Patent ID: 7801401

Claim:
An optical element comprising: a diffraction grating having a periodic structure made from a plurality of grating grooves and formed to allow control of an amount of outgoing light using polarization-dependent characteristics when incident light is outputted as the outgoing light; and a mark indicating at least one of either a grating groove direction of the diffraction grating or a periodic direction of the diffraction grating; and wherein a photonic element that can perform at least one of either light emission or light reception can be fixed and, when the photonic element is fixed, the optical element is formed to be fixed to the photonic element after at least one of either an optical element main body or the photonic element is rotated around an optical axis and adjusted so that the amount of outgoing light controlled by the diffraction grating becomes a desired amount of light; and the mark is formed at a position on the optical element main body allowing identification from an optical axis direction.