On-chip spectrometers for visible and infrared sensing applications

Abstract

The potentials of integrated optical systems for implementing compact and low power consumption yet highly sensitive sensing systems have made them a viable candidate for integrated chemical and biological sensing applications. In these integrated optical sensing systems, spectrometers have a significant role as a building block that enables on-chip spectral analysis. Monitoring the spectral features of the signal using an on-chip spectrometer brings about a variety of new sensing mechanisms and architectures in an integrated platform. Monitoring absorption spectra, measuring Raman emission features, and tracking changes in spectral signatures as a result of environmental changes are some of the schemes made possible by such spectral analysis. In this work, we implement superprism-based photonic crystal devices in planar platforms as on-chip spectrometers. We use planar silicon platform in a silicon-on-insulator (SOI) wafers for the infrared wavelength range. A silicon-nitride (SiN) planar platform is used for the near infrared and visible wavelength ranges. In both SOI and SiN implementations, superprism-based spectrometers are experimentally demonstrated and compared with grating spectrometers made in the same platform. The potentials of the demonstrated spectrometers to meet the requirements of current and future applications in integrated optical sensing are briefly discussed.