Fig. 1. (a) Bright-field scanning TEM image of the QD active layers. (b) PL comparison of InAs/GaAs QDs SLD structure grown on Si to a reference sample grown on native GaAs under the same pump conditions. The inset shows the representative AFM image of an uncapped QD sample grown on Si. (c) Optical micrography of rows of the fabricated narrow-ridge-waveguide laser. (d) Cross-sectional SEM image of the fabricated laser with as-cleaved facets.

Fig. 2. Experimental setup of RIN measurement. ISO, optical isolator.

Fig. 3. Experimental system for data transmission. PC, polarization controller; Amp., radio frequency amplifier; PPG, pseudorandom pattern generator; SMF-28, standard single-mode fiber.

Fig. 4. (a) RT CW LIV curves for total power and single-mode coupled power from a 2.2  μm×2.5  mm narrow-ridge-waveguide laser. (b) Lateral near-field intensity profiles with different injection currents. Inset: infrared (IR) camera image of lasing near-field at the threshold of 20 mA (well above threshold). (c) High-resolution CW lasing spectrum from a 2.2  μm×2.5  mm narrow-ridge-waveguide laser at an injection current of 40 mA. (d) Measured CW L-I curve from a 2.2  μm×4  mm narrow-ridge-waveguide laser as a function of temperature.

Fig. 5. (a) RIN spectra up to 16 GHz at gain currents of 40, 60, and 80 mA. (b) Measured RIN in the 6–10 GHz region with bias. (c) Relaxation oscillation frequency with bias.

Fig. 6. (a) Experimental results. 25.6 Gb/s eye diagrams (a) at back-to-back (received power of −7  dBm) and (b) after transmission over 13 km SMF-28. (c) BER at different received power at back-to-back (square marker) and after transmission (circle marker) using threshold detection.