The optical properties of violet-blue InGaN quantum-well (QW) ridge waveguide (RWG) laser diodes (LDs) are numerically investigated with a LASTIP simulation program. The results obtained numerically indicate that best laser performance is obtained when the number of InGaN well layers is two if the emission wavelength is shorter than ~427 nm and one if the emission wavelength is longer than ~427 nm. The results obtained numerically also suggest that, in addition to the dissociation of the high indium content InGaN well layer at a high growth temperature during crystal growth, the inhomogeneous carrier distribution in the QWs also plays an important role in the optical performance of the InGaN QW LDs with an emission wavelength of 392-461 nm.