High-speed low-voltage single-drive push-pull silicon Mach-Zehnder modulators

Area of Science:

• Photonics
• Integrated Optics
• Semiconductor Devices

Background:

• Silicon Mach-Zehnder modulators (MZMs) are crucial components in optical communication systems.
• Push-pull configurations offer advantages in modulation efficiency and linearity.
• Miniaturization and speed enhancement of silicon photonics devices are ongoing research areas.

Purpose of the Study:

• To demonstrate a single-drive push-pull silicon Mach-Zehnder modulator (MZM).
• To characterize its performance in terms of switching speed and drive voltage.
• To investigate the trade-offs between phase shifter length, insertion loss, and switching speed.

Main Methods:

• Fabrication of a single-drive push-pull silicon MZM.
• Electrical and optical characterization of the MZM performance.
• Analysis of device parameters including phase shift voltage, insertion loss, and modulation speed.

Main Results:

• Achieved a π-phase-shift voltage of 3.1 V for the silicon MZM.
• Demonstrated a maximum switching speed of 30 Gb/s with a 6 mm-long phase shifter.
• Observed higher switching speeds (40-50 Gb/s) in devices with shorter phase shifters, albeit with higher drive voltages and lower insertion losses.

Conclusions:

• The single-drive push-pull silicon MZM is a viable component for high-speed optical communications.
• Phase shifter length is a critical parameter influencing the trade-off between speed, drive voltage, and insertion loss.
• Further optimization of phase shifter design can enable even higher modulation speeds for silicon photonics.