Spatially and polarization resolved electroluminescence of 1.3-microm InGaAsP semiconductor diode lasers

A technique for obtaining spatially and polarization resolved maps of the electroluminescence along the length of 1.3-microm InGaAsP semiconductor diode lasers is described. The technique yields valuable information on the mechanical strain and uniformity of material in the active region. Measurements on thirty lasers of two different types-planar buried heterostructure (PBH) and gain guided-are summarized. This technique provides a means of correlating operating characteristics of the lasers with the physical properties of the laser material. Large differences between PBH and gain guided lasers are found. PBH exhibit typically a larger average value of strain and more scattering centers than gain guided lasers. A laser with a bent active region exhibited spectral bistability with respect to temperature. The strain distribution in the active region was observed to change during the first few hours of high temperature aging.