An 8×240 Gbps dense wavelength division multiplexing transmitter with lithium tantalate

Area of Science:

• Photonics and Optical Communications
• Integrated Optics
• Materials Science

Background:

• Dense Wavelength Division Multiplexing (DWDM) significantly boosts optical transmission capacity.
• Electro-optic (EO) material platforms for DWDM face challenges like limited channels, high insertion loss (IL), and low spectral efficiency.

Purpose of the Study:

• To demonstrate an 8-channel DWDM transmitter at the O-band on a lithium-tantalate-on-insulator platform.
• To overcome bottlenecks in existing DWDM EO platforms by proposing a novel optical filter design.

Main Methods:

• Development of a robust flat-top optical filter utilizing a novel coupled Fabry-Perot (FP) cavity.
• Integration of the filter onto a lithium-tantalate-on-insulator platform.
• Realization of an 8-channel DWDM transmitter with 200 GHz channel spacing.

Main Results:

• The flat-top optical filter achieved low insertion loss (~0.1-0.4 dB), a high extinction ratio (~26 dB), and a large free spectral range (12 nm).
• Demonstrated an 8x240 Gbps DWDM transmitter with uniform channel spacing.
• The filter design exhibited large fabrication tolerance.

Conclusions:

• The developed DWDM transmitter offers a critical strategy for enhancing optical link capacity.
• The novel coupled FP cavity filter design shows significant promise for applications in data centers and artificial intelligence.