tailieunhanh - Laser Pulse Phenomena and Applications Part 5

Tham khảo tài liệu 'laser pulse phenomena and applications part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Numerical Simulations of Temperature-dependence on Distributed Bragg Reflector DBR and Performance Analyses for Proton-Implant Oxide Confined VCSEL Comparison with . 111 Fig. 23. The temperature-dependent spectra of Proton-Implant 850 nm VCSEL Fig. 24. The far-field pattern of Proton-Implant 850 nm as function of injected currents temperature of 30 C diagram it is clear to obtain that the single lasing modes occur suddenly from spontaneous mode once the injected currents increase to mA. While the injected current increases continuously to 1 mA lasing intensities eventually become stronger and the profile remain the same shape. The transverse modes always are single modes. And the threshold current of proton-implanted VCSEL is much smaller than that of the sample treated in oxidized confined process. P. K. Kondratko . 2003 Similarly 80 C laser beam profiles after ion-implanted treatment are shown in Fig. 25. From the profiles it is found that the single fundamental lasing mode occurs suddenly from spontaneous mode once the injected currents increase to mA. And the profiles of far-field pattern remain the quasi-circular shape. While the injected current increases continuously to mA the transverse modes still are single modes. Only lasing intensity becomes stronger like that of the low temperature operation. It can be depicted that the proton-implanted VCSEL have a good performance to be operated in higher circumambient temperature. The experimental results in summary of the oxidized and proton-implanted confined VCSEL as sown in Table I as well as the assistance of using theoretical DBR simulated with transfer matrix method TMM matrix calculating method MCM Marcatili s method. Table I demonstrates the superior performance of VCSEL treated in ion-implanted process 112 Laser Pulse Phenomena and Applications contrast to the oxidized confined VCSEL. However the low-differential resistance and lower-cost process with high-temperature oxidized treatment in