High-resolution Si₃N₄ spectrometer: architecture & virtual channel synthesis and experimental demonstration

Area of Science:

• Photonics and Optical Engineering
• Telecommunications
• Integrated Optics

Background:

• Accurate network telemetry is vital for optimizing resources in modern communication networks.
• Monitoring the spectral profile of Wavelength Division Multiplexing (WDM) signals in fixed- and flex-grid architectures across the C-band presents significant challenges.

Purpose of the Study:

• To describe a novel two-stage, on-chip spectrometer architecture for quantitative spectral measurement of WDM signals.
• To achieve high-resolution (∼1.4 GHz) spectral analysis across the entire C-band with a single dynamic control.

Main Methods:

• A two-stage spectrometer design integrating a tuneable ring resonator filter and an Arrayed Waveguide Grating (AWG) subsystem.
• Utilizing CMOS-compatible Silicon Nitride (Si3N4) for fabrication of key components.
• Employing a novel virtual channel synthesis algorithm for signal processing.

Main Results:

• Experimental demonstration of complete spectrometer operation over a portion of the C-band.
• The spectrometer achieves high resolution across the C-band with a single dynamic control.
• The novel algorithm enhances robustness by correcting for fabrication variations and relaxes AWG design constraints.

Conclusions:

• The developed on-chip spectrometer is a promising solution for reliable optical performance monitoring.
• The integrated design and novel algorithm offer a robust and efficient method for WDM signal spectral analysis.
• This technology enables improved resource optimization through accurate network telemetry.