# Cyclic spectra for wavelength-routed optical networks

## TL;DR

This paper introduces a cyclic spectrum technique for wavelength-routed optical networks, enhancing tolerance to frequency misalignments and impairments in densely spaced WDM systems by using redundant spectral components within guard bands.

## Contribution

It presents a novel cyclic spectrum approach that improves robustness against impairments in wavelength-routed optical networks with minimal guard band usage.

## Key findings

- Improved tolerance to frequency misalignments.
- Enhanced robustness against impairments from multiplexing elements.
- Effective in systems with 5-20% guard bands on a 50-GHz DWDM grid.

## Abstract

We propose occupying guard-bands in closely-spaced WDM systems with redundant signal spectral components, to increase tolerance to frequency misalignment and channel shaping from multiplexing elements. By cyclically repeating the spectrum of a modulated signal, we show improved tolerance to impairments due to add/drop multiplexing with a commercial wavelength selective switch, in systems using 5-20% guard bands on a 50-GHz DWDM grid.

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Source: https://tomesphere.com/paper/1701.02828