TCO-electrode BTO modulator toward 400G/800G interconnects: achieving 0.09  V·cm and bandwidth beyond 100  GHz

Area of Science:

• Photonics and Optical Engineering
• Materials Science

Background:

• Silicon photonics is vital for high-capacity data transmission in the post-Moore era.
• Electro-optic (EO) modulators are key components for converting electrical signals to optical signals.

Purpose of the Study:

• To develop a highly efficient Mach-Zehnder electro-optic modulator (EOM) using a barium titanate (BTO) platform.
• To enhance modulation efficiency and bandwidth while minimizing optical loss.

Main Methods:

• Utilized a composite electrode structure combining transparent conductive oxide (TCO) and gold.
• Reduced electrode gap to intensify the radio frequency (RF) electric field.
• Implemented a novel dual-drive differential structure for push-pull modulation.

Main Results:

• Achieved a modulation efficiency of 0.09 V·cm.
• Calculated minimal electrode-induced optical absorption loss of 0.001 dB/cm.
• Demonstrated a bandwidth exceeding 100 GHz with low insertion loss (0.07 dB for MMI, 0.69 dB for edge couplers).

Conclusions:

• The BTO EOM with a composite electrode structure offers significant improvements in modulation efficiency and bandwidth.
• The novel dual-drive differential structure effectively enables push-pull modulation and suppresses interference.
• This technology holds promise for next-generation high-capacity optical interconnects.