To provide an optical device and method for manufacturing the same that allow
a reduction in size and the easy fabrication of an optical splitter or an optical
coupler with which the branching ratio or the coupling ratio can be dynamically
changed after device production. An optical device is provided with a photonic
crystal having a periodic refractive index distribution due to a periodic arrangement
of a plurality of materials of different refractive indices, an input-side optical
waveguide for making light incident on the photonic crystal, and an output-side
optical waveguide for emitting light from the photonic crystal, and further includes
an external drive portion for changing a relative position of the photonic crystal
and at least one of the input-side optical waveguide and the output-side optical
waveguide, thereby allowing a small, high-performance optical device to be achieved.
