[en] In this article an attempt has been made to determine the uni-directional (001-direction) pressure effect on the optical gain spectra and corresponding emission wavelength of a designed type-II nano-scale heterostructure based on GaAsSb-InAs material system. As a trial, the range of pressure applied was kept as 1-3 GPa. On introducing the uni-directional (001-direction) pressure (in the range of 1 GPa to 3 GPa) on the GaAsSb-InAs QW heterostructure, the optical gain is reduced significantly from 3050/cm to 1150/cm, while the transition wavelength shows the red shift. (author)