Polarization of the emission in injection lasers

Factors leading to the predominantly TM polarization of heterojunction lasers is experimentally investigated and discussed. In order to determine which of a variety of possible effects plays the leading role in TM polarization of this type of laser, samples were fabricated with waveguide layers that provide complete mode confinement. The TM emissions observed indicate that it is the strain effects which play the governing role. These results are in agreement with those of studies made of the polarization of emissions in optically pumped InGaAsP-InP structures.