Study On Wavelength Conversion In Hydrogenated Amorphous Silicon Waveguides

With the requirement of the information transmission rate and transmission capacity higher and higher,people are not satisfied with the ability of the traditional electrical communication in terms of transmission rate and bandwidth.All optical communication is a good solution to the limited transmission rate and bandwidth.All optical wavelength conversion that based on four-wave mixing(FWM)had promoted the development of all-optical signal processing in the communication band and mid-infrared band.Hydrogenated amorphous silicon(a-Si:H)has the advantages of high non-linear coefficient,low propagation loss,low cost and small size of optical devices easy to integrate in low temperature and low two-photon absorption(TPA)in the communication band.Therefore,a-Si:H waveguides are gradually becoming an ideal platform to achieve all-optical wavelength conversion and has a good application prospects in the field of optical communication on chip.In this paper,the main work is all-optical wavelength conversion that based on FWM effects in hydrogenated amorphous silicon waveguides.The main contents are as follows:1.First,the research background of a-Si:H waveguides was discussed,as well as the development of amorphous semiconductors.Secondly,the structure and nonlinear characteristics of a-Si:H waveguides were analyzed,and the main factors that cause the waveguide loss and the different coupling modes were analyzed.Finally,the species and research progress of all-optical wavelength converters were analyzed.2.The nonlinear Schrodinger equation was deduced by nonlinear transmission theory,and the FWM was theoretically analyzed based on the nonlinear Schrodinger equation.Simultaneously,the common method of realizing the efficient FWM was discussed.3.A broadband wavelength conversion was theoretically investigated based on degenerate four-wave mixing(DFWM)in hydrogenated amorphous silicon waveguides with silicon nitride inter-cladding layer(a-Si:H-Si3N4),through optimizing of the waveguide dimensions,the conversion bandwidth was expanded to 490 nm and the conversion efficiency up to 11.4 dB.4.Mid-infrared(MIR)wavelength conversion based on degenerate FWM was theoretically investigated in a-Si:H waveguides.The broadband phase mismatch was achieved in the normal group-velocity dispersion(GVD)regime.The conversion bandwidth was extended to 900 nm,and conversion efficiency up to-14 dB with a pump power of 70 mW in a 2-mm-long a-Si:H rib waveguides is obtained.