Abstract
The effects of gamma radiation on vertical-cavity surface-emitting laser (VCSEL) characteristics are investigated experimentally. Three groups (batches) of oxide-confined VCSELs are investigated. It is found that radiation can change (increase or decrease) the quantum efficiency of VCSELs considerably, depending on their production batch. Small changes in the threshold current are observed for some devices. Shifts to a longer wavelength in the peak-emission profile are noticed after irradiation, which is found to be reversible in some VCSELs by simply increasing the radiation dose. It is also discovered that gamma radiation affects the total number of competing transverse modes depending on the radiation dose. Self-pulsation characteristics in some devices are not affected by the radiation exposure. Knowledge of the behavior of VCSELs under gamma exposure would be useful for their applications in hostile environment. ©