(19)

(11)

EP 1 301 992 A1

(12)

(43) Date of publication: 16.04.2003 Bulletin 2003/16 (21) Application number: 01927073.5 (22) Date of filing: 17.04.2001

(51) International Patent Classification (IPC)7: H03L 7/18, G06F 1/025 (86) International application number: PCT/US0112/379 (87) International publication number: WO 0200/5431 (17.01.2002 Gazette 2002/03)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR Designated Extension States: AL LT LV MK RO SI (30) Priority: 10.07.2000 US 612689 (71) Applicant: Ciena Corporation Linthicum, MD 21090 (US)	(72) Inventor: CHIANG, Ting-Kuang Saratorga, CA 95070 (US) (74) Representative: Tomlinson, Kerry John  Frank B. Dehn & Co.,European Patent Attorneys,179 Queen Victoria Street London EC4V 4EL London EC4V 4EL (GB)