Microring resonator-assisted Fourier transform spectrometer using thin-film lithium niobate

Area of Science:

• Integrated photonics
• Spectroscopy
• Nanotechnology

Background:

• Integrated Fourier transform spectrometers (FTSs) are crucial for nanotechnology, biological engineering, and chemical sensing.
• Existing integrated FTSs face challenges in simultaneously achieving high resolution, fast acquisition, and a compact size.

Purpose of the Study:

• To demonstrate an integrated FTS on a thin-film lithium niobate (TFLN) platform.
• To overcome the limitations of current integrated FTSs by achieving high resolution, speed, and low power consumption in a compact footprint.

Main Methods:

• Developed a cascaded architecture combining a thermally tunable microring resonator (MRR) and an electro-optically tunable Michelson interferometer (MI).
• Utilized the MRR's full width at half maximum (FWHM) to determine spectral resolution, shifting dependence from the MI's optical path difference (OPD).
• Fabricated the device on a TFLN platform for enhanced performance and integration.

Main Results:

• Achieved an ultra-fine spectral resolution of 58.7 pm.
• Demonstrated a compact device footprint of 2.2 × 0.39 cm².
• Obtained a spectral acquisition time of 4 ms with energy consumption as low as 0.3 mJ over 1500–1600 nm.

Conclusions:

• The TFLN-based integrated FTS successfully combines high resolution, fast acquisition, and low power consumption.
• This approach offers a promising solution for next-generation integrated spectrometers.
• Enables high-performance spectral measurements for advanced applications in sensing and engineering.