Directly modulated 1.3 μm quantum dot lasers epitaxially grown on silicon

D. Inoue, D. Jung, J. Norman, Y. Wan, N. Nishiyama, S. Arai, A. C. Gossard, and J. E. Bowers
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Optical microscope image to show four Fabry-Perot lasers from a cleaved laser bar.
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Optics Express
Vol. 26, No. 6, 7022-7033

We report the first demonstration of direct modulation of InAs/GaAs quantum dot (QD) lasers grown on on-axis (001) Si substrate. A low threading dislocation density GaAs buffer layer enables us to grow a high quality 5-layered QD active region on on-axis Si substrate. The active layer has p-modulation doped GaAs barrier layers with a hole concentration of 5 × 1017 cm3 to suppress gain saturation. Small-signal measurement on a 3 × 580 μm2 Fabry-Perot laser showed a 3dB bandwidth of 6.5 GHz at a bias current of 116 mA. A 12.5 Gbit/s non-return-to-zero signal modulation was achieved by directly probing the chip. Open eyes with an extinction ration of 3.3dB was observed at room temperature. The bit-error-rate (BER) curve showed no error-floor up to BER of 1 × 1013. 12 km single-mode fiber transmission experiments using the QD laser on Si showed a low power penalty of 1 dB at 5 Gbit/s. These results demonstrate the potential for QD lasers epitaxially grown on Si to be used as a low-cost light source for optical communication systems.

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More Research Areas
Epitaxial Growth on Si