US Patent 11184102 Apparatus and adding and dropping method

An apparatus that adds and drops wavelength division multiplexed signal, the apparatus includes a memory and processor. The memory configured to store a first correspondence table indicating relationship with between an optical circuit type information and a first output level target value for a dropping circuit. The processor configured to determine an output level target value for the dropping circuit for each signal wavelength, based on the first correspondence table and optical circuit type information of each signal wavelength.