Abstract

It has been demonstrated that the absorption coefficient in doping superlattices or n-i-p-i structures can be modulated with very low-intensity light.^1,2 Unfortunately the changes have been relatively modest. On the other hand, semiconductor multiple-quantum-well structures (MQWSs) have large optical nonlinearities but require larger excitations.^3,4 A structure which combines the advantages of both n-i-p-i structures and multiple quantum wells is the hetera n-i-p-i, a periodic arrangement of n-type and p-type layers with undoped layers of smaller band-gap material inserted.⁵ In a conventional hetero n-i-p-i, single quantum wells are separated by doped wideband gap regions of comparable width.

© 1988 Optical Society of America