Simple Estimation of the XPM-Induced Phase Error Variance in Hybrid OOK-PSK Systems Kroushkov, Dimitar Ivanov ; Warm, Stefan ; Winter, Marcus ; Petermann, Klaus Abstract Publication: IEEE Photonics Technology Letters Pub Date: May 2012 DOI: 10.1109/LPT.2012.2187332 Bibcode: 2012IPTL...24..733K