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OFDM Based Superchannel Transmission Technology

Figure 1

Figure 1
Three common types of single-band transmitters (SB-TX). VPS: variable power splitter. (a) PDM-n-QAM Transmitter w/o DAC, (b) PDM-n-QAM Transmitter w/DAC, (c) PDM-OFDM/QAM Transmitter.

Figure 2

Figure 2
Three common types of multi-band transmitters (MB-TX). DMUX: wavelength de-multiplexer. (a) OFDM-based multiband transmitter, (b) Nyquist WDM using optical filtering, (c) Nyquist WDM using digital filtering.

Figure 3

Figure 3
Schematic of the experimental setup [35]. Insets: (a) OFDM frame structure; (b) Optical spectra of three 485-Gb/s WDM channels before and after 4800-km transmission; (c) Block diagram of the receiver offline DSP.

Figure 4

Figure 4
Constellations of the OFDM subcarriers (recovered in the back-to-back configuration) when modulated by 16-QAM [35], 32-QAM [11], and 64-QAM [12], respectively, achieving superchannel data rates of 485 Gb/s, 606 Gb/s, and 728 Gb/s. (a) PDM-OFDM-16QAM (485 Gb/s), (b) PDM-OFDM-32QAM (606 Gb/s), (c) PDM-OFDM-64QAM (728 Gb/s).

Figure 5

Figure 5
(a) Probability density function (pdf) of the signal distortion in the back-to-back configuration; (b) pdf after 4800-km transmission at 1 dBm per superchannel.