High-performance waveguide-coupled lateral Ge/Si avalanche photodetector.

Area of Science:

• Optoelectronics
• Semiconductor Devices
• Photonics

Background:

• Avalanche photodetectors (APDs) are crucial for optical communication systems.
• Traditional APD fabrication often involves complex processes like silicon epitaxy and ion implantation.
• There is a continuous need for high-performance APDs with simplified fabrication for cost-effective optical transceivers.

Purpose of the Study:

• To experimentally demonstrate a high-performance waveguide-coupled lateral avalanche photodetector (APD).
• To achieve high responsivity and gain-bandwidth product (GBP) without using silicon epitaxy or charge layer ion implantation.
• To evaluate the APD's suitability for high-speed optical communication applications.

Main Methods:

• Fabrication of a waveguide-coupled lateral APD structure.
• Experimental characterization of the APD's optical and electrical performance at 1550 nm wavelength.
• Measurement of responsivity, gain-bandwidth product (GBP), and eye diagrams at various avalanche gains.

Main Results:

• The demonstrated APD achieved a high responsivity of 48 A/W at 1550 nm.
• A gain-bandwidth product (GBP) of 360 GHz was obtained, indicating excellent high-speed capability.
• Wide-open eye diagrams were observed at 25 Gbps across different avalanche gain settings.

Conclusions:

• The developed waveguide-coupled lateral APD offers high performance without complex fabrication steps.
• The device exhibits excellent responsivity and GBP, making it suitable for demanding optical links.
• This APD technology holds significant potential for integration into high-speed optical transceivers.