TUNABLE OPTICAL ADD/DROP DEVICE AND METHOD

Data loss is reduced and bandwidth efficiency improved while tuning an optical add/drop device comprising a hitless wavelength-tunable optical filter. The hitless wavelength-tunable optical filter includes a broadband reflective surface and a tunable filter surface, the reflective surface and filter surface positioned adjacent to each other. Hitless tuning of the device is accomplished by changing the point at which an optical beam strikes the filter surface along a constant wavelength channel track whenever the beam is incident to the filter surface region. Realignment to a position associat ed with a new wavelength channel track is performed with the optical beam incident to the reflective surface region. Repositioning the optical beam to the filter region occurs at a location corresponding to the new wavelength t o be added/dropped and subsequent optical beam realignment within the filter region is along the new wavelength channel track.