Superluminescent Diodes Based on Asymmetric Double Quantum-Well Heterostructures

In the present work superluminescent diodes (SLDs) based on nanostructure with two ultrathin active layers of different composition were developed and studied. In this case, the width of the amplified spontaneous emission (ASE) spectrum is determined by the distance between the maxima of the optical gain spectra correspondent to quantum transitions from the fundamental subbands of each of the quantum wells. The studied SLDs were based on the separate confinement double heterostructure (SCDH) in (Al
_x
Ga
_1-x
)As/GaAs system with two asymmetric quantum-well (~6 nm) active layers (ADQW) of GaAs and (In
_x
Ga
_1-x
)As, separated by barrier layer with thickness of 10 nm. All structures had the same contact, emitter and waveguide layers, differing only in thickness and the chemical composition of the active layers. These differences are reflected in Table 1. It also shows the wavelengths corresponding to the electroluminescence spectral maxima.