Compact and low-crosstalk silicon-based polarization-insensitive multi-channel and multi-mode waveguide crossing

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Nanophotonics

Background:

• Waveguide crossings are essential components in integrated photonic circuits.
• Achieving polarization-insensitive and multi-mode operation in compact waveguide crossings remains a challenge.

Purpose of the Study:

• To design, optimize, and experimentally validate a polarization-insensitive multi-channel and multi-mode waveguide crossing.
• To achieve a compact footprint, low crosstalk, low insertion loss, and wide bandwidth.

Main Methods:

• Utilized particle swarm optimization and direct-binary-search algorithms for device optimization.
• Employed the finite-difference time-domain (FDTD) method for simulation and analysis.
• Experimental validation of the fabricated silicon-based device.

Main Results:

• The waveguide crossing exhibits a compact size of 13.6 µm × 13.6 µm.
• Achieved crosstalk below -20.4 dB and insertion loss below 1.80 dB for TE0, TM0, TE1, and TM1 modes.
• Demonstrated performance across a wavelength range of 1520 to 1600 nm.

Conclusions:

• The developed silicon waveguide crossing effectively addresses polarization and mode dependency.
• The device offers excellent performance metrics suitable for advanced integrated photonic applications.
• This work contributes to the development of more efficient and versatile photonic integrated circuits.