High Operating Temperature Quantum Cascade Laser Diodes for Free Space Optical Communication

"This proposal will demonstrate the feasibility and design of quantum cascade lasers for uncooled free-space communication in the mid- and far-infrared (3 425 K) operation and multiwatt room temperature peak output power. Removing the cooling subsystems necessary for other mid-infrared diode lasers significantly reduces the overall power consumption and system size. However, long range, high bit ratecommunications in adverse weather conditions requires a higher power source at higher duty cycles than is currently available. In Phase I, determination of laser design and package requirements suitable for free-space communication will be investigated.This program will also demonstrate a room temperature, high average power (>10 mW), high duty cycle (>50 %) QCL laser and a compact (1 W) laser pointer as a basis for a mid- or far-infrared transceiver. Current freespace optical systems are hindered by scattering elements (such as fog or smoke) and scintillation effects. Both act to shorten or completely sever a free space optical link. As predicted by scattering and scintillation theory, a mid- or far-infraredlaser source should have superior transmission through a non-ideal atmosphere as compared to a commercially available near-infrared source. This significant performance boost is especially