To provide an optically active transmission path which reduces the light scattering loss by the nonuniform distribution of rare earth elements and has high efficiency and a method of manufacturing for the same.

The optically active transmission path formed with a light propagation layer 3 of a high refractive index by irradiating the surface or interior of a glass plate 2 added with the rare earth elements with spots of ultrashort pulse laser beams L1 and L2 and the method of manufacturing for the same, in which the wavelengths of the laser beams L1 and L2 described above are set at the wavelengths for excitation near the absorption peak wavelength of the absorption spectra intrinsic to the rare earth elements and the pulse width thereof is kept within a range from several tens to several hundreds femto-seconds.