Calient Technologies announced Wednesday that it's raised $27 million, evidence that the company has gained some traction -- or at least some attention -- in redefining itself as a data-center player and a software-defined networking (SDN) asset.

Calient's product is an all-optical switching system. It uses mirrors -- tiny, pivoting devices that fall into the category of micro-electromechanical systems (MEMS) -- to move an optical signal from one port of the switch to another, without having to look at the data inside the light.

The company's heritage goes back to 1999, when it was peddling the same idea but for a different market: big telecom networks. Then named Calient Networks, the company rode a bubble in optical networking to quickly raise $281 million, most of it in a $225 million third round.

Of course, the bubble didn't last, but as other all-optical startups died out, Calient managed to hang on. For the past few years, the company has been shifting its emphasis to the data center.

It's not a bad fit. Improvements to the optical network could aid the SDN cause greatly, as analyst Nikos Theodosopoulos pointed out recently on SDxCentral. And Plexxi and Calient have teamed up to develop what they're calling the software-defined packet/optical data center network (acronym too horrendous to print here), as shown in a recent DemoFriday™ session.

These days, Calient is run by Chairman and CEO Atiq Raza, who'd done a lot of investing in networking technologies during the bubble. He's managed to attract quite a bit of cash into Calient. In addition to this $27 million round (investors for which were not disclosed), Raza raised $19.4 million sometime around 2010.

The company is also bringing in a CFO -- Jag Setlur, also announced Wednesday. Setlur was once CFO of Cotendo, which got sold to Akamai.

At least two other all-optical companies survived the dot-com days: Glimmerglass and Polatis. They've both found markets beyond telecom, just like Calient did, but neither one seems to have caught the SDN bug yet.