Q-Switched and Mode Locked Short Pulses From a Diode Pumped, YB-Doped Fiber Laser
Swift, Seth M.
Synopsis "Q-Switched and Mode Locked Short Pulses From a Diode Pumped, YB-Doped Fiber Laser"
A diode-pumped, ytterbium (Yb)-doped fiber laser system was designed and demonstrated to operate in continuous wave (cw), passively Q-switched and possibly passively mode locked operation. To our knowledge, this was the first fiber laser oscillator built at the Air Force Institute of Technology. A Cr4+: YAG (Chromium: Ytterbium Aluminum Garnett) crystal was used as a saturable absorber to generate Q-switched pulses. Attempts to mode lock the laserwere performed using a semiconductor saturable absorber mirror (SESAM) and through nonlinear polarization rotation (NPR). The best output power result was 5 Watt (W) while pumping at 8.3 W, yielding 60% efficiency and peak spectral outputs between 1087-1108 nm. Passive Q-switched pulses were generated using the Cr4+: YAGcrystal with a mean width of 2.9 s and repetition rates between 60-150 kHz. This corresponded to pulse energies of 7-24 and peak powers twice as high as the average power. Q-switched and possible mode locked pulses were generated using NPR. Q-switched pulse widths ranged between 1.8-2.8 with repetition rates between 29-72 kHz. Mode locked pulse widths were 10.5 ns with a repletion rate of 17.2 MHz. Mode locking was not achieved using the SESAM, but the results that resemble mode beating are presented, and causes for error were analyzed.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
