23 GHz Ge/SiGe multiple quantum well electro-absorption modulator.

Area of Science:

• Photonics and optoelectronics
• Materials science
• Integrated circuits

Background:

• Silicon photonics is crucial for high-speed optical interconnections.
• Germanium/Silicon-Germanium (Ge/SiGe) multiple quantum wells (MQWs) offer a promising material system for silicon-compatible photonic devices.
• Electro-absorption modulators are key components for modulating optical signals.

Purpose of the Study:

• To demonstrate high-speed operation of a Ge/SiGe MQW electro-absorption modulator.
• To evaluate the performance of the modulator in terms of bandwidth, extinction ratio, and energy consumption.
• To assess the potential of Ge/SiGe MQWs for energy-efficient silicon photonic integrated circuits.

Main Methods:

• Fabrication of a Ge/SiGe MQW waveguide electro-absorption modulator.
• Experimental characterization of the modulator's bandwidth using high-frequency measurements.
• Measurement of extinction ratio and energy consumption under varying voltage conditions.

Main Results:

• Experimental demonstration of a 23 GHz bandwidth from a 3 µm wide and 90 µm long Ge/SiGe MQW waveguide modulator.
• High extinction ratio exceeding 10 dB over a wide spectral range.
• Achieved an extinction ratio of 9 dB with an energy consumption of 108 fJ/bit using a 1 V swing voltage (3-4 V).

Conclusions:

• Ge/SiGe MQW waveguide modulators exhibit high-speed operation suitable for optical interconnections.
• The demonstrated energy efficiency highlights the potential of Ge/SiGe MQWs for low-power silicon photonic integrated circuits.
• Ge/SiGe MQWs are a viable building block for future energy-efficient optical interconnects in silicon photonics.