Mid-IR fiber amplifier cooled with Yb3+ ions

Abstract

Stimulated Raman scattering (SRS) in optical fibers is a well-known method of signal amplification in Raman amplifiers and lasers for the generation a wide range of wavelengths. Today, there are a large number of applications requiring high power beams at wavelengths longer than 2 μm, and non-oxide based glass fibers with low phonon energies and high infrared transparency are very attractive for applications in this region. Fluoride, tellurite, and chalcogenide fibers are the best choices for this purpose. An important issue in high power fiber based Raman amplification (RA) is the heat generated inside the active medium due to the quantum defect between the pump and the amplified wavelengths. The increase in the temperature of the laser medium can detrimentally affect laser performance, by degrading the quality of the amplified beam, causing a decrease in the efficiency of the process, thermal lensing and self focussing. The cooling of the laser medium is a key issue for improving laser performance and increasing the laser's lifetime. Mitigation of the heat generated in Raman lasers using coherent anti-Stokes Raman scattering has been suggested in Ref. [1].