Sensitivity–bandwidth product for electro-optic modulators

For lumped-element electro-optic modulators, the sensitivity ( partial differentialphi/ partial differentialV) of the phase, phi , in response to an applied voltage V is related to the optical group delay, T(g) , and the bandwidth, Domega . This relationship imposes a fundamental trade-off between the sensitivity and the bandwidth of electro-optic modulators: ( partial differentialphi/ partial differentialV)Domega= (dn/dV)(omega /n) , where n is the optical index. A similar relationship for traveling-wave modulators sets an upper limit on ( partial differentialphi/ partial differentialV) that is proportional to T(g) .