An investigation on the characteristics of core and inner cladding of few-mode double-clad optical fibers on the linearly polarised mode cut-off V-values

Using a numerical method, the normalised cut-off V-values (V_cut-off) of a few lower order linearly polarised (LP) modes of a graded-index few-mode double-clad fiber have been calculated. The order of appearance of the LP modes of these fibers holds significant importance to the fiber parameters. The knowledge of the calculation of V_cut-off values for these modes is essential for designing few-mode double-clad fiber devices. In this work, a detailed analysis has been made for calculating V_cut-off values in a few-mode double-clad optical fiber for the first eight modes. Such fibers are essential for the dispersion compensating system, fiber amplifiers, sensors and other communication networks and hence calculation of such mode cut-offs is very important.