Abstract: Consistent with the present disclosure, optical filters are provided in a reconfigurable optical add-drop multiplexer (ROADM). In one example, groups of optical signals are amplified by corresponding erbium-doped fiber amplifiers (EDFAs) and supplied to each optical filter, which has a passband that includes the wavelengths associated with the received optical signal group. Light at wavelengths outside the passband of each optical filter, such as amplified stimulated emission (ASE) light generated by a respective EDFA, is significantly attenuated. Each optical signal group, after such amplification and filtering may then be switched and combined in a multicast switch before being directed toward a desired optical communication path. When, for example, first and second optical signal groups are combined, however, the first optical signal group is accompanied by little or no ASE light at the second optical signal group wavelengths.

Abstract: Consistent with the present disclosure, optical filters are provided in a reconfigurable optical add-drop multiplexer (ROADM). In one example, groups of optical signals are amplified by corresponding erbium-doped fiber amplifiers (EDFAs) and supplied to each optical filter, which has a passband that includes the wavelengths associated with the received optical signal group. Light at wavelengths outside the passband of each optical filter, such as amplified stimulated emission (ASE) light generated by a respective EDFA, is significantly attenuated. Each optical signal group, after such amplification and filtering may then be switched and combined in a multicast switch before being directed toward a desired optical communication path. When, for example, first and second optical signal groups are combined, however, the first optical signal group is accompanied by little or no ASE light at the second optical signal group wavelengths.