DRY-ETCHED WIRE DISTRIBUTED-FEEDBACK LASER

We report on the realization and the properties of dry-etched wire and wire-DFB lasers and compare them with two-dimensional (2-D) reference lasers, The starting vertical structure, which was optimized for low threshold, consists of four GaInAs quantum wells embedded in a GaInAsP waveguide, Even for very small longitudinal confinement factors of the order 0.23, the dry-etched wire lasers show laser operation up to 60 degrees C and a threshold current density at room temperature of 5 kA/cm(2) for simple oxide stripe lasers, For the wire lasers, an increase of the differential material gain of more than one order of magnitude (about a factor of 20) was measured, compared to conventional 2-D lasers. The wires were also arranged periodically with different grating constants to allow gain-coupled DFB laser operation. Clear single-mode emission has been found, as expected, from the gain-coupling mechanism.