US Patent 7894722 Packaged optical device stack

A packaged stack of optical devices includes two or more WDM optical devices, the stack having a reduced per-channel manufacturing cost and an improved mean time between failure relative to individual optical devices. WDM optical devices, which may be contained in a packaged stack, include wavelength selective switches, optical add-drop multiplexers, and dynamic gain equalizers. The optical switching devices in the stack may be configured so that one or more optical elements are shared by multiple switching devices. Optical components that may be shared between the switching devices contained in the stack include cylindrical lenses, diffraction gratings, mirrors, and beam steering units.