| Document and Entity Information | Dec. 13, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | CIENA CORP |
| Amendment Flag | false |
| Entity Central Index Key | 0000936395 |
| Document Type | 8-K |
| Document Period End Date | Dec. 13, 2021 |
| Entity File Number | 001-36250 |
| Entity Incorporation State Country Code | DE |
| Entity Tax Identification Number | 23-2725311 |
| Entity Address, Address Line One | 7035 Ridge Road |
| Entity Address, City or Town | Hanover |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 21076 |
| City Area Code | (410) |
| Local Phone Number | 694-5700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, $0.01 par value |
| Trading Symbol | CIEN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
