Patent ID: 6122096
Filing Date: 2000-09-19
Classification: G02B,H04J

Abstract:
An expandable optical add/drop system includingan optical add/drop multiplexer element having an input port and an output port, said input port for receiving a multi-wavelength optical signal having individual optical signals of different wavelengths, said multiplexer element further including a drop path for carrying at least one of said individual optical signals dropped from said multi-wavelength optical signal, and an add path for carrying at least one optical signal of a particular wavelength to be added to said multi-wavelength optical signal, and a through path coupled between said input port and said output port, wherein a common portion is defined by portions of each of said add, drop and through paths such that said common portion is capable of being used for adding and dropping individual optical signals and for carrying said multi-wavelength signal,a passive optical signal splitting device coupled to said drop path for receiving said at least one individual optical signal to be dropped from said multi-wavelength optical signal, and for distributing said at least one individual optical signal via plural output ports, anda tunable optical filter coupled to one of said plural output ports, said tunable optical filter being operable to selectively pass only one individual optical signal of a particular wavelength,said common portion including a wavelength-selective apparatus with integrated amplification for use in the expandable add/drop system, the apparatus comprising:at least one wavelength selective element disposed in a wavelength-selective path between said input port and said output port;an optically amplifying rare earth-doped fiber section integrated with said wavelength-selective path, said optically amplifying rare earth-doped fiber section includinga first segment coupled between said input port and said at least one wavelength selective element, anda second segment coupled between said at least one wavelength selective element and said output port; anda source of pump light coupled to and operable to pump said optically amplifying rare earth-doped fiber section,wherein said at least one wavelength selective element is adapted to selectively reflect said at least one individual optical signal to be dropped from said multi-wavelength optical signal across said drop path via said first segment,wherein other said plural output ports are adapted to receive additional passive optical signal splitting devices and tunable optical filters in a tree configuration for selectively passing other reflected individual optical signals dropped from said multi-wavelength optical signal.