GaSb-based DBR lasers with high-order Bragg gratings are fabricated without complex process. The 16th-order and 24th-order Bragg gratings are fabricated with double-trench ridge waveguide by using standard contact optical lithography respectively. The 16th-order Bragg grating laser achieves single longitudinal mode continuous-wave (CW) operation at room temperature with side mode suppression ratio (SMSR) as high as 17.5 dB. The maximum single mode continuous-wave output power is more than 10 mW at room temperature. The laser shows a very excellent wavelength stability against injection current. The single spatial mode operation is maintained in the entire injection current range. The 24th-order Bragg grating laser even shows a side mode suppression ratio up to 22.5 dB at room temperature. The emission wavelength is around 2.0 μm.