KR20210049233A - Device for detecting photon - Google Patents

Abstract

An embodiment of the present invention provides a photon detection device, which includes: a plurality of single-mode optical waveguides to which a single photon is incident; a plurality of optical delay units connected to each of the plurality of single-mode optical waveguides to delay time for photons; a photon lantern device which includes a plurality of input terminals connected to the plurality of optical delay units and an output terminal for propagating the photons input to the input terminals in a multi-space mode; a multi-mode optical waveguide connected to the output terminal; a single photon detector for detecting photons passing through the multi-mode optical waveguide; and a time distribution detector for measuring a time distribution of the photons detected by the single photon detector. The present invention provides a photon detection device capable of separately detecting the photons propagating in several separate spatial modes using a minimum single photon detector.

Description

Photon detection device {DEVICE FOR DETECTING PHOTON}

In an embodiment, it relates to a photon detection device, and more particularly, to a photon detection device using a photonic lantern device and a time-resolved detection technique.

Quantum information technology that utilizes photons, the smallest particles constituting light, as information carriers, has been actively researched and developed in recent years.

First, quantum communication technology is a technology that loads one or several bits of information per photon and uses it for long-distance communication, and provides a level of security that conventional optical communication systems cannot provide. Quantitative computation technology, which processes complex information by combining bits carried in multiple photons, is being developed to solve problems that are difficult to access with modern computer technology, and by controlling individual photons with quantum mechanical precision, the fundamental noise of conventional measurement technology. The field of quantum measurement/quantum sensing, which breaks through the limits, is also attracting attention.

The effectiveness of the quantum technology based on single photon control is highly dependent on the efficient and uniform photon detection technology along with the problem of generating photons efficiently.

That is, in the case of quantum communication, several single-photon detectors must be operated simultaneously for fast information processing, and in particular, quantum computation or quantum sensing requires a much larger number of detectors than the number of photons to be used simultaneously. The single photon detector is itself an expensive equipment, and in some cases requires a cryogenic vacuum equipment, so increasing the number seriously impairs the practicality of the technology.

Single photon detectors used in single photon quantum information/quantum sensing technology can be largely divided into semiconductor-based detectors and superconductor-based detectors. In the case of semiconductor-based devices, when manufacturing a small amount, they have relatively economic advantages, but they have low efficiency and large noise depending on the operating wavelength. In the case of superconducting-based devices, they can potentially integrate a large number of devices, and the overall detection performance is reduced. It has the advantage of being excellent, but the volume of the entire device is large and it is expensive. As an effort to overcome the limitations of a given detector device by an optical technique, a structure such as a photon number resolving detector using a time multiplexing technique has been proposed, but a large number of detectors have been proposed. There is no known technology that can be replaced with a single detector using an optical structure, and the above-described limitations exist.

The embodiment provides a photon detection device.

In addition, there is provided a photon detection device capable of distinguishing and detecting photons propagating in several separate spatial modes by using a minimum single photon detector.

In addition, there is provided a photon detection apparatus in which several separated spatial modes are combined into one multimode optical waveguide, and photons from separate spatial modes reach a single photon detector at separate times, thereby improving resource efficiency.

In addition, by connecting a multimode optical waveguide to a plurality of single photon detectors through an optical splitter and measuring the simultaneous coefficient between the single photon detectors, it is possible to measure not only the state of reaching one photon but also the state of reaching a plurality of multiphotons. It provides a photon detection device.

In addition, it provides a photodetector with a high possibility of practical use.

A photon detection apparatus according to an embodiment includes a plurality of single mode optical waveguides in which a single photon is incident; A plurality of optical delay units connected to each of the plurality of single mode optical waveguides to delay a time for a photon; A photon lantern element including a plurality of input terminals connected to the plurality of optical delay units and an output terminal for propagating photons input through the input terminals in a multi-space mode; A multimode optical waveguide connected to the output terminal; A single photon detector for detecting photons passing through the multimode optical waveguide; And a time distribution detector for measuring a time distribution of the photons detected by the single photon detector.

The single mode optical waveguide may be formed of a single mode optical fiber.

The multimode optical waveguide may be formed of a multimode optical fiber.

The photon lantern device may have a taper.

The minimum resolvable time of the time distribution analyzer may be smaller than a difference in minimum delay time between the plurality of optical delay units.

The plurality of optical delay units may provide different delay times.

The different delay times may be multiples of the minimum delay time.

A photon detection apparatus according to another embodiment includes a plurality of single mode optical waveguides in which a single photon is incident; A plurality of optical delay units connected to each of the plurality of single mode optical waveguides to delay a time for a photon; A photon lantern element including a plurality of input terminals connected to the plurality of optical delay units and an output terminal for propagating photons input through the input terminals in a multi-space mode; A multimode optical waveguide connected to the output terminal; An optical splitter connected to the multimode optical waveguide and distributing photons passing through the multimode optical waveguide to a plurality of optical distribution output terminals; A plurality of single photon detectors connected to each of the plurality of light distribution output terminals to detect photons; And a time distribution detector for measuring a time distribution of photons detected by the plurality of single photon detectors.

The time distribution detector may measure a simultaneous coefficient at which at least one of the plurality of single photon detectors simultaneously detects a photon.

The time distribution detector may measure the time distribution of the simultaneous coefficient.

According to an embodiment, a photon detection device may be implemented.

In addition, it is possible to implement a photon detection device capable of detecting photons propagating in several separate spatial modes by classifying each spatial mode using a minimum single photon detector.

In addition, it is possible to implement a photon detection device that improves resource efficiency by combining several separated spatial modes into one multimode optical waveguide, and allowing photons from separate spatial modes to reach a single photon detector at separate times. .

In addition, by connecting a multimode optical waveguide to a plurality of single photon detectors through an optical splitter and measuring the simultaneous coefficient between the single photon detectors, it is possible to measure not only the state of reaching one photon but also the state of reaching a plurality of multiphotons. A photon detection device can be implemented.

In addition, it is possible to provide a photodetector with high practical use possibility.

Various and beneficial advantages and effects of the present invention are not limited to the above description, and will be more easily understood in the course of describing specific embodiments of the present invention.

1 is a conceptual diagram of a photon detection apparatus according to a first embodiment of the present invention,
2 is an enlarged view of part A in FIG. 1,
3 is an enlarged view of part B in FIG. 1,
4 is an enlarged view of part C in FIG. 1,
5 is a diagram illustrating a relationship between a time distribution detector and a light delay unit,
6 is a conceptual diagram of a photon detection apparatus according to a second embodiment.

The present invention is intended to illustrate and describe specific embodiments in the drawings, as various changes may be made and various embodiments may be provided. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as second and first may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, the second element may be referred to as the first element, and similarly, the first element may be referred to as the second element. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. It should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof does not preclude in advance.

Unless otherwise defined, all terms used herein including technical or scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings, but identical or corresponding components are denoted by the same reference numerals regardless of reference numerals, and redundant descriptions thereof will be omitted.

1 is a conceptual diagram of a photon detection apparatus according to a first embodiment of the present invention, FIG. 2 is an enlarged view of part A in FIG. 1, FIG. 3 is an enlarged view of part B in FIG. 1, and FIG. 4 is It is an enlarged view of part C in, and FIG. 5 is a diagram for explaining the relationship between the time distribution detector and the optical delay line.

First, referring to FIG. 1, the photon detection apparatus according to the first embodiment includes a single mode optical waveguide 110, an optical delay unit 120, a photon lantern element 130, a multimode optical waveguide 140, and a single photon detector. 150 and a time distribution detector 160.

First, the single-mode optical waveguide 110 may input a single photon (PT1, PT2, ??PTm). There may be a plurality of single mode optical waveguides 110. In addition, each single mode optical waveguide 110 may be connected to an input terminal of the photon detection device or may function as an input terminal. The photons may be incident on any one of the plurality of single mode optical waveguides 110. In addition, several photons may be incident on one or more single mode optical waveguides 110 at the same time.

Referring to FIG. 2, a single photon PT1 may pass through the single mode optical waveguide 110. In an embodiment, the single mode optical waveguide 110 may include a first core CO and a first outer portion CL, and photons may move through the first core CO. In addition, the first outer portion CL may surround the first core CO to protect the first core CO and suppress loss of photons. In addition, the plurality of single-mode optical waveguides 110 may be formed of a single-mode fiber.

Referring back to FIG. 1, the plurality of single-mode optical waveguides 110 include a first single-mode optical waveguide 110-1, a second single-mode optical waveguide 110-2 to an m-th single-mode optical waveguide 110- m). In addition, at least one of the plurality of single photons PT1, PT2, ??PTm is the first single mode optical waveguide 110-1, the second single mode optical waveguide 110-2 to the m-th single mode optical waveguide ( 110-m) may be applied respectively.

The optical delay unit 120 may be connected to each of the plurality of single mode optical waveguides 110 described above. The optical delay unit 120 may delay a time for a photon. For example, the optical delay unit 120 may be formed by splicing a plurality of optical fibers. Accordingly, the light delay unit 120 may adjust a delay time of a photon by adjusting a path through which light passes.

Since the optical delay unit 120 is connected to each of the plurality of single mode optical waveguides 110, there may be a plurality of optical delay units. In an embodiment, the optical delay unit 120 may include a first optical delay unit 120-1, a second optical delay unit 120-2 to an m-th optical delay unit 120-m.

In this case, the plurality of light delay units 120 may provide different delay times to photons. For example, the first optical delay unit 120-1 may provide a minimum delay time SFa. Alternatively, the second optical delay unit 120-2 may provide a delay time different from the first optical delay unit 120-1, for example, a delay time greater than the minimum delay time SFa. In addition, the m-th optical delay unit 120-m may provide a delay time greater than that of the first optical delay unit 120-1 and the second optical delay unit 120-2. With this configuration, photons from the plurality of single mode optical waveguides 110, which are input terminals, may be temporally divided into a plurality (eg, M).

In addition, the optical delay unit 120 may be located in the single mode optical waveguide 110. Accordingly, the optical delay unit 120 may also be formed of a single-mode fiber as a single mode optical waveguide.

The photon lantern element 130 may include a plurality of input terminals In1 to Inm and an output terminal.

The plurality of input terminals In1 to Inm may be connected to a plurality of optical delay lines. In addition, the output terminal may propagate photons input to the input terminals In1 to Inm in a multi-space mode.

The photon lantern element 130 may connect a plurality of single mode optical waveguides 110 to the multimode optical waveguide 140 through an output terminal out. That is, the photon lantern element 130 may propagate several spatial modes to the multimode optical waveguide 140 connected to the output terminal. In other words, the photon lantern element 130 acts as a connecting element connecting a plurality of single mode optical waveguides and multimode optical waveguides. With this configuration, since the photon signals incident through the plurality of single mode optical waveguides 110 are concentrated to the multimode optical waveguide 140, efficiency can be improved.

Referring to FIG. 4, the photon lantern element 130 may be positioned between the single mode optical waveguide 110 and the multimode optical waveguide 140 to have a taper TP. In other words, the photon lantern device 130 according to the embodiment may be a device to which an optical fiber is tapered, or may be formed of an integrated optics circuit.

1 and 3, the multimode optical waveguide 140 may be connected to an output terminal Out of the photon lantern element 130. Accordingly, photons PT1, PT2, and PT3 moved through the plurality of single-mode optical waveguides 110 and individually delayed may be propagated through the multi-mode optical waveguide 140.

The multi-mode optical waveguide 140 is an optical fiber, and may include an inner second core CO' and a second outer portion CL', and a plurality of photons may move through the second core CO'. . In addition, since the second outer portion CL' surrounds the second core CO', it may protect the second core CO' and provide a function of suppressing light loss.

In addition, in the present specification, the optical waveguide may be formed of an optical fiber, the single mode optical waveguide 110 is formed of a single-mode fiber (SMF), and the multimode optical waveguide 140 is formed of a multi-mode optical fiber (multi-mode optical fiber). mode fiber: MMF). In addition, it should be understood that the single mode optical waveguide may be replaced with a few-mode optical waveguides that propagate only a smaller number of spatial modes than a multimode optical fiber.

A single-photon detector (SPD) 150 may be connected to the multi-mode optical waveguide 140. When a photon is incident, the single photon detector 150 may convert the photon into an electric signal and output it.

The single photon detector 150 may include a semiconductor avalanche photodiode device or a superconducting nanowire device, but is not limited thereto.

According to the embodiment, the single photon detector 150 is input through each single mode optical waveguide 110 and has different delay times through the optical delay unit 120 while the photon lantern element 130 and the multimode optical waveguide ( 140), a plurality of photons PT1, PT2,,., PTm) may be output as an electric signal.

The time distribution detector 160 may determine an input to which the photons are incident, that is, a single mode optical waveguide by measuring a time distribution of a photon detected from the single photon detector 150, that is, an output electrical signal.

The time distribution detector 160 may be formed of a combination of a time-to-amplitude converter (TAC) and a multi-channel analyzer (MCA). Further, the time distribution detector 160 may be configured as a time tagger device, and may utilize a counter based on an FPGA circuit.

In addition, the time distribution detector 160 can easily measure the spatial distribution of photons simultaneously incident to M inputs (i.e., m single-mode optical waveguides) by measuring the time and number of photons output from the reference time. have.

Referring to FIG. 5, the minimum resolution time Td of the time distribution detector 160 according to the embodiment may be smaller than the minimum delay time SF in the plurality of optical delay units 120. Here, the minimum delay time SF will be described based on the minimum value among the relative difference values between the delay times PTL->PTF of the plurality of optical delay units.

Furthermore, the plurality of optical delay units may have a delay time that is a multiple of the minimum delay time SF. Accordingly, the photon detection apparatus according to the embodiment can easily accurately measure the number of photons even if a plurality of photons are simultaneously propagated through a plurality of single mode optical waveguides.

6 is a conceptual diagram of a photon detection apparatus according to a second embodiment.

6, the photon detection apparatus according to the second embodiment includes a single mode optical waveguide 210, an optical delay unit 220, a photon lantern element 230, a multimode optical waveguide 240, and a single photon detector 250. ), a time distribution detector 260 and an optical splitter 270.

The single-mode optical waveguide 210, the optical delay unit 220, the photon lantern element 230, and the multi-mode optical waveguide 240 may be the same as described above.

First, the optical splitter 270 may be connected to the multimode optical waveguide 240. In addition, the optical splitter 270 may be disposed between the multimode optical waveguide 240 and the single photon detector 250.

The optical splitter 270 may distribute a plurality of photons propagating through the multimode optical waveguide 240 in a predetermined number (eg, n). For example, the optical splitter 270 may include a plurality of optical distribution output terminals 271 to 271-n through which distributed photons are output.

The above-described information is applied to the single photon detector 250, and there may be a plurality of single photon detectors 250. Each of the plurality of single photon detectors 250 may be connected to the optical splitter 270. For example, each of the plurality of single photon detectors 250 may be connected to a plurality of light distribution output terminals.

The time distribution detector 260 may be connected to a plurality of single photon detectors 250 to receive electrical signals from each of them.

The time distribution detector 260 may measure a coincidence count arbitrarily set in the plurality of single photon detectors 250, and measure a frequency simultaneously detected within a time within a time window of the coincidence coefficient. That is, the time distribution detector 260 can measure not only the above-described functions but also the number of simultaneous counts by accumulating for a predetermined measurement time. In other words, the time distribution detector can easily detect a case in which multiple photons propagate simultaneously through the multimode optical waveguide 240 by measuring the coefficency between the output signals from the N single photon detectors 250.

For example, photons input through the plurality of single mode optical waveguides 210 are temporally separated through the optical delay unit 220. The distribution of the number of photons incident to the photon detection device can be easily measured according to the simultaneous coefficient of the output signal output through the optical splitter 270 and the plurality of single photon detectors 250.

For example, even if two photons are incident on one single-mode optical waveguide at the same time, two single-photon detectors of the single photon detectors 250-1, 250-2,??, 250-n simultaneously generate a photon detection signal (described above). One electrical signal), and the time distribution detector 260 may generate a simultaneous coefficient for two photons. Accordingly, the photon detection apparatus according to the embodiment can easily measure the number distribution of photons irrespective of the input time and number of photons.

In addition, the time distribution detector 260 may be formed of an electronic circuit based on a field programmable gate array (FPGA).

The term'~ unit' used in this embodiment refers to software or hardware components such as field-programmable gate array (FPGA) or ASIC, and'~ unit' performs certain roles. However,'~ part' is not limited to software or hardware. The'~ unit' may be configured to be in an addressable storage medium, or may be configured to reproduce one or more processors. Thus, as an example,'~ unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays, and variables. Components and functions provided in the'~ units' may be combined into a smaller number of elements and'~ units', or may be further separated into additional elements and'~ units'. In addition, components and'~ units' may be implemented to play one or more CPUs in a device or a security multimedia card.

Although the embodiments have been described above, these are only examples and do not limit the present invention, and those of ordinary skill in the field to which the present invention belongs are not exemplified above without departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

Claims (10)

A plurality of single mode optical waveguides in which a single photon is incident;
A plurality of optical delay units connected to each of the plurality of single mode optical waveguides to delay a time for a photon;
A photon lantern element including a plurality of input terminals connected to the plurality of optical delay units and an output terminal for propagating photons input through the input terminals in a multi-space mode;
A multimode optical waveguide connected to the output terminal;
A single photon detector for detecting photons passing through the multimode optical waveguide; And
A photon detection device comprising a; time distribution detector for measuring the time distribution of the photons detected by the single photon detector.
The method of claim 1,
The single mode optical waveguide is a photon detection device made of a single mode optical fiber.
The method of claim 1,
The multimode optical waveguide is a photon detection device made of a multimode optical fiber.
The method of claim 1,
The photon lantern element is a photon detection device having a taper.
The method of claim 1,
A photon detection device in which the minimum resolvable time of the time distribution analyzer is smaller than a difference in minimum delay time between the plurality of optical delay units.
The method of claim 5,
The photon detection device for providing different delay times for the plurality of optical delay units.
The method of claim 6,
The different delay times are multiples of the minimum delay times.
A plurality of single mode optical waveguides in which a single photon is incident;
A plurality of optical delay units connected to each of the plurality of single mode optical waveguides to delay a time for a photon;
A photon lantern element including a plurality of input terminals connected to the plurality of optical delay units and an output terminal for propagating photons input through the input terminals in a multi-space mode;
A multimode optical waveguide connected to the output terminal;
An optical splitter connected to the multimode optical waveguide and distributing photons passing through the multimode optical waveguide to a plurality of optical distribution output terminals;
A plurality of single photon detectors connected to each of the plurality of light distribution output terminals to detect photons; And
A photon detection apparatus comprising: a time distribution detector for measuring a time distribution of photons detected by the plurality of single photon detectors.
The method of claim 8,
The time distribution detector is a photon detection device for measuring a simultaneous coefficient at which at least one of the plurality of single photon detectors simultaneously detects a photon.
The method of claim 9,
The time distribution detector is a photon detection device for measuring the time distribution of the simultaneous coefficient.

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