High precision optical fiber dispersion measurement based on Fourier domain mode-locked laser sweet spot location

Precise dispersion measurement is important for various applications, including optical communications, laser cavity design, and nonlinear optics. In this work, we present a dispersion measurement method for the fiber under test inside the Fourier Domain Mode-Locked (FDML) laser by locating the sweet spot regime under the different driving frequencies of the Fabry-Perot tunable filter. The group delay resolution achieved is 2.88 ps, an order of magnitude higher than other dispersion measurement methods based on phase shift or pulse delay. The proposed dispersion measurement method has high resolution and simple configuration, making it promising for measuring the dispersion of special fibers or conventional fibers near their zero-dispersion wavelengths.