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 μ m to 1.7 μ m 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.