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Multimode waveguide crossing with ultralow loss and low imbalance
Optics Express
|May 15, 2020
Summary
This study presents an ultralow loss silicon multimode waveguide crossing for mode-division multiplexing (MDM) systems. The novel design significantly reduces insertion loss and crosstalk for enhanced optical communication capacity.
Area of Science:
- Photonics
- Optical Communications
- Integrated Optics
Background:
- Mode-division multiplexing (MDM) is crucial for increasing optical link capacity.
- Ultralow loss waveguide crossings are essential for on-chip MDM systems.
Purpose of the Study:
- To propose and demonstrate an ultralow loss silicon multimode waveguide crossing.
- To reduce insertion loss and crosstalk for two transverse electric (TE) polarized modes.
Main Methods:
- Utilizing a combination of fully etched and shallowly etched waveguides.
- Engineering waveguide geometries and proportions within the multimode-interference coupler region.
- Achieving coinciding self-imaging positions for different TE modes.
Main Results:
- Simulated insertion losses of 0.043 dB (TE0) and 0.084 dB (TE1) at 1550 nm.
- Experimental insertion losses of 0.1 dB (TE0) and 0.12 dB (TE1).
- Measured crosstalk below -30 dB for both modes over a 75 nm wavelength span.
Conclusions:
- The proposed waveguide crossing design enables ultralow loss performance.
- This technology is a key enabler for advanced on-chip mode-division multiplexing systems.
- The demonstrated device offers significant improvements for optical communication.
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