A photonic detection system based on an optical switch network

Abstract

A photonic detection system based on optical switch network, comprising a configurable multi-stage optical switch network and a detection task scheduler, when n optical quantum experiment systems are needed, respectively using E1, E2,..., E n , the number of optical quantum signals needed for each experiment system to perform detection is N1, N2,..., N n , and the total number of all available photonic detector channels is D; the optical quantum signals to be detected in each experiment system are classified, and the number of categories of optical quantum signals in each experiment system is m1, m2,..., m n ; for any specific experiment system E i , different numbers of detector channels are allocated to different categories, a soft and hardware integrated detection system is constructed by using a multi-stage optical switch network and a detection task scheduler, a mapping relationship between the multiple optical quantum signals from multiple optical quantum experiment systems and the limited photonic detector channels is established, that is, the virtualization of the detector channel resources is realized. The use efficiency of single photon detector and the experimental support capability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of soft and hardware integrated photonic detection system based on optical switch network and photonic detection task scheduler, realize the time division multiplexing and virtualization of limited photonic detector channel, can provide single photon and multi-photon detection service for more than actual photonic detector channel number optical quantum signal, belong to quantum optics experiment and quantum computing field. BACKGROUND

[0002] The measurement of optical quantum signal using single photon detector is the key link of quantum information processing using optical quantum system, generally including single photon counting and multi-photon coincidence counting, for the readout of quantum information processing result. For general quantum optics experimental system or general optical quantum computing system, the number of detectable optical quantum signals and the entanglement complexity between different optical quantum signals determine the complexity of quantum information processing tasks or computing ability that can be achieved by the system to some extent. At the same time, more detectable optical quantum signals and more complex entanglement mean that more single photon detector channels and higher photon detection efficiency are needed. Therefore, increasing the number of single photon detector channels and detection efficiency is of great significance to the expansion of experimental or computing ability of optical quantum experiment or computing system. However, the average cost of single channel detection of current commercial high-efficiency single photon detector, such as superconducting nanowire single photon detector, is very expensive, and it needs to work in low temperature environment. Therefore, if we only increase the number of single photon detector channels to meet the demand of the expansion of optical quantum experiment or computing system, the economic cost of building the entire system will become unbearable, and the scalability of the entire system will also be severely restricted. Therefore, under the condition of relatively limited number of single photon detector channels at present, designing an efficient and cost-controllable single photon detector channel multiplexing scheme has important practical value for the expansion of the realized optical quantum experiment or computing system.

[0003] For single large-scale quantum optical experimental systems or multiple independent small-scale quantum optical experimental systems that need to simultaneously occupy the same photon detector, but the number of available detector channels is less than the number of quantum signals to be detected, in practice, the conflict of different experimental systems occupying detector channels is generally resolved by manually plugging and unplugging optical fibers. However, manually plugging and unplugging optical fibers obviously reduces the experimental efficiency of multiple experimental systems and is prone to introducing unnecessary experimental losses or even experimental errors. An optical switch is an optical device with multiple selectable transmission ports that can switch optical signal transmission channels by applying electrical control signals. An optical switch network constructed using high-speed, low-loss optical switches can realize time-division multiplexing of detector channels for multiple quantum signals from different experimental systems. Different optical switch network configurations can be made according to different detection task requirements, thereby realizing different mapping relationships between the quantum signals to be detected and detector channels, completing different detection tasks, and providing a feasible technical approach to expand a single quantum optical experimental system and improve the efficiency of "parallel" experiments of multiple experimental systems. Existing technologies disclose single-photon detector systems and control methods, but they are different from this invention. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem of expanding and efficiently reusing the number of single-photon detector channels in current optical quantum experiments or computing systems. This invention provides a photon detection system based on an optical switch network. Through a configurable multi-level optical switch network and a detection task scheduler, it realizes the expansion and virtualization of limited single-photon detector channel resources, and can provide single-photon and multi-photon detection services for optical quantum signals with more than the actual number of photon detector channels.

[0005] To achieve the above objectives, the technical solution adopted by this invention is: a photon detection system based on an optical switch network, comprising a configurable multi-level optical switch network and a detection task scheduling program, which can be used to detect n photon experimental systems (respectively using E1, E2, ..., E...). n (This indicates that) the detection service is provided, and the number of photonic quantum signals that each experimental system needs to detect are N1, N2, ..., N. n The total number of available photon detector channels is D; the photon signals to be detected in each experimental system are classified, and the number of categories of photon signals in each experimental system is m1, m2, ..., m n For any specific experimental system E i The number of photons in each category of photons it contains is as follows: satisfy Different numbers of detector channels are assigned to different categories, in the following order: in:

[0006] The configurable multi-level optical switch network can be divided into two layers. The first layer is the optical switch network associated with each experimental system. In this layer, the optical switch networks corresponding to different experimental systems are independent of each other. For any experimental system E, the optical switch network can be configured to operate independently. i The corresponding optical switch networks all include m i There are several subnetworks, and the types of the subnetworks are as follows: ,in Indicates that the subnetwork has Road input signal, Output signal. Consider using physically feasible and identical optical switches to construct these subnetworks, assuming the type of optical switch used is S→o: (1) when At that time, among them If it is a positive integer, then it can be used A series of S→o optical switches placed side by side constitute this m i Subnetwork;

[0007] The type of optical switch S→o indicates that the optical switch can select o outputs from S input signals. Then S / o represents the number of input channels "equivalent" to one output of the optical switch on average. Formula (1): Intermediate term This represents the number of input channels for each output "equivalent" mapping in subnetwork j. The entire formula means: when... If the value is close to an integer multiple of S / o, i.e., l times, then l S→o type optical switches can be placed "side by side" and connected to the output of the sub-network to realize the optical switch network required for mapping between the input and output signals of the sub-network.

[0008] (2) When When, use The m S→o optical switches are constructed in a tree-like structure with multiple side-by-side placements. i Each sub-network, meaning the output of the optical switch in the next stage is connected to the input of the optical switch in the previous stage.

[0009] In addition, the second-layer optical switch network is used to map the n·D optical quantum signals output from the first-layer optical switch network from n experimental systems to D detector channels. It is necessary to construct D n→1 sub-networks: (1) When (h-1)·(S / o)<n≤h·(S / o), where h is a positive integer, then D·h S→o optical switches placed side by side can be used to construct these D sub-networks; (2) When (S / o) h-1 < <n≤(S / o) h When, then can be used D sub-networks are constructed according to a plurality of parallelly placed "tree type" structures. The design idea and formulaic expression of the second-stage optical switch network are the same as those of the first-stage optical switch network.

[0010] The light quantum signals in each experimental system are classified, and the correlation measurement modes between different light quantum signals are considered. The classification criteria are: (1) the number of signals involved in the correlation measurement between light quantum signals of the same type is at most o; (2) the number of signals involved in the correlation measurement between any two or more light quantum signals of different types is greater than o, and the maximum value m of the number of light quantum signal categories in all experimental systems is max ≤D. The value of o is generally 1 or 2, and can be selected according to experimental requirements.

[0011] In the detection system, the mapping relationship between all the to-be-detected light quantum signals and the detector channels is transparent to all experimental systems, so each experimental system considers that it occupies all the detector channels, that is, for any experimental system E i , satisfies

[0012] Preferably, the light quantum signals in each experimental system are classified, and the correlation measurement modes between different light quantum signals are mainly considered. The classification criteria are: (1) the number of signals involved in the correlation measurement between light quantum signals of the same type is at most o; (2) the number of signals involved in the correlation measurement between any two or more light quantum signals of different types is greater than o, and the maximum value m of the number of light quantum signal categories in all experimental systems is max ≤D.

[0013] Preferably, in the detection system, the mapping relationship between all the to-be-detected light quantum signals and the detector channels is transparent to all experimental systems, so each experimental system can consider that it occupies all the detector channels, that is, for any experimental system E i , satisfies

[0014] Compared with the prior art, the present application has the following beneficial effects: the present application uses a multi-level optical switch network and a detection task scheduler to construct a hardware and software integrated detection system, which is more efficient in realizing time division multiplexing of a to-be-detected optical quantum signal to limited single-photon detector channel resources compared with the manual optical fiber plugging mode, improves the "parallel" experimental efficiency of a multi-experimental system, and effectively improves the experimental capacity and scalability of the optical quantum experimental system. According to existing experimental experience, it is estimated that the number of experimental systems connected to the detection system is 3-4, which is more appropriate. The expected effect of the photon detection system based on the optical switch network designed by the present application is that, compared with the case where the optical switch network is not introduced and multiple experimental systems can only work in series, the average efficiency of multiple experimental systems in experiments is significantly improved, and the average experimental task throughput of the multi-experimental system is improved. Moreover, when a new experimental system needs to be connected, the corresponding sub-network can be added directly based on the original optical switch network, which is easy to expand.

[0015] The present application establishes a mapping relationship between multiple optical quantum signals from multiple optical quantum experimental systems and limited photon detector channels, that is, realizes the virtualization of the detector channel resources. Through the multi-level optical switch network and the detection task scheduler, the detection system can receive and process photon detection tasks from multiple optical quantum experimental systems in real time, effectively improving the use efficiency of the single-photon detector and the support capability for parallel experiments of multiple optical quantum experimental systems. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic diagram of a photon detection system framework based on an optical switch network;

[0017] Figure 2 is a schematic diagram of a photon detection system structure based on an optical switch network for two-photon detection channels of two optical quantum experimental systems.

[0018] Figure 3 is a schematic diagram of a photon detection system structure based on an optical switch network for two-photon detection channels of three optical quantum experimental systems. DETAILED DESCRIPTION

[0019] The present application will be further illustrated below in combination with the drawings and specific embodiments, and it should be understood that these examples are only used to illustrate the present application and do not limit the scope of the present application, and after reading the present application, those skilled in the art can make various equivalent modifications to the present application, which all fall within the scope defined by the appended claims of the present application.

[0020] A photon detection system based on an optical switch network, as shown in Figure 1As shown, a hardware-software integrated detection system was constructed using a multi-level optical switch network and a detection task scheduler. This established a mapping relationship between multiple optical quantum signals from various optical quantum experimental systems and a limited number of photon detector channels, effectively virtualizing detector channel resources. Through the multi-level optical switch network and detection task scheduler, the system can receive detection tasks from multiple optical quantum signals from various optical quantum experimental systems in real time. Based on the scheduling and analysis results of the detection tasks, different optical switch network configurations are implemented, and the acquired detection results are ultimately sent to the corresponding experimental systems. In other words, it can simultaneously provide detection services to multiple optical quantum experimental systems.

[0021] When it is necessary to prepare n photon experimental systems (referred to as E1, E2, ..., E...), n (This indicates that) the detection service is provided, and the number of photonic quantum signals that each experimental system needs to detect are N1, N2, ..., N. n The total number of available photon detector channels is D. The photon signals to be detected in each experimental system are classified, with the number of categories for each system being m1, m2, ..., m... n For any specific experimental system E i The number of photons in each category of photons it contains is as follows: satisfy Different numbers of detector channels are assigned to different categories, in the following order: correspond Output signal; where:

[0022] The configurable multi-level optical switch network can be divided into two layers. The first layer is the optical switch network associated with each experimental system. In this layer, the optical switch networks corresponding to different experimental systems are independent of each other. For any experimental system E... i The corresponding optical switch network includes m i There are several subnetworks, and the types of the subnetworks are as follows: ,in Indicates that the subnetwork has Road input signal, Output signal. Consider using physically feasible and identical optical switches to construct these subnetworks, assuming the type of optical switch used is S→o: (1) when At that time, among them If it is a positive integer, then it can be used A series of S→o optical switches placed side by side constitute this m i Subnetworks; (2) When When, then can be used The m S→o optical switches are constructed in a tree-like structure with multiple side-by-side placements. i Each sub-network, that is, the output of the next stage optical switch is connected to the input of the previous stage optical switch. In addition, the second-layer optical switch network is used to map the n·D optical quantum signals from n experimental systems output by the first-layer optical switch network to D detector channels, which requires the construction of D n→1 sub-networks: (1) When (h-1)·(S / o)<n≤h·(S / o), where h is a positive integer, then D·h S→o optical switches placed side by side can be used to construct these D sub-networks; (2) When (S / o) h-1 << n≤(S / o) h When, then can be used The D sub-networks are constructed by placing multiple S→o optical switches side by side in a tree-like structure.

[0023] The detection task scheduling program primarily maintains a task queue for detection tasks received from multiple experimental systems and schedules tasks according to a "first-in, first-out" (FIFO) strategy. All detection task descriptions follow the same instruction format: "Experimental System Information + Detection Task Type + Detection Channel Mode + Detection Task Time + ...". Here, "Experimental System Information" refers to the experimental system number, used for addressing when returning the detection task results; "Detection Task Type" generally includes classical optical power measurement, single-channel photon count measurement, multi-photon coincidence count measurement, and single-photon or multi-photon time series information measurement; "Detection Channel Mode" mainly describes the channel corresponding to the multi-channel correlation measurement; and "Detection Task Time" describes the expected time to complete the detection task described by the instruction, which is related to the specific measurement equipment in the detection system. Based on the scheduling results of the task queue, the detection system selects a specific detection task instruction from the task queue, performs parsing processing, and, based on the parsing results (mainly including the experimental system number, detection channel mode, etc.), completes the configuration of the multi-level optical switch network and returns the measurement results to the corresponding experimental system, completing the entire detection service process.

[0024] Example 1

[0025] In the case of two photonic quantum experimental systems and two detector channels, a photon detection system based on an optical switch network, such as... Figure 2 As shown, both photonic quantum experimental systems have 16 photonic quantum signals to be detected, i.e., N1 = N2 = 16. These signals can be divided into two categories, each containing 8 photonic quantum signals. For each photonic quantum experimental system, one detector channel is allocated to every 8 photonic quantum signals, i.e., m1 = m2 = 2. The S=2, o=1 type optical switch is selected to construct the optical switch network. Therefore, the first layer optical switch network needs 28 optical switches in total, and four 8→1 sub-networks are constructed according to the "binary tree" structure, each of which contains two experimental systems. In addition, the second layer optical switch network needs two 2→1 optical switches arranged side by side to complete the mapping of two experimental systems each with two optical quantum signal channels to two detector channels.

[0026] In addition, if the photon detection system receives a detection instruction "1+ two-photon coincidence counting measurement + [1, 12]+…", that is, it needs to complete the two-photon coincidence counting measurement between the first and twelfth optical quantum signals in the optical quantum experimental system 1, at this time, as shown in Figure 2 The configuration information of the optical switch network can be represented as "S1-S7: 00011000", wherein "0" for each optical switch configuration represents selecting the previous channel, and "1" represents selecting the next channel. The detection instruction information from different experimental systems enters the task queue, and the scheduler performs task scheduling according to the "first-in, first-out" strategy.

[0027] Embodiment 2

[0028] The photon detection system based on the optical switch network under the condition of three optical quantum experimental systems and two detector channels is shown in Figure 2 As shown in the figure, two optical quantum experimental systems each have 8 optical quantum signals to be detected, that is, N1=N2=N3=8, which can be divided into two categories, each of which contains 4 optical quantum signals. For each optical quantum experimental system, one detector channel is allocated for every 4 optical quantum signals, that is, m1=m2=m3=2, The S=4, o=1 type optical switch is selected to construct the optical switch network. Therefore, the first layer optical switch network needs 6 optical switches in total, and six 4→1 sub-networks are constructed by directly arranging them side by side, each of which contains two experimental systems. In addition, the second layer optical switch network needs two 4→1 optical switches arranged side by side to complete the mapping of three experimental systems each with two optical quantum signal channels to two detector channels. The specific detection task processing method is described in the description of Example 1.

[0029] The key of the application is that a photonic detection system based on an optical switch network is utilized, a soft and hardware integrated detection system is constructed by using a multi-level optical switch network and a detection task scheduling program, a mapping relationship between multiple optical quantum signal from multiple optical quantum experiment systems and limited photonic detector channels is established, that is, virtualization of the detector channel resources is realized. Through the multi-level optical switch network and the detection task scheduling program, the detection system can receive and process photonic detection tasks from multiple optical quantum experiment systems in real time, effectively improving the use efficiency of single photon detector and the support ability for parallel experiments of multiple optical quantum experiment systems.

[0030] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A photonic detection system based on an optical switch network, characterized in that, The application comprises a configurable multi-stage optical switch network and a detection task scheduler, when n optical quantum experiment systems need to be provided with detection services respectively by E1, E2,..., E n The number of optical quantum signals needed to be detected by each experiment system is N1, N2,..., N n , and the total number of available photon detector channels is D; the optical quantum signals to be detected in each experiment system are classified, and the number of classes of optical quantum signals in each experiment system is m1, m2,..., m n ; for any specific experiment system E i , the number of classes of optical quantum signals contained is m i , and the number of optical quantum signals in each class of optical quantum signals is satisfies and different numbers of detector channels are allocated to different classes, which are wherein: The configurable multi-stage optical switch network is divided into two layers as a whole, the first layer is the optical switch network related to each experiment system, in which the optical switch networks corresponding to different experiment systems are independent of each other, for any one experiment system E i The corresponding optical switch network includes m i sub-networks, the types of the sub-networks are Among them indicates that the sub-network has input signals, output signals; considering the feasibility of using physical implementation level and the same type of optical switch to build these sub-networks, it is assumed that the type of optical switch used is S→o: (1) when wherein is a positive integer, then a first layer of optical switch network is constructed using side-by-side placed S→o optical switches; (2) when then use S→o optical switches, a first layer optical switch network is constructed according to a plurality of side-by-side placed "tree type" structure, that is, the output end of the next stage optical switch is connected to the input end of the previous stage optical switch. In addition, the second layer optical switch network is used for mapping nD optical quantum signals from n experimental systems output by the first layer optical switch network to D detector channels, and D n→1 sub-networks need to be constructed: (1) when (h-1) · (S / o) < n ≤ h·(S / o), where h is a positive integer, then D·h S→o optical switches placed side by side are used to construct the D sub-networks; (2) when (S / o) h-1 <<n≤(S / o) h then use D S→o optical switches to construct the D sub-networks in a "tree-like" structure with multiple parallel branches. Specifically, each of the three optical quantum experiment systems has 8 optical quantum signals to be detected, i.e., N1=N2=N3=8, which are divided into two types, each of which contains 4 optical quantum signals, and for each optical quantum experiment system, 1 detector channel is allocated for every 4 optical quantum signals, i.e., m1=m2=m3=2, The optical switch network is constructed by selecting an optical switch of type S=4, o=1; therefore, the first layer optical switch network needs a total of 6 optical switches, which are directly placed side by side to construct 6 4→1 sub-networks, each of which contains 2 for each experiment system.

2. The photonic probing system based on an optical switch network according to claim 1, characterized in that, The classified standards are: (1) the number of signals involved in the correlation measurement between the same type of optical quantum signals is at most o; (2) the number of signals involved in the correlation measurement between any two or more different types of optical quantum signals is greater than o, and the maximum value m of the number of optical quantum signal categories in all experimental systems max ≤D; in the detection system, the mapping relationship between all the optical quantum signals to be detected and the detector channels is transparent to all experimental systems, so each experimental system considers that it occupies all the detector channels, that is, for any experimental system E i , satisfies 3. The photonic probing system based on an optical switch network of claim 1, wherein, The classified standard is: (1) the number of signals involved in the correlation measurement between the same type of optical quantum signals is at most o; (2) the number of signals involved in the correlation measurement between any two or more different types of optical quantum signals is greater than o, and the maximum value m of the number of optical quantum signal categories in all experimental systems is required to be less than D. max ≤D.

4. The photonic probe system based on an optical switch network of claim 1, wherein the optical switch network is a 2x2 optical switch network. In the detection system, the mapping relationship between all the to-be-detected optical quantum signals and the detector channels is transparent to all the experimental systems, and therefore each experimental system considers that it occupies all the detector channels, that is, for any experimental system E i , the following condition is met

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