Edge-emitting laser diode with GaAs triple QW in active region investigated by NOBIC

The application of near-field imaging to optoelectronic devices and laser diodes provides subwavelength information on a device structure. The fiber tip used for near-field imaging can be used also as a local tunable optical source exciting a photocurrent in the near-field region of an investigated structure. We demonstrate the structure and layer properties of laser diodes based on triple GaAs quantum well structures in AlGaAs active region emitting at wavelength 850 nm. The near-field optical beam induced current analysis is here demonstrated. From the vertical scan across the laser facet the active region with quantum wells and p-, n-doped confinement layers are identified.