High Efficiency Erbium/Ytterbium (Er/Yb) Doped Fibers for Eye-safe Fiber Laser Sources

We propose a new process, distinct from conventional vapor deposition that overcomes limitations which plague current glass fabrication methods. Specifically, these limitations include level of co-dopant concentration, precision in control of dopant concentration and homogeneity, and size of core and cladding regions. These parameters are known to affect slope efficiency and other critical operating parameters of Er/Yb double clad fiber lasers. It is expected that this new process can achieve Er/Yb and co-dopant levels not normally achievable by vapor deposition and that these levels are required to achieve the required high slope efficiencies. This new process also allows precise control of refractive index critical for large core fibers. Amorphous nano-sized particles are prepared by a modified sol-gel process. These are subsequently deposited from an organic-slurry by electrophoresis to form the core and primary cladding of an optical fiber preform. Separation of the glass formation and deposition processes allows greater compositional diversity with precise dopant control, more homogeneous glass and increased quantity of core and cladding.