Measurement of the tuneable absorption in GaN-based multi-section laser diodes

Abstract

We present an experimental technique to measure the absorption spectra of the absorber section of GaNbased multi-section laser diodes using optical gain spectroscopy. We find that the absorption of the examined laser diodes decreases with increasing negative bias, which results from a reduction of the internal field in the quantum wells by the external voltage. A maximum modal absorption as high as 250 cm^–1 at the laser wavelength of 413 nm is measured at 1 V absorber voltage. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)