@INPROCEEDINGS {11963,
author={L.   Cancela and J.  Rebola and J. J. O.  Pires},
doi={},
booktitle={IEEE Photonics Conf. - IPC},
title={In-Band Crosstalk Tolerance of Direct Detection DQPSK Optical Systems},
year={2012},
month={September},
volume={-},
pages={---} 
}