Strain-induced non-linear optical properties of straddling-type indium gallium aluminum arsenic/indium phosphide nanoscale-heterostructures

Non-linear optical properties of indium gallium aluminum arsenic/indium phosphide (InGaAlAs/InP) material system based unstrained and strained lasing nano-heterostructures of straddled type (type-I) under TE (transverse electric) polarization mode have been studied. To produce the different states of strain at the heterointerfaces in the structure, the different layers of the active region of InGaAlAs (width ~6 nm) with different lattice constants (due to different mole fractions) have been assumed to be deposited in between the barriers of In0.41Ga0.34Al0.25As followed by claddings of In0.52Al0.48As. The entire nano-structure is a type of step SCH (separate confinement heterostructure) and has been assumed to grow over InP substrate. To study the strain induced non-linear optical properties of the structure, single effective mass and Kohn–Luttinger Hamiltonian equations have been solved to obtain quantum states and envelope wave functions in the heterostructure. In addition, the optical gain, differential gain, and the anti-guiding factor in order to support the gain calculation have been computed and reported. On behalf of simulation and previously reported experimental results, it has been suggested that either unstrained or compressive strained InGaAlAs/InP nano-heterostructures are more suitable for novel applications in the emerging areas of nano-opto-electronics due to the maximum gain occurring at lasing wavelength of 1.55 µm which is the wavelength of minimum optical attenuation.