Fiber-optic networks are becoming a hive of private equity activity.

A newcomer, Court Square Capital Partners, has paid handsomely for a fiber operator that could be a base for future acquisitions.

Meanwhile, Abry Partners LLC completed its $1.2 billion purchase of RCN Corp. and broke off the company's metropolitan fiber arm into a separate business that will likely weigh fiber deals.

There is already one PE-backed serial acquirer, Zayo Group LLC, as well as telecoms that have shopped for fiber.

Court Square's agreement to buy Fibertech Networks LLC for $535 million creates a new competitive dynamic in the business, for a number of reasons. The company is paying above 10 times Fibertech's Ebitda for the past 12 months, creating a tough comp for other sales.

There are reasons that Fibertech is getting a healthy valuation. The Rochester, N.Y., company has grown revenue at more than 30% a year, has a clear window into future sales and has a customer base with a low level of churn.

Still, the takeout multiple is a strong data sign for the sector. Bear in mind that Court Square is a private equity firm, not a telecom that would expect to find savings and other benefits in the acquisition. The firm is taking out investors Nautic Partners LLC and Ridgemont Equity Partners, recently spun out of Bank of America Corp. (NYSE:BAC).

Fibertech operates in cities throughout the Midwest and Northeast. With its new backing, the company will look to expand, through deals or by breaking ground itself, in markets north of Florida and east of the Mississippi.

Meanwhile, Abry's RCN Metro now has greater freedom to buy metro fiber assets. Abry agreed in March to buy RCN, which also offers cable and telecom services to residential and business users. As part of the deal, Abry decided to break the companies apart upon closing.

RCN Metro has fiber-optic systems from Boston and New York to mid-Atlantic markets such as Washington and a number of other cities, including Chicago and Toronto.

Zayo Group, of Louisville, Colo., has backing from Battery Ventures, Centennial Ventures Inc., Charlesbank Capital Partners LLC, Columbia Capital, M/C Venture Partners, Morgan Stanley Alternative Investment Partners and Oak Investment Partners.

Since its 2007 launch, Zayo has made 15 acquisitions. Its most recent is the late-June purchase of American Fiber Systems Holding Corp. for more than $100 million.

More traditional telecoms have also taken part in the fiber bonanza. Windstream Corp. (NASDAQ:WIN) said in August that it would pay $782 million for Q-Comm Corp., which owns expansive fiber assets.

Driving these deals is the belief that online media, smartphones, cloud computing and other data-consuming applications will create the demand for fat pipes. Of course, during the great Internet bubble, many high-profile investors overestimated the demand for bandwidth. RCN itself was a victim.

In the last tech crash, however, the Internet was not as robust as it is today. There were no iPhones and iPads.

Court Square's multiple demonstrates that the competition for the pipes that will carry that data is getting more serious.