| 摘要 |
An optical multiplexer/demultiplexer for fiber optical communication is disclosed. The device includes a collimator configured to collimate a beam of wavelength-division-multiplexed optical signal received from an optical fiber; a splitter for dividing the collimated beam from the collimator into two parallel propagating beams which are polarized 90 DEG from each other; a retarder, such as a half-wave plate, for rotating the polarization direction of one of the beams by 90 DEG so that both beams are polarized in the same direction; a beam steerer, such as a prism, for modifying the diameter of the split and rotated beams in the direction parallel to the polarization direction and for modifying the propagation direction of the beams; a wavelength dispersing element, such as a diffraction grating, for separating each of the split, rotated and steered beams into a plurality of beams, each having a different center wavelength and propagating along a different angular direction relative to a predetermined direction. The optical elements in the multiplexer/demultiplexer are arranged in such a way to direct the diffracted beams through the optical elements, except the wavelength dispersing element itself, in reverse order, resulting in a plurality of beams of different center wavelengths, which may be launched into a corresponding plurality of optical fibers. The parameters of the optical elements may be chosen to be suitable for multimode dense wavelength multiplexing/demultiplexing applications. The device is also suitable for demultiplexing signals from a single-mode fiber.
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