Zero-bias 40Gbit/s germanium waveguide photodetector on silicon

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Silicon photonics is a key technology for high-speed optical communication.
• Germanium photodetectors are crucial for detecting optical signals in silicon photonic integrated circuits.
• Integrating high-performance photodetectors onto silicon platforms remains a challenge.

Purpose of the Study:

• To report on the development and characterization of lateral pin germanium photodetectors.
• To demonstrate the high-speed performance of these germanium photodetectors integrated with silicon waveguides.
• To assess their suitability for next-generation optical communication systems.

Main Methods:

• Selective growth of lateral pin germanium photodetectors at the end of silicon waveguides.
• Characterization of optical bandwidth using three experimental setups.
• Measurement of responsivity at 1550 nm.
• Demonstration of open eye diagrams at 40Gb/s under zero-bias conditions.

Main Results:

• A very high optical bandwidth, estimated up to 120 GHz, was achieved for 10 µm long germanium photodetectors.
• A responsivity of 0.8 A/W at 1550 nm was measured.
• Open eye diagrams at 40 Gb/s were demonstrated under zero-bias operation at 1.55 µm wavelength.

Conclusions:

• Lateral pin germanium photodetectors can be successfully integrated with silicon waveguides.
• These photodetectors exhibit excellent high-speed performance, suitable for 40Gb/s and beyond optical communications.
• The demonstrated performance highlights the potential of these devices for advanced photonic integrated circuits.