High-performance silicon nitride (de)multiplexer based on ring-assisted MZIs

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Optical (de)multiplexers are crucial for wavelength division multiplexing in fiber optic communication systems.
• Silicon nitride photonics offers advantages in low loss and high nonlinearities.
• Existing devices often struggle with sharp spectral responses and wide, flat passbands.

Purpose of the Study:

• To design and characterize the first multistage ring-assisted Mach-Zehnder interferometer (RAMZI) lattice (de)multiplexer.
• To optimize the device for four channels with 100 GHz spacing in the L-band using silicon nitride.
• To achieve a sharp, box-like spectral response with a flat passband and low crosstalk.

Main Methods:

• Design and fabrication of a two-stage RAMZI lattice (de)multiplexer using silicon nitride.
• Experimental characterization of the device's spectral response, including passband flatness, shape factor, and crosstalk.
• Performance evaluation against Next-Generation Passive Optical Network 2 (NG-PON2) standards.

Main Results:

• The device exhibits a sharp, box-like spectral response with a shape factor of 0.9.
• A maximally flat passband was achieved across the entire channel bandwidth.
• Crosstalk levels were measured to be better than -14 dB.
• The passband width is twice the maximum spectral excursion defined in the NG-PON2 standard.

Conclusions:

• The demonstrated multistage RAMZI lattice (de)multiplexer is a significant advancement for optical communication.
• Silicon nitride is a suitable material for achieving high-performance optical (de)multiplexers with superior spectral characteristics.
• The device's performance meets and exceeds critical parameters for advanced optical network standards like NG-PON2.