Research On Single-mode Polarization-stabilized Vertical Cavity Surface-emitting Laser

As a new type of optoelectronic device,Vertical Cavity Surface Emitting Laser(VCSEL)has a single longitudinal mode,low threshold current,small size,easy integration of two-dimensional arrays,circular output spots,and chip on-chip testing.It has been widely used in optical storage,optical communication,sensing,medical,military and other fields,and has important research value and broad development prospects.With the development of semiconductor technology,Sub-Wavelength Gratings(SWG),as important optical functional elements,have been widely used in the optical field.This thesis takes VCSEL as the main research object,and on the basis of exploring new structure and new performance,it is integrated with sub-wavelength grating to improve the performance of traditional VCSEL.Focusing on the theoretical foundation,structural design,simulation calculation,and device preparation of VCSEL.Focusing on the research on single-mode polarization-stabilized VCSELs,and achieves the single-horizon model by adjusting the size of the VCSEL oxidation aperture;integrate VCSELs with sub-wavelength gratings to achieve the polarization stability characteristics of VCSELs,and improve the performance of the device;A micro-nano all-optical switch based on optical gradient force is simulated.Paper main research content for the following three parts:(1)Studying on the polarization stability characteristics of periodic subwavelength gratings.Basing on the strict coupled wave theory and finite element analysis,two periodic high transmission one-via wavelength gratings are designed.The working wavelength of the incident sub-wavelength grating is 850nm,and the grating material is based on silicon.Firstly,a grating thickness of 250 nm,a period of 380 nm,and a duty ratio of 0.8 are designed.This design achieves high transmission of sub-wavelength grating TE light with a transmittance of 93.6%.The thickness of another grating material is 500nm,grating period is 300 nm,and duty ratio is 0.5.This design achieves high transmission of sub-wavelength grating TM light with a transmittance of 97.6%.Both structures can achieve polarization stabilization characteristics.(2)Basing on the theoretical foundation of VCSEL,the material gain and Bragg Reflector Reflectance(DBR)spectrum of the design device are simulated first.Through simulation design,the gain of the device material near 850nm was greater than the loss,and the reflectivity of DBR was greater than 98%.The VCSEL's P-I characteristics,spectral characteristics,and mode characteristics are simulated.The threshold current of the VCSEL is 1.6 m A and the maximum output optical power is 4 m W.Considering the red shift phenomenon of the laser,the designed lasing wavelength is 835 nm.In order to achieve the single-mode output characteristics of VCSELs,the oxidized aperture of the device is designed to be 3um,so as to suppress the high-order mode to obtain a single transverse mode output.By comparing the P-I characteristics of the single transverse mode with the total P-I characteristic curve of the device,the output power of the single transverse mode is approximately equal to the total power,so the VCSEL has the single transverse mode output characteristics.(3)A micro-nano all-optical switch bases on optical gradient force is designed and prepared.One arm(Arm1)of the switch is fixed,and the other arm(Arm2)is set as a floating waveguide.Arm2 is suspended from the Si O₂layer of the substrate.The suspended beam length of the etched waveguide is 30um,the cross-sectional depth is200nm,and the width is 400nm.Through testing,the corresponding mechanical displacement D of the suspension arm is proportional to the power P of the control light,allowing low-loss single-mode optical transmission.The device's footprint is only 200?m×60?m,which is far smaller than other solutions based on optical fibers and semiconductor optical amplifiers(typical size>1mm×0.3mm).Its extinction ratio is 12d B and the response time is 18ns.It has broad application prospects in high-end optical packet switching communication systems and silicon photonic integrated circuits.