Abstract

Large N × N passive star couplers can be quite useful for multiple-access frequency-division-multiplexed (FDM) networks or switches.¹ However, the inherent 1/N splitting loss as well as the excess loss can limit the size of the star. One way to accommodate more users, N, is to incorporate an erbium-doped fiber (EDF) amplifier² in each output port to compensate for the star loss. A 14-dB sensitivity enhancement has been achieved³ by using an EDF in an FDM frequency-shift-keyed (FSK) 1-Gb/s system. A major disadvantage is that each receiver requires its own EDF, pump laser, and pump/signal combiner, which can be quite expensive.

© 1991 Optical Society of America