32  Gbps heterogeneously integrated quantum dot waveguide avalanche photodiodes on silicon

Area of Science:

• Quantum dot (QD) optoelectronics
• Silicon photonics integration
• Avalanche photodiode (APD) technology

Background:

• High-speed optical receivers are crucial for modern communication systems.
• Integrating advanced photodetector materials with silicon photonics platforms presents significant challenges.
• Quantum dots offer unique optoelectronic properties for next-generation devices.

Purpose of the Study:

• To develop and characterize a heterogeneous Gallium Arsenide (GaAs)-based quantum dot (QD) avalanche photodiode (APD) on a silicon platform.
• To evaluate the performance metrics of the QD APD for high-speed data transmission.
• To investigate the potential of QD APDs for wavelength division multiplexing (WDM) systems.

Main Methods:

• Fabrication of a heterogeneous GaAs-based QD APD integrated onto a silicon substrate.
• Measurement of key photodiode parameters including dark current, 3 dB bandwidth, and gain-bandwidth product (GBP).
• Bit error rate (BER) testing using open eye diagrams to assess data transmission capabilities at 32 Gb/s and 1310 nm wavelength.

Main Results:

• Achieved an ultralow dark current of 10 pA at -1 V.
• Demonstrated a 3 dB bandwidth of 20 GHz and a record gain-bandwidth product (GBP) of 585 GHz.
• Observed open eye diagrams up to 32 Gb/s, with a measured k-factor as low as 0.14.
• Investigated and observed polarization dependence on gain and bandwidth.

Conclusions:

• The developed QD APD on silicon exhibits excellent performance characteristics for high-speed optical communication.
• The record GBP and low dark current highlight the potential of QD technology for advanced photodetectors.
• This work demonstrates the feasibility of integrating high-speed QD-based receivers into silicon photonics platforms for WDM applications.