The present invention provides a stable, sterile, pharmaceutical product that consists essentially of lyophilized ifosfamide and solutions thereof. According to the present invention, in forming a semiconductor laser device, an electrode comprising Au is patterned so that the electrode does not exist in the vicinity of a light emitting end surface. The method includes measuring by each magnetometer a vector bi,m of which each coordinate represents the value of the magnetic field projected onto a respective measurement axis of the magnetometer, and a union of vectors bi,m forming a measured magnetic signature Sm, where the index \u201ci\u201d is an identifier of the magnetometer.