SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
Jul. 30, 2022
Accounting Policies [Abstract]
Newly Issued Accounting Standards - Effective and Not Yet Effective	Newly Issued Accounting Standards - Effective In December 2019, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2019-12 (“ASU 2019-12”), Income Taxes (ASC 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by removing certain exceptions to the general principles in ASC 740. The amendments also improve consistent application of and simplify GAAP for other areas of ASC 740 by clarifying and amending existing guidance. Most amendments within this standard are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. ASU 2019-12 was effective for Ciena beginning in the first quarter of fiscal 2022. Ciena adopted ASU 2019-12 beginning in the first quarter of fiscal 2022 without any material impact on its financial position and results of operations. In November 2021, the FASB issued ASU No. 2021-10 (“ASU 2021-10”), Government Assistance, to increase transparency of government assistance including the disclosure of (1) the types of assistance, (2) an entity’s accounting for the assistance, and (3) the effect of the assistance on an entity’s financial statements. ASU 2021-10 was effective for annual periods beginning after December 15, 2021. Early adoption was permitted. Ciena adopted ASU 2021-10 in the first quarter of fiscal 2022 without any material impact on its financial position and results of operations. In March 2020, the FASB issued ASU No. 2020-04 (“ASU 2020-04”), Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. ASU 2020-04 provides temporary optional guidance on contract modifications and hedging accounting to ease the financial reporting burdens of the expected market transition from the London Interbank Offered Rate (“LIBOR”) to alternative reference rates. In January 2021, the FASB issued ASU No. 2021-01, which refines the scope of Topic 848 and clarifies some of its guidance as part of the FASB’s monitoring of global reference rate activities. The new guidance was effective upon issuance and may be applied prospectively through December 31, 2022. Ciena adopted Topic 848 beginning in the first quarter of fiscal 2022 without any material impact on its financial position and results of operations. Newly Issued Accounting Standards - Not Yet Effective In October 2021, the FASB issued ASU No. 2021-08 (“ASU 2021-08”), Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers to improve the accounting for acquired revenue contracts with customers in a business combination to address recognition of an acquired contract liability and payment terms and their effect on subsequent revenue recognized by the acquirer. ASU 2021-08 is effective for annual periods beginning after December 15, 2022 on a prospective basis. Early adoption is permitted. Ciena is currently evaluating the impact of this ASU on its condensed consolidated financial statements and related disclosures.

In December 2019, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update No. 2019-12 (“ASU 2019-12”), Income Taxes (ASC 740): Simplifying the Accounting for Income Taxes, which simplifies the accounting for income taxes by removing certain exceptions to the general principles in ASC 740. The amendments also improve consistent application of and simplify GAAP for other areas of ASC 740 by clarifying and amending existing guidance. Most amendments within this standard are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. ASU 2019-12 was effective for Ciena beginning in the first quarter of fiscal 2022. Ciena adopted ASU 2019-12 beginning in the first quarter of fiscal 2022 without any material impact on its financial position and results of operations.

In November 2021, the FASB issued ASU No. 2021-10 (“ASU 2021-10”), Government Assistance, to increase transparency of government assistance including the disclosure of (1) the types of assistance, (2) an entity’s accounting for the assistance, and (3) the effect of the assistance on an entity’s financial statements. ASU 2021-10 was effective for annual periods beginning after December 15, 2021. Early adoption was permitted. Ciena adopted ASU 2021-10 in the first quarter of fiscal 2022 without any material impact on its financial position and results of operations.

In March 2020, the FASB issued ASU No. 2020-04 (“ASU 2020-04”), Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. ASU 2020-04 provides temporary optional guidance on contract

modifications and hedging accounting to ease the financial reporting burdens of the expected market transition from the London Interbank Offered Rate (“LIBOR”) to alternative reference rates. In January 2021, the FASB issued ASU No. 2021-01, which refines the scope of Topic 848 and clarifies some of its guidance as part of the FASB’s monitoring of global reference rate activities. The new guidance was effective upon issuance and may be applied prospectively through December 31, 2022. Ciena adopted Topic 848 beginning in the first quarter of fiscal 2022 without any material impact on its financial position and results of operations.

In October 2021, the FASB issued ASU No. 2021-08 (“ASU 2021-08”), Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers to improve the accounting for acquired revenue contracts with customers in a business combination to address recognition of an acquired contract liability and payment terms and their effect on subsequent revenue recognized by the acquirer. ASU 2021-08 is effective for annual periods beginning after December 15, 2022 on a prospective basis. Early adoption is permitted. Ciena is currently evaluating the impact of this ASU on its condensed consolidated financial statements and related disclosures.