Abstract: A sensing system for characterizing analytes of interest in a sample comprises a photonic integrated circuit with an integrated interferometer. The integrated interferometer is configured for spectroscopic operation. The integrated interferometer comprises at least a sensing arm and a reference arm, both the sensing arm and the reference arm having an exposable segment available for interaction with the sample, whereby the exposable segment of the reference arm has an optical path length which is smaller than twice the optical path length of the exposable segment of the sensing arm. The exposable section of the sensing arm is selective to the analyte of interest, whereas the exposable section of the reference arm is not selective to the analyte of interest.

Abstract: A sensing device for sensing a substance includes a photonics integrated circuit having a resonator element that supports two different radiation modes, e.g. radiation modes of different polarisation, at a predetermined resonance wavelength. The resonator element is configured to convert a phase change or amplitude change experienced by the two different radiation modes upon formation of a layer of receptor molecules onto a sensing surface of the device into a resonance wavelength shift for the two different radiation modes. The sensing device also includes a detection unit arranged to detect the resonance wavelength shift for the two different radiation modes. The detection unit includes a processor that is configured to derive from the detected resonance wavelength shifts for the two different radiation modes, a layer thickness and refractive index of the layer of receptor molecules.