Topology optimized mode multiplexing in silicon-on-insulator photonic wire waveguides

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Silicon photonics enables integrated optical circuits.
• Efficient mode (de-)multiplexing is crucial for increasing data capacity.
• Existing devices often face trade-offs between size, loss, and bandwidth.

Purpose of the Study:

• To design and experimentally verify a topology-optimized two-mode (de-)multiplexer.
• To achieve low loss and broadband operation in a compact footprint.
• To demonstrate the scalability of the design method for multi-mode operation.

Main Methods:

• Topology optimization for device design.
• Fabrication of silicon photonic wire waveguides.
• Experimental characterization of insertion loss, crosstalk, and extinction ratio.

Main Results:

• A two-mode (de-)multiplexer was successfully designed and verified.
• The device exhibits <1.2 dB loss over a 100 nm bandwidth around 1570 nm.
• Measured crosstalk < -12 dB and extinction ratio > 14 dB in the C-band.
• The design approach was extended to include higher-order modes.

Conclusions:

• Topology optimization is effective for designing high-performance silicon photonic devices.
• The demonstrated device offers a promising solution for advanced optical communication systems.
• The design method's scalability supports future development of complex photonic integrated circuits.