Precise linewidths measurement using short delay self-heterodyne interferometry and multiple peak-to-valley differences

We propose a precision linewidths measurement using short-delay self-heterodyne interferometers and multiple peak-to-valley differences (MPVD). The method of MPVD of the coherent envelope to determine the laser linewidth is proved to be stable. Based on the relationship within MPVD values, the delay length and laser linewidth were calculated theoretically and via simulations. We also eliminate the effect of the broadened spectrum induced by the 1/f frequency noise and the influence of noise floor on the measurement using short-delay self-heterodyne techniques, providing MPVD that can satisfy high-precision measurements without being affected by noise. The results showed that this new method is capable of significantly improving the measurement accuracy of narrow linewidth.