| 摘要 |
An inexpensive optical bi-directional module by which diffraction efficiency of light beams having different wavelengths can be maximized at different diffraction orders, respectively, and light utilization efficiency is enhanced. The optical bi-directional module comprises a light emitting element for transmitting an optical signal toward the end of an optical fiber, a light receiving element for receiving an optical signal from the end of the optical fiber, and a grating having stepwise profiles repeated at a desired pitch. Assuming the position of the grating is on the DOE plane and the light emitting elements are located, respectively, at the end of the optical fiber and the position of the light receiving element, planar pitch of the grating is set such that a phase function being given as an equiphase-difference line on the DOE plane by causing interference of two light beams of the assumed light emitting elements has a phase function value representing an equiphase curve of integral multiples of 360°.
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