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IEC 62077:2022 applies to circulators used in the field of fibre optics bearing all of the following features:

• they are non-reciprocal optical devices, in which each port is either an optical fibre or fibre optic connector;
• they are passive devices in accordance with the categorization and definition provided in IEC TS 62538;
• they have three or more ports for directionally transmitting optical power.

An example of optical circulator technology and application is described in Annex A and Annex B, respectively. This fourth edition cancels and replaces the third edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:

1. harmonization of terms and definitions with IEC TS 62627-09;
2. change of Clause 4 regarding requirements