Gain spectra measurement of strained and strain-compensatedInGaAsP-AlGaAs laser structures for Λ≈800 nm

摘要

InGaAsP single quantum wells (QWs) for wavelengths around 800 nmnembedded in AlGaAs large optical-cavity waveguide structures areninvestigated by measuring modal gain spectra and broad-area (BA) lasernparameters. The modal net-gain spectra are determined by the variablenstripe-length method using current injection. Thick (18 nm) and nearlynunstrained QWs show gain spectra without resolved subband structures.nThe modal gain in TE-polarization is twice as high as innTM-polarization. For thinner (13 nm) compressively strained (0.6%) QWs,nthe modal gain in TM-polarization and the transparency current densitynare lowered. For highly strained (1%) QWs, strain compensation byntensily strained GaAsP barriers improves the device performance. BAnlasers with 5-nm-thick QWs with strain compensation show a 10% higherndifferential efficiency in comparison to structures without strainncompensation