Experimental Demonstration of a Multicorrugation-Pitch-Modulated (MCPM) DFB Semiconductor Laser Based on Reconstruction-Equivalent-Chirp Technology

A multicorrugation-pitch-modulated (MCPM) distributed-feedback semiconductor laser is experimentally demonstrated for the first time to achieve stable single longitudinal mode (SLM) performance. The MCPM structure was equivalently realized based on a sampled grating using reconstruction equivalent chirp (REC) technology. The proposed REC-MCPM structure can effectively flatten the optical intensity distribution along the laser cavity, leading to the strong suppression in spatial hole burning. In addition, the REC-MCPM grating structures can be readily fabricated using conventional holographic lithography combined with low-cost standard micrometer-level photolithography. A proof-of-principle study both in a simulation and an experiment is presented in this paper. The fabricated 400- $\mu\hbox{m} $-long REC-MCPM semiconductor laser shows very good SLM performance with SMSRs being more than 42 dB under test conditions of a large injection current range (up to 300 mA) and different ambient temperatures.