||T. H. Wood, C. A. Burrus, D. A. B. Miller,
D. S. Chemla, T. C. Damen, A. C. Gossard and W. Wiegmann "High-Speed Optical
Modulation with GaAs/GaAlAs Quantum Wells in a p-i-n Diode Structure," Proc. IEEE
Int. Electron Devices Meeting, December 1983, Washington, D.C.
A new type of high
speed optical modulator is proposed and demonstrated. An electric field is applied
perpendicular to GaAs/GaAlAs multiple quantum well layers using a "p-i-n" diode
doping structure of 4 um total thickness. The optical absorption edge, which is
particularly abrupt because of exciton resonances, shifts to longer wavelengths with
increasing field giving almosta factor of 2 reduction in transmission at 857 nm with 8V
reverse bias. The shifts are ascribed to changes in carrier confinement energies in the
wells. The observed switching time of 2.8 ns is attributed to RC time constant and
instrumental limitations only, and fundamental limits may be much faster.