Research On The Properties Of 2-10 ?m Supercontinuum In As₂Se₃ Photonic Crystal Fibers

Photonic crystal fiber?PCF?is a new type of optical fiber in a periodic arrangement of air holes,the diameter of air hole reach microns level.The complex structural characteristic makes it has many advantages,such as no cut-off single-mode,high nonlinearity,controllable dispersion and so on.And therefore has a broad application prospect in the field of optical communication,to generate supercontinuum is one of the important applications.Supercontinuum is refers to the ultra short pulses in the optical fiber transmission,various nonlinear effect to generate new frequency in the pulse spectrum,the initial pulse greatly broadening spectrum.supercontinuum is mainly affected by the self-phase modulation?SPM?,cross phase modulation?XPM?,four wave mixing?FWM?and other nonlinear effect,supercontinuum has been the focus of research at home and abroad.When supercontinuum is applied to medical and optical pulse compression so the situation of coherence is an important aspect of supercontinuum,which needed to carry on a thorough research on it.In the article,the CUDOS software has been applied to simulate the spectral broadening in three kinds of PCF.On the basis of the PCFs,the generation of supercontinuum and coherence has been researched,conclusions are as follows:Firstly,based on the generalized nonlinear Schrodinger equation,in the case of an initial pulse of 4.3?m,simulating and discussing the situation that the initial pulse in the normal dispersion regime and anomalous dispersion region.By choosing different hole sizes and the pitch parameters of the As₂Se₃ PCF,the optimized nonlinear coefficients and dispersion profile of the fiber in the mid-infrared regime can be obtained.The result show that:in the initial pulse is 4.3?m,the broadband SC from 2to 10?m can be generated,and has a very good flatness.When the initial pulse near the zero dispersion wavelength,the broadband of the SC can be improved.Moreover,the pump peak power of the pump laser have positive influence on the spectrum broadening.Secondly,simulating and discussing how the coherence property of the generated supercontinuum in different fibre length,input pulse width and peak power.The result show that:the width of supercontinuum is same roughly,the coherence property of supercontinuum is different when the PCF is d/?43??28?0.35,and different fibre length:0.1 cm,0.5 cm and 1 cm,the input pulse width:100 fs,150 fs and 200 fs,the peak power:700 w,1000 w and 1500 w.In detail,when decrease the fibre length,input pulse width and input pulse energy,the coherence property of supercontinuum will be better.In practical application,we can get supercontinuum by optimized parameter.