Researchers at the Massachusetts Institute of Technology (MIT; Cambridge, MA) are developing miniature chip-based spectrometers that are just as accurate and powerful as conventional large devices with six-figure price tags. The new spectrometers could be mass-produced using standard chipmaking processes. This approach could open up new uses for spectrometry that previously would have been physically and financially impossible.
Called the digital Fourier-transform (dFT) spectrometer, the device contains a reconfigurable Mach-Zehnder interferometer (MZI) with optical switches on each arm that direct light to waveguides of different and unique path lengths, scaled in powers of 2. As a result, the channel count scales exponentially with the number of optical switches. This is in contrast to other chip-based approaches that add one device per channel, resulting in a linear scaling.