| 摘要 |
<p>This invention relates to optical waveguide filters and, in particular, to a switchable optical filter particularly useful for gain equalization, for adding and dropping optical channels, and for optical cross-connection. A filter comprises a Mach-Zehnder interferometer (11) comprising a pair of waveguide arms (12,13) extending between a pair of couplers (14,15). The arms include a series of phase shifters ( phi 1... phi N+1) in at least one arm separated by reflective filters ( LAMBDA 1... LAMBDA N) on both arms. By adjusting the phase shifters, the reflection by the filter of signals at wavelengths corresponding to the reflective filters can be adjusted independently. <IMAGE></p> |
