Analysis and demonstration of network utilization improvement through format-agnostic multi-channel wavelength converters

The effectiveness of using all-optical wavelength converters (AO-WCs) to improve optical network utilization is evaluated by performing both network simulations and experiments. The employed AO-WCs enable format-agnostic and multi-channel operations, in which the wavelengths of multiple input channels are simultaneously shifted by the same amount. Such unique features are not available in conventional optical-electrical-optical-conversion-based wavelength converters (OEO-WCs). Network simulations show that the wavelength conversion can double the network utilization (the carried traffic), while the number of required wavelength converters can be significantly reduced by 60% by employing AO-WCs instead of OEO-WCs. In addition, simulation results confirm the importance of AO-WC cascadability for achieving low blocking probabilities. Our simulation analysis also identifies an optimum AO-WC specification value, the maximum wavelength shift, for maximizing sharing of the installed AO-WCs. In the experiment, the performance of a prototyped AO-WC is evaluated under a realistic network setup employing a wavelength-selective-switch-based optical node installing the AO-WC and fiber transmission lines. Wavelength division multiplexing signals of different modulation formats, including dual-polarization quadrature phase shift keying (DP-QPSK), dual-polarization 16 quadrature amplitude modulation (DP-16QAM), and on-off keying (OOK), spanning over a 1000 GHz bandwidth are successfully shifted simultaneously by 1400 GHz or 200 GHz without significant signal quality degradation, confirming the guard-band-less, multi-channel, and modulation-format/ line-rate-agnostic capabilities of the AO-WC.