We have fabricated an integrated twin-guide (ITG) InGaAs-GaAs 980 nm laser with a surface-grating-etching (SGE) structure for single mode selectivity. It is possible to design the ITG lasers so that only two propagation modes exist in the cavity. It is difficult to fabricate wavelength filters using conventional ITG structures, thus, we introduced SGE in ITG lasers for wavelength selectivity. The threshold gain modulation as a function of wavelength is possible, as a result of the coupling of two propagation modes in twin-guide by the incorporation of SGE. We demonstrate the principle and the possibility of single mode selectivity using a simple fabrication technology.