Research On Polarization Splitting Rotator Of Micro-nano Silicon Photonics

The important technological industries in the current social development,from high-performance computers to communication networks,have put forward higher requirements for high-speed interconnection and large-capacity information transmission.With the improvement of integrated circuit manufacturing process nodes,the size of microelectronic devices is approaching the physical limit,causing problems such as delay and energy consumption in electrical interconnections.Therefore,optical interconnection technology that uses photons as information carriers has received more attention.This paper starts from solving the polarization sensitivity problem of silicon-based optical interconnection technology based on silicon-on-insulator(SOI)material,and designs a polarization splitter and rotator(PSR)that can control the random polarization state of the on-chip input.Realize the adjustment of the polarization state of the optical fiber input system-on-chip.Based on the principle of mode cross-polarization coupling,a directional coupling structure PSR composed of ridge waveguides is designed.Using the ridge waveguide's weaker restriction on the TM mode,higher mode coupling conversion efficiency can be obtained at a shorter distance.Using the software Lumerical's finite difference time domain algorithm(FDTD)for simulation,it is finally obtained that the device achieves a conversion efficiency of 96%for the TM mode at a working wavelength of 1550 nm,and the length of the coupling region for mode conversion is only 12?m.In order to increase the bandwidth of the coupled polarization splitter-rotator,a reverse cone directional coupling structure is designed.By optimizing the width of the reverse tapered waveguide and the length of the coupling region with respect to the performance of the device,efficient coupling conversion can be achieved in a larger wavelength range,and the process tolerance of the device has also been improved.The extinction ratio of the final TM mode is greater than 20d B within the wavelength of1500nm-1630nm.And when the coupled waveguide width is changed within the range,the device still maintains a better performance with an extinction ratio greater than15d B.Considering the process conditions and the integration with the strip waveguide device,the PSR of the tapered double-layer etched waveguide cascade reverse-tapered coupling structure based on the principle of mode evolution is designed.The tapered double-layer etched waveguide part ensures efficient TM₀-TE₁ conversion in a wide wavelength range,and the reverse taper coupling structure ensures that the wavelength of the separated conversion part of TE₁-TE₀ is insensitive.The device simulation results show that in the 200nm wavelength range,the extinction ratio of the device can reach20d B,and the insertion loss is less than 1d B.Based on an SOI wafer with a top silicon thickness of 220nm,using a CMOS process compatible silicon optical device processing technology,double-layer etched PSR devices are taped out.Summarize the main manufacturing process technology of silicon optical devices,and introduce the manufacturing process of PSR devices in this article.The processed PSR device was tested experimentally,and the test result spectrum was analyzed.Finally,the current research work is summarized,and the future development and application direction of the polarization beam splitting rotator is prospected.