Patent ID: 7421157

Claim:
An optical device comprising: an optical fiber mount with an optical fiber disposed thereon; and an optical demultiplexer having a slit defined in said optical fiber across an optical axis thereof, and an optical demultiplexing member inserted in the slit for demultiplexing a portion of an optical signal beam transmitted through said optical fiber, wherein said optical demultiplexer guides a demultiplexed optical signal beam from said optical demultiplexing member out of said optical fiber; an optical path changer for changing an optical path of said demultiplexed optical signal beam guided out of said optical fiber; a waveguide serving as at least a medium to which said demultiplexed optical signal beam is emitted from said optical path changer; a filter disposed on a surface of said waveguide; and a positioning portion disposed on said optical fiber mount to align said optical path changer and said waveguide longitudinally along said optical axis of said optical fiber.