Controllable all-optical switch using an EDF-ring coupled M-Z Interferometer

We propose a new all-optical switch for 1.55-μm signal by using an erbium-doped fiber (EDF) ring resonator coupled to one arm of Mach-Zehnder interferometer. Because of the high nonlinearity of EDF and compensating losses in the ring by the gain of EDF amplifier, the switching power-length product is reduced to the order of 10/sup -4/ Wm. When we design the device with the ring length of 0.3 m, and adjust the 980-nm pump power from 14 to 19 mW, the gain changes from 3 to 4 dB, and then the switching power and switching time can be changed from 6 to 11 mW and 22 to 16 ns, respectively.