Hitless Rate Switching for Dynamically Reconfigurable Optical Systems

We propose a set of techniques to enable hitless rate switching for reconfigurable optical systems and validate, by computer simulations, their applicability to NRZ, RZ, and Nyquist pulse shapes. The polarization-multiplexed quadrature phase-shift keying (PM-QPSK) and 16 quadrature amplitude modulation (16QAM) modulation formats are investigated. Error transients that appear during lower-to-higher rate switching are avoided by sufficiently long equalizer training periods. The robustness of the proposed scheme to polarization mode dispersion (PMD) and signal phase noise is also demonstrated.