Microring resonator-assisted Fourier transform spectrometer with enhanced resolution and large bandwidth in single...

Area of Science:

• Photonics
• Spectroscopy
• Integrated Optics

Background:

• On-chip spectrometers are crucial for compact chemical and biological sensing.
• Current integrated spectrometers struggle to achieve both high resolution and broad bandwidth.
• Existing technologies limit the widespread adoption of on-chip spectral analysis.

Purpose of the Study:

• To demonstrate a novel microring resonator-assisted Fourier-transform (RAFT) spectrometer on a single chip.
• To overcome the resolution limitations of existing tunable Mach-Zehnder interferometer (MZI) based Fourier-transform spectrometers.
• To enable robust, compact, and cost-effective chemical and biological sensing and spectral imaging.

Main Methods:

• Integration of a tunable Mach-Zehnder interferometer (MZI) with a tunable microring resonator (MRR) on a single chip.
• Utilizing the MRR to enhance spectral resolution beyond the Rayleigh criterion.
• Incorporating a photodetector for on-chip signal acquisition.

Main Results:

• Achieved a spectral resolution of 0.47 nm, significantly surpassing tunable MZI-based Fourier-transform spectrometers.
• Demonstrated a single channel bandwidth of approximately 90 nm.
• Reported low power consumption: 35 mW for MRR and 1.8 W for MZI, with a trade-off in signal-to-noise ratio due to time-multiplexing.

Conclusions:

• The RAFT spectrometer offers a promising solution for high-resolution, on-chip spectral analysis.
• Future integration of RAFT element arrays can dramatically extend bandwidth for diverse spectral applications.
• This technology has significant potential for advancing chemical/biological sensing, spectroscopy, and image spectrometry.