[1] INRS Energie Mat & Telecommun, 1650 Blvd Lionel Boulet, Varennes, PQ J3X 1S2, Canada
[2] Sapienza Univ, CNR, INFM, Res Ctr SOFT, I-00185 Rome, Italy
[3] Univ Pavia, Dipartimento Elettr, I-27100 Pavia, Italy
[4] Infinera Ltd, Sunnyvale, CA 94089 USA
[5] Univ Sydney, Sch Phys, CUDOS, Sydney, NSW 2006, Australia