Wavelength `add/drop´ switch

One of the most attractive features of optical switching is the potential to use the wavelength domain as well as the space and time domains to increase the capacity of a switching network. Several switching architectures have been proposed which are based on the selection of a specific wavelength from within a broadband multiplexed signal. The authors describe the design and fabrication of a three channel `add/drop´ wavelength switch in InP for operation in the 1.55 μm wavelength band. The object is to route signals selectively between an optical bus and a second `add/drop´ line. Any one of the three wavelength channels can be selected from the broadband multiplexed signal on the optical bus and dropped onto the second line. Conversely, signals can be `added´ to the bus