A procedure is described to accurately measure the self phase-tuning in a coupled fiber laser. A fiber is designed and fabricated to eliminate the effects of self-tuning from wavelength shifting, thermal expansion, and thermally induced index change, allowing us to study the phase effects produced by Kramers-Kronig phase shifting as a function of various cavity parameters. For sufficient pump power, we observe that the Kramers-Kronig effect is capable of compensating for all path length errors introduced into the cavity, resulting in efficient lasing under all path length conditions. We have directly measured the Kramers-Kronig-induced phase shift and present experimental evidence that this additional phase compensates for the applied phase error and promotes efficient lasing.

Date Published: 7 March 2014
PDF: 7 pages
Proc. SPIE 8960, Laser Resonators, Microresonators, and Beam Control XVI, 89601E (7 March 2014); doi: 10.1117/12.2042910

Published in SPIE Proceedings Vol. 8960:
Laser Resonators, Microresonators, and Beam Control XVI
Alexis V. Kudryashov; Alan H. Paxton; Vladimir S. Ilchenko; Lutz Aschke; Kunihiko Washio, Editor(s)