Researchers from the University of Illinois and Clemson have developed highly rare earth doped optical fiber. This optical fiber . This optical fiber contains a high concentration of Yb. In the highly doped Yb fiber, At high rare earth (Yb) concentrations, Yb no long radiates light and optical pumping power is efficiently converted into thermal energy. The highly Yb doped fiber forms the basis of an efficient micro heating element. This micro heating element has the potential for use as a micro cauterization tool.