A critically coupled Germanium photodetector under vertical illumination

Area of Science:

• Photonics
• Optoelectronics
• Materials Science

Background:

• Silicon photonics is crucial for optical interconnects.
• Efficient photodetectors are needed for high-speed optical receivers.
• Germanium-on-silicon integration faces challenges in performance and compatibility.

Purpose of the Study:

• To propose and study a practical Germanium photodetector design.
• To achieve critical coupling under vertical illumination at 1310 nm.
• To develop a high-performance, cost-effective solution for silicon photonics.

Main Methods:

• Device design and simulation of a Germanium photodetector on a Silicon-on-insulator substrate.
• Optimization of parameters to achieve critical coupling.
• Analysis of efficiency-bandwidth product and spectral width under realistic constraints.

Main Results:

• Achieved critical coupling under vertical illumination at 1310 nm.
• Obtained a high efficiency-bandwidth product exceeding 50 GHz.
• Reached a 3dB spectral full width of approximately 30 nm.
• Demonstrated compatibility with CMOS process technology.

Conclusions:

• The proposed Germanium photodetector design is practical and high-performance.
• The device offers a promising solution for optical receivers in silicon photonics.
• CMOS compatibility ensures potential for low-cost, mass production.