Si-based Mach-Zehnder wavelength/mode multi/demultiplexer for a WDM/MDM transmission system

Area of Science:

• Photonics
• Optical Communications
• Materials Science

Background:

• Wavelength-division multiplexing (WDM) and mode-division multiplexing (MDM) are key technologies for increasing optical communication capacity.
• Existing multi/demultiplexers face challenges in achieving simultaneous mode and wavelength selectivity with low loss and crosstalk.
• Silicon photonics offers a scalable platform for integrated optical devices.

Purpose of the Study:

• To propose and demonstrate a novel Mach-Zehnder multi/demultiplexer.
• To enable simultaneous mode and wavelength multiplexing/demultiplexing.
• To achieve low loss and low crosstalk in a silicon photonics platform.

Main Methods:

• Development of a broadband 3-dB mode divider.
• Integration of the 3-dB mode divider into a Mach-Zehnder filter architecture.
• Fabrication and characterization of the Mach-Zehnder filters on a silicon photonics platform.
• Utilizing TiN heaters for wavelength tuning.

Main Results:

• Experimental demonstration of a low-loss and low-crosstalk Mach-Zehnder mode/wavelength multi/demultiplexer.
• The fabricated 3-dB mode dividers showed excellent agreement with theoretical predictions.
• Modal crosstalk below -24 dB was achieved over a 40-nm wavelength range for a filter with a free spectral range (FSR) of 20 nm.
• Successful demonstration of peak wavelength tuning using TiN heaters.

Conclusions:

• The proposed Mach-Zehnder filter, utilizing a novel 3-dB mode divider, effectively achieves simultaneous mode and wavelength multiplexing/demultiplexing.
• The device exhibits excellent performance metrics, including low loss and low crosstalk.
• This technology holds significant potential for advancing high-capacity optical communication systems.