High laser power levels combined with increasing beam quality bring optics performance into focus. The subject of
optics performance is a hot topic, but lack of a common nomenclature, as well as of proper measurements, makes the
situation confusing. This paper will introduce a nomenclature for comparing the performance of different types of optics.
Further, the paper will present a test setup for characterizing optics, along with test results for different optics materials
and designs. The main influence of high power levels on optics is a focal shift along the optical axis. In industrial
applications, this might influence the performance of the process, especially if the focal shift is in the range of the
Rayleigh length. In the test setup that is to be presented, the optics are exposed to a high power beam, and a pilot beam is
used for measuring the change in focal position. For a proper description of optics performance, the laser beam
parameters should not influence the measured results. In the nomenclature that will be presented, the performance is
related to the Rayleigh length for a fundamental mode beam. The performance of optics when used with multimode
beams will be presented.
For high power laser applications where optical fibers are used the main problem is to keep the power losses as small as possible. To fullfill this demand it is important to utilize the power from the laser efficently and avoid damages on the fiber due to high temperature caused by radition outside the fiber core.
Thererfor the design has to be made in a robust way that protect the fiber from damages caused by the high power.
Depending on the beam quality from the laser two different kind of fibers have to be used, a fiber with polymer cladding for high NA and silica cladded fibers for lower NA. In both cases the core is made of fused silica. Since there is always some radiation not keept within the fibre core the cooling is of great importance. The radiation can be caused by scattering light from the beam itself or from back reflection in the application.
Different kind of design used to keep the power losses as small as possible as well as design of efficient cooling systems will be discussed in this paper. Experimental results from our development of optical fibers will be present.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.