Abstract

Lasers in the eye-safe 2μm spectral region are attracting significant interest in both research and industry as enabling technology for numerous sensing, spectroscopy, and materials processing applications, as well as for nonlinear frequency conversion. As a key pumping source of 2μm, the Tm³⁺-doped fiber lasers operating at 1908nm has a rapid development in recent years. Thulium is a quasi three level laser which suffers from strong ground-state absorption and significant reabsorption loss below 1.95μm which can create challenges for 1908nm operation often observed as instabilities [1, 2].

© 2015 IEEE