LAUSR

We demonstrate intensity-modulated direct-detection optical transmission at a record-high data rate with single wavelength and single polarization. The high data rate is achieved with simple optics by using electronic and electrooptic devices with large operation bandwidths. We use a digital-preprocessed analog-multiplexed digital-to-analog converter with a >100-GHz analog multiplexer (AMUX) to drive an 80-GHz Mach–Zehnder optical modulator (MZM). The AMUX is based on 0.25-μm-emitter-width InP heterojunction bipolar transistor technology, and the MZM has InP n-i-p-n heterostructure optical waveguides with capacitance-loaded travelling-wave electrodes. We employ discrete multi-tone modulation controlled by a margin-adaptive bit-loading algorithm. In the experiment, the signal was transmitted over a 20-km dispersion-compensated single-mode fiber link and received by a single photodiode followed by a digital signal processor including a nonlinear equalizer. At a gross bit rate of 400 Gb/s, the bit error rate of the received signal was below the threshold of 20% overhead soft-decision forward error correction code. This result corresponds to a net data rate of 333 Gb/s.