Switching And Bisability Of Fiber Ring-Resonator

With the rapid development of communication system with large-capacity, optical switches are widely investigated. The electronic-controlling optical switches (EOS) initially studied are commercially obtained now. But those switches'switching speed commonly very slow, do not meet the requirement of future all optical network. Optic-controlling optical switches, ie all optical switches (AOS), because have excellence of stability, high speed and big capability, is paid more attention by the scientists. As a basic device in the all optical switch system, fiber coupler is very important and must be paid more attention.We discuss an active double-coupler ring resonator all-optical switch by replacing a half of fiber ring resonator using a erbium doped fiber (EDF) ,the power of the switch is reduced and the switch's switching effect is changed to completely under this ring resonator, but the switching time is increased at the same time. By controlling the gain of the erbium doped fiber amplifier(EDFA) in the ring, coupler's reflection and so on, we can make a tradeoff between the switching power and the switching time to obtain the desired switching devices. In the last, we find when the switching power is several , the switching time can be controlled under several hundred .We discuss bistability in single-coupler and double-coupler ring resonator which contain erbium doped fiber. We find that under certain condition, the light comes from the ring resonator has bistability in evidence. We sum up the rule of the bistability with the change of coupler reflectivity and single-pass linear phase shift ? 0.The bistability of the reflection and transmission in double-coupler ring resonator is different, that is similar to F-P resonator, these two kinds of bistability are complementary.In the last part of this thesis, considering input threshold power distance of bistability switch point, input threshold power of bistability switch point, stabilization , switching time and so on, we design a erbium doped fiber ring resonator switch with double- directional coupler. In theory, we get input threshold power of bistability switch point is 0.02W and 0.03W, input threshold...