We demonstrate a novel 40-Gb/s transmission system over a 10?01-km standard single mode fiber (SSMF) loop. This system features polarization multiplexed quadrature phase shift keying (PolMux-QPSK), lowvoltage modulation of 2-V peak-to-peak signal amplitude, and home-made 90? optical hybrid with singleended digital coherent detection. Any power amplifers before the modulator and balanced detectors are not used. In the case of low-voltage modulation, coherent detection is much less sensitive to modulator bias offset than delay interferometer-based demodulation.
© 2010 Chinese Optics Letters
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(060.1660) Fiber optics and optical communications : Coherent communications
(060.5060) Fiber optics and optical communications : Phase modulation
Yong Feng, He Wen, Hanyi Zhang, and Xiaoping Zheng, "40-Gb/s PolMux-QPSK transmission using low-voltage modulation and single-ended digital coherent detection," Chin. Opt. Lett. 8, 976-978 (2010)