Integrated reconstructive spectrometer with programmable photonic circuits

• Published in: Nature communications Vol. 14; no. 1; p. 6376
• Main Authors: Yao, Chunhui, Xu, Kangning, Zhang, Wanlu, Chen, Minjia, Cheng, Qixiang, Penty, Richard
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.10.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1075/1079; 639/624/1107/510; 639/624/1111/1116; 639/624/399/1099; Bandwidths; Channels; Circuit design; Circuits; High resolution; Humanities and Social Sciences; multidisciplinary; Photonics; Sampling; Science; Science (multidisciplinary); Spectrometers; Spectroscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-42197-3

Optical spectroscopic sensors are a powerful tool to reveal light-matter interactions in many fields. Miniaturizing the currently bulky spectrometers has become imperative for the wide range of applications that demand in situ or even in vitro characterization systems, a field that is growing rapidly. In this paper, we propose a novel integrated reconstructive spectrometer with programmable photonic circuits by simply using a few engineered MZI elements. This design effectively creates an exponentially scalable number of uncorrelated sampling channels over an ultra-broad bandwidth without incurring additional hardware costs, enabling ultra-high resolution down to single-digit picometers. Experimentally, we implement an on-chip spectrometer with a 6-stage cascaded MZI structure and demonstrate <10 pm resolution with >200 nm bandwidth using only 729 sampling channels. This achieves a bandwidth-to-resolution ratio of over 20,000, which is, to our best knowledge, about one order of magnitude greater than any reported miniaturized spectrometers to date. Recent years have seen a growing need for miniaturized spectroscopic tools. Here, authors present a novel integrated spectrometer with programmable photonic circuits, achieving record-high resolution and bandwidth via only a few filtering components.