Progress and Summary of Photodarkening in Rare Earth Doped Fiber

Abstract

In this paper, we summarize the research on photodarkening in optical fibers. The causes of photodarkening in fiber, the influence of photodarkening on fiber laser, the experimental device of photodarkening, and the mathematical model used to study the phenomenon of photodarkening are described in detail. At the end of the paper, we summarize the means and methods to suppress photodarkening.

Keywords

• photodarkening (PD)
• excited-state absorption (ESA)
• energy transfer upconversion (ETU)
• avalanche upconversion
• cooperative luminescence
• photobleaching (PB)