Time Warner Cable (s TWC) of New York is spending $600 million in cash to buy DukeNet, a fiber optic network that is part-owned by Duke Energy, the company announced today. The Charlotte, NC-based DukeNet will help Time Warner improve its network and business services in the Carolinas. Time Warner Cable had announced its intention to build a gigabit network in the Carolina earlier this year. In related news, Zayo, a large fiber network operator based in Boulder, Colorado announced that it was buying Fiberlink, a small Midwestern fiber operator that owns 1,200 miles of dark fiber that runs between Denver and Chicago (and runs via Omaha and Des Moines.) The terms of the deal were not disclosed.