Purpose of this research is that capillary optic fiber transmission and energy distribution of internal energy. Contains only single from the initial silica capillary fiber energy transfer within the simulation, and then changing the different input conditions (different incident angles, multi- mode and single mode) optical observation of the capillary wall modes and modal distribution between hole mode. Mode simulation, containing only the capillary in the simple addition of a layer of high-dielectric fiber optic ring to change its transmission mechanism, by analog control of its high dielectric ring geometry (thickness) of air holes the size of its hole mode can simulate the type of transmission mode number. By single-and double- layer energy transfer capillary mode simulation and modal changes in different input conditions, and further understanding of the capillary mode fiber transmission characteristics. Combining the concept of adding fiber coupler and single-mode optical fiber capillary to produce a new original, and then by capillary tube method to make thick plugs can be more convenient and rapid production of a new type of coupler components.