Effect of thermionic electron emission from the active layer on the internal quantum efficiency of InGaAsP lasers operating at 1.3 μm

We have experimentally characterized the quantum efficiency in InGaAsP lasers operating at 1.3 /spl mu/m. The observed reduction in external quantum efficiency with increasing temperature and increasing bias current is found to be caused almost entirely by a reduction of the internal quantum efficiency. The internal quantum efficiency is reduced approximately linearly with bias current in the temperature range investigated. The experimental results are well explained with a theoretical model based on thermionic emission of carriers out of the active region.>