Ciena trumps NSN to buy Nortel ops for $769 mln -sources

* Ciena to buy Nortel optical networking, ethernet ops

* To pay $769 million; 530 mln cash, $239 mln notes -sources

* Rival Nokia Siemens Networks final bid came close

* NSN says further bidding was not financially justified

By Anupreeta Das and Tarmo Virki

NEW YORK/HELSINKI, Nov 23 (Reuters) - Ciena Corp (CIEN.O: Quote, Profile, Research) will buy the optical networking and carrier ethernet business of bankrupt Nortel for $769 million, after trumping Nokia Siemens Networks in a three-day auction, sources told Reuters.

The deal will more than double turnover of U.S. network equipment maker Ciena, raising market worries over integration of operations, and over increase of its debt load.

Ciena's winning offer consists of $530 million in cash and $239 million in convertible notes, one of the sources said, speaking on condition of anonymity since details of the auction have not been made public. [ID:nN22395163]

The final bid by rival Nokia Siemens Networks [NSN.UL], which had teamed with private equity firm One Equity Partners, came "very close" to Ciena's offer, the source said.