Research On Electro-optical Modulation Mode Division Multiplexing Integrated Device Based On Photonic Crystal Microcavities And Nanowire Waveguides

With the development of 6G networks,the demand for transmission capacity of communication systems continues to increase.In order to further increase the capacity of the optical communication system,the optical communication network adopts various multiplexing systems to expand the capacity,and the mode division multiplexing system is one of them.Modulators and mode division multiplexers,as the key components of the mode division multiplexing system,are currently developing in the direction of miniaturization,and the optical communication system is also developing in the direction of integration.To achieve these goals,silicon-based optoelectronic integration technology is the best way to achieve it.Silicon-based optoelectronic integration adopts CMOS technology,which integrates photonic devices and optoelectronic devices on a chip with silicon material as the substrate.It has many outstanding advantages such as low power consumption,high integration and high reliability.In this paper,two silicon-based photonic crystal electro-optical modulation and mode-division multiplexing integrated devices are proposed.The electro-optical modulation module is composed of photonic crystal microcavity electro-optical modulator,and the mode-division multiplexing module is composed of parallel asymmetric nanowire waveguides.One is a photonic crystal electro-optical modulation and silicon-based two-mode mode-division multiplexing integrated device based on a WM-type microcavity,which can realize electro-optical modulation and two-mode mode-division multiplexing functions with an operating wavelength of 1550 nm.Through the design and optimization of the integrated device,the simulation results show that at the operating wavelength of 1550 nm,the insertion loss of TE₀mode and TE₁ mode are 0.186 d B and0.18 d B,respectively,the extinction ratio is 29.6 d B and 24.5 d B,and the modulation depth is 0.998and 0.996,the channel crosstalk is lower than-49 d B,the modulation rate is 18.2 GHz,and the device size is about 56 um×21 um×0.22 um.In order to enrich the working wavelength and expand the channel capacity,another integrated device of photonic crystal electro-optic modulation and silicon-based three-mode mode division multiplexing based on H1-type microcavity is proposed,which can realize electro-optic modulation and three-mode mode division at the working wavelength of 1570 nm.Multiplexing function,simulation research and analysis show that at the operating wavelength of 1570 nm,the insertion loss of TE₀ mode,TE₁ mode and TE₂ mode are0.146 d B,0.264 d B and 0.457 d B,respectively,and the extinction ratios are 23.42 d B,23.938 d B and 22.218 d B,modulation depth is 0.995,channel crosstalk is lower than-40 d B,modulation rate is 25 GHz,and the device size is about 107 um×28 um×0.22 um.These two integrated devices have excellent performance and compact structure,and are expected to be applied to large-scale optical communication systems.