Deep quantum well electro-absorption modulator
AssigneeAvago Technologies Fiber IP (Singapore) Pte. Ltd.
InventorsDavid P. Bour, Ashish Tandon, Michael R. T. Tan
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Abstract
Double well structures in electro-absorption modulators are created in quantum well active regions by embedding deep ultra thin quantum wells. The perturbation introduced by the embedded, deep ultra thin quantum well centered within a conventional quantum well lowers the confined energy state for the wavefunction in the surrounding larger well and typically results in the hole and electron distributions being more confined to the center of the conventional quantum well. The extinction ratio provided by the electro-absorption modulator is typically increased.
Claims20
An electro-absorption modulator comprising:
- a substrate;
- a plurality of semiconductor layers formed on said substrate;
- one of said plurality of semiconductor layers comprising a first quantum well region having a first composition;
- and
- a second quantum well region having a second composition, said second quantum well region being embedded in said first quantum well region;
- wherein the second quantum well region embedded in the first quantum well region results in an increase in spatial overlap of the hole and electron wave functions;
- wherein the increase in spatial overlap of the hole and electron wave functions increases the quantum well absorption.
A method for an electro-absorption modulator comprising:
- providing a substrate;
- forming a plurality of semiconductor layers on said substrate wherein
- one of said semiconductor layers comprises a first quantum well region having a first composition;
- and
- embedding a second quantum well region in said first quantum well region, said second quantum well region having a second composition;
- wherein the second quantum well region embedded in the first quantum well region results in an increase in spatial overlap of the hole and electron wave functions;
- wherein the increase in spatial overlap of the hole and electron wave functions increases the quantum well absorption.
Dependencies are inferred from the claim text.