Assessment of high power diode laser arrays by Fourier-transform photocurrent measurements

We present new results on aging properties of high-power laser diode arrays (LDA) obtained by Fourier-transform (FT) spectroscopy. The FT spectrometer was used as excitation source for performing photocurrent measurements on two sets of aged 10 W high power LDA. The photocurrent (PC) Spectra were found to reveal aging induced changes of the LDA. Both the evolution of defect contributions located in the optically active layer as well as modifications of the interband contribution of the spectrum can be used as a measure of the aging status of an individual LDA. Thus we introduce a new, fast and nondestructive method for the assessment of high power LDA. Furthermore, additional insight into the microscopic nature of the processes accompanied by aging is provided.