Linear and nonlinear gain spectra are studied in Sb-based quantum-dot (QD) semiconductor optical amplifiers (SOAs). Quantum size, homogenous linewidth and effect of Sb-composition in the QD, wetting and barrier layers are studied also. InSb and InAs0.3Sb0.7 QD-SOAs give enough gain saturation. The study covers (1000-7000nm) wavelength range. This work covers some new patents in this field.