High Performance Quantum Cascade Lasers for Free Space Communications

In this Phase I effort, Maxion will assess the feasibility of developing a high-operating-temperature, high average power, quantum cascade laser emitting in the 9-10 micron wavelength region for application in free space communications. The effort willfocus on laser design and fabrication methodologies that lead to low threshold current density and effective heat removal from the device's active region, enabling the necessary performance at high operating temperatures. Devices will be fabricated in anepi-side-up geometry in a manner that incorporates an effective lateral heat conduction path, promoting two dimensional heat conduction. Additionally, active region design will incorporate features that minimize transparency current and reduce thresholdcurrents. The demonstrated quantum cascade lasers will be thoroughly tested and their performance characteristics will be compared to those of the free space optical communication application. The performance requirements of the free space applicationwill be determined using reasonable optical link parameters and power level budgets. Necessary improvements to device performance characteristics will be identified and addressed. If successful, this project will lead to quantum cascade lasers thatoperate in the 9-10 micron region at high temperatures under cw conditions and with high average powers at room temperature. The device design and fabrication principles that enable this performance level can then be used to extend the wavelength rangewhere high performance is available. The resulting quantum cascade lasers can then be used in a variety of application areas in addition to free space communications. Applications areas of importance include the trace level sensing of a wide variety ofchemicals in diverse fields including pollution monitoring, industrial process controls, medical diagnostics and therapeutics, and explosives detection.