Optical Science and Engineering ETDs


Don Seeley

Publication Date



High power ytterbium doped fiber amplifier arrays in a master oscillator-power amplifier configuration and the phase noise in such a system is studied. An effective method of coherently combining the elements in such an array is LOCSET. A potential drawback to the effectiveness in LOCSET is the increased phase noise that is present in higher power amplifiers. The theory of LOCSET and the impact of this noise on LOCSET is researched. A mathematical model is developed to study this issue. The theory of phase noise and linewidth broadening due to amplified spontaneous emission is presented. Previous research on the magnitude of phase noise in ytterbium doped fiber amplifier is investigated and compared to the phase noise measurements at the AFRL high power fiber test bed. Phase noise measurements from the AFRL high power fiber test bed are provided to support this research and these data are analyzed in both an open loop configuration and when the control loop is closed by LOCSET. The ability of LOCSET to reduce this noise is analyzed and compared to the predicted results from LOCSET model.

Degree Name

Optical Science and Engineering

Level of Degree


Department Name

Optical Science and Engineering

First Advisor

Thomas, James

Second Advisor

Shay, Thomas

First Committee Member (Chair)

Diels, Jean-Claude


Army Research Laboratory-Sensors and Electronic Devices Division Department of Defense High Energy Laser Joint Technology Office Air Force Research Laboratory-Laser Division-Solid State and Fiber Laser Branch

Document Type