Design and fabrication of 1.3 μm buried ridge stripe lasers on semi-insulating InP substrate

The achievement of a monolithic integrated transmitter imposes specific requirements on the laser device, such as low threshold current, and demands complex processes, namely several epitaxial growth, steps etching, and fine lithography to be used alternatively. Thus, it is especially desirable to benefit from techniques such as MOVPE or MBE which allow the growth of high quality material in terms of uniformity and morphology. The laser structure the authors have developed, the so-called buried ridge (BRS) structure fulfils all these requirements. To integrate later this laser structure with electronic devices, it is grown on an InP semi-insulating substrate. Such lasers exhibit characteristics very similar to lasers with the same structure but grown on an n⁺ substrate, with threshold current around 20 mA and output power of 10 mW. Also, they have set up an accurate equivalent electrical model of the BRS structure to optimise its modulation properties. BRS lasers with different current injection configurations have been investigated, and comparison with experimental modulation responses shows a good agreement with this model