The long-awaited Infinera Corp. (Nasdaq: INFN) IPO could be ready for takeoff within the next few weeks.

Infinera has sent lock-up agreements to its shareholders, sources say, barring them from selling stock within a certain time period. It's a routine part of the IPO process and, if it's really happened, is a sure sign that Infinera is ready to file its S-1 with the Securities and Exchange Commission (SEC) .

"I have definitely heard the S-1 is close to imminent," says Joe Chiasson, an analyst with Susquehanna Financial Group . Chiasson hadn't heard about the lock-up agreements but notes that the timing for an Infinera IPO seems right.

"Clearly, the market is back," he says. "The market has looked as healthy as it has to me for seven years, in terms of demand."

Infinera, which sells a highly integrated DWDM system, has long been presumed to be on an IPO track. (See Infinera Declares WDM War.)

A growing customer list that includes XO Communications Inc. -- and a bit of testimonial from BT Group plc (NYSE: BT; London: BTA), which said Infinera might find a place in the 21CN project -- got Infinera reinstated to Light Reading's Top Ten Private Companies last year. (See Infinera Inc.)

IPO speculation flared up in the summer, sparked by the company's sudden change of CFOs in June. But the company also scooped up some funding in July, possibly a sign that it was knew the IPO would have to wait a bit. (See Infinera: $1B IPO Imminent?, Infinera's CFO Quits, and Infinera Raises Another $110M.)

So, is this latest round of talk the real thing, or just another tease? Infinera won't tell; a spokesman contacted by Light Reading reiterated the company line about not commenting on financial matters.

— Craig Matsumoto, West Coast Editor, Light Reading