Generalized Modular Spectrometers Combining a Compact Nanobeam Microcavity and Computational Reconstruction

Compact and integrated spectrometers are sought after with great effort for the applications of portable spectroscopy devices and lab-on-a-chip systems. Material engineered spectrometers exhibited superior performances in terms of their compact footprint and high resolution after assistance by computational reconstruction but were still hindered by low yield, poor scalability, and poor transplantation to other frequency bands. Here we propose a structure engineered spectrometer based on an ultracompact photonic crystal nanobeam cavity (PCNC) array with computational reconstruction. The spectrometer shows a compact footprint, good scalability and good transplantability simultaneously. We fabricate the PCNC structure on a silicon-on-insulator chip and demonstrate the reconstruction of incident-light spectra around 1580 nm with the measured powers of the nanobeam filter array. The spectrometer is proven to be easily transplanted to other operation bands, such as 1310 and 2400 nm. With the advantages of high yield fabrication and structure flexibility, this PCNC spectrometer can be easily customized as a generalized modular solution to realize various commercial spectrometer products for different spectroscopy bands.