Sagnac loop incorporating a semiconductor optical amplifier without bias current to receive/modulate weak RF signals

This paper describes the conception, design and numerical simulations of an electromagnetic-receiver & optical-modulator based on a solely semiconductor optical amplifier (SOA) and a fibre-optic Sagnac loop incorporating a SOA both without bias current. Only the interferometric device was able to detect weak high-frequency RF carriers from hundred pW to hundreds nW power delivering an output with 37% optical offset in the 0.3-10.0 GHz frequency range. Even though the adopted SOA model presents around 1 ns gain recovery time, RF carriers up to 30 GHz frequency were received/modulated because a full gain recovery was not needed.