Equivalent λ/4 phase shift to improve the single longitudinal mode property of asymmetric sampled Bragg grating semiconductor laser

Abstract

A special sampled Bragg grating (SBG) configuration, which consists of two sections with same length and different effective refractive index, is proposed. Because an equivalent λ/4 phase shift based on reconstruction equivalent chirp (REC) technology is introduced, the asymmetric structure can effectively suppress the lasing in its 0th channel, and then its single longitudinal mode (SLM) property is improved. This proposed method can also be used to fabricate high performance multiwavelength laser array (MLA) with high yield.