Simulation and Analysis of Distributed Blagg Reflectors 850 nm VCSELs

• Main Authors: KE , LI-TAI, 柯力泰
• Other Authors: S. L. Yang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/77748781537535105928

碩士 === 國立交通大學 === 理學院碩士在職專班應用科技學程 === 94 === In this thesis work, we simulated and analyzed the optoelectronic properties of 850 nm oxide-confined vertical-cavity surface-emitting laser (VCSEL) diodes using ISE-TCAD simulation software. For the optimized characteristicsof VSCELs, n type DBR doping concentration = 2.5x1O18 cm-3 and p type DBR doping concentration = 1x1O19 cm-3 .Even thought we can increase the doping density in the advantage process, still need to follow > are expected. Considering the resistance and threshold current concerns of VCSELs, we simulated the graded and tensile strain cladding layers. Judging from the L-I-V characteristics, we found the fact that the thicker tensile-strain cladding layer greater than 10nm may prohibit the device from lasing. And the 3 nm-thick tensile-strain cladding layer can give low threshold currents and high lasing efficiency of VCSELs. Furthermore, we simulated the optical reflectance of various DBR structures. In the graded DBRs, when the thickness of the graded layers are over 20 nm, 25 pairs more DBR structures can give the same reflectance of regular abrupt DBRs. As the thickness of DBR layers are in 2% variation, processes, 25 pairs more DBR structure can also provide the same reflectance values of non-variant DBRs at the main wavelength and applicable stop-band width. Finally we utilized the matrix optics to analyze the effects of pair numbers and light incident angle on the reflectivity spectra of DBR. For the case of 45º incident angle of light ,the resonant wavelength shift about 20 nm.