| 摘要 |
<p>A wavelength division multiplexing/demultiplexing device is presented utilizing a polarization-based filter to separate odd and even wavelengths, or upper and lower channels of an input optical signal. The wavelength filter first converts the input signal to a predetermined polarization. A series of birefringent waveplates provide a polarization-dependent optical transmission function such that the polarized beam is decomposed into a first beam component carrying the first spectral band at a first polarization and a second beam component carrying the second spectral band at a second, orthogonal polarization. A beam displacer spatially separates the beam components into a pair of orthogonally-polarized beams. A quarter-wave plate converts these orthogonally-polarized beams into a pair of circularly-polarized beams, which are reflected by a mirror back along parallel optical paths through the quarter-wave plate, beam displacer, and waveplates. In the return pass, the quarter-wave plate converts the reflected circularly-polarized beams into two orthogonally-polarized beams having polarizations that are rotated by 90 degrees from those in the forward pass. The waveplates further purify the spectral characteristics of the reflected beams and maintain the polarization of one of the reflected beams, while rotating the polarization of the other reflected beam by 90 degrees so that both reflected beams have substantially the same polarization. A routing element directs one of the reflected beams exiting the waveplates to a first output port and the other reflected beam to a second output port.</p> |
