Lally, Evan M.2014-03-142014-03-142006-08-11etd-08242006-115533http://hdl.handle.net/10919/34739Linewidth is a measure of the frequency stability of any kind of oscillator, and it is a defining characteristic of coherent lasers. Narrow linewidth laser technology, particularly in the field of fiber-based infrared lasers, has progressed to the point where highly stable sources are commercially available with linewidths on the order of 1-100 kHz. In order to achieve a higher level of stability, the laser must be augmented by an external frequency stabilization system. This paper presents the design and operation of a frequency locking system for infrared fiber lasers. Using the Pound-Drever-Hall technique, the system significantly reduces the linewidth of an input laser with an un-stabilized linewidth of 2 kHz. It uses a high-finesse Fabry-Perot cavity, which is mechanically and thermally isolated, as a frequency reference to measure the time-varying frequency of the input laser. An electronic feedback loop works to correct the frequency error and maintain constant optical power. Testing has proven the Pound-Drever-Hall system to be highly stable and capable of operating continuously for several seconds at a time.In CopyrightLinewidthPound-Drever-HallFabry-PerotLaserInfraredFiberFrequency NoisePhase LockStabilizationThesishttp://scholar.lib.vt.edu/theses/available/etd-08242006-115533/