, But Uses Copper
Intel to Device Makers: Light Peak is Ready... Sans Light | News & Opinion | PCMag.com