摘要 |
System and method for wavelength discrimination using a DWDM (N+1)-stage cascade tree structure with distributed filtering to provide acceptable optical isolation and acceptable flat-top wavelength response. Each channel has a Mach-Zehnder interferometer (MZI) that provides wavelength discrimination. The input channel includes an inverted Fabry-Perot etalon (FPE) filter or an inverted, non-symmetric MZI filter that helps provide a desired flat-top response. Each channel in a second stage has a selected conventional MZI filter, and each channel in a third stage has a selected FPE filter, to help provide the desired optical isolation. The number of output channels may be 32, 64 or more.
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