Computational spectrometer with multi-channel cascaded silicon add-drop micro-ring resonators

Area of Science:

• Photonics
• Integrated optics
• Spectroscopy

Background:

• Miniaturized spectrometers are crucial for portable spectral analysis.
• Computational spectrometers offer a promising solution for device miniaturization.
• Silicon-on-insulator (SOI) technology enables complex integrated photonic devices.

Purpose of the Study:

• To design and implement an integrated computational spectrometer on an SOI substrate.
• To achieve high spectral resolution and broadband capabilities in a compact footprint.
• To explore the potential of micro-ring resonators for advanced spectral analysis.

Main Methods:

• Utilized a 5-stage binary tree architecture with cascaded silicon add-drop micro-ring resonators (MRRs).
• Incorporated 31 signal branches, each with 4 MRRs, and one reference channel.
• Designed MRRs with arbitrary coupling coefficients, cavity perimeters, and center distances for 62 filter channels.

Main Results:

• Achieved a chip footprint of 1.5 mm².
• Demonstrated a spectral resolution of 0.11 nm in the C-band.
• Successfully performed broadband spectrum reconstruction with a bandwidth exceeding 10 nm.

Conclusions:

• The integrated computational spectrometer is a viable solution for portable spectral analysis.
• The MRR-based design offers high performance in a compact form factor.
• This technology paves the way for advanced miniaturized spectral sensing applications.