Provided are a diffractive element for optical pickup and an optical module including the diffractive element. In the decoding, coefficients or elements of a vector w are calculated in a unit or module by an iterative method as a solution to a system of linear equations represented by the matrix equation Rw=h, where R is a matrix of known elements and h is a known vector. The source region and the drain region are provided in contact with the insulating layer which releases a small amount of oxygen, thereby suppressing the increase of the resistance of the source region and the drain region. Despite the numerous advantages provided by this system, this level of functionality and control was heretofore unseen in the marking industry. The link processing device sets the link destinations based on the link destinations reported from the link destination selection device. The combined side plates and tow bracket are pivotally coupled to both the bar pivot attachment member and one end of the connecting link by a first pivot pin.