Compact and low-crosstalk multimode waveguide crossing utilizing subwavelength holey metamaterial waveguides

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Integrated Optics

Background:

• On-chip optical communication requires high transmission capacity, driving demand for advanced multiplexing technologies.
• Multimode waveguide crossings are essential components for hybrid division multiplexing in photonic integrated circuits.

Purpose of the Study:

• To propose and experimentally demonstrate a compact multimode waveguide crossing.
• To leverage subwavelength holey metamaterial waveguides (SHMWs) for enhanced performance.

Main Methods:

• Integration of subwavelength periodic holes into a multimode interference (MMI) coupler to create SHMWs.
• Design and simulation of a three-mode waveguide crossing (TE0, TM0, TM1).
• Experimental validation of the proposed device at a 1550 nm wavelength.

Main Results:

• Achieved low insertion loss (< 0.74 dB simulated, 0.72 dB for TE0, 0.27 dB for TM0, 0.90 dB for TM1 experimentally).
• Demonstrated low reflection loss (<-13.1 dB) and crosstalk (<-31.6 dB simulated, <-38 dB experimentally).
• Fabricated a compact device with a footprint of 27.4 µm × 27.4 µm.

Conclusions:

• The SHMW-based multimode waveguide crossing offers a flexible, compact, and high-performance solution.
• This technology is suitable for photonic integrated circuits, enabling efficient mode control and multiplexing.
• The device significantly contributes to increasing transmission capacity in optical communication systems.