Milliwatt and nanosecond all-optical switching in a double-coupler ring resonator containing an EDFA

We proposed an active double-coupler ring resonator all-optical switch, in which half of the fibre ring is made by a 980 nm laser-pumped erbium-doped fibre to form an erbium-doped fibre amplifier (EDFA). The switching is based on self-modulation by the signal light at 1.55 µm and has milliwatt switching power and nanosecond switching time for a 0.2 m ring length. Because the gain of the EDFA compensates the losses in the ring and the EDF has high nonlinearity, the switching power can be reduced dramatically. Both switching time and switching power of such a switch can be controlled by adjusting the 980 nm pumping power to make a trade-off between both parameters.