In this study, we propose a new method to tune the semiconductor laser lasing frequency and reducing the laser linewidth using an external deriving field. We redeveloped Floquet S-matrix which determines the transmission probabilities and the shape and position of the induced quasibound state, which accumulated incident electrons. We explored the S-matrix numerically for various system parameters. We found that the oscillating field amplitude V1 plays a curial rule in defining the profile of electrons accumulations in the quasibound state and the field`s strength made sift the position of the quasibound state. This sift in the bound state energy due field`s strength is used to tune the lasing frequency and the output of the semiconductor laser linewidth is improved by changing the field`s amplitude the deriving field. By narrowing down the electron accumulations profile the laser linewidth would be narrower.