We propose and demonstrate that a conventional multimode fiber can function as a high-resolution, low-loss spectrometer. The proposed spectrometer consists only of the fiber and a camera that images the speckle pattern generated by interference among the fiber modes. Traditional spectrometers use a grating/prism to disperse light. The spectral resolution scales with the optical path length from the grating to the detec-tors, imposing a trade-off between device size and resolution. There is relatively low loss of signal over large distances at specific wavelengths.
