Hi Umer,
For the design of ring resonator , the circuit must be divided at least into four elements namely, the two coupling regions and several bent elements. They are symmetrical, so you can simulate just one using OptiBPM as mentioned by Asif. you also have to describe the phase delay (perhaps also losses) in the bent arcs. The realistic ring resonator design and its representation in OptiSystem can be done by Co-simulation with OptiBPM. You can refer to link https://optiwave.com/optibpm-manuals/bpm-ring-resonator/
Regards