Fiber Fuse Propagation Characteristics of LP01 and LP11 Modes in Few-Mode Fiber

We observe fiber fuse propagation in the LP11 mode in few-mode fiber by selective propagation mode launching via a PLC-based mode multiplexer. We focus on two fiber fuse propagation parameters, namely, the propagation power threshold P-th, and the diameter of the melted area Dmelted. We confirm experimentally that P-th in the LP11 mode was higher than that in the LP01 mode. P-th of the LP01 and LP11 modes increases linearly with the Gaussian beam width, which is similar to the dependence of the mode field diameter of P-th in the LP01 mode. We also find a specific relationship between the power density and Dmelted normalized by the Gaussian beam width regardless of input mode conditions and fiber type. Therefore, we believe that we can utilize the Gaussian beam width of the near field pattern of the LP01 and LP11 modes for predicting the characteristics of fiber fuse propagation in both modes.