CN111427217B

CN111427217B - Light source module and device for various quantum optical experiments

Info

Publication number: CN111427217B
Application number: CN202010299281.0A
Authority: CN
Inventors: 周志远; 李银海; 张万斌; 史保森
Original assignee: Hefei Hengyuan Quantum Technology Co ltd; Qingdao Quantum Application Technology Co ltd
Current assignee: Hefei Hengyuan Quantum Technology Co ltd; Qingdao Quantum Application Technology Co ltd
Priority date: 2020-04-16
Filing date: 2020-04-16
Publication date: 2023-06-13
Anticipated expiration: 2040-04-16
Also published as: CN111427217A

Abstract

The invention relates to the technical fields of laser technology, nonlinear photophysics and atomic physics, in particular to a light source module and a device for various quantum optical experiments. The invention has the advantages that: all optical devices in the light source module are collinear, which is beneficial to optical fiber alignment and coupling operation. The wavelength used by the device belongs to a communication wave band and is suitable for long-distance propagation.

Description

Light source module and device for various quantum optical experiments

Technical Field

The invention relates to the technical fields of laser technology, nonlinear photophysics and atomic physics, in particular to a light source module and a device for various quantum optical experiments.

Background

Quantum photon sources are essential for nearly all types of research and applications in quantum information science and technology. The preparation of high quality quantum photon sources has been the goal of quantum information science and technology pursuit. Common methods for preparing quantum light sources are spontaneous parametric down-conversion or spontaneous four-wave mixing in a nonlinear process. Spontaneous parametric down-conversion was widely used to generate various entangled photon sources since the first observation of spontaneous parametric down-conversion by d.c. burns in 1970.

There are two types of prior art:

1. the sagnac interferometer is used for generating the polarization entangled photon source, and the structure of the interferometer is complicated to adjust, the collimation and alignment processes of light rays are complicated, and many optical devices are needed, so that the experimental operation process is complicated.

2. The BBO crystal with orthogonal optical axes is used for generating a bias entangled photon source, and the effective nonlinear coefficient of the BBO crystal is low, so that imaging brightness is low, and a pumping beam with higher power is required to be equipped in an experiment.

Disclosure of Invention

In order to establish a multipurpose entangled light source with simple structure and high quality, the invention provides a light source module and a device for various quantum optical experiments. The invention adopts the following technical scheme:

a light source module for multiple quantum optical experiments comprises a pump laser, a first polarization modulation component, a first lens, a first crystal, a second lens, a KTP crystal, a first optical filter, a first single-mode optical fiber and dense wavelength division multiplexing, wherein the pump laser, the first polarization modulation component, the first lens, the first crystal, the second lens, the KTP crystal, the first optical filter, the first single-mode optical fiber and the dense wavelength division multiplexing are arranged according to light paths.

Specifically, the first crystal is any one of PPKTP crystal, BBO crystal, PPLN crystal and aluminum nitride crystal.

Specifically, the length of the PPKTP crystal is 2mm, the polarization period is 46.2 μm, and the situation of coating films along the light transmission direction is as follows: front end face S1 AR@775nm, AR@1550nm and rear end face S2 AR@775nm, AR@1550nm.

Specifically, the length of KTP crystal is 1mm, and the coating condition along the light passing direction is: front end face S1 AR@775nm, AR@1550nm and rear end face S2 AR@775nm, AR@1550nm.

The device for the light source module for the various quantum optical experiments further comprises an entanglement generation and projection module arranged behind the light source module, wherein the entanglement generation and projection module comprises one or more of an HOM interference unit, a time energy entanglement unit and a polarization entanglement unit.

Specifically, the HOM interference unit includes a second single mode fiber, a second polarization modulation component and a first polarization beam splitter that are sequentially arranged, the first polarization beam splitter splits a light beam into two paths, one path sequentially passes through a third polarization modulation component and a third single mode fiber, the other path sequentially passes through a fourth polarization modulation component and a fourth single mode fiber, photons in the third single mode fiber and the fourth single mode fiber are input into the first fiber beam splitter, and the second single mode fiber obtains the light beam in a set channel in dense wavelength division multiplexing at the output end of the light source module.

Specifically, the time energy entanglement unit comprises a fifth single-mode fiber, a fifth polarization modulation component and a second polarization beam splitter which are sequentially arranged, the second polarization beam splitter divides light beams into two paths, one path of the light beams is output from the first interferometer after passing through the sixth single-mode fiber, the other path of the light beams is output from the second interferometer after passing through the seventh single-mode fiber, and the fifth single-mode fiber obtains the light beams in a set channel in dense wavelength division multiplexing at the output end of the light source module.

Specifically, the polarization entanglement unit comprises a signal light path and an idler light path which are respectively used for transmitting photons of a signal channel and photons of an idler channel in dense wavelength division multiplexing at the output end of the light source module, wherein the signal light path comprises a first optical fiber polarization controller, an eighth single-mode optical fiber, an arbitrary phase retarder, a sixth polarization modulation component and a third polarization beam splitter which are sequentially arranged; the idler frequency light path comprises a second optical fiber polarization controller, a ninth single-mode optical fiber, a seventh polarization modulation component and a fourth polarization beam splitter which are sequentially arranged.

Specifically, the arbitrary phase retarder comprises a sixth quarter-wave plate, a sixth half-wave plate and a seventh quarter-wave plate which are sequentially arranged.

Specifically, the system further comprises a measurement module comprising a first detector and a second detector for detecting photons transmitted by the corresponding channels, and a first coincidence counter for receiving signals from the first detector and the second detector.

The invention has the advantages that:

(1) All optical devices in the light source module are collinear, and the alignment and coupling operation of optical fibers are facilitated. The wavelength used by the device belongs to a communication wave band and is suitable for long-distance propagation.

(2) The nonlinear coefficient of the PPKTP crystal is high, so that imaging brightness is high.

(3) In the invention, the light source module utilizes the wavelength to distinguish different entangled photon pairs, and the channels in the dense wavelength division multiplexing are divided according to the wavelength. The photons coming out of the pump laser are converted in the PPKTP crystal under the spontaneous parameter of type II, namely the photons are split into a photon pair in the recrystallization, the original photons are called as "pump photons", and the two photons in the photon pair are respectively and arbitrarily called as "signal photons" and "idler photons". According to the law of conservation of energy and the law of conservation of momentum, the total energy and the total momentum of the photon pair are equal to the energy and the momentum of the pump photon. However, there is a difference in frequency between photons, and in the invention, the photons are separated according to wavelength by using dense wavelength division multiplexing to form different output channels, and each output channel has H photons and V photons, so that different experiments are performed according to different channels.

(4) The device can be used for an HOM interference unit, a time energy entanglement unit and any one or any several of polarization entanglement units simultaneously work.

Drawings

FIG. 1 is an experimental setup of a high quality universal photon source device for multiple quantum optical experiments of the present invention;

FIG. 2 is a block diagram of a light source module according to the present invention;

fig. 3 is a block diagram of an HOM interference module, which is the first version of the entanglement generation and projection module of the present invention.

FIG. 4 is a block diagram of a two-photon Franson interference module, which is a second embodiment of the entanglement generation and projection module of the present invention;

FIG. 5 is a block diagram of an experimental module for polarization entanglement generation and characterization, which is the third scheme of the entanglement generation and projection module of the present invention;

FIG. 6 is a block diagram of a test module provided by an example of the present invention;

FIG. 7 shows experimental results of different kinds of photon sources provided by the embodiment of the present invention, in which FIG. 7 (a) shows the result of device measurement when the entanglement generation and projection module adopts the first scheme, FIG. 7 (b) shows the result of device measurement when the entanglement generation and projection module adopts the second scheme, FIG. 7 (c) shows the visibility parameters of the relevant channels when the entanglement generation and projection module adopts the third scheme, and FIG. 7 (d) shows the curve interference visibility values corresponding to the two channels when the entanglement generation and projection module adopts the third scheme;

fig. 8 is a reconstructed density matrix of polarization entangled photon pairs of front and back facets S1 and I1 provided by an embodiment of the present invention.

Fig. 9 is an analog spectrum of photon pairs emitted by a light source module of the present invention and a transmission spectrum of 100GHz dense optical wave multiplexing.

The meaning of the reference symbols in the figures is as follows:

1-light source module 11-pump laser

12-first polarization modulating component 121-first quarter wave plate 122-first quarter wave plate

13-first lens 14-PPKTP crystal 15-second lens 16-KTP crystal

17-first optical filter 18-first single mode optical fiber

19-dense wavelength division multiplexing 191-central channel C34-192-signal channel 193-idler channel

2-entanglement generation and projection module

211-second single mode fiber 212-second polarization modulation component

2121-second quarter wave plate 2122-second half wave plate

213-first polarizing beam splitter 214-third polarization modulating assembly

2141-third quarter wave plate 2142-third half wave plate

215-third single mode fiber 216-fourth polarization modulation component

2161-fourth quarter wave plate 2162-fourth half wave plate

217 fourth single mode fiber 218 first fiber splitter

221-fifth single-mode fiber 222-fifth polarization modulation assembly

2221-fifth quarter wave plate 2222-fifth half wave plate

223-second polarizing beam splitter

224-sixth single mode fiber 225-first unbalanced Michelson interferometer

226-seventh single mode fiber 227-second unbalanced Michelson interferometer

231-first fiber polarization controller 232-second fiber polarization controller

233-eighth single mode fiber 234-ninth single mode fiber

235-arbitrary phase retarder 2351-sixth quarter wave plate

2352-sixth-seventh quarter wave plate 2353-sixth-quarter wave plate

236-sixth polarization modulation assembly

2361-eighth quarter wave plate 2362-seventh half wave plate

237-seventh polarization modulating component

2371-ninth quarter wave plate 2372-eighth quarter wave plate

238-third polarizing beam splitter 239-fourth polarizing beam splitter

31-first detector 32-second detector 33-first coincidence counter

Detailed Description

Example 1

As shown in fig. 2, a light source module for multiple quantum optical experiments includes a pump laser 11, a first polarization modulation component 12, a first lens 13, a PPKTP crystal 1614, a second lens 15, a KTP crystal 16, a first optical filter 17, a first single-mode optical fiber 18, and a dense wavelength division multiplexing 19, which are sequentially arranged.

The pump laser 11 is used for exciting pump laser, the wavelength is 775.06nm, and the line width is less than 1MHz.

The first polarization modulation component 12 includes a first half-wave plate 121 and a first quarter-wave plate 122 with center wavelengths of 775nm, and the polarization states of the pump light are controlled by adjusting the fast axis directions of the first half-wave plate 121 and the first quarter-wave plate 122, so as to provide conditions for type II spontaneous parametric down-conversion in the PPKTP crystal 1614. In this scheme, the PPKTP crystal may be replaced with BBO crystal, PPLN crystal, or aluminum nitride crystal.

The first lens 13 is used for focusing the pump light, so that the pump light can be focused in the PPKTP crystal 1614 to have a proper beam waist, and the coating parameter of the first lens 13 is AR@775nm.

The length of the PPKTP crystal 1614 is 2mm, the polarization period is 46.2 mu m, and the plating conditions along the light transmission direction are as follows: the front end face S1 AR@775nm, AR@1550nm and the rear end face S2 AR@775nm, AR@1550nm can generate a type II spontaneous parametric down-conversion process of pump light in the PPKTP crystal 1614, the polarization of H photons and V photons generated by the pump light are orthogonal, and the generated photon pair is nearly degenerate in frequency.

The second lens 15 is used for collimating the H-photon and the V-photon, so that the H-photon and the V-photon can be coupled into the first single-mode optical fiber 18 with high efficiency; the coating parameter of the second lens 1515 is AR@1550nm.

The length of the KTP crystal 16 is 1mm, and the film plating condition along the light transmission direction is as follows: the front end face S1 AR@775nm, AR@1550nm and the rear end face S2 AR@775nm, AR@1550nm have their optical axes orthogonal to the optical axis of the PPKTP crystal 1614, and function to compensate for the time delay between H-photons and V-photons.

The first filter 17 filters out the original pump beam to allow the H-photon and the V-photon to pass smoothly.

The first single mode fiber 18 transmits the coupled in H-photons and V-photons to the dense wavelength division multiplex 19.

The dense wavelength division multiplexing 19 has 32 channels, the channel frequency interval is 100GHz, the transmission width of each channel is 66GHz, and the channel isolation width is 34GHz. In this embodiment, the channel is selected to correspond to a wavelength of 1550.12nm.

As specifically described in table 1:

project	Dense wavelength division multiplexing 19 channels	Wavelength (nm)
			Central channel	C34	1550.12
Signal channel 1-idler channel 1	C33–C35	1550.92-1549.32
			Signal channel 2-idler channel 2	C32–C36	1551.72–1548.52
Signal channel 3-idler channel 3	C31–C37	1552.52–1547.72
			Signal channel 4-idler channel 4	C30–C38	1553.33–1546.92
Signal channel 5-idler channel 5	C29–C39	1554.13–1546.12
			Signal path 6-idler path 6	C28–C40	1554.94–1545.32

The corresponding wavelengths of the correlated signal and idler channel 193 photons are defined in table 1. The pump wavelength is 775.06nm and the center wavelengths of the signal channel 192 photons and idler channel 193 photons are centered in channel C34 (1550.12 nm).

The light source module 1 is used to output the H-photons and V-photons with the selected channel wavelength in an orthogonal state, and the analog spectrum of the emitted photon pair and the transmission spectrum of the 100GHz dense optical wave multiplexing provided by the light source module 1 are shown in fig. 9.

Example 2

As shown in fig. 1, an apparatus including a light source module for various quantum optical experiments according to an embodiment includes an entanglement generation and projection module 2 disposed behind a light source module 1, the entanglement generation and projection module 2 including one or more of an HOM interference unit, a temporal energy entanglement unit, and a polarization entanglement unit. A measurement module 3 for detecting entanglement generation and projection module 2 results is also included.

The entanglement generation and projection module 2 and the measurement module 3 are described in detail below, respectively.

Measuring module

As shown in fig. 6, the measurement module includes a first superconductor nanowire single photon detector and a second detector 32 for detecting photons transmitted by the corresponding channels, the first detector 31 and the second detector 32 being superconductor nanowire single photon detectors, and a first coincidence counter 33 for receiving signals from the first and second detectors 32. The first coincidence counter 33 is a Timeharp 260Pico, and the coincidence window is 0.8 nanosecond, which performs coincidence measurement on the electric signals transmitted by the first detector 31 and the second detector 32.

HOM interference unit

As shown in fig. 3, the HOM interference unit includes a second single-mode fiber 211, a second polarization modulation component 212, and a first polarization beam splitter 213 that are sequentially disposed, where the first polarization beam splitter 213 splits a light beam into two paths, one path sequentially passes through a third polarization modulation component 214 and a third single-mode fiber 215, and the other path sequentially passes through a fourth polarization modulation component 216 and a fourth single-mode fiber 217, photons in the third single-mode fiber 215 and the fourth single-mode fiber 217 are input into the first fiber beam splitter 218, and the second single-mode fiber 211 obtains a light beam in a set channel in the dense wavelength division multiplexing 19 at the output end of the light source module 1.

The second single mode fiber 211 receives signals in the central channel C34191 of the dense wavelength division multiplexing 19, the signals being H-photons and V-photons with a wavelength of 1550.12nm, and the second single mode fiber 211 transmits polarized orthogonal H-photons and V-photons into the second polarization modulation component 212.

The second polarization modulation assembly 212 includes a second quarter wave plate 2121 (center wavelength @1550 nm) and a second half wave plate 2122 (center wavelength @1550 nm), the second quarter wave plate 2121 and the second half wave plate 2122 being sequentially replaceable in order to compensate for the polarization of the photons. In order to align the polarization states of the photons with the polarization states at the time of generation, the polarization states of the H and V photons are controlled by adjusting the fast axis directions of the second quarter wave plate 2121 and the second half wave plate 2122.

The first polarization beam splitter 213 is configured to separate H photons with orthogonal polarization and V photons, where the H photons are transmitted from the horizontal direction, the V photons are deflected by 90 ° and emitted to the surface of the V photons, and the parameters of the film-coated wave of the first polarization beam splitter 213 are ar@1550nm, and the incident angle is 0 °.

The third polarization modulation assembly 214 includes a third quarter wave plate 2141 (center wavelength @1550 nm) and a third half wave plate 2142 (center wavelength @1550 nm). By adjusting the fast axis direction of third quarter wave plate 2141 and third quarter wave plate 2142, the polarization state of the H-photons can be controlled.

The third single-mode fiber 215 is configured on a one-dimensional translation stage, and the direction of the one-dimensional translation stage is the optical path direction, and the one-dimensional translation stage is used for transmitting the H-photon with the polarization direction being the horizontal direction, so as to change the optical path difference between the H-photon and the V-photon.

The fourth polarization modulation assembly 216 includes a fourth quarter wave plate 2161 (center wavelength at 1550 nm) and a fourth quarter wave plate 2162 (center wavelength at 1550 nm). By adjusting the fast axis direction of the fourth quarter wave plate 2161 and fourth quarter wave plate 2162, the polarization state of the V-photons can be adjusted.

The fourth single mode fiber 217 is configured to transmit the V-photon having a polarization direction of a vertical direction.

The first optical fiber splitter 218 is a 2×2 device with an operating wavelength of 1550nm, which interferes the H-photons and V-photons with orthogonal polarization in the first optical fiber splitter 218, and outputs the photons to the test module. The two output ends of the first fiber optic beam splitter 218 are respectively connected to the first superconductor nanowire single photon detector and the second superconductor nanowire single photon detector 32.

Based on the general photon source device formed by the light source module 1, the HOM interference unit and the measurement module, the experimental result is shown in fig. 7 (a), the delay time is taken as an independent variable, the function image with the count as a vertical axis is met, when the time delay of the H photon and the V photon is zero, the number of the coincidence counts is close to zero, and when the time delay of the H photon and the V photon is increased, the number of the coincidence counts is increased. Interference visibility (v= (C) _max -C _min )/C _max ) Is (99.50+ -0.12)%, wherein C is _max Is the maximum coincidence count number, C _min Is the minimum coincidence count number. The half width of the region is 9.46ps and is consistent with the transmission bandwidth (66 GHz) of dense optical wave multiplexing. In the present embodiment, the pump laser 11 has a power of 256mW and a wavelength of 775.08nm, and the single-pass counts of the two detectors are 2.1X10 respectively ⁴ cps and 1.7X10 ⁴ cps. After interference with zero delay in the first fiber beam splitter 218, the photons are in a photon number and path entangled state

Time energy entanglement unit

As shown in fig. 4, the time-energy entanglement unit includes a fifth single mode fiber 221, a fifth polarization modulation component 222, and a second polarization beam splitter 223 sequentially disposed, where the second polarization beam splitter 223 splits the light beam into two paths, one path of the light beam is output from the first unbalanced michelson interferometer 225 after passing through the sixth single mode fiber 224, and the other path of the light beam is output from the second unbalanced michelson interferometer 227 after passing through the seventh single mode fiber 226.

The fifth single mode fiber 221 receives signals in the central channel C34191 of the dense wavelength division multiplexing 19, the signals being H-photons and V-photons with a wavelength of 1550.12nm, and the second single mode fiber 211 transmits polarized orthogonal H-photons and V-photons into the fifth polarization modulating component 222.

The fifth single mode fiber 221 transmits H photons and V photons with orthogonal polarization to the fifth polarization modulation assembly 222.

The fifth polarization modulation assembly 222 has a fifth quarter wave plate 2221 (center wavelength at 1550 nm) and a fifth half wave plate 2222 (center wavelength at 1550 nm). The polarization states of the H-photon and the V-photon can be controlled by adjusting the fast axis directions of the fifth quarter wave plate 2221 and the fifth half wave plate 2222 so that the polarization states of the photons coincide with the polarization states at the time of generation.

The sixth single mode fiber 224 is configured to transmit the H-photon having the polarization direction being the horizontal direction.

The seventh single mode fiber 226 is configured to transmit the V-photons having a polarization direction of vertical direction.

The second polarization beam splitter 223 is configured to separate the H-photons with orthogonal polarization from the V-photons, where the H-photons are transmitted from the horizontal direction and the V-photons are refracted at 90 °. The surface coating of the second polarization beam splitter 223 is ar@1550nm, and the incident angle is 0 °.

The first unbalanced michelson interferometer 225 consists of one 50:50 and two faraday rotator mirrors, the phase shift phi is varied by varying the temperature of the first unbalanced michelson interferometer 225 _s The optical fiber beam splitter equally divides the H photons into two paths of propagation along a short path S and propagation along a long path L, and the Faraday rotary mirror returns the photons of the corresponding paths to be output to the corresponding superconductor nanowire single photon detectors in the test module through the optical fiber beam splitter.

The second unbalanced michelson interferometer 227 consists of one 50:50 and two faraday rotating mirrors, wherein the temperature of the second unbalanced michelson interferometer 227 is kept unchanged, the optical fiber beam splitter equally divides the V photons into two paths of propagation along a short path S and propagation along a long path L, and the faraday rotating mirrors return photons of corresponding paths and output the photons to corresponding superconductor nanowire single photon detectors in the test module through the optical fiber beam splitter.

The experimental result of the universal photon source device formed by the light source module 1, the time energy entanglement unit and the measurement module is shown in fig. 7 (b), and the phase shift phi of the second unbalanced michelson interferometer 227 is used _s The time difference between the two arms of the first unbalanced michelson interferometer 225 and the second unbalanced michelson interferometer 227 is 1.6ns, which is an independent variable, and corresponds to the function image with the count as the vertical axis, and the effect is to perform two-photon Franson interference, and photons cannot be distinguished when passing through a long path and a short path. The expression can be expressed as:

l denotes a long path and S denotes a short path. We pass the formula v= (C _Max -C _Min )/(C _Max +C _Min ) To calculate interference visibility, where C _Max And C _Min Representing the maximum and minimum coincidence count numbers, respectively. When phi is ₁ When 0, the interference visibility is (99.17.+ -. 0.35)%, when φ ₁ Equal to->

At the time of interference visibility (99.59.+ -. 0.24)%, two photons were shown to have very high entanglement quality, and the single pass counts of the two detectors were 7.3X10, respectively ³ cps and 6.7X10 ³ cps。

Polarization entanglement unit

As shown in fig. 5, the polarization entanglement unit includes a signal optical path and an idler optical path for transmitting photons of the signal channel 192 and photons of the idler channel 193 in the dense wavelength division multiplexing 19 at the output end of the light source module 1, respectively, the signal optical path including a first optical fiber polarization controller 231, an eighth single mode optical fiber 233, an arbitrary phase retarder 235, a sixth polarization modulation component 236, and a third polarization beam splitter 238, which are disposed in this order; the idler path includes a second fiber polarization controller 232, a ninth single-mode fiber 234, a seventh polarization modulation component 237, and a fourth polarization beam splitter 239, all disposed in sequence. The specific description of the components is as follows:

the signal channels 192 may transmit photons of the signal channels 192 in the dense wavelength division multiplexing 19 of the corresponding wavelength; the idler channel 193 may transmit photons of the idler channel 193 in the dense wavelength division multiplex 19 of the corresponding wavelength. The corresponding wavelengths of the correlated signal and idler channel 193 photons can be found in table 1.

A first optical fiber polarization controller 231, the input end of which inputs photons of the signal channel in the dense wavelength division multiplexing 19;

the input end of the second optical fiber polarization controller 232 inputs photons of the idler frequency channel in the dense wavelength division multiplexing 19;

the eighth single mode fiber 233 is configured to transmit photons of the signal channel 192 having a polarization direction of a horizontal direction.

The ninth single mode fiber 234 is configured to transmit photons of the idler channel 193 having a polarization direction of a vertical direction.

The arbitrary phase retarder 235 includes a sixth quarter-wave plate 2351, a sixth half-wave plate 2352, and a seventh quarter-wave plate 2353, which are sequentially arranged, and the relative phase θ of the superimposed state is changed by adjusting the fast axis directions of the three.

The sixth polarization modulation component 236 includes an eighth quarter wave plate 2361 and a seventh half wave plate 2362 arranged in the optical path. By adjusting the fast axis direction of both, adjusting the polarization state of the photons of the control signal channel 192 can be achieved.

The seventh polarization modulation element 237 includes a ninth quarter wave plate 2371 and an eighth quarter wave plate 2372 disposed along the optical path. By adjusting the fast axis direction of both, an adjustment control of the polarization state of photons of idler channel 193 can be achieved.

The eighth polarization modulation component comprises a ninth quarter wave plate and an eighth half wave plate, and by adjusting the fast axis directions of the eighth quarter wave plate and the eighth half wave plate, the polarization state of photons of the control signal channel 192 can be adjusted.

The third polarization beam splitter 238, in combination with the eighth polarization modulation component, performs a projection measurement of photons of the signal channel 192 and outputs the photons to a detector corresponding to the test module.

The fourth polarization beam splitter 239, in combination with the seventh polarization modulation assembly 237, performs projection measurements on photons of the idler channel 193 and outputs the photons to a detector corresponding to the test module.

The general photon source device formed based on the light source module 1, the polarization entanglement unit and the measurement module has the following photon polarization states:

wherein H represents horizontal polarization, V represents vertical polarization, lambda _s Represents the wavelength of H photon lambda _i Representing the wavelength of the V photon, θ represents the relative phase of the superimposed states. Taking channels 33 and 35 as an example, we plot a functional image with the phase of signal channel 192 on the horizontal axis and the number of counts on the vertical axis, as shown in fig. 7 (c), with all relevant channel pairs having a visibility of greater than 97%. We examined the Bell inequality violation of channels for C33 and C35, and measured S parameters of 2.764 ±0.0139 against 55 standard deviations. As shown in FIG. 7 (d), the interference visibility values of the two curves are (99.20.+ -. 0.11)% and (98.80.+ -. 0.14)%, respectively, and the single-pass counts of the two detectors are 3X 10, respectively ⁴ cps and 1.6X10 ⁴ cps. To examine the entanglement quality of different entanglement pairs, we measured the interference visibility of the 45 degree basis, we reconstructed the corresponding density matrix using quantum state chromatography techniques to determine the quantum states, the imaginary values of the reconstructed density matrix were all zero, the real part of the density matrix is shown in fig. 8. HH denotes a pair of horizontally polarized photons, HV denotes one of the photon pairs being horizontally polarized and one being vertically polarized. VH is one vertical polarization in the photon pair, one horizontal polarization, and VV is both vertical polarizations in the photon pair. The fidelity of the reconstruction density is 0.9739 +/-0.0018, and the experimental deviation is mainly caused by the imprecision of the rotation angle of the wave plate.

The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims

1. The device for the light source module of the various quantum optical experiments is characterized by comprising a pump laser (11), a first polarization modulation component (12), a first lens (13), a first crystal, a second lens (15), a KTP crystal (16), a first optical filter (17), a first single-mode optical fiber (18) and dense wavelength division multiplexing (19) which are arranged according to an optical path;

the device for the light source module of the various quantum optical experiments further comprises an entanglement generation and projection module (2) arranged behind the light source module (1), wherein the entanglement generation and projection module (2) comprises one or more of an HOM interference unit, a time energy entanglement unit and a polarization entanglement unit.

2. The apparatus of claim 1, wherein the first crystal is any one of PPKTP crystal (1614), BBO crystal, PPLN crystal, and aluminum nitride crystal.

3. The device for a light source module for multiple quantum optical experiments according to claim 2, wherein the length of the PPKTP crystal (1614) is 2mm, the polarization period is 46.2 μm, and the plating conditions along the light passing direction are: front end face S1 AR@775nm, AR@1550nm and rear end face S2 AR@775nm, AR@1550nm.

4. The device for a light source module for multiple quantum optical experiments according to claim 1, wherein the KTP crystal (16) has a length of 1mm, and the film plating condition along the light passing direction is: front end face S1 AR@775nm, AR@1550nm and rear end face S2 AR@775nm, AR@1550nm.

5. The device for a light source module for multiple quantum optical experiments according to claim 1, wherein the HOM interference unit comprises a second single-mode fiber (211), a second polarization modulation component (212) and a first polarization beam splitter (213) which are sequentially arranged, the first polarization beam splitter (213) divides a light beam into two paths, one path sequentially passes through a third polarization modulation component (213), a third single-mode fiber (215) and the other path sequentially passes through a fourth polarization modulation component (216) and a fourth single-mode fiber (217), photons in the third single-mode fiber (215) and the fourth single-mode fiber (217) are input into the first single-mode fiber beam splitter (218), and the second single-mode fiber (211) obtains the light beam in a set channel in the dense wavelength division multiplexing (19) at the output end of the light source module (1).

6. The device for a light source module for multiple quantum optical experiments according to claim 1, wherein the time-energy entanglement unit comprises a fifth single-mode fiber (221), a fifth polarization modulation component (222) and a second polarization beam splitter (223) which are sequentially arranged, the second polarization beam splitter (223) divides a light beam into two paths, one path of the light beam is outputted from a first interferometer, the other path of the light beam is outputted from the second interferometer through a seventh single-mode fiber, and the fifth single-mode fiber (221) obtains the light beam in a set channel in a dense wavelength division multiplexing (19) at the output end of the light source module (1).

7. The apparatus of a light source module for multiple quantum optical experiments according to claim 1, wherein the polarization entanglement unit comprises a signal light path and an idler light path for transmitting photons of a signal channel (192) and photons of an idler channel (193) in dense wavelength division multiplexing (19) at an output end of the light source module (1), respectively, the signal light path comprising a first optical fiber polarization controller (231), an eighth single mode optical fiber (233), an arbitrary phase retarder (235), a sixth polarization modulation component (236), a third polarization beam splitter (238) arranged in this order; the idler frequency optical path comprises a second optical fiber polarization controller (232), a ninth single-mode optical fiber (234), a seventh polarization modulation component (237) and a fourth polarization beam splitter (239) which are sequentially arranged.

8. The apparatus of claim 7, wherein the arbitrary phase retarder (235) includes a sixth quarter-wave plate (2351), a sixth half-wave plate (2352), and a seventh quarter-wave plate (2353) arranged in that order.

9. The device for a light source module for a plurality of quantum optical experiments according to claim 1, further comprising a measurement module (3), the measurement module (3) comprising a first detector (31) and a second detector (32) for detecting photons transmitted by the corresponding channels, and a first coincidence counter (33) for receiving signals of the first detector (31) and the second detector (32).