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arXiv · 1603.01612

Evanescently coupled multimode spiral spectrometer

Brandon Redding·Seng Fatt Liew·Yaron Bromberg·Raktim Sarma·Hui Cao
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Abstract

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 broad-band 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.

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Brandon Redding, Seng Fatt Liew, Yaron Bromberg, Raktim Sarma, Hui Cao. 2016-06-30. Evanescently coupled multimode spiral spectrometer. https://doi.org/10.1364/optica.3.000956

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