Document and Entity Information (USD $) In Billions, except Share data, unless otherwise specified	12 Months Ended
	Oct. 31, 2011	Dec. 15, 2011	Apr. 29, 2011
Document and Entity Information [Abstract]
Entity Registrant Name	CIENA CORP
Entity Central Index Key	0000936395
Current Fiscal Year End Date	--10-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Oct. 31, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		97,442,608
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2.1