Patent ID: 7708471

Claim:
A bidirectional optical module for use in a bidirectional optical fiber communication with a wavelength division multiplexing method, the bidirectional optical module comprising: a light-emitting element for transmitting an optical signal toward an end of an optical fiber; a light-receiving element for receiving an optical signal from the end of the optical fiber; and a grating in which stair shapes are repeated with a predefined pitch, wherein a phase function of the grating is defined as phase-difference contour lines on a DOE plane arranged at a position of the grating, the phase-difference contour lines being formed by making two light fluxes interfere with each other, the two light fluxes being emitted from light-emitting elements each assumed to be arranged at a position of the end of the optical fiber and a position of the light-receiving element, and a planar pitch of the grating is formed such that values of the phase function form phase contour lines each representing an integer multiple of 360 degrees.