Modulation doped quantum well waveguide modulator

Claim 2

A modulation doped quantum well waveguide modulator comprising, in combination: a) a first thin planar GaAs quantum well layer; b) a second thin Al x Ga 1-x As barrier layer disposed atop said GaAs quantum well layer; c) a third thin AlGaAs barrier layer disposed atop said Al x Ga 1-x As barrier layer, wherein x is equal to or greater than 20%; d) a silicon doped N region disposed in the center of said Al x Ga 1-x As barrier layer.

Claim 3

The device of claim 1 wherein said layers of GaAs, Al x Ga 1-x As and AlGaAs are coextensive with one another.

Claim 4

The device of claim 1 wherein said GaAs quantum well layer has a thickness of about 150 Å; said Al x Ga 1-x As barrier layer has 100 Å regions on either side of said silicon doped N region.

Claim 5

The device of claim 2 wherein said GaAs quantum well layer has a thickness of about 150 Å; said Al x Ga 1-x As barrier layer has 100 Å regions on either side of said silicon doped N region.

Claim 6

The device of claim 1 wherein said AlGaAs layer has a higher barrier than that of said Al x Ga 1-x As layer.

Claim 7

The device of claim 3 wherein said AlGaAs layer has a higher barrier than that of said Al x Ga 1-x As layer.

Claim 8

The device of claim 6 wherein said layers of GaAs, Al x Ga 1-x As and AlGaAs are coextensive with one another.

Claim 9

The device of claim 1 which contains a plurality of sets of said first, second and third layers.

Claim 10

The device of claim 8 wherein said layers of GaAs, Al x Ga 1-x As and AlGaAs are coextensive with one another.

Claim 11

The device of claim 9 wherein said GaAs quantum well layer has a thickness of about 150 Å; said Al x Ga 1-x As barrier layer has 100 Å regions on either side of said silicon doped N region.

Claim 12

The device of claim 9 wherein said AlGaAs layer has a higher barrier than that of said Al x Ga 1-x As layer.

Claim 13

The device of claim 8 which further has a layer of P type cladding on top of the free surface of said AlGaAs layer, and a layer of N type cladding on the bottom of said layer of said third AlGaAs.

Claim 14

The device of claim 2 which further has a layer of P type cladding on top of the free surface of said AlGaAs layer, and a layer of N type cladding on the bottom of said layer of said third AlGaAs.

Claim 15

The device of claim 3 which further has a layer of P type cladding on top of the free surface of said AlGaAs layer, and a layer of N type cladding on the bottom of said layer of said third AlGaAs.

Claim 16

The device of claim 5 which further has a layer of P type cladding on top of the free surface of said AlGaAs layer, and a layer of N type cladding on the bottom of said layer of said third AlGaAs.

Claim 17

An electron-transfer modulation doped, quantum well, waveguide phase modulator comprising: an active modulation doped multiple quantum well waveguiding core formed of alternating layers of AlGaAs and GaAs; a p-type doped AlGaAs cladding region disposed on one side of said waveguiding core; an n-type doped AlGaAs cladding region disposed on the other side of said waveguiding core; and an n-type GaAs substrate disposed adjacent said n-type doped cladding region, wherein the waveguiding core includes a plurality of layers which each contain: (a) a planar GaAs undoped quantum well layer between 100 Å and 200 Å in width; (b) a first undoped Al x Ga 1-x As barrier between 100 Å and 200 Å, wherein x is greater than 20% and wherein said first undope barrier serves as a spacer layer which is disposed below said quantum well layer; (c) an n-type Si-doped Al x Ga 1-x As barrier between 200 Å and 400 Å in width, wherein said Si-doped barrier is disposed under said first undoped barrier and is doped to approximately 1-5×10 18 cm -3 ; (d) a second undoped Al x Ga 1-x As barrier approximately 50 Å in width, said second undoped barrier being disposed below the Si-doped barrier; (e) a second doped Al y Ga 1-y As wherein y≧x+5% and wherein said second undoped barrier is disposed below the second undoped barrier and is approximately 500 Å; and (f) an interim undoped Al y Ga 1-y As barrier which is approximately 500 Å; wherein said interim layer is disposed between said p-type cladding region and the waveguiding core.

Claim 18

An electron-transfer modulation doped, quantum well, waveguide phase modulator comprising: an active modulation doped multiple quantum well waveguiding core formed of alternating layers of AlGaAs and GaAs; a p-type doped AlGaAs cladding region disposed on one side of said waveguiding core; an n-type doped AlGaAs cladding region disposed on the other side of said waveguiding core; and an n-type GaAs substrate disposed adjacent said n-type doped cladding region, wherein the waveguiding core includes a plurality of layers which each contain: (a) a planar GaAs undoped quantum well layer between 100 Å and 200 Å in width; (b) a first undoped Al x Ga 1-x As barrier between 100 Å and 200 Å, wherein x is greater than 20% and wherein said first undope barrier serves as a spacer layer which is disposed below said quantum well layer; (c) an n-type Si-doped Al x Ga 1-x As barrier between 200 Å and 400 Å in width, wherein said Si-doped barrier is disposed under said first undoped barrier and is doped to approximately 1-5×10 18 cm -3 ; (d) a second undoped Al x Ga 1-x As barrier approximately 50 Å in width, said second undoped barrier being disposed below the Si-doped barrier; (e) a second doped Al y Ga 1-y As wherein y≧x+5% and wherein said second undoped barrier is disposed below the second undoped barrier and is approximately 500 Å; and (f) an interim undoped Al y Ga 1-y As barrier which is approximately 500 Å; wherein said interim layer is disposed between said p-type cladding region and the waveguiding core.

Claim 19

An electron-transfer modulation doped, quantum well, waveguide phase modulator comprising: an active modulation doped multiple quantum well waveguiding core formed of alternating layers of AlGaAs and GaAs; a p-type doped AlGaAs cladding region disposed on one side of said waveguiding core; an n-type doped AlGaAs cladding region disposed on the other side of said waveguiding core; and an n-type GaAs substrate disposed adjacent said n-type doped cladding region, wherein the p-type cladding region includes a 1 to 1.5 micrometer AlGaAs p-type beryllium doped layer wherein a AlAs fraction is larger than y, a second p + -type doped AlGaAs layer which is 1000 Å in width, and thin p + -GaAs layer which serves as a cap layer.

Claim 20

An electron-transfer modulation doped, quantum well, waveguide phase modulator comprising: an active modulation doped multiple quantum well waveguiding core formed of alternating layers of AlGaAs and GaAs; a p-type doped AlGaAs cladding region disposed on one side of said waveguiding core; an n-type doped AlGaAs cladding region disposed on the other side of said waveguiding core; and an n-type GaAs substrate disposed adjacent said n-type doped cladding region, wherein the p-type cladding region includes a 1 to 1.5 micrometer AlGaAs p-type beryllium doped layer wherein a AlAs fraction is larger than y, a second p + -type doped AlGaAs layer which is 1000 Å in width, and thin p + -GaAs layer which serves as a cap layer.