Facilities

We investigate, both experimentally and theoretically, the gain characteristics of modulation p-doped 1.3 μm quantum dot lasers epitaxially grown on silicon. Gain spectra and transparency points are measured for structurally identical lasers with varying levels of p doping in the active region. A many-body model is employed to facilitate understanding of the material gain characteristics. It has been found that appropriate p doping greatly reduces transparency and improves differential gain.

We demonstrate 10 Gbit/s operation of InAs/InGaAs quantum dot (QD) p-i-n photodiodes (PDs) grown on on-axis (001) GaP/Si substrates. A 3.0 50 lm2 QD PD shows a small dark current of 0.2 nA at a bias voltage of 3 V, which corresponds to a dark current density of 0.13 mA/cm2 . This low-dark current characteristic obtained from a narrow-stripe device indicates that sidewall and threading dislocations have small effects on the dark current. The 3 dB bandwidth was 5.5 GHz at a bias voltage of 5 V. Large signal measurement with non-return-to-zero signals shows 10 Gbit/s eye opening.