795nm单模垂直腔面发射激光器

795 nm Single-Mode Vertical-Cavity Surface-Emitting Laser

针对铷原子能级跃迁对光谱的特殊需求,设计并制备了795 nm单模垂直腔面发射激光器(VCSEL)。根据对VCSEL的光场和模式的分析和计算结果,设计了单模VCSEL芯片结构。采用MOCVD技术生长了外延结构,制备了不同有源区直径的氧化限制型VCSEL芯片并进行了测试。当有源区直径从6μm减小到3μm时,VCSEL芯片的边模抑制比(SMSR)由8.76 d B增加到34.05 d B,阈值电流由0.77 m A减小到0.35 m A。有源区直径为6,5,4和3μm的VCSEL芯片的输出功率分别为0.37,0.46,0.58和0.44 m W,有源区直径为4μm的VCSEL芯片的远场为圆形光束,发散角为15°。85℃时3.5μm有源区直径的VCSEL芯片输出功率为0.125 m W,激射波长为795.3 nm。室温3 d B带宽大于8 GHz,满足了铷原子传感器对VCSEL单模光谱、输出功率及调制速率的要求。

For the special spectrum requirements of the rubidium atomic energy level transition,a single-mode vertical-cavity surface-emitting laser（ VCSEL） emitting at 795 nm wavelength was designed and fabricated. The structure of the single-mode VCSEL chip was designed based on the analysis and calculated result of the optical fields and modes of the VCSEL. The epitaxial structure was grown by the MOCVD technology,and the oxide-confined VCSEL chips with different active diameters were fabricated and tested. The side-mode suppression ratio（ SMSR） of the VCSEL chip increases from 8. 76 d B to34. 05 d B,and the threshold current of the VCSEL chip decreases from 0. 77 m A to 0. 35 m A when the active diameter changes from 6 μm to 3 μm. The output powers of the VCSEL chip with active diameters of 6,5,4 and 3 μm are 0. 37,0. 46,0. 58 and 0. 44 m W respectively,and the far-fields of the VCSEL chip with 4 μm active diameter are almost perfectly circular beam shape with a divergence angle of15°. The output power of 0. 125 m W and lasing wavelength of 795. 3 nm of the VCSEL chip with 3. 5 μm active diameter are obtained at 85 ℃. The 3 d B bandwidth above 8 GHz is achieved at room temperature,which satisfies the requirements of the rubidium atomic sensor for the VCSEL single-mode spectrum,output power and modulation rate.