Research On The Dual-loop Coupling All-optical Buffer

All-optical network,which is based on OPS(Optical Packet Switching)has been the uptrend of the future optical communication network.all-optical buffer in optical packet switching network can effectively solve the competition problem of packet swithes,so it is widely concerned.The dual-loop coupling all-optical buffer based on a collinear 3×3 fiber coupler utilize the cross-phase modulation of SOA or fiber to accomplish read and write operation of signal, compared to buffer based on fiber-loop, it has simple and compact configuration, the read and write control is also simpler, so it will become an important all-optical buffer scheme of the future optical packet switches.Then it is studied as follows:1. Studies the noise of the DLOB in which SOA is used as the nonlinear element based upon a simple noise model,studies the relationship between signal to noise ratio and loop circulations and get its theoretical curves, the conclusion indicate that the signal to noise ratio is much lower than the input signal to noise ratio. The control light pulse brings the phase difference between clockwise signal and counter-clockwise signal, it is introduced by WDM,so we analyze the power of control light pulse and get the theoretical curves of control light pulse power in the different small-signal gain and line width enhancement factor,we get the optimal control light pulse power when buffering signal,also,we get the theoretical curves between output signal and loop circulations in the state of gauss pulse,the conclusion indicate that the leakage of light is severe after buffering certain loops.2.Srudies the buffering principle of DLOB in which fiber is used as the nonlinear element,compared the signal to noise ratio with the DLOB in which SOA is used as the nonlinear element,we conclude that the former can reduce noise level,that is , with the same signal to noise ratio,the former can buffer more circulations than the latter.