An optical packet header identifier having a simplified configuration and being
superior in reliability, stability, and economical efficiency, an optical router
incorporating the identifier therein, and a routing method using the optical router
are provided. The optical packet header identifier includes an optical waveguide,
optical focusing elements, and a photo receiver. Tilted gratings for diffracting
an incident optical beam and emitting the beams as diffracted optical beams to
the outside of the waveguide are formed within the optical waveguide. The tilted
gratings are not formed uniformly in a longitudinal direction of a core of the
optical waveguide, but are arranged at intervals. The length of a portion containing
a set of gratings and the length of a portion containing no gratings can be defined
in increments of length "L". "L" equals to the spatial length which 1 bit in an
optical signal occupies.
