New WDM DFB laser structure for facet phase-free uniform performances

A new concept for a DFB MQW monomode laser has been proposed and demonstrated. The new structure combines high SMSR, excellent uniformity, high efficiency and low divergence. Uniform spectral performances have been demonstrated with a SMSR of 44 dB at 3 mW, showing that standard processing techniques can be used to fabricate monomode devices with uniformity performances and a theoretical yield of 100% similar to that of Fabry-Perot lasers. Threshold as low as 14 mA, an efficiency of 0.32 W/A and a divergence of 14°×16° could also be obtained with the proposed principle. These results are very promising and open the way for the fabrication of selection-free monomode lasers for WDM applications with highly competitive performances.