A novel large-scale star coupler with only two EDFAs

We propose a novel design for constructing a large-scale transmission 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 unidirectional wavelength-division multiplexing (WDM) star networks, but also its size can be increased by a factor of m. This alternative greatly decreases the complexity and cost of making large-bandwidth couplers and relaxes the requirement of designing couplers with a large bandwidth to accommodate the multiple wavelengths.