Optical Gain in Type-II InAsN/GaSb Strained Quantum Wells Laser Diodes and Its Pressure Dependence

Theoretical calculations of the hydrostatic pressure influence on the electronic band structure and the optical gain of N-containing InAs0.98N0.02/GaSb quantum wells laser diodes are presented. A k · p model, taking into account, the p-like valence band, the s-like and p-like conduction band, and the nitrogen resonant level is introduced. We have used a unitary transformation that block diagonalizes the 16 × 16 Hamiltonian into two 8 × 8 blocks that are real symmetric in the finite difference formulation. Numerical results have been determined over a pressure range from 0 to 30 kbar. It has been shown that the hydrostatic pressure changes the electronic band structure and as a result the optical gain decreases with the hydrostatic pressure by about 80% and 50% for [111] and [001] growth directions, respectively for transverse electric modes. Hence, the emission spectrum is shifted to shorter wavelength (i.e., for [111] direction, from 2.65 μm to 1.16 μm).