Choi Hyeon Yeong, Tsuritani Takehiro, Morita Itsuro
KDDI R&D Laboratories Inc., 2-1-15 Ohara, Fujimino, Saitama, 356-8502 Japan.
Opt Express. 2012 Dec 17;20(27):28772-8. doi: 10.1364/OE.20.028772.
We propose a new 16QAM optical transmitter based on a combination of a dual-drive Mach-Zehnder modulator (DD-MZM) and a dual-parallel Mach-Zehnder modulator (DP-MZM) with electrical binary drive signals. For 16QAM generation, two arms of DD-MZM are independently driven by two different binary data, and consequently, the DD-MZM produces an offset square 4QAM of the 16QAM constellation. This 4QAM signal is then switched over other quadrants through a typical QPSK modulation scheme by the following DP-MZM, and resulting in 16QAM. By using the proposed transmitter together with a digital coherent receiver, we successfully demonstrate the 224-Gb/s and 320-Gb/s PDM-RZ-16QAM systems. Their OSNR sensitivities at 3.8x10(-3) BER are observed to be 19.8 dB and 23 dB, respectively.
我们提出了一种基于双驱动马赫-曾德尔调制器（DD-MZM）和双并行马赫-曾德尔调制器（DP-MZM）组合以及电二进制驱动信号的新型16QAM光发射机。对于16QAM生成，DD-MZM的两个臂由两个不同的二进制数据独立驱动，因此，DD-MZM产生16QAM星座图的偏移方形4QAM。然后，该4QAM信号通过后续的DP-MZM通过典型的QPSK调制方案切换到其他象限，从而产生16QAM。通过将所提出的发射机与数字相干接收机一起使用，我们成功演示了224-Gb/s和320-Gb/s的偏振复用归零（PDM-RZ）-16QAM系统。观察到它们在误码率为3.8×10^(-3)时的光信噪比（OSNR）灵敏度分别为19.8 dB和23 dB。
