A high-precision fast ranging system fusing HBT interferometer and HOM interferometer

Abstract

The application provides a high-precision fast ranging system and method fusing HBT interferometer and HOM interferometer. The system comprises a high-brightness quantum entanglement source, a first fiber coupler, a first fiber beam splitter, a fiber delay device, a fiber disc, a beam expansion collimation transceiver system, an angle mirror, a second fiber beam splitter, a HOM interference module, a multi-channel single-photon detector, a time-to-digital converter and a control system. Through the design of a suitable optical path structure, the high-precision ranging based on the HBT interferometer and the HOM interferometer can be realized simultaneously with the aid of a single quantum light source. In actual use, the fast measurement is realized through the HBT ranging device, and then the measurement precision is improved by using the HOM interference measurement. The two are organically combined, and the fast and high-precision ranging and positioning functions can be realized through the complementary advantages.

Description

Technical Field

[0001] This invention relates to the field of quantum navigation and positioning technology, and in particular to a high-precision and rapid ranging system and method that integrates HBT interferometer and HOM interferometer. Background Technology

[0002] Ranging technology is fundamental for locating and navigating unknown targets, and the ranging accuracy of a positioning system directly determines its positioning accuracy. Traditional ranging technologies, such as ultrasonic ranging, infrared ranging, and laser ranging, are all based on classical physics, and their ranging accuracy is always limited by the standard quantum limit.

[0003] With the continuous advancement of quantum ranging technology, various quantum ranging schemes based on different interferometer structures have been developed and are gradually being explored in fields such as navigation and positioning, inter-satellite ranging, and quantum radar. Among them, ranging schemes based on HBT interferometers and HOM interferometers have great application prospects.

[0004] The HBT interferometer's ranging relies primarily on the coincidence measurement of the reference beam and the signal beam. During HBT ranging, the signal beam is collimated and emitted to a corner mirror at the target point, then returns along the same path and is received by a single-photon detector; the reference beam, emitted from the light source, is directly received by the single-photon detector. The outputs of the two detectors are connected to a time-to-digital converter to record the arrival time sequence of the two signals, and coincidence measurement is performed. The ranging function is achieved by calculating the optical path difference between the two signals. The HBT interferometric measurement process is based on a coincidence measurement algorithm, enabling rapid ranging. However, due to time jitter in devices such as the single-photon detector, the measurement accuracy of the HBT interferometer is limited to approximately 100 micrometers.

[0005] The distance measurement of a Homo Optimus interferometer (HOM) relies primarily on the intensity interference of the reference beam and the signal beam at the beam splitter. During HOM interferometric ranging, the signal beam is collimated and emitted to a corner mirror at the target point, then returns along the same path. The reference beam interferes with the reflected signal beam at the beam splitter, and the two beams are then received by single-photon detectors along their respective paths. By adjusting the optical path difference between the reference and signal beams to make them equal, the coincidence count reaches its minimum, and the relevant distance information is calculated based on the compensation data from the reference beam. While the HOM interferometric measurement process is based on the intensity interference of two beams and requires an adjustable delay device to adjust the optical path difference, resulting in a relatively slow measurement speed, its accuracy can reach below 10 micrometers, or even the nanometer scale. Summary of the Invention

[0006] This invention proposes a measurement device based on a single light source that simultaneously incorporates HBT interferometry and HOM interferometry, combining the speed of HBT interferometry with the high precision of HOM interferometry, and can be used in the fields of quantum ranging and quantum positioning.

[0007] In a first aspect, the present invention provides a high-precision and fast ranging system integrating an HBT interferometer and a HOM interferometer, comprising: a high-brightness quantum entanglement source, a first fiber coupler, a first fiber beam splitter, a fiber delayer, a fiber disk, a beam expander and collimator transceiver system, a corner mirror, a second fiber beam splitter, a HOM interferometer module, a multi-channel single-photon detector, a time-to-digital converter, and a control system. The high-brightness quantum entanglement source is used to output entangled photon pairs or correlated photon pairs to form a reference beam and a signal beam; The first fiber coupler is used to connect the reference beam output by the high-brightness quantum entanglement source and transmit it to the first fiber beam splitter; The first fiber beam splitter is used to split the incoming reference beam into a first reference sub-beam and a second reference sub-beam; and to transmit the first reference sub-beam to the first channel of the multi-channel single-photon detector, and to transmit the second reference sub-beam to the fiber delayer; The fiber delayer and the fiber disk are used to control the delay time of the second reference sub-beam and to transmit the processed second reference sub-beam to the HOM interferometer module. The beam-expanding and collimating transceiver system is used to receive the signal beam output by the high-brightness quantum entanglement source, transmit the signal beam to the corner reflector to receive the signal beam reflected by the corner reflector along the original path, and transmit the signal beam reflected by the corner reflector along the original path to the second fiber beam splitter. The second fiber beam splitter is used to split the incoming signal beam into a first signal sub-beam and a second signal sub-beam; and to transmit the first signal sub-beam to the fourth channel of the multi-channel single-photon detector, and the second signal sub-beam to the HOM interferometer module; The HOM interference module is used to interfere with the second reference sub-beam and the second signal sub-beam, and then transmit the two interfering beams into the second and third channels of the multi-channel single-photon detector, respectively. The multi-channel single-photon detector is used to detect photons in the beam of light received by each channel and transmit the detection signal of each channel to the corresponding channel of the time-to-digital converter. The time-to-digital converter is used to record the photon arrival time of each channel; The control system is used to calculate a first distance value between the target point to be measured and the high-precision fast ranging system based on the time difference between the first channel and the fourth channel, and to calculate a second distance value between the target point to be measured and the high-precision fast ranging system based on the time difference between the second channel and the third channel.

[0008] Furthermore, the high-brightness quantum entanglement source was constructed using a method based on narrow-linewidth laser-pumped PPKTP crystals.

[0009] Furthermore, the beam-expanding and collimating transceiver system includes a second fiber coupler, a fiber optic circulator, and a telescope system; The signal beam output from the high-brightness quantum entanglement source enters from the first port of the fiber optic circulator after passing through the second fiber optic coupler, and then exits from the second port of the fiber optic circulator to the telescope system, and from the telescope system to the corner mirror; the signal beam reflected by the corner mirror is output from the third port of the fiber optic circulator to the second fiber optic beam splitter.

[0010] In a second aspect, the present invention provides a high-precision, rapid ranging method integrating an HBT interferometer and a HOM interferometer, applied to the high-precision, rapid ranging system described in the first aspect, comprising: Calibrate the high-precision, fast ranging system by: placing the corner mirror within a preset distance range of the beam expander and collimator transceiver system; and measuring the first optical path difference L between the reference beam and the signal beam based on the time difference between the first and fourth channels. A Based on the time difference between the second and third channels, the fiber optic delay is adjusted to bring the HOM interference module to a balanced state, and the reading L of the fiber optic delay is recorded at this time. B ; The corner mirror is placed at the target point, and the second optical path difference L between the reference beam and the signal beam is measured based on the time difference between the first and fourth channels. C Then, the first distance value L between the target point and the high-precision fast ranging system is calculated. HBT =(L C -L A ) / 2; Set the length of the fiber optic disk to L D L D The value is slightly smaller than the first distance value L. HBT ; The fiber optic delayer is adjusted to bring the HOM interference module to a balanced state, and the reading L of the fiber optic delayer is recorded at this time. E Then, the second distance value L between the target point and the high-precision fast ranging system is calculated. HOM =(L D +L E -L A ) / 2.

[0011] The beneficial effects of this invention are as follows: This invention, through the design of a suitable optical path structure and the use of a single quantum light source, enables high-precision ranging based on both HBT and HOM interferometers. In practical applications, rapid measurement is first achieved using the HBT ranging device, followed by HOM interferometry to improve measurement accuracy. The organic combination of these two methods, through their complementary advantages, enables rapid and high-precision ranging and positioning. Attached Figure Description

[0012] Figure 1 A schematic diagram of a high-precision, rapid ranging system integrating an HBT interferometer and a HOM interferometer is provided in this embodiment of the invention. Figure 2 This is a schematic diagram of the beam-expanding and collimating transceiver system provided in an embodiment of the present invention; Figure 3 A flowchart illustrating a high-precision, rapid ranging method integrating an HBT interferometer and a HOM interferometer, provided for an embodiment of the present invention; Figure 4 This is a schematic diagram showing the placement of the angle reflector during calibration and actual distance measurement, provided in an embodiment of the present invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0014] With the development of quantum theory, various forms of quantum ranging devices have gradually emerged based on quantum entangled or quantum correlated signals. Among them, measurement devices based on HBT interferometers and HOM interferometers show great application potential in quantum navigation, inter-satellite ranging, and quantum radar. HBT interferometer-based ranging devices mainly rely on a direct coincidence measurement algorithm between the reference and signal lights, enabling rapid measurement. However, due to timing jitter in the measurement device, the measurement accuracy is typically around 100 micrometers. HOM interferometer-based quantum ranging devices require compensation for the optical path difference between the reference and measurement signals using an adjustable fiber optic delay, resulting in slower measurement speeds. However, because the reference and signal lights undergo intensity interference via a beam splitter before the coincidence measurement in the HOM interferometer, the measurement accuracy can be reduced to within ten micrometers, or even down to the nanometer scale. This invention, through the design of a suitable optical path structure and the use of a single quantum light source, can simultaneously achieve high-precision ranging based on both HBT and HOM interferometers. In practical applications, rapid measurement is first achieved using an HBT ranging device, followed by HOM interferometry to improve measurement accuracy. By combining the two organically and complementing each other's strengths, a rapid and high-precision ranging and positioning function can be achieved.

[0015] like Figure 1 As shown, this embodiment of the invention provides a high-precision, fast ranging system integrating an HBT interferometer and a HOM interferometer, comprising: a high-brightness quantum entanglement source, a first fiber coupler (corresponding to...) Figure 1 Coupler 1), first fiber optic beam splitter (corresponding to) Figure 1 The components include: fiber optic beam splitter 1), fiber optic delay unit, fiber optic disk, beam expander, collimator, transceiver system, corner mirror, and second fiber optic beam splitter (corresponding to...). Figure 1 The components include: fiber optic beam splitter 2), HOM interferometer module, multi-channel single-photon detector, time-to-digital converter, and control system; Specifically, a high-brightness quantum entanglement source outputs entangled photon pairs or correlated photon pairs to form a reference beam and a signal beam; a first fiber coupler connects to the reference beam output from the high-brightness quantum entanglement source and transmits it to a first fiber beam splitter; the first fiber beam splitter divides the connected reference beam into a first reference sub-beam and a second reference sub-beam; and transmits the first reference sub-beam to the first channel (corresponding to) of a multi-channel single-photon detector. Figure 1 The second reference sub-beam is transmitted to the fiber delayer via the port ① of the single-photon detector in the optical fiber; the delay time of the second reference sub-beam is controlled by the fiber delayer and the fiber disk, and the processed second reference sub-beam is transmitted to the HOM interferometer module. The beam-expanding and collimating transceiver system receives the signal beam output from the high-brightness quantum entanglement source, transmits the signal beam to the corner mirror to receive the signal beam reflected by the corner mirror along its original path, and transmits the signal beam reflected by the corner mirror along its original path to the second fiber beam splitter; the second fiber beam splitter splits the received signal beam into a first signal sub-beam and a second signal sub-beam; and the first signal sub-beam is transmitted to the fourth channel (corresponding to) of the multi-channel single-photon detector. Figure 1 The second signal sub-beam is transmitted to the HOM interferometer module via port ④ of the single-photon detector. The HOM interferometer module interferes with the second reference sub-beam and the second signal sub-beam, and then transmits the two interferometric beams to the second and third channels of the multi-channel single-photon detector (corresponding to...). Figure 1 Ports ② and ③ of the single-photon detector in the image). A multi-channel single-photon detector detects photons in the beam received by each channel and transmits the detection signal of each channel to the corresponding channel of a time-to-digital converter; the time-to-digital converter records the photon arrival time of each channel. The control system calculates the first distance between the target point and the high-precision fast ranging system based on the time difference between the first and fourth channels, and calculates the second distance between the target point and the high-precision fast ranging system based on the time difference between the second and third channels.

[0016] This invention utilizes a spontaneous parametric down-conversion method to prepare photon pairs with entanglement properties, employs a single-photon detector to detect photons in the signal and reference optical paths, and uses a time-to-digital converter to obtain the arrival time series of photons in the signal and reference optical paths. Specifically, the signals received from ports ① and ④ of the time-to-digital converter form an HBT interference pattern; the signals received from ports ② and ③ of the time-to-digital converter form a HOM interference pattern.

[0017] In one embodiment, a high-brightness quantum entangled source is constructed using a method based on a narrow-linewidth laser-pumped PPKTP crystal. Specifically, the PPKTP crystal has a high nonlinear coefficient, enabling efficient generation of photon pairs during spontaneous parametric down-conversion (SPDC). Combining this with narrow-linewidth laser pumping further improves the photon pair generation efficiency, thereby achieving a high-brightness entangled source.

[0018] In one embodiment, such as Figure 2 As shown, the beam-expanding and collimating transceiver system includes a second fiber coupler, a fiber optic circulator, and a telescope system; the signal beam output from the high-brightness quantum entanglement source passes through the second fiber coupler and exits from the first port of the fiber optic circulator (corresponding to...). Figure 2 It enters from port Ⓐ in the middle, and then enters from the second port of the fiber optic circulator (corresponding to...) Figure 2 The signal beam output from port 12 of the fiber optic circulator is sent to the telescope system, and then from the telescope system to the corner mirror; the signal beam reflected by the corner mirror is sent from the third port of the fiber optic circulator (corresponding to...) Figure 2 The output of port Ⓒ is sent to the second fiber optic beam splitter.

[0019] Based on the above-mentioned high-precision and fast ranging system, such as Figure 3 and Figure 4 As shown, this embodiment of the invention provides a high-precision and rapid ranging method that integrates HBT interferometer and HOM interferometer, including the following steps: S101: Calibrate the high-precision fast ranging system, including: placing the corner reflector within a preset distance range of the beam expander and collimator transceiver system (in practical applications, it should be placed close to the beam expander and collimator transceiver system, such as...). Figure 4 As shown, specifically, it should be placed close to the telescope system); the first optical path difference L between the reference beam and the signal beam is obtained based on the time difference between the first and fourth channels. A Based on the time difference between the second and third channels, the fiber optic delay is adjusted to bring the HOM interference module to a balanced state, and the reading L of the fiber optic delay is recorded at this time. B ; Specifically, the core function of an optical fiber delayer is to create a controllable time delay as the optical signal propagates in the optical fiber. This time delay is achieved by increasing the transmission path length of the optical signal within the fiber. In this embodiment, the HOM interference module reaching equilibrium means that the second reference sub-beam and the second signal sub-beam have the same phase and path length at the beam splitter inside the HOM interference module, thereby achieving optimal quantum interference effects.

[0020] S102: Place the corner mirror at the target point and perform a coincidence measurement based on the time difference between the first and fourth channels to obtain the second optical path difference L between the reference beam and the signal beam. C Then, the first distance value L between the target point and the high-precision fast ranging system is calculated. HBT =(L C -L A ) / 2; S103: Set the length of the fiber optic cable to L D L D The value is slightly smaller than the first distance value L. HBT ; Specifically, in actual ranging processes, the distance to the target point is unknown, and the range of the fiber optic circulator is limited. There are situations where it is impossible to achieve a balanced state by simply adjusting the optical path using a fiber optic delay device. Therefore, it is necessary to use a fiber optic disk to compensate for the optical path difference.

[0021] S104: Adjust the fiber optic delayer to bring the HOM interference module to a balanced state, and record the reading L of the fiber optic delayer at this time. E Then, the second distance value L between the target point and the high-precision fast ranging system is calculated. HOM =(L D +L E -L A ) / 2.

[0022] In this embodiment of the invention, rapid distance measurement is performed using an HBT interferometric measurement device, primarily utilizing the detection data from ports ① and ④ of the time-to-digital converter for coincidence measurement to obtain a distance value L. HBT =(L C -L A On the other hand, high-precision ranging is performed using a HOM interferometer, and the measured distance value is L. HOM =(L D +L E -L A ) / 2. The entire system integrates the advantages of HBT interferometry and HOM interferometry, achieving rapid and high-precision ranging.

[0023] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision, rapid ranging system integrating HBT and HOM interferometers, characterized in that, include: High-brightness quantum entanglement source, first fiber coupler, first fiber beam splitter, fiber delayer, fiber disk, beam expander collimation transceiver system, corner mirror, second fiber beam splitter, HOM interferometer module, multi-channel single-photon detector, time-to-digital converter and control system; The high-brightness quantum entanglement source is used to output entangled photon pairs or correlated photon pairs to form a reference beam and a signal beam; The first fiber coupler is used to connect the reference beam output by the high-brightness quantum entanglement source and transmit it to the first fiber beam splitter; The first fiber beam splitter is used to split the incoming reference beam into a first reference sub-beam and a second reference sub-beam. The first reference sub-beam is fed into the first channel of the multi-channel single-photon detector, and the second reference sub-beam is fed into the fiber optic delayer. The fiber delayer and the fiber disk are used to control the delay time of the second reference sub-beam and to transmit the processed second reference sub-beam to the HOM interferometer module. The beam-expanding and collimating transceiver system is used to receive the signal beam output by the high-brightness quantum entanglement source, transmit the signal beam to the corner reflector to receive the signal beam reflected by the corner reflector along the original path, and transmit the signal beam reflected by the corner reflector along the original path to the second fiber beam splitter. The second fiber beam splitter is used to split the incoming signal beam into a first signal sub-beam and a second signal sub-beam; and to transmit the first signal sub-beam to the fourth channel of the multi-channel single-photon detector, and the second signal sub-beam to the HOM interferometer module; The HOM interference module is used to interfere with the second reference sub-beam and the second signal sub-beam, and then transmit the two interfering beams into the second and third channels of the multi-channel single-photon detector, respectively. The multi-channel single-photon detector is used to detect photons in the beam of light received by each channel and transmit the detection signal of each channel to the corresponding channel of the time-to-digital converter. The time-to-digital converter is used to record the photon arrival time of each channel; The control system is used to calculate a first distance value between the target point to be measured and the high-precision fast ranging system based on the time difference between the first channel and the fourth channel, and to calculate a second distance value between the target point to be measured and the high-precision fast ranging system based on the time difference between the second channel and the third channel.

2. The high-precision, rapid ranging system integrating HBT and HOM interferometers according to claim 1, characterized in that, The high-brightness quantum entanglement source was constructed using a method based on narrow-linewidth laser-pumped PPKTP crystals.

3. The high-precision, rapid ranging system integrating HBT and HOM interferometers according to claim 1, characterized in that, The beam-expanding and collimating transceiver system includes a second fiber coupler, a fiber optic circulator, and a telescope system. The signal beam output from the high-brightness quantum entanglement source enters from the first port of the fiber optic circulator after passing through the second fiber optic coupler, and then exits from the second port of the fiber optic circulator to the telescope system, and from the telescope system to the corner mirror; the signal beam reflected by the corner mirror is output from the third port of the fiber optic circulator to the second fiber optic beam splitter.

4. A high-precision and rapid ranging method integrating HBT interferometer and HOM interferometer, characterized in that, The high-precision, fast ranging system according to any one of claims 1 to 3 includes: Calibrate the high-precision, fast ranging system by: placing the corner mirror within a preset distance range of the beam expander and collimator transceiver system; and measuring the first optical path difference L between the reference beam and the signal beam based on the time difference between the first and fourth channels. A Based on the time difference between the second and third channels, the fiber optic delay is adjusted to bring the HOM interference module to a balanced state, and the reading L of the fiber optic delay is recorded at this time. B ; The corner mirror is placed at the target point, and the second optical path difference L between the reference beam and the signal beam is measured based on the time difference between the first and fourth channels. C Then, the first distance value L between the target point and the high-precision fast ranging system is calculated. HBT =(L C -L A ) / 2; Set the length of the fiber optic disk to L D L D The value is slightly smaller than the first distance value L. HBT ; The fiber optic delayer is adjusted to bring the HOM interference module to a balanced state, and the reading L of the fiber optic delayer is recorded at this time. E Then, the second distance value L between the target point and the high-precision fast ranging system is calculated. HOM =(L D +L E -L A ) / 2.

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