Monolithically integrated 112 Gbps PAM4 optical transmitter and receiver in a 45 nm CMOS-silicon photonics process

Area of Science:

• Photonics
• Electrical Engineering
• Materials Science

Background:

• Silicon photonics is crucial for high-speed optical communication.
• Monolithic integration of components reduces complexity and cost.
• O-band wavelengths are essential for dense wavelength-division multiplexing.

Purpose of the Study:

• To demonstrate a fully integrated silicon photonics transmitter and receiver for O-band optical communication.
• To achieve high data rates and energy efficiency in an integrated platform.
• To present an alternative to hybrid integration methods.

Main Methods:

• Utilized the GlobalFoundries Fotonix (45SPCLO) silicon photonics platform.
• Monolithically integrated modulator drivers, Mach-Zehnder modulators, control circuitry, photodetectors, and transimpedance amplifiers (TIAs).
• Employed gain-peaking techniques in driver and TIA designs for high bandwidth.

Main Results:

• Demonstrated an open 112 Gbps PAM4 eye diagram.
• Achieved an energy efficiency of 4.3 pJ/bit (excluding the laser).
• Successfully integrated all necessary components on a single silicon photonics chip.

Conclusions:

• The developed integrated silicon photonics transmitter and receiver offer a viable alternative to conventional BiCMOS driver and TIA bump-bonding.
• This monolithic approach advances the development of energy-efficient, high-performance optical communication systems.
• The results pave the way for more scalable and cost-effective silicon photonics transceivers.