The cash keeps rolling for systems vendor Infinera Inc., which today announced it has picked up another $52 million in venture funding and some key contacts in Asia.

Infinera has now raised $205 million since launching as Zepton in 2000. The latest round included the entire slate of previous venture investors: Accel Partners, Benchmark Capital, Jafco Ventures, Kleiner Perkins Caufield & Byers, Mobius Venture Capital, Sprout Group, Sutter Hill Ventures, Venrock Associates, and WorldView Technology Partners.

Because Infinera is building a complete system and owns a manufacturing facility, its costs have run high compared with the austerity forced on more recent startups; its employee count is now more than 250. Infinera isn't saying how much more cash it might need, nor is the company making the usual startup prediction of getting to breakeven on its latest round.

"The motive for the round was that we're seeing a lot of customer action and wanted to strike while the iron was hot. We didn't want to run into cash constraints," says CEO Jagdeep Singh. "Turning out customers requires cash."

The funding round includes two new investors, UTStarcom Inc. (Nasdaq: UTSI) and Itochu Techno-Science Corp. (CTC), that could boost Infinera's standing in Asia.

CTC is a Japanese distributor that works with the likes of Cisco Systems Inc. (Nasdaq: CSCO), Oracle Corp. (Nasdaq: ORCL), and Sun Microsystems Inc. (Nasdaq: SUNW) -- and now, Infinera. As for the UTStarcom relationship, the companies aren't divulging details but say they will pair up Infinera's Wavelength Division Multiplexing (WDM) system, the DTN, with the UTStarcom NetRing optical transport, targeting Asian carriers.

Infinera officials won't say whether UTStarcom will be able to resell the DTN, but the companies are "working with customers in Asia," says CEO Singh.

Infinera's other strategic investors are Agilent Technologies Inc. (NYSE: A), Applied Materials Ventures, Cypress Semiconductor Corp. (NYSE: CY), and Juniper Networks Inc. (Nasdaq: JNPR).

Infinera's DTN offers an electrical alternative to all-optical switches and add/drop multiplexers. While electrical switching is a more old-school concept, Infinera managed to shrink and integrate the optical component to fit on an indium phosphide chip. The idea is to lower the cost of electrical switching enough to make carriers give up on all-optical dreams (see Infinera Declares WDM War).

For all the attention it's gathered, Infinera still faces the startup's dilemma: Until it amasses customers, it won't appear stable enough to attract customers. The company has claimed to be in several lab trials but hasn't announced any wins in live networks. "That's what worries [carriers]. It'd be great if they had some systems sold," says one source close to the company.

Singh notes that the company is "on track to meet the goals that we had," which include deployment of the DTN by the end of the year.

— Craig Matsumoto, Senior Editor, Light Reading