A method used to introduce an arbitrary equivalent-phase-shift (EPS) into an asymmetric sampled Bragg grating (SBG) is reported. Under the same structural parameters except for the sampling pattern, the asymmetric SBG offers better performance than that of a normal SBG structure for keeping single-longitudinal-mode (SLM) operation. This is because the proposed sampling pattern can suppress the 0th-order light resonance due to the mismatch between the two different grating sections along the whole SBG. This method can be used to design and fabricate semiconductor lasers and multiwavelength laser arrays (MLAs) with the required EPS at high yield and low cost.