1. T. Kawanishi, S. Sakamoto, M. Izutsu, High-speed control of lightwave amplitude, phase, and frequency by use of electrooptic effect. IEEE J. Select. Top. Quantum Electron. 13, 79–91 (2007)
2. G.L. Li, P.K.L. Yu, Optical intensity modulators for digital and analog applications, IEEE/OSA J. Lightwave Technol. 21, 2010–2030 (2003)
3. A.H. Gnauck, G. Raybon, S. Chandrasekhar, J. Leuthold, C. Doerr, L. Stulz, E. Burrows, 25× 40-Gb/s copolarized DPSK transmission over 12 × 100-km NZDF With 50-GHz channel spacing IEEE Photonics Technol. Lett. 15, 467–469 (2003)
4. N. Yoshikane, I. Morita, 1.14 b/s/Hz spectrally efficient 50 × 85.4 Gb/s transmission over 300 km using copolarized RZ-DQPSK Signals, J. Lightwave Technol. 23, 108–114 (2005)
5. A.H. Gnauck, P.J. Winzer, S. Chandrasekher, C. Dorrer, Spectrally efficient (0.8 b/s/Hz) 1-Tb/s (25 × 42.7 Gb/s) RZ-DQPSK transmission over 28 100-km SSMF spans with 7 optical add/drops, ECOC 2004 PD, Th4.4.1