Ring Resonator has become one of the most interesting research topics nowadays since this device has high finesse value at resonance frequency and high sensitivity as well. There have been many scientific publications in the device's characteristic dynamic conditions, structures (single, multi and combination), and their applications as well, such as sensors, filters and others. The performance characteristics of double coupler structured single ring resonator has been discussed so far but the effect of coupling coefficient variation has not been discussed yet. Meanwhile, in previous research we have investigated the effect of coupling coefficient variation on single coupler structured single ring resonator. Now, we explore further the effect of coupling coefficient variation on the power transfer function output of a double couplers structured single ring resonator. Besides, single beam and double beams inputs are utilized to get the transmission powers as the output characteristics from both of drop and through ports of the ring resonator. The simulation results show, for the drop port output, as the higher coupling coefficient is, the peak of the power transfer function output gets higher for both the drop port output of single beam input and double counter directional inputs, but the double counter directional inputs, shows the peak of the power transfer function output much higher compared to its of the single beam input. Meanwhile for through port output, the result with double parallel inputs configuration shows a bit different behavior with its of single beam configuration, where as the result of the double parallel input configuration exhibits peak of the power transfer output almost similar to the simulation result utilizing single ring resonator with single coupler configuration that has already published previously. This simulation works may be useful in the design of resonator performance when transmission power is one of the important parameters to be considered.