Fiber Optics

AdValue optical isolator delivers fiber laser power for Air Force SBIR

July 31, 2015

AdValue Photonics developed an all-fiber-based optical isolator for the Air Force under SBIR project number FA9451-11-C-0138.

Gail Overton

A high-power fiber laser array at AFRL Directed Energy Directorate uses an AdValue Photonics optical isolator developed under a US Air Force SBIR/STTR.

AdValue Photonics (Tucson, AZ), working with the Air Force under a Small Business Innovation Research (SBIR) award for the titled "Isolator for Fiber Laser Amplifier Arrays" project under contract number FA9451-11-C-0138 developed an optical isolator using proprietary, highly doped ytterbium Faraday rotator fiber and a fiber-based polarizer. Until now, the performance of all fiber-optic isolator prototypes was comparable to commercial free-space optical isolators.

The Department of Defense needs hundreds of kilowatt-class fiber lasers for missile defense applications. Generating this increased power requires fiber amplifiers separated by an isolator in order to maintain stable operation. Currently, free-space fiber-pigtailed isolators are used, but free-space isolators take away the ruggedness and high reliability of fiber lasers--two key advantages of fiber lasers over free-space solid-state lasers.

The DOD identifies high-power fiber lasers (HPFLs) as one of the critical technologies for future warfighters. In order to maintain stable and efficient operation for HPFLs, optical isolators are necessary between fiber laser amplifiers. An optical isolator is used to block the back-reflected light; otherwise the back reflected light will be amplified and cause catastrophic damage to the HPFL.

With the SBIR funding, AdValue demonstrated an all-fiber isolator by using a new type of fiber-based polarizer. This all-fiber component potentially enables the reliable operation of high-power single-mode fiber lasers. AdValue launched a commercial product, which attracts a significant amount of interest from university labs, defense research institutes, and industrial laser companies. This all-fiber isolator will not only improve the reliability of fiber lasers for defense applications, but also increase the lifetime of industrial fiber lasers. This innovative technology was selected for an R&D 100 award in 2014 and continues to receive support from JTO-HEL for further improvements in packaging and power-handling capability.

SOURCE: US Air Force; http://www.afsbirsttr.com/Publications/Documents/75_Innovation_20150707_AF093-008_AdValue.pdf

About the Author

Gail Overton | Senior Editor (2004-2020)

Gail has more than 30 years of engineering, marketing, product management, and editorial experience in the photonics and optical communications industry. Before joining the staff at Laser Focus World in 2004, she held many product management and product marketing roles in the fiber-optics industry, most notably at Hughes (El Segundo, CA), GTE Labs (Waltham, MA), Corning (Corning, NY), Photon Kinetics (Beaverton, OR), and Newport Corporation (Irvine, CA). During her marketing career, Gail published articles in WDM Solutions and Sensors magazine and traveled internationally to conduct product and sales training. Gail received her BS degree in physics, with an emphasis in optics, from San Diego State University in San Diego, CA in May 1986.