Measuring the central wavelength and bandwidth of an LED with the Michelson interferometer

Abstract A method for measuring the central wavelength and bandwidth of a light emitting diode (LED) using the Michelson interferometer is proposed. It is easy to see the interference fringes on the screen by setting the optical path properly. Based on it, the central wavelength and bandwidth of LEDs with three different colours are measured, and the experimental results are consistent with the results from a spectrometer. The experiment will be helpful for students to understand the spectral and coherence characteristics of LEDs. It can also be an extended content of Michelson interferometer.