High-efficient subwavelength structure engineered grating couplers for 2-µm waveband high-speed data transmission

Area of Science:

• Photonics and Optical Communications
• Integrated Optics
• Semiconductor Devices

Background:

• The 2-µm waveband is crucial for next-generation high-speed optical communication systems.
• Minimizing signal-to-noise ratio (SNR) loss through reduced coupling is essential for on-chip data transmission.
• Grating couplers are key components for efficiently coupling light into and out of silicon photonic integrated circuits.

Purpose of the Study:

• To develop and characterize high-performance grating couplers for the 2-µm waveband.
• To enable efficient on-chip optical data transmission by suppressing coupling losses.
• To demonstrate the capability of these grating couplers for high-speed data transmission.

Main Methods:

• Fabrication of grating couplers using a single-step fully etched process on a 340 nm silicon-on-insulator (SOI) platform.
• Experimental characterization of coupling efficiency and 1-dB bandwidth for both TE and TM polarized light at 2-µm.
• Demonstration of high-speed data transmission using pulse amplitude modulation 8-level (PAM-8) signals.

Main Results:

• Achieved high coupling efficiency of -4.0 dB for TE and -4.5 dB for TM polarized light.
• Demonstrated a 1-dB bandwidth of 70 nm for TE and 58 nm for TM polarized light.
• Successfully transmitted data at 81 Gbps using PAM-8 signals, showcasing the practical application of the developed grating couplers.

Conclusions:

• The developed grating couplers represent state-of-the-art performance for the 2-µm waveband.
• These devices are critical for advancing high-speed on-chip optical communication.
• The demonstrated high-speed data transmission validates the potential of these couplers for future communication networks.