The effective refractive index of the active region of 1.3 μm edge-emitting tilted wave lasers based on InAs/InGaAs self-assembled quantum dots by the analysis of the far-field pattern is investigated. The obtained values of 3.485 and 3.487 in the operating lasers and in the cold waveguides, respectively, are well comparable with the refractive index of bulk InAs at corresponding wavelength. Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots Downloaded From: http://nanophotonics.spiedigitallibrary.org/ on 09/29/2016 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Gordeev et al.: Refractive index of laser active region based on InAs/InGaAs quantum dots