56-Gb/s 3D-integrated silicon optical transmitter based on micro-transfer printing.

Area of Science:

• Photonics and Semiconductor Devices
• Integrated Optics
• High-Speed Electronics

Background:

• Silicon photonics and SiGe BiCMOS technologies are crucial for high-speed optical communication.
• Heterogeneous integration is key to combining different material properties for advanced functionalities.
• Micro-transfer printing offers a scalable method for integrating dissimilar materials.

Purpose of the Study:

• To demonstrate a novel optical transmitter by integrating a SiGe BiCMOS driver amplifier with a silicon photonic chip.
• To achieve high data rates and power efficiency in a compact form factor.
• To explore the potential of micro-transfer printing for scalable transceiver fabrication.

Main Methods:

• Heterogeneous integration of a SiGe BiCMOS driver amplifier onto a silicon photonic chip using micro-transfer printing.
• Fabrication using a modified SiGe BiCMOS on SOI process with a release step for micro-transfer printing.
• Post-print metallization process involving DVS-BCB for step height compensation and gold deposition for electrical connection.

Main Results:

• Achieved 56 Gb/s non-return to zero (NRZ) and 28 GBd 4-level pulse amplitude modulation (PAM-4) data rates.
• Demonstrated a total transmitter power efficiency of 9.1 pJ/bit for both modulation formats.
• Verified operation through high-speed measurement and eye diagram capture.

Conclusions:

• Micro-transfer printing enables efficient 3D integration of SiGe BiCMOS drivers with silicon photonics.
• The developed optical transmitter meets high-speed and power efficiency requirements for data center applications.
• This integration approach significantly enhances scalability and fabrication throughput for optical transceivers.