Patent ID: 6996311

Claim:
An optical communication device, comprising: a light source that emits a light beam; an optical fiber having a core and a cladding, said optical fiber having a light entrance face having a core region and a cladding region, the light beam emitted by said light source being incident on the core region and being transmitted through said optical fiber, the entrance face being configured to generate a light intensity distribution in light reflected by said light entrance face depending on a position where the light beam is incident on the entrance face; a converging lens arranged between the light source and the optical fiber, said converging lens converging the light beam emitted by said light source to form a beam spot on the entrance face of said optical fiber; a light receiving device having a light receiving surface that receives the reflected light that is a reflection of the light beam emitted by said light source and reflected by the entrance face of said optical fiber, said light receiving device outputting a signal corresponding to the light intensity distribution; a beam spot moving structure that is controlled to move the beam spot on the entrance face; and a controller that controls the beam spot moving structure to move the beam spot on the entrance face such that the output signal of said light receiving device corresponds to a reference intensity distribution which is the intensity distribution when the incident position of the light beam is adjusted, the entrance face having a stepped structure in which the core region is stepped by a predetermined height with respect to the cladding region, the reflected light being diffracted by the stepped structure, a diffraction pattern being formed on said light receiving surface of said light receiving device by the reflected light.