GaInAsP/InP Membrane Lasers for Optical Interconnects

In this paper, the state-of-the art of long-wavelength GaInAsP/InP membrane semiconductor lasers, one of the most promising candidate light sources for optical interconnects and on-chip optical wiring between large-scale integrated circuits, is described. After an extensive review of research activities focused on laser preparation on either Si or Si-on-insulator substrate, the findings of our recent research activities on low power consumption lasers are presented. Specifically, our interest was set on the low-damage fabrication of strongly index-coupled grating, which is generally opted forDFB and distributed reflector (DR) lasers consisting of wire-like active regions, as well as of high index-contrast membrane waveguides. A submilliampere threshold current and a differential quantum efficiency close to 50% from the front facet were achieved in the case of the DR laser. On the other hand, a lateral current injection (LCI) structure, which can be combined with the membrane laser, was adopted for the realization of an injection-type membrane laser. The successful continuous wave operation of LCI lasers, prepared on a semiinsulating InP substrate, was achieved with moderately low threshold current at room temperature.