Immersion Layer in Columnar Quantum Dash Structure as a Polarization Insensitive Light Emitter at 1.55 µm

We report on polarization independent 1.55 µm room temperature edge emission from an InGaAs immersion layer, being a quasi-two-dimensional surrounding of columnar quantum dashes formed during the close stacking self assembled growth. Calculations performed in an 8 band k · p model revealed that the in-plane strain distribution across the immersion layer induces a significant heavy hole–light hole valence states mixing leading to equal transverse electric and transverse magnetic components of the optical transition intensity.