Design of an on-chip Fourier transform spectrometer based on waveguide Mach–Zehnder Interferometer and fluidics

An on-chip Fourier transform spectrometer based on the semiconductor waveguide Mach–Zehnder Interferometer (MZI) is proposed. The MZI is constructed by rectangular silicon-on-insulate waveguides. With the help of digital microfluidics, the sensing arm of MZI can be covered by liquid step-by-step, and as a result, the output of the MZI can be modulated accordingly. The length of the MZI arm is 3 mm for a theoretical demonstration. This spectrometer works well in the wavelength range of 1.5 μm to 1.7 μm with the spectral resolution reaching up to 3.1 nm. The performance can be further improved by extending the MZI arms along with the liquid channel.