Quantum dot-based diode comb lasers can provide a single multi-channel-laser source for short-reach, high-speed WDM interconnects. In this paper, we review the technology and demonstrate for the first time a 15 channel, low RIN comb laser with 80 GHz channel spacing. We show that each of the Fabry-Perot (FP) modes can be externally modulated at 10 Gb/s or all modes directly modulated, at 3.2 Gb/s so far. The latter indicates that the comb laser may be an ideal broadband light source in WDM-PON applications. We further demonstrate that the whole comb laser spectrum can be amplified by a quantum dot SOA without increasing relative density noise (RIN) of the individual channels. The small signal amplification factor was measured up to 30dB and the saturated output power was as high as 15 dBm.