AFRL Research Advances Light-Emitting Diodes for Laser Applications

  • Published
  • By Air Force Office of Scientific Research
  • AFOSR
In-house sponsorship of an AFRL optoelectronics team is advancing Air Force combat systems through research into high-brightness/high-efficiency emission sources (e.g., light-emitting diodes and lasers) for laser radar and infrared countermeasures applications. In one effort, the team of AFRL sensors scientists utilized a novel thin film as an electrical interconnection between monolithically grown stacks of laser diodes for higher-slope-efficiency lasers. The outcome of this effort revealed that use of this technique produces much greater laser light output power with no significant loss of modulation speed in the output. In a separate effort, the team utilized state-of-the-art heat sinking and advanced designs to construct a surface-emitting laser with the capacity to achieve higher powers while maintaining single-mode emissions.

The researchers are also working on a laser that emits light without modulation (external modulator design) in the 50-60 GHz range. Light instead passes through a separate device--an optical modulator--which puts a high-speed signal on the carrier. The team is now investigating the possibility of small-signal modulation in three-stage, surface-emitting lasers at a speed greater than 9 GHz (with 10 GHz speeds on the horizon and 15-20 GHz representing the cutting edge of the technology).