Add/drop filter for a multi-wavelength lightwave system

A method and apparatus are disclosed for providing optical channel adding/dropping capability within a WDM filter-bypass device. The device comprises an optical filter, an optical switch, and means for receiving a control signal to configure the optical switch. When configured in a filter state, the switch routes the WDM signal through the filter to drop, add or drop and add one or more pre-selected WDM channels. When configured in a bypass state, the WDM signal bypasses the filter. A series of filter-bypass devices may be interconnected to increase the number of optical channels that can be dropped or added.