Abstract

Electro-optic (EO) modulators commonly use lithium niobate (LiNbO₃) as the substrate because of its high EO coefficient. However, LiNbO₃ is dispersive, so the optical and electrical signals have different propagation times along the modulator electrodes. If this time difference is not very short compared with a period at the modulation frequency there will be an averaging effect that will reduce the net modulation. This gives rise to the well-known sine-function frequency response of traveling-wave EO modulators. For a modulator to be effective at high frequency, the electrodes must be kept short; this, in turn, reduces the sensitivity of the modulator.

© 1992 Optical Society of America