The MEMS-FPI spectrum sensor is a ultra-compact sensor that houses a MEMS-FPI (Fabry-Perot Interferometer) tunable filter that can vary its transmission wavelength depending on the applied voltage and InGaAs PIN photodiode in a single package. The spectral response range is 1550 to 1850 nm. It is suitable for installation in compact devices for identifying materials in plastic and solutions and other similar applications.