Eyesafe Short Wave Infrared (SWIR) Laser for Laser Ranging

Within the past decade, ballistic missiles have emerged as major threats to American and friendly armed forces. As of early 1998, at least 30 nations were known to have more than 10,000 ballistic missiles in their arsenals and the threat is growing daily. Several of these countries are also known to be pursuing development or to have developed nuclear, chemical and biological capabilities for their missiles. To counter this threat the Missile Defense Agency (MDA) has sponsored the development of the Airborne Laser (ABL), which is a system centered around a high-energy chemical oxygen iodine laser (COIL) carried aboard a modified Boeing 747-400F freighter. Airborne Laser (ABL) will locate and track missiles in the boost phase of their flight, then accurately point and fire the high-energy laser, destroying enemy missiles near their launch areas. This proposal addresses critical new technology for the ABL tracking function contained within the Active Ranging System (ARS). The currently deployed ARS utilizes a CO2 laser rangefinder to generate both a range and instantaneous radial velocity of the missile with respect to the airborne platform. Although the technology that is employed is mature and highly functional, the emission of the CO2 laser at 11.15 ƒYm is not eyesafe, and is therefore hazardous to humans. Eyesafe operation of the laser rangefinder is a goal for the Next Generation Active Ranging System (NGARS), which will utilize a transmitter that operates between 1.4 and 1.6 mm and newly developed InGaAs avalanche photo-diodes (APD) that are sensitive in this region. Not only is eyesafe operation important for ABL; it is becoming a standard requirement on new laser rangefinder and laser radar (ladar) systems. The primary goal of this SBIR program is to develop an eyesafe all-fiber high power laser transmitter for the NGARS that will meet or exceed the performance specifications for the NGARS. This effort will lead to affordable commercialized eyesafe laser rangefinder and imaging ladar systems.