In this paper, ridge waveguide quarterly
wavelength shifted distributed feedback (RW-QWS-
DFB) laser was modeled and analyzed. In this behavioral
model, some characteristics of the device, such as thresh-
old current, line width, power of output wave, spectrum of
output wave, and laser stability in high powers, were
investigated in accordance with different physical and
geographical parameters such as sizes and structures of the
layers. Considering a new proposed algorithm, the analysis
of the mentioned structures was performed using transfer
matrix method (TMM), the solution of coupled waves and
carrier rate equations. The results showed the advantages
of some parameters in this structure.

• Analysis and modeling of ridge waveguide quarterly wavelength shifted distributed feedback laser with three rate equations