Abstract

Blind equalization and carrier phase recovery in a simulated 14 Gbaud 16-QAM optical coherent system are investigated. Equalization techniques to compensate for linear transmission impairments are presented using the constant modulus algorithm (CMA), the recursive least-squares (RLS)-CMA, and the radius directed equalization (RDE). With 7 T/2-spaced taps, the RDE and the RLS-CMA can compensate up to 1000 ps/nm of CD in the 16-QAM coherent system with performances comparable to the decision-directed (DD) equalizer. We show that the RDE is a promising technique for blind equalization in a 16-QAM coherent system with lower complexity than the RLS-CMA. Blind carrier phase recovery is investigated in a decision-directed-mode. We show that the blind carrier phase recovery algorithm can recover the Square-16-QAM constellation for laser beat linewidths of $\Delta \nu T_{s} \sim 10^{-4}$ in a polarization-multiplexed (POLMUX) 16-QAM coherent system with the RDE algorithm giving better overall performance than the CMA when compensating for CD and differential group delay (DGD). Finally, the dynamical characteristics of the equalizers to track endless polarization rotations are discussed. With the adaptation parameters optimized, the equalizers can track angular rate of rotation ${\sim 10}^{5}~$ rad/s.

© 2009 IEEE

PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription