12.5 Gbit/s directly modulated InAs/GaAs quantum dot lasers grown on Si (001) substrate with strong optical feedback...

In this paper, we demonstrate a 12.5 Gbit/s directly modulated InAs/GaAs quantum dot (QD) lasers epitaxially grown on Si (001) substrate with strong optical feedback resistance. The active region of the QD laser consists of p-modulation-doped eight-layer QDs. It is shown that the QD laser with a ridge waveguide structure of 3×600 µm² can operate in continuous-wave (CW) mode from 25°C to 75°C, with a maximum output power of 16.9 mW at room temperature (RT). Furthermore, small-signal measurements reveal that the laser has a 3 dB bandwidth of 3.8 GHz and 2.7 GHz at 25°C and 55°C, respectively. Non-return-to-zero (NRZ) large signal measurements reveal that the laser can achieve a maximum modulation rate of 12.5 Gbit/s at RT. Dynamic optical feedback measurements using a 10 Gbit/s signal exhibit that the QD laser has a strong optical feedback tolerance, leading to a low bit error ratio (BER) of 6×10^-6 even at a maximum feedback intensity of -9 dB. These results presented here prove the great application potential of the QD lasers on Si (001) for large scale, low-cost and isolator-free silicon photonics integrated circuits (PICs).