Patent ID: 7425726

Claim:
An electroabsorption modulator, comprising: first and second electrodes; first and second cladding regions between the first and second electrodes; an active region between the first and second cladding regions and including a light absorption region located between an upper portion and a lower portion of the active region; and a tunnel junction structure between the active region and one of the first and second cladding regions comprising an n-type semiconductor layer and a p-type semiconductor layer, wherein the n-type semiconductor layer and the p-type semiconductor layer are characterized by respective depletion layer thicknesses x n and x p in thermal equilibrium, the n-type semiconductor layer has a thickness t n of at least about 0.9·x n and less than about 2.0·x n , and the p-type semiconductor layer has a thickness t p of at least about 0.9·x p and less than about 2.0·x p .