Evanescently coupled multimode spiral spectrometer

Brandon Redding, Seng Fatt Liew, Yaron Bromberg, Raktim Sarma, Hui Cao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

104 Scopus citations


We designed a high-resolution compact spectrometer based on an evanescently coupled multimode spiral waveguide. Interference between the modes in the waveguide forms a wavelength-dependent speckle pattern, which is used as a fingerprint to identify the input wavelength after calibration. Evanescent coupling between neighboring arms of the spiral results in a non-resonant broadband enhancement of the spectral resolution. Experimentally, we demonstrated a resolution of 0.01 nm at a wavelength of 1520 nm using a 250 µm radius spiral structure. Spectra containing 40 independent spectral channels are recovered simultaneously, and the operation bandwidth is significantly increased by applying compressive sensing to sparse spectra reconstruction. The ability to achieve such high resolution with low loss in a compact footprint is expected to have a significant impact on low-cost portable sensing and to add functionality to lab-on-a-chip systems.

Original languageAmerican English
Pages (from-to)956-962
Number of pages7
Issue number9
StatePublished - 20 Sep 2016
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2016 Optical Society of America.


Dive into the research topics of 'Evanescently coupled multimode spiral spectrometer'. Together they form a unique fingerprint.

Cite this