Study On The All-optical Temporal Differentiator Based On The SFS Fiber Interferometer

In the current optical network,transmission is in optical domain,but signal processing is still performed in the electrical domain.With the advent of the information explosion era,the limitations of electrical signal processing technology in response speed and device operation bandwidth have become increasingly prominent,and the demand for all-optical signal processing technology has become more urgent.As an important device of the all-optical signal processing circuit,the all-optical temporal differentiator is used to obtain the differentiation of the input optical signal in the optical domain directly,which could avoid the optical-electrical-optical conversion and has the advantages of fast response speed and high operation rate.The all-optical temporal differentiator is also an important part of the future all-optical network,which has extensive applications in the fields of ultra-short optical pulse shaping,ultra-high-speed coding,ultra-high-speed inductive control,and waveform detection.In this paper,based on the full research and analysis of the existing implementation of the all-optical temporal differentiator,an alloptical temporal differentiator based on the single mode-few mode-single mode fiber interferometer is proposed.The main achievements of the paper are as follows:(1)The operation principle and the key parameters to evaluate the performance of an all-optical temporal differentiator have been analyzed.The existing implementation schemes of the all-optical temporal differentiator have been summarized and analyzed.(2)The realization scheme of all-optical temporal differentiator based on core-offset single mode-dual mode-single mode fiber interferometer is proposed,and the relationship between the core-offset distance and the order of all-optical temporal differentiator is analyzed.On this basis,combined with actual fiber parameters,all-optical temporal differentiators with orders of 0.265,0.347 are designed and analyzed,of which the processing error are 16.39% and 19.03%,respectively.(3)The realization scheme of all-optical temporal differentiator based on axisaligned single mode-four mode-single mode fiber interferometer is proposed,and the relationship between the power coupling coefficient and the order of all-optical temporal differentiator is analyzed.On this basis,combined with actual fiber parameters,all-optical temporal differentiators with fractional orders of 0.82,1,1.22 are designed and analyzed,of which the processing error are 7.08%,5.63%,13.6%,respectively.