Photoluminescence of AlGaInAs/InP non-identical multiple quantum wells laser design is performed to study the emission spectrum. The active region comprises of three 6.4 nm and six 5 nm wells, with 1.35% compressive strain in quantum wells and 0.74% tensile strain in barriers. The quantized energy levels of the different wells are separated by 50 nm to achieve extend gain spectrum. Modulation spectroscopy is applied to identify each quantized energy levels in active region.