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

• Published in: Nature communications Vol. 10; no. 1; p. 2349
• Main Authors: Zheng, S. N., Zou, J., Cai, H., Song, J. F., Chin, L. K., Liu, P. Y., Lin, Z. P., Kwong, D. L., Liu, A. Q.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28.05.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 140/133; 639/624/1075/1079; 639/624/399/1099; 639/766/1130/2799; Bandwidths; Fourier transform spectrometers; Fourier transforms; Humanities and Social Sciences; Mach-Zehnder interferometers; multidisciplinary; Organic chemistry; Power consumption; Product development; Resonators; Science; Science (multidisciplinary); Spectrometers; Spectrometry; Spectroscopy; Time multiplexing
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-10282-1

Single chip integrated spectrometers are critical to bring chemical and biological sensing, spectroscopy, and spectral imaging into robust, compact and cost-effective devices. Existing on-chip spectrometer approaches fail to realize both high resolution and broad band. Here we demonstrate a microring resonator-assisted Fourier-transform (RAFT) spectrometer, which is realized using a tunable Mach-Zehnder interferometer (MZI) cascaded with a tunable microring resonator (MRR) to enhance the resolution, integrated with a photodetector onto a single chip. The MRR boosts the resolution to 0.47 nm, far beyond the Rayleigh criterion of the tunable MZI-based Fourier-transform spectrometer. A single channel achieves large bandwidth of ~ 90 nm with low power consumption (35 mW for MRR and 1.8 W for MZI) at the expense of degraded signal-to-noise ratio due to time-multiplexing. Integrating a RAFT element array is envisaged to dramatically extend the bandwidth for spectral analytical applications such as chemical and biological sensing, spectroscopy, image spectrometry, etc. Here, the authors demonstrate a microring resonator-assisted Fourier-transform spectrometer, which is realized using a thermally tunable photonic Mach-Zehnder interferometer cascaded with a tunable microring resonator to enhance the resolution, all integrated with a photodetector onto a single chip.