Wavelength-tunable sources are important for applications such as fiber optics sensing, medical instrumentation, and optical communication. A tunable source design can use a Fabry-Perot (FP) cavity configuration with a tunable filter inserted into the system. In this work we experimentally demonstrated a wavelength-tunable fiber laser by the use of a PM-Er:Yb double-clad fiber placed in a FP cavity formed by two Dichroic Mirrors (DM). Our pump laser wavelength was 976 nm and the maximal output power from this laser that we can introduce to the fiber was 20 W. To get wavelength tunability we included a Diffractive Grating (DG) with 600 l/mm in our laser cavity. The zero order reflection from the DG is the output coupler and the first order diffracted beam is reflected back into the fiber using a DM. We included a half-wave plate and a polarizer in the cavity to increase the stability of the continuous wave laser operation and also to impose a linear polarization at the laser output. With this configuration we can tune the wavelength from 1535 to 1567 nm by rotating a DM at a rate of 0.02 degrees/nm. With our configuration wide tunability was possible only when we used fiber lengths between 2.5 and 3.6 m. The maximal output power was 850 mW using 3.6 m of fiber length. We believe that a Q-switched extension of this source can be used in nonlinear optics applications, such as Terahertz generation.

Date Published: 17 May 2010
PDF: 6 pages
Proc. SPIE 7721, Solid State Lasers and Amplifiers IV, and High-Power Lasers, 77211A (17 May 2010); doi: 10.1117/12.854394

Published in SPIE Proceedings Vol. 7721:
Solid State Lasers and Amplifiers IV, and High-Power Lasers
Thomas Graf; Gerhard G. Paulus; Jacob I. Mackenzie; Vincent Bagnoud; Catherine Le Blanc; Helena Jelinková, Editor(s)