Infrared modulator, optical device including the infrared modulator, and optical computing system including the optical device

1 . An optical device comprising:

a silicon substrate;

an infrared modulator on the silicon substrate; and

a photodetector on the silicon substrate and electrically connected to the infrared modulator,

wherein the infrared modulator comprises:

a multiple buffer layer on the silicon substrate, the multiple buffer layer comprising indium phosphide (InP);

a first type semiconductor layer on the multiple buffer layer, the first type semiconductor layer comprising InP;

a light absorption layer on the first type semiconductor layer, the light absorption layer comprising a quantum well structure comprising indium gallium arsenic phosphide (InGaAsP); and

a second type semiconductor layer on the light absorption layer, the second type semiconductor layer comprising InP, and

wherein the photodetector comprises:

the multiple buffer layer of the infrared modulator;

a portion of the first type semiconductor layer;

a portion of the second type semiconductor layer; and

a second light absorption layer comprising GaAs, the second light absorption layer being continuously disposed between the first type semiconductor layer and the second type semiconductor layer.

2 . The optical device of claim 1 , wherein the multiple buffer layer comprises:

a first layer comprising germanium (Ge);

a second layer on the first layer, the second layer comprising gallium arsenide (GaAs);

a third layer on the second layer, the third layer comprising a superlattice structure comprising pairs of an aluminum arsenide (AlAs) layer and a GaAs layer that are stacked a plurality of times; and

a fourth layer on the third layer, the fourth layer comprising InP.

3 . The optical device of claim 2 , wherein a thickness of the first layer is greater than or equal to 0.1 μm and less than or equal to 5 μm.

4 . The optical device of claim 2 , wherein a thickness of the second layer is greater than or equal to 0.1 μm and less than or equal to 5 μm.

5 . The optical device of claim 2 , wherein each of the AlAs layer and the GaAs layer of the third layer has a thickness greater than or equal to 1 nm and less than or equal to 10 nm.

6 . The optical device of claim 2 , wherein a thickness of the fourth layer is greater than or equal to 0.5 μm and less than or equal to 20 μm.

7 . The optical device of claim 1 , further comprising:

a first cladding layer between the first type semiconductor layer and the light absorption layer, the first cladding layer comprising indium (In), gallium (Ga), arsenide (As), and phosphide (P), and a bandgap energy of the first cladding layer being greater than a bandgap energy of a quantum barrier layer; and

a second cladding layer between the light absorption layer and the second type semiconductor layer, the second cladding layer comprising In, Ga, As, and P, and a bandgap energy of the second cladding layer being greater than the bandgap energy of the quantum barrier layer.

8 . The optical device of claim 7 , wherein the quantum well structure comprises In x Ga y As w P z , where x+y=z+w=1, 0.4≤x≤0.6, and 0.5≤z≤1.0,

wherein the quantum barrier layer comprises In x Ga y As w P z , where x+y=z+w=1, 0.5≤x≤0.7, and 0.5≤z≤0.8, and

wherein each of the first cladding layer and the second cladding layer comprises In x Ga y As w P z , where x+y=z+w=1, 0.65≤x≤0.85, and 0.4≤z≤0.6.

9 . The optical device of claim 1 , wherein the light absorption layer is configured to transmit or absorb light having a wavelength of 1,550 nm, based on a voltage applied between the first type semiconductor layer and the second type semiconductor layer.

10 . The optical device of claim 1 , further comprising an amplifier on the silicon substrate, the amplifier being configured to amplify light transmitted through the infrared modulator.

11 . The optical device of claim 1 , further comprising an optical waveguide on the silicon substrate, the optical waveguide being configured to branch and guide an incident light to the photodetector and the infrared modulator.

12 . An optical computing system comprising:

a light source;

an optical device configured to output a decision signal based on a type of a light input from the light source; and

a processor configured to adjust an input signal to the optical device and process an output from the optical device,

wherein the optical device comprises:

a silicon substrate;

an infrared modulator on the silicon substrate; and

a photodetector on the silicon substrate, the photodetector being electrically connected to the infrared modulator, and

wherein the infrared modulator comprises:

a multiple buffer layer comprising indium phosphide (InP);

a first type semiconductor layer on the multiple buffer layer, the first type semiconductor layer comprising InP;

a light absorption layer on the first type semiconductor layer, the light absorption layer comprising a quantum well structure comprising indium gallium arsenic phosphide (InGaAsP); and

a second type semiconductor layer on the light absorption layer, the second type semiconductor layer comprising InP, and

wherein the photodetector comprises:

the multiple buffer layer of the infrared modulator;

a portion of the first type semiconductor layer;

a portion of the second type semiconductor layer; and

a second light absorption layer comprising GaAs, the second light absorption layer being continuously disposed between the first type semiconductor layer and the second type semiconductor layer.

13 . The optical computing system of claim 12 , wherein the photodetector comprises the multiple buffer layer of the infrared modulator.

14 . The optical computing system of claim 12 , further comprising at least one optical circuit on the silicon substrate and optically connected to an input terminal of the optical device or an output terminal of the optical device.

15 . The optical computing system of claim 12 , wherein the multiple buffer layer comprises:

a first layer comprising germanium (Ge);

a second layer on the first layer, the second layer comprising gallium arsenide (GaAs);

a third layer on the second layer, the third layer comprising a superlattice structure comprising pairs of an aluminum arsenide (AlAs) layer and a GaAs layer that are stacked a plurality of times; and

a fourth layer on the third layer, the fourth layer comprising InP.

16 . The optical computing system of claim 12 , further comprising:

a first cladding layer between the first type semiconductor layer and the light absorption layer, the first cladding layer comprising indium (In), gallium (Ga), arsenide (As), and phosphide (P), and a bandgap energy of the first cladding layer being greater than a bandgap energy of a quantum barrier layer; and

a second cladding layer between the light absorption layer and the second type semiconductor layer, the second cladding layer comprising In, Ga, As, and P, and a bandgap energy of the second cladding layer being greater than the bandgap energy of the quantum barrier layer.