High-speed SOI Optical Modulator Structure Design And Process Research

With the rapid development of science and technology,the requirements raised by high-speed optical fiber communication systems are getting higher and higher,but Moore's Law is close to its physical limit,and basic electrical interconnection can no longer meet its needs.In this case,the combination of light and electricity is proposed to obtain higher bandwidth and transmission rate.At the same time,silicon-based technology is compatible with traditional CMOS and has the advantages of low cost,high bandwidth,and small size.Combining these advantages with the existing microelectronics technology has become the key to solving the bottleneck problem.In order to continue Moore's Law,it has opened up a new direction of development.Optical fiber communication systems mainly include key devices such as lasers,modulators,and detectors.This paper mainly studies the structure design and process research of SOI-based electro-optic modulator based on MZI structure.In this paper,the ridge waveguide structure is optimized and the single-mode ridge waveguide structure size is determined.The ridge height is 150nm and the ridge width is 350nm⁵50nm.Based on the mode-switching effect of the reversed wedge-shaped waveguide structure,this paper proposes a double-layer etched 1×2multimode interferometer whose input/output waveguide is an inverted-cone structure,in which the typer width at 220 nm is 2.9?m.At 15?m,the multimode area has a width of 19.94?m and a length of 40.67?m.The 70nm typer has a width of 1.35?m and a length of 30?m.The multimode area has a width of 5?m and a length of 25.4?m.For 0.43 dB,the MMI split ratio for double-layer etching is 45.9%,and the MMI for single-layer etching can only reach 39.1%.This article uses Lumerical software to design the electrical structure and optical structure,change the width of the ridge waveguide,the position of the PN junction and the concentration of doped carriers at the PN junction,and use its influence on the change of the effective refractive index to determine the modulator.The optimum value of the modulation arm ridge waveguide is 400 nm,the ridge height is 150 nm,the thickness of the flat plate layer is 70 nm,the distance yoffset from the center of the p-type doped region is 20³5 nm,dn+=1.48?m,dp+=1.52?m,at the PN junction,the doping concentration of N region and P region is greater than or equal to2×10¹77 cm^-3,N+,P+region is the transition region of carriers,the doping concentration is 10¹⁹/cm³,and the heavily doped region is 10²¹/cm³.The resulting modulation arm has a loss of 3.78 dB/cm,an extinction ratio of 3.7 dB,a modulation bandwidth of 37 GHz,and a modulation rate of up to 50 Gbps.Based on the simulation design,the production of silicon-based electro-optic modulators was completed using the 8-inch process platform of the Chinese Academy of Sciences Institute of Microelectronics.The waveguide loss was determined to be6dB/cm by measuring the loss of the waveguide group,the measured bandwidth was17GHz at-4V bias,and the modulation rate was 30Gbit/s.Slot ridge waveguides were proposed and their structural parameters were optimized.It was found that when the waveguide widths on both sides are 220 nm,the slit width is 40 nm,and the slit etching Si thickness is 220 nm,the slits are normalized.The maximum power is 13.54%.