| 摘要 |
The present invention relates to interleaver/deinterleaver devices for combining/separating optical channels. An interleaver/deinterleaver is "folded" when an optical signal follows an optical path that passes through a birefringent assembly multiple times. Double-pass refers to optical signals following a (folded) path throu gh the birefringent assembly twice. Multi-pass refers to optical signals following a (folded) path through the birefringent assembly multiple times. When operating as a deinterleaver, the interleaver/deinterleaver separates an optical signal (e.g., WDM signal) int o subsets of optical signals (e.g., even and odd ITU channels). When operating as an interleaver, the interleaver/deinterleaver mixes subsets of optical signals into a multiplexe d optical signal. The interleaver/de-interleaver can be used to increase the bandwidth of an optical network. For example, the interleaver/deinterleaver can be used to interface components designed for a first channel spacing (e.g., 100 GHz) to components designed for a second channel spacing (e.g., 200 GHz). Folded interleaver/deinterleavers cause dispersion because the speed at which the ordinary beam of an optical signal passes through the birefringent assembly is different that the speed at which the extraordinary beam of the optical signal passes through the birefringent assembly. In order to reduce or eliminate dispersion, the polarization of the optical signal is reversed for alternati ng passes through the birefringent crystal. For example, if a signal is horizontally polarized for a first pass through the birefringent crystal, the signal is rotated so that it is vertically polarized for a second pass through the birefringent crystal. For a third pass through the birefringent assembly, the signal is rotated so that it is again horizontally polarized.< /SDOAB>
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