摘要 |
A wavelength division multiplex transmission system has an optical fiber trunk (12) with one or more branching units (18) each providing an add/drop channel (22, 20). In the branch, components are provided for pre-dispersing the wavelength of the add channel, prior to route to the trunk (12), with a dispersion characteristic of opposite sign to the dispersion occurring in the trunk, thereby to compensate for dispersion of that wavelength occurring along the trunk.
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