The finesse and Q factor physical implication are related to the round trips number that energy makes within the resonator prior to being lost internally and the wave guides of the bus. This phenomenon has temporary nature and should be looked into with response of transient manner. Within a Q factor, the finesse is such that it depicts the round trip number made though the rings light prior to the reduction of energy by 1/e of its original value. This factor is furthermore responsible for representing the oscillation number within the field prior to energy circulation starts depleting by 1e of the original value of energy. For defining this factor, excitation of micro-ring is done to a specific level and the power decay rate is taken into consideration. From this perspective, it can be depicted that losses in round trip along with directional couplers coupling effect are factors of loss which requires to be decreased for obtaining resonances with higher Q (Hausmann et al., 2013). Henceforth, a resonator with all pass will require exhibiting a high Q factor in comparison to the resonators with added drop wherein the devices are operating in a closer manner to the essential coupling. It is possible to differentiate between Q factors which are loaded with the one which is unloaded. The resonators unloaded Q factor is the factor when resonator does not have any coupling with the waving guides. When coupling is done with the wave guides, more losses get introduced for the cavity. Therefore, this loaded Q is small in comparison to the Q which is unloaded.
Finesse or F is the FSR ratio and the resonance width for a particular wave length. Quality factor is closely related to Finesse which is the resonance sharpness measure and is defined as the resonance width ratio with the operation wavelength (Matere et al., 2016).
Q factor further can be regarded as the energy storage divided through the optical cycle with each power loss. The ring resonator intensity can be high than within the wave guides of the bus. This is because the wave of travelling within the resonator forms an interference with the input wave of the resonance constructively. Therefore, amplitude results in building up. Additionally, to this increase in the intensity, the field further results in experiencing integral 2pie multiple within individual round trip. The increase in intensity or the factor B of the build-up is further essential.