Pb2+/Al3+ codoped germano-silicate optical fiber with high non-resonant third-order nonlinearity

A germano-silicate optical fiber codoped with Pb2+ and Al3+ was developed by modified chemical vapor deposition and solution doping techniques. The non-resonant third-order optical nonlinearity was measured to be 6.9105 × 10−20 m2/W by using the continuous-wave self-phase modulation method. The enhanced non-resonant nonlinearity was ascribed to the increasing number of non-bridging oxygens due to the incorporation of the glass modifiers Pb2+ and Al3+, the large molar refraction from heavy metal ions Pb2+, and the enhanced hyper-polarization from PbO doped into the core of the made fiber.