Frequency chirp in optical reflection modulators

Pulse broadening produced by positive frequency chirping resulting from the intensity modulation processes used in optical communications limits the maximum achievable transmission distance. Although compensation schemes have been the subject of much research any improvements possible at the initial modulation stage will further enhance system performance. In the present paper the chirping behaviour of resonant modulators is considered and an expression analogous to the chirp parameter given. Using the example of an InGaAsP Franz-Keldysh effect reflection modulator the chirp introduced by a resonant device is quantified and the implications of the results considered