Direct modulation of 1.3 μm quantum dot lasers on silicon at 60 °C

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Quantum dot (QD) lasers offer unique optical properties.
• Integrating III-V materials with silicon is crucial for advanced photonic integrated circuits (PICs).
• Direct bonding is a promising technique for heterogeneous integration.

Purpose of the Study:

• To demonstrate direct modulation of an InAs/GaAs QD laser integrated on a silicon substrate.
• To evaluate the performance of the QD laser under various conditions.
• To assess the potential of this technology for PIC applications.

Main Methods:

• Fabrication of a Fabry-Pérot QD laser on Si using ultraviolet-activated direct bonding.
• Formation of a laser cavity using cleaved facets without specialized coatings.
• Characterization of the laser's performance under continuous-wave pumping at room temperature.
• Direct modulation testing with non-return-to-zero (NRZ) signals at different data rates and temperatures.

Main Results:

• Successful operation of the bonded QD laser on Si at room temperature with a threshold current of 41 mA and 30 mW output power.
• Direct modulation achieved at 10 Gbps with a 1.9 dB extinction ratio at room temperature.
• Stable 6 Gbps modulation demonstrated up to 60 °C with a 4.5 dB extinction ratio.
• Simple device structure and fabrication process confirmed.

Conclusions:

• The direct modulation of InAs/GaAs QD lasers on Si is feasible and shows promising performance.
• This technology represents a significant step towards realizing high-performance silicon photonic integrated circuits.
• The demonstrated device performance is encouraging for future optoelectronic integration.