Two coupled exciton-polariton condensates (EPCs) in a double-well photonic potential are suggested to form the optical Josephson oscillation (JO) whose dependences on the pump arrangement, the potential geometry, and the exciton-photon detuning are studied through the Gross-Pitaevskii equations. When the pump detuning is slightly positive with respect to the polariton energy and the phase difference between the two EPCs is near π/2 (both are controlled by the pump beams), the system demonstrates the optical JO. The optical JO tunneling strength (J) depends on the distance (d) and barrier (
Λ
) between the two wells, for which an empirical formula is fitted, i.e.,
J
≈
0.42
exp
(
−
d
Λ
/
18.4
)
with the energy and length units in meV and μm. Since the double-well potential adopted is general, this fitting relation can show a guidance in practice for designing the optical devices based on the optical JO.