Low-power DAC-less PAM-4 transmitter using a cascaded microring modulator

Area of Science:

• Photonics and optical communications
• Integrated silicon photonics
• High-speed data transmission

Background:

• Future data centers and supercomputing require high-speed, low-power optical interconnects.
• Spectral efficient modulation formats like PAM-4 are crucial for increasing data rates.
• Existing PAM modulators often require power-hungry digital-to-analog converters (DACs).

Purpose of the Study:

• To demonstrate a low-power, DAC-less PAM-4 optical modulator.
• To achieve ultrahigh data rates (60 Gb/s) using silicon photonics.
• To reduce power consumption in optical transmitters.

Main Methods:

• Utilized a dual-microring silicon photonics circuit.
• Implemented a DAC-less architecture for PAM-4 signal generation.
• Measured power consumption including thermal adjustments.

Main Results:

• Achieved 60 Gb/s pulse-amplitude modulation (PAM-4) of an optical signal.
• Demonstrated a DAC-less PAM modulator with power consumption below 100 fJ/bit.
• Reported the lowest power consumption for DAC-less PAM signaling beyond 40 Gb/s.

Conclusions:

• Silicon photonics offers a viable path towards low-power, high-speed optical interconnects.
• The developed DAC-less PAM modulator significantly reduces energy consumption.
• This technology is key for next-generation data centers and supercomputing systems.