The MFA mode field matcher (mode matcher) is a special process used to reduce the loss during the fusion of fiber with different mode field diameters and numerical aperture, so that the fundamental mode signal can obtain the maximum transmittance at the melting point, and the transmission direction from small mode field to large mode field is positive, and vice versa.The MFA produced by Xiao Xiaoguang utilizes mode optimization techniques to achieve high transmission efficiency and low beam degradation.Mode matchers are often used in high-power fiber lasers and fiber amplifiers.