[1] [1] Rouskas G, Perros H. A tutorial on optical networks. Advanced lectures on networking, 2002, 2497: 496-500

[2] [2] Gnauck A, Winzer P J. Optical phase-shift-keyed transmission. Lightwave Technology, Journal of, 2005, 23(1): 115-130

[3] [3] Winzer P J, Raybon G, Song H, Adamiecki A, Corteselli S, Gnauck A H, Fishman D A, Doerr C R, Chandrasekhar S, Buhl L L, Xia T J, Wellbrock G, Lee W, Basch B, Kawanishi T, Higuma K, Painchaud Y. 100-Gb/s DQPSK transmission: from laboratory experiments to field trials. Journal of Lightwave Technology, 2008, 26(20): 3388-3402

[4] [4] van den Borne D, Jansen S L, Gottwald E, Schmidt E D, Khoe G D, de Waardt H. DQPSK modulation for robust optical transmission. In: Proceedings of 2008 OFC/NFOEC. Berlin: Springer, 2008, OMQ1

[5] [5] Yu Y, Zhang X, Huang D, Li L, Fu W. 20-Gb/s all-optical format conversions from RZ signals with different duty cycles to NRZ signals. Photonics Technology Letters, IEEE, 2007, 19(14): 1027-1029

[6] [6] Yu Y, Zhang X, Huang D. Simultaneous all-optical multi-channel RZ and CSRZ to NRZ format conversion. Optics Communications, 2010, 284(1): 129-135

[7] [7] Zhang Z, Yu Y, Zhang X. Simultaneous all-optical demodulation and format conversion for multi-channel (CS) RZ-DPSK signals. Optics Express, 2011, 19(13): 12427-12433