In some embodiments, a spectrometer is presented. In accordance with some embodiments, the spectrometer includes an optical sensor array, the optical sensor array including a substrate and an array of pixels formed on the substrate; a spectral filter array formed over the pixels of the optical sensor array, the spectral filter array filtering incident light such that each pixel receives light of a spectral transmission profile associated with the pixel; a transparent spacer formed over the spectral filter array; and an opaque mask having input apertures allowing light through the transparent spacer and onto a portion of the spectral filter array. The spectrometer can be formed from the optical sensor array using a combination of photolithographic techniques and bonding of certain layers.