We derive general equations to calculate the electrooptically induced optical phase shift in resonantly enhanced modulators. The equations are useful in designing modulator electrodes with optimal length and optimal mismatch between electrical and optical velocities. We demonstrate the existence of an optimal velocity mismatch depending on the resonant mode used.
Collado, C.; Menéndez, O.; Santos, M. C.; Mateu, J.; O'Callaghan, J. General equations for the induced phase shift in resonant electro-optic modulators. IEEE Photonics technology letters, 2005, vol. 17, núm. 2, p. 330-332.