Publikationsserver der RWTH Aachen University
Untersuchung zur thermischen Gestaltung von Hochleistungsfaserlasern
Abstract
dc:descriptionA fundamental limit for the scaling of the output power of fiber lasers is the heat generated in the core of the active fiber and fiber components. In this work the heat generation in fiber laser components is examined and means for heat removal are analyzed. To determine the heat load in the active fiber the temperature is measured along the fiber. The heat transport is examined with two models: A one-dimensional model allows the analytical study of the subject. The thermal resistances of the individual fiber layers are determined to examine how the fiber design affects the heat transport. Furthermore the convective cooling of the fiber is evaluated and interacting groups of fiber layers are optimized for the heat transport. To optimize the fiber cooling two- and three-dimensional models of the fiber are generated and experimentally verified. With the models a cooling scheme for the fiber is designed which avoids the direct contact of the fiber with water but provides a heat removal comparable to convective water cooling up to a heat load of 150 W/m. The heat sink is optimized using the one-dimensional model. The results of the temperature measurements are used to analyze the thermo-optical effects in the fiber. It is shown, that their influence on the modal properties of the fiber is an order of magnitude smaller than the effects from bending the fiber for mode selection. Furthermore the thermal characteristics of splices, fiber Bragg gratings and a new concept for pump fiber coupling are analyzed. Temperature measurements like on the active fiber allow conclusions concerning the causes of the heat generation. As an example a cooling scheme for splices is analyzed which allows the removal of local heat loads up to 4000 W/m. Thus a cooling scheme for fiber integrated resonator with up to 2 kW output power is developed. The method applied to the design process is presented in a way which allows the transfer and application to other configurations and powers of fiber lasers.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2008
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Zintzen, Bernhard
- Contributors dc:contributor
-
- Loosen, Peter
Subjects
dc:subject × 17Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger