980nm大功率垂直腔面发射激光器温度和远场分布特性

Temperature and far-field distribution characteristics of 980 nm high power VCSEL

采用发射波长为980nm的InGaAs／GaAs应变量子阱，在垂直腔面发射结构中共设计生长3组、每组3个量子阱，形成9个量子阱的周期性增益结构，并使每组均位于腔场极大处，以获得最好的增益匹配。为提高激光器的输出功率及获得较好的光束质量，采用大台面直径和由衬底面出射激光的结构。每个单元器件的P面台面直径为400-600μm，经湿氮气氛下40min的侧氧化后在有源区形成直径300-500μm的电流限制孔。而N面出光孔的直径仍为相应的400-600μm。在室温连续工作下器件的最大输出功率达到1．4W。随着注入电流的增大，观察到激光远场分布从空心圆环向中心单亮斑转化的过程。对不同温度下的激光输出特性进行了变温测试，结果表明通过DBR和有源区结构设计上较好的匹配，实现了室温下最低的激射闽值电流。

A novel periodic gain structure VCSEL with emitting wavelength of 980 nm was investigated. The periodic gain section was consisted of nine InGaAs/GaAs quantum wells, which were divided into three groups. Each group was positioned at the antinodes of the cavity to enhance the matching between optical gain and the electrical field inside the cavity. Large emitting aperture and bottom emitting configuration were designed to increase the output power and improve beam quality. The diameter of the laser is from 400 μm to 600 μm. A current aperture of about 300 μm to 500μm was formed after 40min of wet nitrogen oxidation. The maximum output power of 1.4 W was realized at CW operation with a farfield angle of 16 degree. The field distribution changed from a hollow ring to a strong light spot at the center of the ring. With the increase of input current,the temperature characteristics of the device were measured in the temperature range from 0 degree to 100 degree.Temperature test of laser output charactristic was made at different temperature.And the experimental results show that the lowest threshold current at room temperature results from an optimal matching between DBR and active region.