Net-400-Gbps PS-PAM transmission using integrated AMUX-MZM.

Simple high-speed optical transmission technologies are desired for use in intra-and inter-datacenter networks. In this study, we demonstrate simple single-carrier intensity-modulated direct-detection (IMDD) transmissions at a net data rate of 400 Gbps (516.7 Gbps gross) over 20 km with a compact transmitter subassembly. The subassembly consists of a 2:1 analog multiplexer (AMUX) and an InP Mach-Zehnder modulator (MZM) placed close to each other and connected via wires. We employed 162-Gbaud single-carrier probabilistically shaped pulsed amplitude modulation (PS-PAM). The baseband signals with a bandwidth of around 81 GHz to drive the MZM were generated by a super-digital-to-analog converter (super-DAC) consisting of two sub-DACs and the AMUX. Digital nonlinear pre-distortion enabled us to transmit the signals with normalized generalized mutual information (NGMI) larger than the threshold of a soft-decision forward error correction (SD-FEC) code of 0.857. Truncation of the PS-PAM symbol distribution further enhanced performance. To the best of our knowledge, this is the first net-400-Gbps single-carrier IMDD transmission using a compact transmitter subassembly.

Single-carrier 1-Tb/s PDM-16QAM transmission using high-speed InP MUX-DACs and an integrated OTDM modulator.

We generated a 1-Tb/s single-carrier PDM-16QAM signal using a single optical modulator with external PDM emulation. To achieve the high symbol rate of 125 Gbaud, we used high-speed InP MUX-DAC modules, each consisting of six 2:1 MUXs and a 6-bit DAC in a single package, and an integrated optical modulator, which contains a generator of two orthogonal CSRZ pulse trains for spectrally efficient OTDM followed by IQ modulators for each tributary. The signal was received and demodulated without using any time-domain demultiplexing. Transmission over 80-km SSMF was demonstrated.

409-Tb/s + 409-Tb/s crosstalk suppressed bidirectional MCF transmission over 450 km using propagation-direction interleaving.

We demonstrate bidirectional transmission over 450 km of newly-developed dual-ring structured 12-core fiber with large effective area and low crosstalk. Inter-core crosstalk is suppressed by employing propagation-direction interleaving, and 409-Tb/s capacities are achieved for both directions.