* Sees first-quarter revenue $515 mln-$545 mln vs est $537.7 mln
* Fourth-quarter adjusted earnings $0.16/share vs est $0.24
* Revenue $583.4 mln vs est $568.5 mln
* Shares down 11 pct before the bell
(Adds details, updates share movement)
Dec 12 (Reuters) - Network equipment maker Ciena Corp reported a lower-than-expected quarterly profit as costs rose 20 percent and forecast current-quarter revenue largely below Wall Street estimates, sending its shares down 11 percent before the bell.
Ciena and rivals such as Juniper Networks Inc, whose products expand capacity of fiber-optic networks, have benefited in the past year as major U.S. telecom companies upgrade their wireless and wireline networks.
AT&T Inc, Ciena's biggest source of revenue last year, and other customers such as Verizon Communications Inc and Vodafone Group Plc are widely thought to have held back on spending in the last few months of the year.
"Verizon and AT&T are extra-focused on delivering strong free cash flow in fourth quarter 2013 and are not expected to have meaningful budget-flushes this year," MKM Partners analyst Michael Genovese said in a pre-earnings note.
Ciena forecast revenue of $515 million to $545 million for the first-quarter ending Jan. 31.
Analysts on average had expected revenue of $537.7 million, according to Thomson Reuters I/B/E/S.
Ciena's net loss narrowed to $9.8 million, or 9 cents per share in the fourth quarter, from $38.8 million, or 39 cents per share, a year earlier.
But excluding items, the company earned 16 cents per share.
Revenue rose 25 percent to $583.4 million.
Analysts on average had expected earnings of 24 cents on revenue of $568.5 million.
Nasdaq-listed Ciena also said on Thursday it would transfer its listing to the New York Stock Exchange, and would start trading on the NYSE from Dec. 23.
Ciena's shares were trading at $20.30 before the bell.
(Writing by Sruthi Ramakrishnan and Neha Alawadhi in Bangalore; Editing by Sriraj Kalluvila)