400-Gb/s direct modulation using a DFB+R laser.

We demonstrate a direct-modulation and direct-detection system with a back-to-back line rate of 411.6 (net bit rate of 337.5) Gb/s using a 65 GHz DFB+R laser. The O-band laser with a chirp parameter of 0.6 supports dispersion-tolerant transmissions up to 15 km without an optical amplifier.

PAM-4 transmission up to 160 Gb/s with surface-normal electro-absorption modulators.

We report multi-level modulation in polarization-independent surface-normal electro-absorption modulators (SNEAMs). Four-level pulse amplitude modulation (PAM-4) at a line rate of 44 Gb/s is demonstrated on a fully packaged SNEAM with a 30 µm active area diameter and a 14 GHz electro-optic bandwidth. High-capacity PAM-4 transmission at 112 and 160 Gb/s is demonstrated on an unpackaged SNEAM chip, with a 15 µm active area diameter and ultrawide electro-optic bandwidth (≫65GHz). Fiber transmission is investigated for direct detection link lengths up to 23 km at 44 Gb/s and 2 km at 112 and 160 Gb/s, the highest multi-level modulation rates achieved on a SNEAM.

Distributed Raman amplification in a 8 x 10-Gb/s, 40-km, 1:128 TWDM PON.

We demonstrate distributed Raman amplification compatible with the wavelength plans and rates defined in ITU's specification for TWDM PON. We report downstream and upstream gains of 9.8 dB and 8.6dB, respectively, for a 42-km, 8-wavelength TWDM PON with 80-Gb/s symmetric capacity and 1:128 split. Raman gain and system performance are also reported for 21-km and 10-km feeder lengths.