KR102730847B1 - single-photon source device and single-photon source system including the same - Google Patents

Abstract

The present invention discloses a single-photon light source device and a single-photon light source system including the same. The device includes a substrate, a straight waveguide extending in one direction on the substrate, a first coupling layer provided on the straight waveguide and having a first point defect, at least one first electrode provided on the first coupling layer adjacent to the first point defect, a ring waveguide provided on the substrate adjacent to the straight waveguide, and at least one second electrode provided on the ring waveguide.

Description

{single-photon source device and single-photon source system including the same}

The present invention relates to a single-photon light source system, and more particularly, to a single-photon light source element in a communication wavelength band and a single-photon light source system including the same.

In general, quantum cryptography can exchange information using light of a single photon. Current quantum cryptography light sources use laser light whose intensity is attenuated to a single photon or less. A single photon light source can enable quantum cryptography communication with complete security because there is only one photon that occurs simultaneously per time.

The problem of the present invention is to provide a single-photon light source device capable of increasing the extraction efficiency of a single photon and a single-photon light source system including the same.

The present invention discloses a single photon light source device. The device comprises: a substrate; a straight waveguide extending in one direction on the substrate; a first coupling layer provided on the straight waveguide and having a first point defect; at least one first electrode provided on the first coupling layer adjacent to the first point defect; a ring waveguide provided adjacent to the straight waveguide; and at least one second electrode provided on the ring waveguide.

According to one example, the ring waveguide may further include a second coupling layer provided on the ring waveguide and having a second point defect.

In one example, the first bonding layer and the second bonding layer may include silicon carbide.

In one example, the first point defect and the second point defect may include a silicon deficiency, a double deficiency, or a carbon antisite deficiency pair.

In one example, the ring waveguide and the second coupling layer may have a circular shape.

In one example, the first point defect and the second point defect may be arranged adjacent to each other.

According to one example, the first electrode may be provided on one side of the first point defect, the second electrode may be provided on the other side of the second point defect, and may be arranged within the second coupling layer and the ring waveguide.

In one example, the first bonding layer may have a pear shape.

In one example, the straight waveguide and the ring waveguide may comprise silicon or silicon nitride.

According to one example, the straight waveguide and the ring waveguide may further include a lower clad layer below the straight waveguide. The lower clad layer may include silicon oxide.

According to one embodiment of the present invention, a single photon light source device includes: a substrate; a lower clad layer provided on the substrate; a straight waveguide provided on the lower clad layer and extending in one direction; a first coupling layer provided on the straight waveguide and having a first point defect; a ring waveguide provided adjacent to the straight waveguide and arranged on the lower clad layer; and a second coupling layer provided on the ring waveguide and having a second point defect adjacent to the first point defect.

According to one example, the straight waveguide may further include an upper clad layer provided on the lower clad layer outside the ring waveguide.

According to one example, the first electrode may further be provided on the first bonding layer and the upper clad layer on one side of the first point defect.

According to one example, the device may further include a second electrode disposed facing the first electrode and provided on the second bonding layer and the upper clad layer on the other side of the second point defect.

In one example, the upper clad layer and the lower clad layer may include silicon oxide.

A single photon light source system according to one embodiment of the present invention includes: a first light source providing a first light; and a single photon light source provided on one side of the first light source and generating a single photon using the first light. Here, the single photon light source element may include: a substrate; a straight waveguide extending in one direction on the substrate; a first coupling layer provided on the straight waveguide and having a first point defect; at least one first electrode provided on the first coupling layer adjacent to the first point defect; a ring waveguide provided adjacent to the straight waveguide; and at least one second electrode provided on the ring waveguide.

According to one example, the device may further include a second light source provided adjacent to the first light source and providing a second light.

In one example, the first light source and the second light source may include light-emitting diodes or laser diodes.

According to one example, the device may further include a beam splitter provided between the first light source and the second light source.

As described above, the single photon light source device according to an embodiment of the present invention can increase the extraction of a single photon by utilizing the first point defect in the first coupling layer.

FIG. 1 is a plan view showing an example of a single photon light source system according to the concept of the present invention.
Figure 2 is a cross-sectional view taken along line II' of Figure 1 .
FIG. 3 is a plan view showing an example of a single photon light source system according to the concept of the present invention.
FIG. 4 is a plan view showing an example of the single photon light source device of FIG. 1 .
FIG. 5 is a plan view showing an example of the single photon light source device of FIG. 1 .
FIG. 6 is a plan view showing an example of a single photon light source device of FIG. 1 .
FIG. 7 is a flow chart showing a method for manufacturing the single photon light source device of FIG. 2 .
Figures 8 to 11 are process cross-sectional views of the single photon light source device of Figure 2 .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The advantages and features of the present invention and the method for achieving them will become clear with reference to the embodiments described in detail below together with the attached drawings. However, the present invention is not limited to the embodiments described herein, but may be embodied in different forms. Rather, the embodiments introduced herein are provided so that the disclosed contents can be thorough and complete and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of describing embodiments only and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. The terms “comprises” and/or “comprising” as used in the specification do not exclude the presence or addition of one or more other components, steps, operations, and/or elements mentioned. In addition, it will be understood that the meaning mainly used in the field of optical communications in the specification is used. Since it is according to a preferred embodiment, reference signs presented in the order of the description are not necessarily limited to that order.

The above-described contents are specific examples for implementing the present invention. The present invention will include not only the embodiments described above, but also embodiments that can be simply designed or easily modified. In addition, the present invention will also include technologies that can be easily modified and implemented in the future using the embodiments described above.

Figure 1 shows an example of a single photon light source system (100) according to the concept of the present invention.

Referring to FIG. 1 , a single photon light source system (100) of the present invention may include first light sources (10) and a single photon light source element (20).

Each of the first light sources (10) can generate a first light (12) and provide it to a single photon light source element (20). For example, the first light sources (10) can include a light emitting diode or a laser diode. The first light (12) can have a plurality of different wavelengths. The first light (12) can be a pump light or an excitation light of laser light, but the present invention is not limited thereto.

A beam splitter (13) may be provided between the first light sources (10). The beam splitter (13) may transmit a portion of the first light (12) to the single photon light source element (20) and reflect another portion of the first light to the single photon light source element (20).

A single photon light source device (20) can generate a single photon (14) using the first light (12). The single photon (14) can be an optical signal at the single photon level, but the present invention is not limited thereto.

Figure 2 shows a cut along line II' of Figure 1 .

Referring to FIGS. 1 and 2 , a single photon light source device (20) may include a substrate (21), a lower clad layer (23), a straight waveguide (22), a first coupled layer (24), a ring waveguide (26), first electrodes (28), and a second electrode (29).

The substrate (21) can support a lower clad layer (23), a straight waveguide (22), and a ring waveguide (26). The substrate (21) can include a silicon wafer, but the present invention is not limited thereto.

A lower clad layer (23) may be provided on the substrate (21). The lower clad layer (23) may include silicon oxide (SiO ₂ ). The lower clad layer (23) may have a refractive index lower than the refractive index of the straight waveguide (22) and the ring waveguide (26).

A straight waveguide (22) may be provided on the substrate (21) and the lower clad layer (23). The straight waveguide (22) may extend in one direction from one side of the substrate (21) and the lower clad layer (23) to the other side. The straight waveguide (22) may have a refractive index higher than the refractive index of the lower clad layer (23). The straight waveguide (22) may include crystalline silicon and/or epitaxial silicon. Alternatively, the straight waveguide (22) may include silicon nitride (SiN), but the present invention is not limited thereto. For example, the straight waveguide (22) may have a width and thickness of about 50 nm to about 1 ㎛ or less.

The first coupling layer (24) may be provided on the straight waveguide (22). The first coupling layer (24) may have a pear shape in a planar view. The first coupling layer (24) may include crystalline silicon carbide (SiC) or epitaxial silicon carbide. Although not shown, the first coupling layer (24) may be doped with a conductive impurity, and the present invention is not limited thereto. According to one example, the first coupling layer (24) may have a first point defect (25).

The first point defect (25) may be provided in the first bonding layer (24). The first point defect (25) may include a silicon vacancy, a di-vacancy, or a carbon antisite-vacancy pair, but the present invention is not limited thereto. The first point defect (25) may absorb the first light (12) to obtain a gain of a single photon (14). In addition, the first point defect (25) may obtain a gain of a single photon (14) by utilizing an electric field (not shown) between the first electrodes (28). Alternatively, the first point defect (25) may generate a single photon (14), but the present invention is not limited thereto. Therefore, the single photon light source device (20) of the present invention can increase the extraction efficiency of a single photon (14) by utilizing the first point defect (25).

An upper clad layer (27) may be provided on the lower clad layer (23) outside the straight waveguide (22) and the first coupling layer (24). The upper clad layer (27) may be provided outside and inside the ring waveguide (26). The upper clad layer (27) may have a refractive index that is the same as that of the lower clad layer (23). The upper clad layer (27) may include silicon oxide (SiO ₂ ).

The first electrodes (28) may be provided on the first coupling layer (24) and the upper clad layer on both sides of the first point defect (25). The first electrodes (28) may provide a first power voltage (not shown) to the first point defect (25) to generate a single photon (14). That is, the first coupling layer (24), the first point defect (25), and the first electrodes (28) may function as a resonator of the single photon (14). The first electrodes (28) may include a metal such as titanium (Ti), platinum (Pt), nickel (Ni), and gold (Au). Each of the first electrodes (28) may have a width of about 500 nm or less, but the present invention is not limited thereto.

The ring waveguide (26) may be provided adjacent to the straight waveguide (22). The ring waveguide (26) may have a circular ring shape in a planar view. The ring waveguide (26) may include the same material as the material of the straight waveguide (22). For example, the ring waveguide (26) may include crystalline silicon or silicon nitride. The ring waveguide (26) may have a width and thickness of about 50 nm to about 1 μm or less. The ring waveguide (26) may function as a resonator of a single photon (14).

The second electrode (29) may be provided on the ring waveguide (26). The second electrode (29) may provide a second power voltage (not shown) within the ring waveguide (26) to tune the wavelength of a single photon (14). The ring waveguide 26) and the second electrode (29) may function as a wavelength converter and a wavelength tuner, but the present invention is not limited thereto.

FIG. 3 shows an example of a single photon light source system (100) according to the concept of the present invention.

Referring to FIG. 3 , the single photon light source system (100) of the present invention may further include a second light source (16). The second light source (16) may be provided between the first light source (10) and the straight waveguide (22). The second light source (16) may be different from or the same as the first light source (10). The second light source (16) may include a light emitting diode or a laser diode. The second light source (16) may provide second light (18) into the straight waveguide (22) to generate a single photon (14) within the first coupling layer (24). The second light (18) may have a wavelength different from that of the first light (12). Alternatively, the second light (18) may have a wavelength the same as that of the first light (12). Beam splitters (13) or dichroic mirrors may be provided between the first light sources (10) and between the first light sources (10) and the second light source (16). The beam splitters (13) may transmit the first light (12) to the straight waveguide (22) and reflect the second light (18) to the straight waveguide ( 22 ). The second light (18) may generate a single photon (14) within the first coupling layer (24) without an electric field within the first point defect (25). That is, the first electrodes (28) of FIGS. 1 and 2 may be removed and/or omitted by the second light (18) of the second light source (16).

The lower clad layer (23), the straight waveguide (22), the first coupling layer (24), the ring waveguide (26), and the second electrode (29) can be configured in the same manner as in Fig. 1 .

FIG. 4 shows an example of a single photon light source element (20) of FIG. 1 .

Referring to FIG. 4 , the single photon light source device (20) may further include a second coupling layer (30).

The second coupling layer (30) may be provided on the ring waveguide (26). The second coupling layer (30) may have the same shape as the ring waveguide (26). The second coupling layer (30) may have a circular ring shape in a planar view. For example, the second coupling layer (30) may include silicon carbide. According to an example, the second coupling layer (30) may have a second point defect (31). The second point defect (31) may be provided within one side of the second coupling layer (30). The second point defect (31) may be the same as the first point defect (25) of FIG. 1 . For example, the second point defect (31) may include a silicon vacancy, a di-vacancy, or a carbon antisite-vacancy pair, but the present invention is not limited thereto.

The second electrodes (29) may be provided on the second coupling layer (30) on both sides of the second point defect (31). When the second power voltage is provided within the second electrodes (29), the second electrodes (29) may induce an electric field within the second point defect (31) to generate a single photon (14). The second point defect (31) and the second electrodes (29) may function as a resonator of the single photon (14). Furthermore, the second coupling layer (30), the second point defect (31), and the second electrodes (29) may remove and/or omit the first coupling layer (24), the first point defect (25), and the first electrode (28) of FIG. 1 .

The lower clad layer (23) and the straight waveguide (22) can be configured identically to Fig. 1 .

Fig. 5 shows an example of a single photon light source element (20) of Fig. 1 .

Referring to FIG. 5 , the first coupling layer (24) and the second coupling layer (30) of the single photon light source device (20) may be arranged adjacent to each other. The first coupling layer (24) and the second coupling layer (30) may have a first point defect (25) and a second point defect (31), respectively. The first point defect (25) and the second point defect (31) may be provided adjacent to each other. The first point defect (25) may include a silicon deficiency, a double deficiency, or a carbon antisite deficiency pair of the first coupling layer (24). Similarly, the second point defect (31) may include a silicon deficiency, a double deficiency, or a carbon antisite deficiency pair.

A first electrode (28) may be provided on one side of the first point defect (25), and a second electrode (29) may be provided within the ring waveguide (26) on the other side of the second point defect (31). The first electrode (28) may be provided on the first coupling layer (24) and the upper clad layer (27) on one side of the first point defect (25). The second electrode (29) may be provided on the second coupling layer (30) and the upper clad layer (27) on the other side of the second point defect (31).

The first point defect (25) and the second point defect (31) can be provided between the first electrode (28) and the second electrode (29).

When a power voltage is supplied to the first electrode (28) and the second electrode (29), the first point defect (25) can generate a gain of a single photon (14). The second point defect (31) can vary and/or change the wavelength of the single photon (14).

The first coupling layer (24) and the second coupling layer (30) can be configured in the same manner as the straight waveguide (22) and the ring waveguide (26) of FIG. 1 .

Fig. 6 shows an example of a single photon light source element (20) of Fig. 1 .

Referring to FIG. 6 , the first coupling layer (24) and the second coupling layer (30) of the single photon light source device (20) may have the same shape as the straight waveguide (22) and the ring waveguide (26) of FIG . 1. The first coupling layer (24) may have a straight shape. The second coupling layer (30) may have a ring shape.

The first electrode (28) may be provided on both sides of the first point defect (25) in the first bonding layer (24). The second electrode (29) may be provided on both sides of the second point defect (31) in the second bonding layer (30).

Although not shown, the first coupling layer (24) and the second coupling layer (30) may be provided on the straight waveguide (22) and the ring waveguide (26) of FIG. 1, respectively, and the present invention is not limited thereto.

Fig. 7 shows a method for manufacturing a single photon light source device (20) of Fig . 2. Figs. 8 to 11 are process cross-sectional views of the single photon light source device (20) of Fig. 2 .

Referring to FIGS. 7 and 8 , a substrate (21) is prepared (S10). The substrate (21) may include crystal silicon. A lower clad layer (23) and a waveguide layer (22a) may be formed on the substrate (21). The lower clad layer (23) may include silicon oxide. The waveguide layer (22a) may include crystal silicon. Alternatively, the substrate (21), the lower clad layer (23), and the waveguide layer (22a) may be prepared as a SOI (Silicon On Isolator) substrate.

Referring to FIGS. 7 and 9 , a bonding layer (24a) is formed (S20). The bonding layer (24a) may include crystalline silicon carbide and/or epitaxial silicon carbide formed by a metal organic vapor deposition method. As an example, the bonding layer (24a) may have a first point defect (25). The first point defect (25) may be measured by an optical microscope or an electron microscope.

Next, a coordinate marker (33) is formed for the first point defect (25) (S30). The coordinate marker (33) can indicate the location of the first point defect (25). The coordinate marker (33) can include a dielectric of silicon nitride (SiN) and silicon oxide (SiO ₂ ). Alternatively, the coordinate marker (33) can include a metal of titanium (Ti), chromium (Cr), or gold (Au), and the present invention is not limited thereto. Although not shown, the coordinate marker (33) can have a grid shape. The coordinate marker (33) can be formed to have a spacing distance of about 5 μm to about 100 μm.

Referring to FIG. 7 and FIG. 10 , the first bonding layer (24) is patterned (S40). The first bonding layer (24) can be patterned by an electron beam lithography process or a photolithography process. The first bonding layer (24) can have a first point defect (25). The first bonding layer (24) can include crystalline silicon carbide and/or epitaxial silicon carbide formed by a transferring method, but the present invention is not limited thereto.

Next, a straight waveguide (22) and a ring waveguide (26) are formed (S50). The straight waveguide (22) and the ring waveguide (26) can be formed by an electron beam lithography process of the waveguide layer (22a). Alternatively, the straight waveguide (22) and the ring waveguide (26) can be formed by a photolithography process and an etching process, and the present invention is not limited thereto. The straight waveguide (22) can have a width wider than the width of the first coupling layer (24). The lower clad layer (23) can be exposed to the outer surface of the straight waveguide (22) and the ring waveguide (26).

Referring to FIG. 7 and FIG. 11 , an upper clad layer (27) is formed (S60). The upper clad layer (27) may be formed on the straight waveguide (22) and the lower waveguide layer (27) outside the first coupling layer (24). The upper clad layer (27) may include silicon oxide formed by a chemical vapor deposition method. The coordinate marker (33) may be removed before or after the formation of the upper clad layer (27).

Referring to FIG. 2 and FIG. 7 , first electrodes (28) and second electrodes (29) are formed (S70). The first electrodes (28) and second electrodes (29) can be formed through a metal deposition process, a photolithography process, and an etching process. The first electrodes (28) can be formed on the first bonding layer (24) and the upper clad layer (27) on both sides of the first point defect (25). The second electrode (29) can be formed on the ring waveguide (26).

The above-described contents are specific examples for implementing the present invention. The present invention will include not only the embodiments described above, but also embodiments that can be simply designed or easily modified. In addition, the present invention will also include technologies that can be easily modified and implemented in the future using the embodiments described above.

Claims (19)

substrate;
A straight waveguide extending in one direction on a substrate;
A first coupling layer provided on the above straight waveguide and having a first point defect;
At least one first electrode provided on the first bonding layer adjacent to the first point defect;
A ring waveguide provided on the substrate adjacent to the straight waveguide;
At least one second electrode provided on the ring waveguide; and
A single photon light source device provided on the above ring waveguide and including a second coupling layer having a second point defect.
delete In paragraph 1,
A single photon light source device wherein the first coupling layer and the second coupling layer comprise silicon carbide.
In the third paragraph,
A single photon light source device wherein the first point defect and the second point defect include silicon deficiency, double deficiency, or carbon antisite deficiency pairs.
In paragraph 1,
A single photon light source device wherein the ring waveguide and the second coupling layer have a circular shape.
In paragraph 1,
A single photon light source element wherein the first point defect and the second point defect are arranged adjacent to each other.
In paragraph 6,
The above first electrode is provided on one side of the first point defect,
A single photon light source element wherein the second electrode is provided on the other side of the second point defect and is arranged within the second coupling layer and the ring waveguide.
In paragraph 1,
The above first coupling layer is a single photon light source device having a pear shape.
In paragraph 1,
The above straight waveguide and the above ring waveguide are single photon light source devices including silicon or silicon nitride.
In paragraph 1,
Further comprising a lower clad layer below the above straight waveguide and the above ring waveguide,
The lower clad layer is a single photon light source device comprising silicon oxide.
substrate;
A lower clad layer provided on the above substrate;
A straight waveguide provided on the lower clad layer and extending in one direction;
A first coupling layer provided on the above straight waveguide and having a first point defect;
A ring waveguide provided adjacent to the straight waveguide and disposed on the lower clad layer; and
A single photon light source device comprising a second coupling layer provided on the ring waveguide and having a second point defect adjacent to the first point defect.
In Article 11,
A single photon light source device further comprising an upper clad layer provided on the lower clad layer outside the straight waveguide and the ring waveguide.
In Article 12,
A single photon light source device further comprising a first electrode provided on the first coupling layer and the upper clad layer on one side of the first point defect.
In Article 13,
A single photon light source device further comprising a second electrode disposed facing the first electrode and provided on the second coupling layer and the upper clad layer on the other side of the second point defect.
In Article 12,
A single photon light source device wherein the upper clad layer and the lower clad layer comprise silicon oxide.
a first light source providing a first light; and
A single photon light source provided on one side of the first light source and generating a single photon using the first light,
The above single photon light source device:
substrate;
A straight waveguide extending in one direction on a substrate;
A first coupling layer provided on the above straight waveguide and having a first point defect;
At least one first electrode provided on the first bonding layer adjacent to the first point defect;
A ring waveguide provided on the substrate adjacent to the straight waveguide;
At least one second electrode provided on the ring waveguide; and
A single photon light source system comprising a second coupling layer provided on the ring waveguide and having a second point defect.
In Article 16,
A single photon light source system further comprising a second light source provided adjacent to the first light source and providing a second light.
In Article 17,
A single photon light source system wherein the first light source and the second light source include light-emitting diodes or laser diodes.
In Article 17,
A single photon light source system further comprising a beam splitter provided between the first light source and the second light source.