“…For fractional Laplace operator operators, we usually have two definitions, one is the spectral definition [1, 2, 19, 23], and the other is integral definition [4, 21, 22]. Through literature review, we found that for the optimal control problem of fractional Laplace operator in the spectral definition, a series of works have been developed in recent years based on Caffarelli–Silverstre extension, for example, see [1, 2, 19, 23], etc.…”