Preparation And Spectral Analysis Of 895 Nm Vertical Cavity Surface Emitting Laser

Vertical cavity surface emitting laser(VCSEL),with characteristics of small volume,circular symmetric light spot,low threshold current,single longitudinal mode,wide frequency response,well modulation characteristics,and easy realize two-dimensional array integration,have important applications and broad development prospects in areas of optical communication,optical data storage,sensor technology,medicine and so on.The VCSEL devices need to achieve following requirements for application in chip atomic clock(CSAC),it should stable lasing at 895 nm wavelength under high temperature environments(70? ? 90 ?),threshold current ? 0.5 mA,side mode rejection ratio ? 20 dB.In this paper,the structure design,process optimization and spectral performance of VCSEL devices are studied.By studying the effect of cavity mode on lasing wavelength and the influence of mesa diameter andoxide aperture structure on lasing performance for the VCSEL devices,the prepared devices realize single mode lasering at 894.6 nm with higher side mode suppression of 35 dB,and the operating conditions are under driving current of 0.5 mA,70 ??90 ? working temperature.The main contents of this study are as follows:(1)The structure and material of the 895 nm vertical cavity surface emitting laser have been designed and grown.The effects of materials component film thickness and the doping concentration on the DBR reflectivity and stop band have been analyzed.The process of grating etching,mesa etching and chip cleavage have been optimized by single-parameter variable method.VCSEL devices with high quality have been prepared by optimized processing technology.(2)The cavity mode position of the deigned 895 nm vertical cavity surface emitting laser has been scanned and the effect of optical thickness change on the cavity mode has been analyzed.The structure of the VCSEL device with cavity mode position at 890.5 nm was designed through testing and analyzing for the cavity mode,output wavelength and temperature drift coefficient.The VCSEL devices were fabricated after the laser materials epitaxial growth,and the device realize output wavelength at 894.6 nm under 85 ? high temperature.(3)Different mesa etching structures have been designed and the influence of mesa diameter and structures of oxide aperture on lasing performance has been studied.When mesa etching structure is compensation mesa circular oxidation aperture will be obtained.The larger of the mesa in VCSEL device,the higher the threshold current.The more circular the oxide aperture,the higher the side mode suppression ratio.