“…The strained In x Ga 1-x As/GaAs of well/barrier layers, which serve as the active region, have different indium mole fractions (x) of 0.17, 0.24, 0.34, and 0.34 nm and thicknesses of 8.1, 7.2, 5.4, and 9.4 nm corresponding to emission wavelengths of 950, 1000, 1050, and 1100 nm, respectively. The different-wavelengths-emission-designed MQW can effectively broaden optical gain spectrum [9,10]. The number of MQWs of each wavelength equals two.…”