CN105897414B - Continuous variable quantum key distribution system based on Faraday-Michelson interference - Google Patents
Continuous variable quantum key distribution system based on Faraday-Michelson interference Download PDFInfo
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Abstract
The invention discloses a Faraday-Michelson interference-based continuous variable quantum key distribution system.A transmitting end is used for generating a pulse light source with coincident parameters such as repetition frequency, pulse width and the like, and modulating positive components X and P of signal light; the communication channel is an optical propagation channel and is used for transmitting the signal light modulated by the transmitting end and the local oscillator light not modulated to the receiving end; the receiving end demodulation module realizes measurement and base selection: and the receiving end homodyne detection module is used for detecting and processing the signals to obtain the modulation information data of the signals. The invention introduces two unequal arm Faraday-Michelson interference rings, and makes the polarization disturbance self-compensated in the pulse round-trip process by means of the Faraday polarization rotating mirror, thereby being beneficial to improving the stability of the system and being not easy to be interfered by polarization; the existing detection technology and post-processing algorithm can be combined to realize long-distance stable quantum key distribution.
Description
Technical Field
The invention relates to a quantum key distribution scheme, in particular to a continuous variable quantum key distribution system based on Faraday-Michelson interference.
Background
Since the idea of quantum communication using Continuous Variable Quantum Key Distribution (CVQKD) was proposed in 1999, CVQKD has attracted attention from many scholars. DVQKD is distributed relative to the now-studied mature discrete variable quantum key. The CVQKD gets rid of the constraints of a single photon source and the low detection efficiency of 1550nm wave band, adopts strong light communication equivalent to classical light intensity, and uses a homodyne detector with mature technology in the traditional communication for measurement, so that higher key generation rate and the fusion with the traditional optical network become possible.
In 2002, a CVQKD protocol based on gaussian modulation was proposed, and then the unconditional security of this scheme was also successively demonstrated in the case of distribution key asymptotic limits and limitations. The CVQKD scheme based on Gaussian modulation gradually enters the experimental and practical process.
At present, the CVQKD can already realize the key generation rate of 1Mbps, and the communication distance also realizes the breakthrough of 100Km on the premise of sacrificing the key generation rate. However, in both domestic and foreign CVQKD schemes, which are based on the double unequal arm M-Z scheme, since signal light and pulse light pass through different arms of the mach-zehnder interferometer, the polarization interference cannot be completely consistent, and when a long-range quantum channel is experienced, the polarization drift is aggravated under environmental interference, thereby directly affecting the interference stability of the detection end. Therefore, the anti-interference capability of the key distribution system is poor, the stability cannot be maintained, and the safety of the CVQKD cannot be guaranteed.
Disclosure of Invention
The invention aims to provide a continuous variable quantum key distribution system based on Faraday-Michelson interference aiming at the defects of the prior art, and the system can overcome the problem that the key distribution system is unstable due to polarization drift in a continuous variable quantum key distribution scheme.
In order to achieve the technical aim, the invention adopts the technical scheme that the continuous variable quantum key distribution system based on Faraday-Michelson interference comprises a transmitting end, a communication channel and a receiving end; the output end of the transmitting end is connected with the input end of the communication channel, and the output end of the communication channel is connected with the input end of the receiving end; the method is characterized in that:
the transmitting end comprises a light source module and a modulation module, and the output end of the light source module is connected with the input end of the modulation module; the light source module comprises a continuous Laser, an amplitude modulator AM1 and an isolator ISO which are sequentially connected; the continuous Laser is used for generating continuous Laser with required wavelength, and the amplitude modulator AM1 is used for regulating and controlling the output light parameters of the Laser; the output light of the amplitude modulator AM1 is connected to the input end of the isolator ISO; the other end of the isolator ISO is connected with a modulation module; the modulation module is an F-M ring modulation module; the F-M ring modulation module comprises a 2 x 2 beam splitter BS1, a Faraday rotation mirror FM2, a phase modulator PM1 and an amplitude modulator AM1; the 2 x 2 beam splitter BS1 has four beam splitting arms, which are beam splitting arm B1, beam splitting arm B2, beam splitting arm B3, and beam splitting arm B4, respectively; the beam splitting arm B3 and the beam splitting arm B4 are different in arm length; the front ends of the four beam splitting arms respectively correspond to four ports, namely a port BS11, a port BS12, a port BS13 and a port BS14; the port BS11 is connected with the isolator ISO, and the port BS12 is connected with a communication channel; the port connected with the light source module is an incident end, and the port connected with the communication channel is an emergent end; the port BS13 is connected with a Faraday rotator FM1, and the port BS14 is connected with a Faraday rotator FM2; continuous laser generated by the light source module enters the 2 x 2 beam splitter BS1 through the incident end, and is split by the 2 x 2 beam splitter BS1 to form local oscillation light and signal light, wherein the local oscillation light enters the port BS13, and the signal light enters the port BS14; local oscillation light and signal light respectively enter a 2 x 2 beam splitter BS1 after being reflected by a Faraday rotation mirror FM1 and a Faraday rotation mirror FM2 and are coupled; both the Faraday rotator FM1 and the Faraday rotator FM2 are 90-degree rotating Faraday reflectors and are used for rotating the polarization direction of reflected light by 90 degrees relative to incident light; reflected light of the local oscillator light and the signal light is coupled by a beam splitter BS1 and then enters an port BS11 and a port BS12; wherein the reflected light of the entrance port BS11 is lost by the light source module isolator ISO, and the reflected light of the entrance port BS12 is accessed to the communication channel;
the communication channel is an optical propagation channel and is used for transmitting the signal light modulated by the transmitting end and the local oscillator light which is not modulated to the receiving end;
the receiving end comprises a demodulation module and a homodyne detection module; the demodulation module is a demodulation F-M ring module, and the demodulation F-M ring module comprises a circulator CIR2, a 2 x 2 unequal arm beam splitter BS3, a Faraday rotation mirror FM4 and a phase modulator PM2; a C21 port of the circulator CIR2 is connected with a communication channel, a C22 port is connected with the BS3, and a C23 port is connected with a homodyne detection component; the beam splitting ratio of the beam splitter BS3 is 50; the beam splitter BS3 is a 2 × 2 beam splitter and has four beam splitting arms, namely a beam splitting arm B5, a beam splitting arm B6, a beam splitting arm B7 and a beam splitting arm B8; the front ends of the four beam splitting arms respectively correspond to four ports, namely a port BS31, a port BS32, a port BS33 and a port BS34; the port BS31 is connected with a communication channel, the port BS32 is connected with the photoelectric detector PIN4, the port BS33 is connected with the Faraday rotator FM3, and the port BS34 is connected with the Faraday rotator FM4; the difference between the arm lengths of the beam splitting arm B7 and the beam splitting arm B8 is equal to the difference between the arm lengths of the beam splitting arm B3 and the beam splitting arm B4, i.e. | l B7 -l B8 |＝|l B3 -l B4 L, |; port BS31 connection ringThe reflected light of the Faraday rotation mirror FM3 and the Faraday rotation mirror FM4 is input into the port C22 of the circulator CIR2 and then is input into the photoelectric detector PIN3 through the port C23 of the circulator CIR 2; the homodyne detection module comprises a photoelectric detector PIN3, a photoelectric detector PIN4 and a processing circuit; and the homodyne detection module is used for carrying out difference processing on the results of the photoelectric detector PIN3 and the photoelectric detector PIN4 so as to obtain modulation signal information data.
As a further improved technical scheme of the invention, the higher pulse intensity is defined as local oscillator light, the lower pulse intensity is defined as signal light, and the beam splitting arm B4 where the signal light is located is ensured to be the shorter arm of the beam splitting arm B3 and the beam splitting arm B4; the pulses are pulses split by the 2 x 2 beam splitter BS1, reflected by the faraday rotator and combined at the 2 x 2 beam splitter BS 1.
As a further improved technical solution of the present invention, a phase modulator PM1 of a modulation module is disposed on a beam splitting arm B4 where a signal light is located or on a beam splitting arm B2 after being combined, and the phase modulator PM1 is configured to perform phase modulation on the signal light; the local oscillator light is not modulated, and is directly accessed into a communication channel through a port BS 12.
As a further improved technical solution of the present invention, an amplitude modulator AM2 is connected to the beam splitting arm B2, and the amplitude modulator AM2 is configured to modulate the amplitude of the signal light.
As a further improved technical scheme of the invention, the modulation values of the amplitude modulator AM2 and the phase modulator PM1 are calculated by regular components X and P of signal light, and the amplitude modulation values
Phase modulation value
X and P follow a gaussian distribution.
As a further improved technical solution of the present invention, the modulation module further includes an adjustable delay line DL1 disposed on the beam splitting arm B3 or the beam splitting arm B4, and the adjustable delay line DL1 is used to adjust the relative time delay between the signal light and the local oscillation light.
As a further improved technical scheme of the invention, a beam splitter BS2 and an adjustable attenuator VOA combination are arranged on a beam splitting arm B4 where the signal light at the transmitting end is positioned, and the combination is used for realizing the detection and control of the power of the signal light.
As a further improved technical scheme of the invention, the transmitting end also comprises a circulator CIR1, a port C12 of the circulator CIR1 is connected with a communication channel, a port C11 is connected with a port BS12, and a port C13 is connected with a photoelectric detector for detecting virus attack.
As a further improved technical scheme of the invention, the communication channel is an optical waveguide medium, a free space, a split optical element, an optical fiber optical element or a combination of any two or more of the optical waveguide medium, the free space, the split optical element and the optical fiber optical element;
as a further improved technical scheme of the invention, the characteristics of the receiving end Faraday reflectors FM3 and FM4 are the same as those of the transmitting end Faraday reflectors FM1 and FM 2.
As a further improved technical solution of the present invention, the characteristics of the circulator CIR2 and the transmitting-end circulator CIR1 are the same, and the light is input from a C21 port, output from a C22 port, input from a C22 port, and output from a C23 port; light is input from the C11 port, output from the C12 port, input from the C12 port, and output from the C13 port.
As a further improved technical solution of the present invention, the demodulation module at the receiving end further includes an adjustable delay line DL2, where the DL2 may be disposed on any one of the beam splitting arms B7 and B8, and cooperates with the adjustable delay line DL1 to adjust the arm length difference between the beam splitting arms B7 and B8 of BS3 to be equal to the arm length difference between the beam splitting arms B3 and B4 of BS1, so that the local oscillation light respectively traveling along the long arm and the short arm at the transmitting end and the signal light respectively traveling along the short arm and the long arm at the receiving end reach the beam combiner BS3 at the same time, thereby implementing interference.
As a further improved technical scheme of the invention, the phase modulator PM2 at the receiving end is arranged on a relatively shorter arm of the beam splitting arms B7 and B8, and only performs phase modulation on local oscillation light.
As a further improved technical solution of the present invention, the phase modulator PM2 at the receiving end is randomly modulated to 0 ° or 90 ° according to a binary random number, thereby realizing the function of measuring and selecting a basis.
This based on Faraday-Michelson interference continuous variable quantum key distribution system work flow:
1. after a narrow linewidth laser with the consistent wavelength is selected, the repetition frequency, the pulse width and the amplitude of output light are modulated through an amplitude modulator AM1, and the obtained pulse light is unidirectionally connected into a 2 x 2 beam splitter through an isolator ISO.
2. The light source output light is split into two beams after passing through the beam splitter BS1, which are respectively called local oscillation light and signal light, and respectively enter the beam splitter port BS13 and the port BS14. Generally, the higher intensity local oscillator light (about 10^8 photons/pulse) is selected to pass through the longer arm of beam splitting arms B3 and B4, and the lower intensity signal light passes through the shorter arm of beam splitting arms B3 and B4.
3. After the reflection of Faraday rotator FM1 and Faraday rotator FM2, the polarization of two beams of light is deflected by 90 degrees, and the polarization influences self-compensation in the process of reciprocating.
4. The local oscillator light reflected by the faraday rotator FM1 of the port BS13 of the beam splitter BS1 is not modulated and is directly coupled into a communication channel through the port BS12 of the beam splitter BS 1.
5. The transmitting end modulates the regular position X or the regular momentum P of the optical field of the signal light through the phase modulator PM1 of the port BS4 and the amplitude modulator AM1 of the port BS12 according to the prepared modulation random number.
6. By means of unequal arm lengths of the beam splitting arm B3 and the beam splitting arm B4 and the adjustable delay line DL1, the local oscillation light and the signal light have relative delay in the transmission time domain.
7. The local oscillator light and the signal light enter the communication channel through the port BS12 by the time division multiplexing technique.
8. The signal light and the local oscillator light reach a receiving end, are split by a 3dB beam splitter BS3 and enter an unequal-arm F-M ring which is symmetrical to a transmitting end, and the arm length difference of an F-M ring modulation module of the transmitting end is equal to that of the unequal-arm F-M ring of the receiving end.
9. After the light is reflected by a Faraday rotation mirror FM3 and a Faraday rotation mirror FM4 on the unequal-arm F-M ring, the time delay of partial signal light and local oscillation light is compensated. The local oscillation light of the long arm and the local oscillation light of the short arm are respectively transmitted at the transmitting end and the receiving end, and the signal light of the short arm and the signal light of the long arm are respectively transmitted at the transmitting end and the receiving end to the beam splitter BS3 at the same time, so that interference occurs.
10. And a phase modulator PM2 is arranged on an arm where local oscillation light of a receiving end is positioned, and phase modulation of 0 or 90 degrees is selected through random binary numbers, so that selective measurement of a measurement basis X component or P component is realized.
11. The signal light and the local oscillator light interfere at a 3dB beam splitter (namely a beam splitter BS 3) and enter a homodyne detection module. Through homodyne detection, the receiving end obtains a string of symbol values associated with the transmitting end, the symbol values and the transmitting end are subjected to quantization processing to convert symbols into binary codes, data post-processing is further performed, and finally a safe binary key is obtained.
The invention mainly comprises a light source module, a modulation F-M ring module, a communication channel, a demodulation F-M ring module and a homodyne detection module, wherein the light source module is positioned at a transmitting end; the invention depends on the optical rotation characteristic of the Faraday mirror, so that the polarization disturbance of light in the incident and reflected light paths is automatically compensated, and stable quantum key distribution is realized. At present, research directions on CVQKD are concentrated to improve the detection efficiency of a detector and upgrade of an algorithm, innovation is provided from a key distribution device, and the method can be used by combining the detection and data post-processing technology, so that a CVQKD system can stably and safely transmit a quantum key. The invention introduces two unequal arm Faraday-Michelson interference rings, and makes the polarization disturbance self-compensated in the pulse round-trip process by means of the Faraday polarization rotating mirror, thereby being beneficial to improving the stability of the system and being not easy to be interfered by polarization; the long-distance stable quantum key distribution can be realized by combining the existing detection technology and post-processing algorithm. In a word, the invention provides a novel continuous variable quantum key distribution scheme, which is beneficial to improving the stability of a system and is not easy to be interfered by polarization; the long-distance stable quantum key distribution can be realized by combining the existing detection technology and post-processing algorithm.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention;
fig. 2 is a schematic diagram of the CVQKD implementation scheme of the present invention.
Detailed Description
Example 1
Referring to fig. 1 and fig. 2, the faraday-michelson interference-based continuous variable quantum key distribution system includes a transmitting end, a communication channel, and a receiving end; the output end of the transmitting end is connected with the input end of the communication channel, and the output end of the communication channel is connected with the input end of the receiving end.
The transmitting end comprises a light source module and a modulation module, and the output end of the light source module is connected with the input end of the modulation module; the light source module comprises a continuous Laser, an amplitude modulator AM1 and an isolator ISO which are sequentially connected; the continuous Laser is used for generating continuous Laser with required wavelength, and the amplitude modulator AM1 is used for regulating and controlling the output light parameters of the Laser; the output light of the amplitude modulator AM1 is connected to the input end of the isolator ISO; the other end of the isolator ISO is connected with a modulation module;
the modulation module is an F-M ring modulation module; the F-M ring modulation module comprises a 2 x 2 beam splitter BS1, a Faraday rotation mirror FM2 and a phase modulator PM1; the 2 × 2 beam splitter BS1 has four beam splitting arms, which are beam splitting arm B1, beam splitting arm B2, beam splitting arm B3, and beam splitting arm B4, respectively; the beam splitting arm B3 and the beam splitting arm B4 are different in arm length; the front ends of the four beam splitting arms respectively correspond to four ports, namely a port BS11, a port BS12, a port BS13 and a port BS14; the port BS11 is connected with the isolator ISO, and the port BS12 is connected with a communication channel; the port connected with the light source module is an incident end, and the port connected with the communication channel is an emergent end; the port BS13 is connected with a Faraday rotator FM1, and the port BS14 is connected with a Faraday rotator FM2; continuous laser generated by the light source module enters the 2 x 2 beam splitter BS1 through the incident end, local oscillation light and signal light are formed after beam splitting of the 2 x 2 beam splitter BS1, the local oscillation light enters the port BS13, and the signal light enters the port BS14; local oscillator light and signal light are reflected by a Faraday rotation mirror FM1 and a Faraday rotation mirror FM2 respectively and then enter a 2 x 2 beam splitter BS1 to be coupled; both the Faraday rotator mirror FM1 and the Faraday rotator mirror FM2 are 90-degree Faraday reflectors which are used for rotating the polarization direction of reflected light by 90 degrees relative to incident light; reflected light of the local oscillation light and the local oscillation light is coupled by a beam splitter BS1 and then enters an inlet BS11 and an inlet BS12; wherein the reflected light of the entrance port BS11 is lost by the light source module isolator, and the reflected light of the entrance port BS12 is accessed into the communication channel;
the pulse which is split by the BS1, reflected by the FM and combined at the BS1 is defined as local oscillation light with higher intensity and signal light with lower intensity, and the beam splitting arm B4 where the signal light is located is ensured to be the shorter arm of the beam splitting arms B3 and B4.
A phase modulator PM1 of the modulation module is arranged on a beam splitting arm B4 where the signal light is marked or on a beam splitting arm B2 after beam combination, and the phase modulator PM1 is used for carrying out phase modulation on the signal light; the local oscillator light is not modulated at all and is directly accessed into a communication channel through a port BS 12.
An amplitude modulator AM2 is connected to the beam splitting arm B2, and the amplitude modulator AM2 modulates the amplitude of the signal light.
The modulation values of the amplitude modulator AM2 and the phase modulator PM1 are calculated from the regular components X, P of the signal light, the amplitude modulation values
Phase modulation value
In general, X and P follow a gaussian distribution.
The modulation module further comprises an adjustable delay line DL1 disposed on the beam splitting arm B3 or the beam splitting arm B4, and the adjustable delay line DL1 is used for adjusting the relative time delay of the signal light and the local oscillator light.
A beam splitter BS2 and an adjustable attenuator VOA combination are disposed on the beam splitting arm B4 where the signal light of the transmitting end is located, so as to implement detection and control of the signal light power.
The transmitting end system also comprises a circulator CIR1, a port C12 of the circulator CIR1 is connected with the communication channel, a port C11 is connected with a port BS12, and a port C13 is connected with a photoelectric detector and used for detecting attacks such as Trojan horses.
The communication channel is a light propagation channel, is used for transmitting the signal light modulated by the transmitting end and the local oscillator light not modulated to the receiving end, and can be an optical waveguide medium, a free space, a separation optical element, an optical fiber optical element or a combination of any two or more of the optical waveguide medium, the free space, the separation optical element and the optical fiber optical element;
the receiving end comprises a demodulation module and a homodyne detection module; the demodulation module is a demodulation F-M ring module, and the demodulation F-M ring module comprises a circulator CIR2, a 2 x 2 unequal arm beam splitter BS, a Faraday rotation mirror FM3, a Faraday rotation mirror FM4 and a phase modulator PM2; the C21 port of the circulator CIR2 is connected with a communication channel, the C22 port is connected with the BS3, and the C23 port is connected with a homodyne detection component. The unequal arm F-M ring uses a beam splitter BS3 with a beam splitting ratio of 50; the beam splitter BS3 is a 2 × 2 beam splitter, and has four beam splitting arms, namely a beam splitting arm B5, a beam splitting arm B6, a beam splitting arm B7, and a beam splitting arm B8; the front ends of the four beam splitting arms respectively correspond to four ports, namely a port BS31, a port BS32, a port BS33 and a port BS34; the port BS31 is connected with a communication channel, the port BS32 is connected with the photoelectric detector PIN4, the port BS33 is connected with the Faraday rotation mirror FM3, and the port BS34 is connected with the Faraday rotation mirror FM4; the difference between the arm lengths of the beam splitting arm B7 and the beam splitting arm B8 is equal to the difference between the arm lengths of the beam splitting arm B3 and the beam splitting arm B4, i.e. | l B7 -l B8 |＝|l B3 -l B4 L; the port BS31 is connected with a port C22 of the circulator CIR2, reflected light of the Faraday rotation mirror FM3 and the Faraday rotation mirror FM4 is input into the port C22 of the circulator CIR2, and then is input into the photoelectric detector PIN3 through a port C23 of the circulator CIR 2; the homodyne detection module comprises a photoelectric detector PIN3, a photoelectric detector PIN4 and a processing circuit; and the homodyne detection module is used for carrying out difference processing on the results of the photoelectric detector PIN3 and the photoelectric detector PIN4 so as to obtain modulation signal information data.
The receiving end faraday mirrors FM3 and FM4 have the same characteristics as the transmitting ends FM1 and FM 2. The circulator CIR2 has the same characteristics as the transmitting-side circulator CIR1, and inputs light from the C21 (C11) port and outputs the light from the C22 (C12) port, and inputs light from the C22 (C12) port and outputs the light from the C23 (C13) port.
The demodulation module of the receiving end also comprises an adjustable delay line DL2, the DL2 can be arranged on any one of the beam splitting arms B7 and B8 and cooperates with the DL1 to adjust and enable the arm length difference of the beam splitting arms B7 and B8 of the BS3 to be equal to the arm length difference of the beam splitting arms B3 and B4 of the BS1, and therefore the local oscillation light respectively walking the long arm and the short arm at the transmitting end and the signal light respectively walking the short arm and the long arm at the receiving end can simultaneously reach the beam combiner BS3, and interference is achieved.
The phase modulator PM2 at the receiving end should be arranged on a relatively short arm of B7 and B8, and only performs phase modulation on local oscillation light. The phase modulator PM2 randomly modulates to 0 degree or 90 degrees according to the binary random number to realize the function of measuring and selecting the basis.
Through homodyne detection, a receiving end obtains a string of symbol values associated with a transmitting end, the symbol values and the symbol values are subjected to quantization processing, symbols are converted into binary codes, data post-processing is further carried out, and finally a safe binary key is obtained.
Claims (14)
1. A continuous variable quantum key distribution system based on Faraday-Michelson interference comprises a transmitting end, a communication channel and a receiving end; the output end of the transmitting end is connected with the input end of the communication channel, and the output end of the communication channel is connected with the input end of the receiving end; the method is characterized in that:
the transmitting end comprises a light source module and a modulation module, and the output end of the light source module is connected with the input end of the modulation module; the light source module comprises a continuous Laser, an amplitude modulator AM1 and an isolator ISO which are sequentially connected; the continuous Laser is used for generating continuous Laser with required wavelength, and the amplitude modulator AM1 is used for regulating and controlling the output light parameters of the Laser; the output light of the amplitude modulator AM1 is connected to the input end of the isolator ISO; the other end of the isolator ISO is connected with a modulation module; the modulation module is an F-M ring modulation module; the F-M ring modulation module comprises a 2 x 2 beam splitter BS1, a Faraday rotator FM2, a phase modulator PM1 and an amplitude modulator AM2; the 2 × 2 beam splitter BS1 has four beam splitting arms, which are beam splitting arm B1, beam splitting arm B2, beam splitting arm B3, and beam splitting arm B4, respectively; the beam splitting arm B3 and the beam splitting arm B4 are different in arm length; the front ends of the four beam splitting arms respectively correspond to four ports, namely a port BS11, a port BS12, a port BS13 and a port BS14; the port BS11 is connected with the isolator ISO, and the port BS12 is connected with a communication channel; the port connected with the light source module is an incident end, and the port connected with the communication channel is an emergent end; the port BS13 is connected with a Faraday rotator FM1, and the port BS14 is connected with a Faraday rotator FM2 through a phase modulator PM1; continuous laser generated by the light source module enters the 2 x 2 beam splitter BS1 through the incident end, and is split by the 2 x 2 beam splitter BS1 to form local oscillation light and signal light, wherein the local oscillation light enters the port BS13, and the signal light enters the port BS14; local oscillator light and signal light are reflected by a Faraday rotation mirror FM1 and a Faraday rotation mirror FM2 respectively and then enter a 2 x 2 beam splitter BS1 to be coupled; both the Faraday rotator mirror FM1 and the Faraday rotator mirror FM2 are 90-degree rotating Faraday reflectors and are used for rotating the polarization direction of reflected light by 90 degrees relative to incident light; reflected light of the local oscillator light and the signal light is coupled by a beam splitter BS1 and then enters an port BS11 and a port BS12; wherein the reflected light of the entrance port BS11 is lost by the light source module isolator ISO, and the reflected light of the entrance port BS12 is accessed into the communication channel;
the communication channel is an optical propagation channel and is used for transmitting the signal light modulated by the transmitting end and the local oscillator light which is not modulated to the receiving end;
the receiving end comprises a demodulation module and a homodyne detection module; the demodulation module is a demodulation F-M ring module, and the demodulation F-M ring module comprises a circulator CIR2, a 2 x 2 unequal arm beam splitter BS3, a Faraday rotation mirror FM4 and a phase modulator PM2; a C21 port of the circulator CIR2 is connected with a communication channel, a C22 port is connected with a BS3, and a C23 port is connected with a photoelectric detector PIN3 in the homodyne detection module; the beam splitting ratio of the beam splitter BS3 is 50; the beam splitter BS3 is a 2 × 2 beam splitter and has four beam splitting arms, namely a beam splitting arm B5, a beam splitting arm B6, a beam splitting arm B7 and a beam splitting arm B8; the front ends of the four beam splitting arms respectively correspond to four ports, namely a port BS31, a port BS32, a port BS33 and a port BS34; the port BS31 is connected with a communication channel, the port BS32 is connected with the photoelectric detector PIN4, the port BS33 is connected with the Faraday rotator FM3, and the port BS34 is connected with the Faraday rotator FM4; the difference between the arm lengths of the beam splitting arm B7 and the beam splitting arm B8 is equal to the difference between the arm lengths of the beam splitting arm B3 and the beam splitting arm B4, i.e. | l B7 -l B8 |＝|l B3 -l B4 L, |; the port BS31 is connected with a port C22 of the circulator CIR2, reflected light of the Faraday rotation mirror FM3 and the Faraday rotation mirror FM4 is input into the port C22 of the circulator CIR2, and then is input into the photoelectric detector PIN3 through a port C23 of the circulator CIR 2; the photoelectric detector comprises a photoelectric detector PIN3, a photoelectric detector PIN4 and a processing circuit; for performing difference processing on the results of the photo detector PIN3 and the photo detector PIN4 to obtain the information number of the modulation signalAccordingly.
2. The faraday-michelson interference based continuously variable quantum key distribution system of claim 1, wherein: defining that the higher pulse intensity is local oscillation light, the lower pulse intensity is signal light, and the beam splitting arm B4 where the signal light is located is the shorter arm of the beam splitting arm B3 and the beam splitting arm B4; the pulses are pulses split by the 2 x 2 beam splitter BS1, reflected by the faraday rotator and combined at the 2 x 2 beam splitter BS 1.
3. The faraday-michelson interference based continuously variable quantum key distribution system of claim 1, wherein: a phase modulator PM1 of the modulation module is arranged on a beam splitting arm B4 where the signal light is marked to be located or on a beam splitting arm B2 after the signal light is combined, and the phase modulator PM1 is used for carrying out phase modulation on the signal light; the local oscillator light is not modulated at all and is directly accessed into a communication channel through a port BS 12.
4. A faraday-michelson interference based continuously variable quantum key distribution system according to claim 3, wherein: an amplitude modulator AM2 is connected to the beam splitting arm B2, and the amplitude modulator AM2 modulates the amplitude of the signal light.
5. The faraday-michelson interference based continuously variable quantum key distribution system of claim 4, wherein: the modulation values of the amplitude modulator AM2 and the phase modulator PM1 are calculated from the regular components X, P of the signal light, the amplitude modulation values
Phase modulation value
X and P follow a gaussian distribution.
6. The system according to claim 1, wherein: the modulation module further comprises an adjustable delay line DL1 disposed on the beam splitting arm B3 or the beam splitting arm B4, and the adjustable delay line DL1 is used for adjusting the relative time delay of the signal light and the local oscillator light.
7. The faraday-michelson interference based continuously variable quantum key distribution system of claim 5, wherein: a beam splitter BS2 and an adjustable attenuator VOA combination are disposed on the beam splitting arm B4 where the signal light of the transmitting end is located, so as to implement detection and control of the signal light power.
8. The faraday-michelson interference based continuously variable quantum key distribution system of claim 2, wherein: the transmitting end also comprises a circulator CIR1, a port C12 of the circulator CIR1 is connected with a communication channel, a port C11 is connected with a port BS12, and a port C13 is connected with a photoelectric detector PIN2 and used for detecting virus attack.
9. The faraday-michelson interference based continuously variable quantum key distribution system of claim 1, wherein: the communication channel is an optical waveguide medium, free space, split optics, fiber optics, or a combination of any two or more thereof.
10. The faraday-michelson interference based continuously variable quantum key distribution system of claim 1, wherein: the receiving end Faraday reflectors FM3 and FM4 have the same characteristics as the transmitting end Faraday reflectors FM1 and FM 2.
11. The system according to claim 1, wherein: the circulator CIR2 and the transmitting-end circulator CIR1 have the same characteristics, and input light from a C21 port and output from a C22 port, and input light from the C22 port and output from a C23 port; input light from the C11 port is output from the C12 port, input light from the C12 port is output from the C13 port.
12. The system according to claim 1, wherein: the demodulation module of the receiving end also comprises an adjustable delay line DL2, the DL2 can be arranged on any one of the beam splitting arms B7 and B8 and cooperates with the adjustable delay line DL1 to adjust and enable the arm length difference of the beam splitting arms B7 and B8 of the BS3 to be equal to the arm length difference of the beam splitting arms B3 and B4 of the BS1, and therefore the local oscillation light respectively walking the long arm and the short arm at the transmitting end and the signal light respectively walking the short arm and the long arm at the receiving end can simultaneously reach the beam combiner BS3, and interference is achieved.
13. The system according to claim 1, wherein: the phase modulator PM2 at the receiving end is disposed on a relatively shorter one of the beam splitting arms B7 and B8, and performs phase modulation only on the local oscillation light.
14. The faraday-michelson interference based continuously variable quantum key distribution system of claim 11, wherein: and the receiving end phase modulator PM2 randomly modulates to 0 degree or 90 degrees according to the binary random number to realize the function of measuring and selecting the basis.
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Families Citing this family (17)
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| CN110896328B (en) * | 2018-09-12 | 2022-04-19 | 中国科学技术大学 | Continuous variable quantum key distribution system based on single reference light pulse single homodyne detection |
| CN109391471B (en) * | 2018-10-15 | 2021-07-06 | 中国科学技术大学 | Hybrid waveguide integrated interferometer and quantum key distribution system |
| CN110932857B (en) * | 2019-12-18 | 2021-01-15 | 北京邮电大学 | Quantum key distribution system capable of completely symmetrical receiving and transmitting keys |
| CN111721193B (en) * | 2020-06-04 | 2021-05-07 | 华东师范大学 | Teaching demonstration device and demonstration method for measuring quantum noise in laser interferometer |
| CN115225247B (en) * | 2022-07-11 | 2023-12-01 | 北京邮电大学 | Phase modulation loop-back time synchronization device, method and system |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103546280A (en) * | 2013-10-28 | 2014-01-29 | 中国科学技术大学 | Encoder and decoder for quantum cryptographic communication |
| CN205912067U (en) * | 2016-05-26 | 2017-01-25 | 安徽问天量子科技股份有限公司 | Based on faraday michelson interferometer continuous variable quantum key distribution system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1651947A (en) * | 2004-02-02 | 2005-08-10 | 中国科学技术大学 | Polarization control coding method coder and quantum key distributing system |
| CN102322880B (en) * | 2011-08-18 | 2013-06-05 | 天津大学 | Polarization sensitive distributive optical frequency domain reflection disturbance sensor and demodulation method |
-
2016
- 2016-05-26 CN CN201610362912.2A patent/CN105897414B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103546280A (en) * | 2013-10-28 | 2014-01-29 | 中国科学技术大学 | Encoder and decoder for quantum cryptographic communication |
| CN205912067U (en) * | 2016-05-26 | 2017-01-25 | 安徽问天量子科技股份有限公司 | Based on faraday michelson interferometer continuous variable quantum key distribution system |
Non-Patent Citations (1)
| Title |
|---|
| 光纤量子密钥分发系统中的偏振无关相位调制;李瑞雪等;《激光与光电子学进展》;20160410(第04期);全文 * |
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