Study of the spatial and current dynamics of optical loss in semiconductor laser heterostructures by optical probing

The spatial and temporal dynamics of the optical loss and carrier density in the heterostructure of a semiconductor laser with a segmented contact are studied using an optical pump–probe technique based on the injection of probe radiation with a wavelength of 1560 nm into a semiconductor laser chip under study that is based on an AlGaAs/InGaAs/GaAs heterostructure and emits at wavelength of 1010 nm. It is demonstrated that employing probe light at a wavelength of 1560 nm enables sensitivity in measuring an internal optical loss of no less than 1 cm$^{-1}$. The segmented design of the current pumping region made it possible to estimate the absolute internal optical loss. It is shown that changing the configuration of the Fabry–Perot eigenmodes of the laser affects the carrier distribution and the internal optical loss both in the current pumping region and in the passive, current unpumped part of the laser chip.