Semiconductor Optical Amplifier for Detection Function in Radio Over Fiber Systems

This paper demonstrates that in broadband networks in-line semiconductor optical amplifiers (SOAs) beside providing system gain can also be used as simultaneous transceivers. The SOA branching stages are studied and presented for bus configuration. Using a steady-state model, we have made a small-signal approximation applying an equivalent circuit for detection based on the rate equations. The theory enables us to explain the detection functionality, the optimal working state of the multifunctional SOA, and to analyze noise properties. The measurements support the calculations. So the SOA-transceivers are potentially useful in subcarrier multiplexed access systems.