Effect of External Heating on Top-Emitting 980 nm VCSELs, Resonance Frequency and Damping Factor
The effect of external heating (stage heating) on top-emitting 980 nm vertical cavity surface emitting lasers (VCSELs) on the resonance frequency and damping factor is investigated. The measurements demonstrated that increasing the stage temperature reduces the resonance frequency and damping factor, thus limiting the 3-dB modulation bandwidth of VCSELs. Considering that the relationship between the damping and resonance frequency is the power of 2, an 8 µmactive diameter laser exhibits a maximum intrinsic 3-dB frequency bandwidth of 24.7 GHz. At room temperature, the device exhibits a threshold current, maximum output power, and slope efficiency of 0.4 mA, 1.6 mW, and 36%, respectively.