A novel large-scale star coupler with only two EDFAs

In this letter, we propose a novel design for constructing a large-scale tr ansmission star coupler by making use of several conventional passive star couplers and only two high-power erbium-doped fiber amplifiers (EDFAs), Not only the proposed architecture can be adapted to both bidirectional and un idirectional wavelength-division multiplexing (WDM) star networks, but also its size can be increased by a factor of m. This alternative greatly decre ases the complexity and cost of making large-bandwidth couplers and relaxes the requirement of designing couplers with a large bandwidth to accommodat e the multiple wavelengths.