The present disclosure relates to a device for measuring an optical absorption property of a fluid as function of wavelength. The device comprises a broadband light source for emitting light, a plurality of integrated optical waveguides for guiding this light, and a light coupler for coupling the emitted light into the integrated optical waveguides such that the light coupled into each integrated optical waveguide has substantially the same spectral distribution. The device also comprises a microfluidic channel for containing the fluid, arranged such as to allow an interaction of the light propagating through each waveguide with the fluid in the microfluidic channel. Each integrated optical waveguide comprises an optical resonator for filtering the light guided by the waveguide according to a predetermined spectral component. The spectral component corresponding to each waveguide is substantially different from the spectral component corresponding to another of the waveguides.