CN115412237A - Hardware secret communication system and method based on dispersion-double-loop self-phase encryption - Google Patents

Abstract

The invention provides a hardware secret communication system and method based on dispersion-double-loop self-phase encryption, and relates to the technical field of optical fiber communication. The invention makes the optical pulse of the optical signal distorted by the dispersion component, then the phase modulator makes the phase encryption to the optical signal according to the encryption key, the optical signal output by the phase modulator generates the encryption key through two encryption branches and returns to the phase modulator for the phase encryption to the subsequent optical signal, the two encryption branches can obtain the encryption key with high security, thereby ensuring the security of the system, and can use the existing commercial devices and optical fiber channels to be compatible with the existing optical fiber network system, and realize the high-speed data transmission on the premise of ensuring the data security.

Description

Hardware secret communication system and method based on dispersion-double-loop self-phase encryption

Technical Field

The invention relates to the technical field of optical fiber communication, in particular to a hardware secret communication system and method based on dispersion-double-loop self-phase encryption.

Background

With the rapid development of modern optical communication technology, the autonomous optical fiber communication technology in China not only can meet different requirements of a large number of domestic network constructions, but also gradually moves to the construction of international social communication networks. These wide applications benefit from the advantages of low loss, large transmission capacity, and strong anti-electromagnetic interference capability of optical fiber communication, however, optical fiber communication also exposes potential security issues while providing high-quality and efficient communication for human beings, and how to provide large-capacity and high-speed optical communication on the premise of ensuring security becomes the focus of attention of many researchers.

Currently, researchers have proposed various optical network encryption technologies, which are roughly classified into software-based encryption systems, hardware-based encryption systems, and software-and-hardware-based encryption systems. The hardware-based encryption system mainly comprises a quantum encryption system, a chaotic encryption system, an optical pulse broadening encryption system and the like. Through these techniques, the security and confidentiality of data can be effectively improved, but some disadvantages still exist. Quantum cryptography can theoretically provide unlimited security, but has the problems of high cost and poor compatibility with conventional optical communication systems. The chaos encryption system is a mainstream technology based on hardware optical network encryption at present, a broadband chaos signal is used for encrypting an optical modulation signal, the encryption mode is divided into chaos modulation and chaos hiding, and chaos synchronous with a transmitting end is generated on the basis of the same hardware structure and parameters at a receiving end for decryption. The optical pulse broadening encryption system realizes encryption by broadening optical pulse signals to hide in system noise, is a solution of a broadband optical access network, and has the advantages of strong anti-interference capability, large transmission capacity and the like, but an optical pulse light source is incompatible with a modern high-speed optical communication system. Therefore, a more efficient and reliable hardware encryption technology is explored, so that the high-capacity and long-distance transmission can be realized, the reliable transmission can be further ensured, the compatibility with the existing optical network system is realized, and the method has important practical significance.

Publication No.: CN112600661A, published 2021-04-02, is a secret communication system based on double chaos modulation, the invention uses double chaos to spread spectrum for digital information, synchronously generates completely identical chaos sequences, after a sending end receives information modulation, a receiving end uses synchronous local signals to demodulate information, and secret communication is realized. However, it is difficult to achieve chaotic synchronization in long-distance communication, and since the chaotic bandwidth is limited by the relaxation oscillation frequency, the limited chaotic carrier bandwidth limits the transmission rate of chaotic optical communication, making it difficult to be compatible with the existing high-speed optical fiber communication system.

Disclosure of Invention

The present invention overcomes the above-mentioned problems and provides a hardware security communication system and method based on chromatic dispersion-dual-loop self-phase encryption, which can support long-distance data transmission and is highly compatible with the existing commercial optical components and optical fiber transmission systems.

The technical scheme of the invention is as follows:

the system comprises: the device comprises a signal generation module, a signal encryption module, an optical fiber transmission module, a signal decryption module and an optical demodulator;

the signal encryption module comprises a first dispersion component; the signal decryption module comprises a second dispersion component;

the signal generation module generates an optical signal to be encrypted and sends the optical signal to the signal encryption module, a first dispersion component in the signal encryption module scrambles the light intensity of the optical signal, then the signal encryption module performs phase encryption on the optical signal with the scrambled light intensity through a double-ring self-phase structure to obtain an encrypted optical signal, and the optical signal is sent to the signal decryption module through the optical fiber transmission module;

the signal decryption module decrypts the phase of the optical signal through a double-ring self-phase structure, and then a second dispersion component in the signal decryption module recovers the light intensity of the optical signal after the phase decryption to obtain the decrypted optical signal;

the optical signal transmission after the signal decryption module recovers the light intensity gives the optical demodulator, the optical demodulator converts the received optical signal into the electrical signal.

The technical scheme provides a hardware secret communication system based on dispersion-double-ring self-phase encryption, optical pulse broadening is carried out on optical signals through a dispersion component to enable the intensity of the optical signals to be distorted, then a double-ring self-phase structure carries out phase encryption on the optical signals, two encryption branches form a double-ring self-phase structure to obtain an encryption key with high safety, so that the system confidentiality is guaranteed, the existing commercial devices and optical fiber channels can be used to be compatible with the existing optical fiber network system, and high-speed data transmission is achieved on the premise that data safety is guaranteed.

Further, the signal generation module includes: the device comprises an external cavity semiconductor laser, a Mach-Zehnder modulator and a data generation module; the output end of the external-cavity semiconductor laser is connected with the first input end of the Mach-Zehnder modulator, the output end of the data generation module is connected with the second input end of the Mach-Zehnder modulator, the data generation module generates a driving signal, the external-cavity semiconductor laser sends out an optical carrier used for carrying the driving signal, the Mach-Zehnder modulator modulates the driving signal to the optical carrier to generate a high-order modulation signal, the output end of the Mach-Zehnder modulator is the output end of the signal generation module, and the output end of the signal generation module outputs an optical signal to be encrypted and sends the optical signal to the signal encryption module.

Further, the double-loop self-phase structure in the signal encryption module comprises: the device comprises a first phase modulator, a first optical coupler, a second optical coupler, a first encryption branch, a second encryption branch and a first arithmetic unit;

the double-loop self-phase structure in the signal decryption module comprises: the first optical coupler, the second optical coupler, the first decryption branch, the second arithmetic unit and the second phase modulator are connected in series;

the first dispersion part transmits the optical signal with the disturbed light intensity to a first phase modulator, the first phase modulator conducts phase encryption on the input optical signal according to an encryption key of the driving end, then outputs the optical signal with the encrypted phase, and the optical signal with the encrypted phase is transmitted to a first optical coupler;

the first optical coupler sends a part of optical signals through a first output end of the first optical coupler, the optical signals output by the first output end of the first optical coupler reach a second input end of the first arithmetic unit through the first encryption branch, and the first optical coupler sends the rest optical signals to the second optical coupler through a second output end of the first optical coupler;

the second optical coupler sends out a part of optical signals through a first output end of the second optical coupler, the optical signals output by the first output end of the second optical coupler reach a first input end of a first arithmetic unit through a second encryption branch, the first arithmetic unit superposes two paths of input signals to obtain an encryption key, and the encryption key is output to a drive end of the first phase modulator; the second output end of the second optical coupler outputs the rest optical signal, and the optical signal is sent to a third optical coupler in the signal decryption module through the optical fiber transmission module;

the third optical coupler sends out a part of optical signals through a first output end of the third optical coupler, the optical signals output by the first output end of the third optical coupler reach a first input end of the second arithmetic unit through the first decryption branch, and the third optical coupler sends the rest optical signals to the fourth optical coupler through a second output end of the third optical coupler;

the fourth optical coupler sends out a part of optical signals through a first output end of the fourth optical coupler, the optical signals output by the first output end of the fourth optical coupler reach a second input end of a second arithmetic unit through a second decryption branch, the second arithmetic unit superposes two paths of input signals to obtain a decryption key, and the decryption key is output to a drive end of a second phase modulator; and the second output end of the fourth optical coupler inputs the rest optical signal to the second phase modulator, the second phase modulator decrypts the optical signal according to the decryption key at the driving end, the decrypted optical signal is input to the second dispersion part, and the second dispersion part restores the intensity of the optical signal.

Further, the optical fiber transmission module includes: single mode fiber, dispersion compensating fiber, optical amplifier;

and the encrypted optical signal enters a transmission link consisting of a single-mode optical fiber and a dispersion compensation optical fiber matched with the dispersion value of the single-mode optical fiber for transmission, and then the optical amplifier is used for carrying out power amplification on the transmitted optical signal and transmitting the optical signal to the input end of the third optical coupler.

Furthermore, the signal encryption module further comprises a first radio frequency amplifier, an input end of the first radio frequency amplifier is connected with an output end of the first arithmetic unit, an output end of the first radio frequency amplifier is connected with a driving end of the first phase modulator, and the first radio frequency amplifier amplifies the electric signal; the signal decryption module further comprises a second radio-frequency amplifier, the input end of the second radio-frequency amplifier is connected with the output end of the second arithmetic unit, the output end of the second radio-frequency amplifier is connected with the driving end of the second phase modulator, and the second radio-frequency amplifier amplifies the electric signals.

Further, the first encryption branch comprises: the optical fiber delay line, the first variable optical attenuator and the first photoelectric detector are sequentially connected, the input end of the first variable optical delay line is connected with the first output end of the first optical coupler, the output end of the first photoelectric detector is connected with the second input end of the first arithmetic unit, and the first photoelectric detector converts an optical signal into an electric signal;

the second encryption branch comprises: the input end of the second adjustable optical fiber delay line is connected with the first output end of the second optical coupler, the output end of the second photoelectric detector is connected with the first input end of the first arithmetic unit, and the second photoelectric detector converts an optical signal into an electric signal;

the first decryption branch comprises: the input end of the third adjustable optical fiber delay line is connected with the first output end of the third optical coupler, the output end of the third photoelectric detector is connected with the first input end of the second arithmetic unit, and the third photoelectric detector converts an optical signal into an electric signal;

the second decryption branch comprises: the input end of the fourth adjustable optical fiber delay line is connected with the first output end of the fourth optical coupler, the output end of the fourth photoelectric detector is connected with the second input end of the second arithmetic unit, and the fourth photoelectric detector converts the optical signal into an electrical signal.

Further, the optical amplifier is an erbium-doped fiber amplifier.

Further, the dispersion values of the single mode fiber and the dispersion compensating fiber are matched, and the dispersion values of the first dispersion member and the second dispersion member are matched.

Further, the first dispersion part and the second dispersion part both use chirped fiber gratings.

A hardware secret communication method based on dispersion-double loop self-phase encryption comprises the following steps:

s1, modulating an electric signal to an optical carrier to generate an optical signal to be encrypted;

s2, disturbing the light intensity of the optical signal and outputting the optical signal;

s3, phase encryption is carried out on the optical signal according to the encryption key, and the encrypted optical signal is output;

s4, generating an encryption key by a part of the encrypted optical signals through a double-ring self-phase structure, encrypting the newly received optical signals, and outputting the rest encrypted optical signals;

s5, receiving the encrypted optical signal and decrypting the encrypted optical signal;

s6, generating a decryption key by a part of the encrypted optical signals through a double-ring self-phase structure, carrying out phase decryption on the rest optical signals according to the decryption key, and outputting the optical signals after the phase decryption;

s7, restoring the light intensity of the optical signal after the phase decryption, and outputting the decrypted optical signal;

and S8, demodulating the decrypted optical signal into an electric signal to complete data transmission.

The technical scheme provides a hardware secret communication system based on dispersion-double-loop self-phase encryption, and compared with the prior art, the technical scheme of the invention has the beneficial effects that: the optical signal is subjected to optical pulse broadening through the dispersion component to distort the intensity of the optical signal, then the double-ring self-phase structure is used for carrying out phase encryption on the optical signal, and the two encryption branches form the double-ring self-phase structure to obtain an encryption key with high safety, so that the system confidentiality is ensured, the existing commercial devices and optical fiber channels can be used to be compatible with the existing optical fiber network system, and high-speed data transmission is realized on the premise of ensuring the data security.

Drawings

FIG. 1 is a schematic diagram of a hardware secure communication system based on dispersion-dual-loop self-phase encryption;

wherein: 1. a signal generating module; 101. an external cavity semiconductor laser; 102. a Martin-Zehnder modulator; 103. a data generation module;

2. a signal encryption module; 21. a first encryption branch; 22. a second encryption branch; 201. a first dispersion member; 202. a first phase modulator; 203. a first optical coupler; 204. a first tunable fiber delay line; 205. a first variable optical attenuator; 206. a second optical coupler; 207. a second tunable fiber delay line; 208. a second variable optical attenuator; 209. a first photodetector; 210. a second photodetector; 211. a first arithmetic unit; 212. a first radio frequency amplifier; .

3. An optical fiber transmission module; 301. a single mode optical fiber; 302. a dispersion compensating fiber; 303. an erbium-doped fiber amplifier;

4. a signal decryption module; 41. a first decryption branch; 42. a second decryption branch; 401. a third optical coupler; 402. a third tunable fiber delay line; 403. a third variable optical attenuator; 404. a fourth optical coupler; 405. a fourth tunable fiber delay line; 406. a fourth variable optical attenuator; 407. a third photodetector; 408. a fourth photodetector; 409. a second arithmetic unit; 410. a second radio frequency amplifier; 411. a second phase modulator; 412. a second dispersive component;

5. an optical demodulator.

Detailed Description

For clearly illustrating the present invention, a hardware security communication system based on the dispersion-dual-loop self-phase encryption will be further described with reference to the embodiments and the drawings, but the scope of the present invention should not be limited thereby.

Example 1

A hardware secure communication system based on dispersion-double loop self-phase encryption, as shown in figure 1,

the system comprises: the device comprises a signal generation module 1, a signal encryption module 2, an optical fiber transmission module 3, a signal decryption module 4 and an optical demodulator 5;

the signal encryption module 2 includes: a first dispersion unit 201, a first phase modulator 202, a first optical coupler 203, a second optical coupler 206, a first encryption branch 21, a second encryption branch 22, and a first arithmetic unit 211;

the signal decryption module 4 includes: a third optical coupler 401, a fourth optical coupler 404, a first decryption branch 41, a second decryption branch 42, a second operator 409, a second phase modulator 411, and a second dispersion unit 412;

the signal generation module 1, the signal encryption module 2, the optical fiber transmission module 3, the signal decryption module 4 and the optical demodulator 5 are connected in sequence, specifically:

the signal generation module 1 generates an optical signal to be encrypted and sends the optical signal to the signal encryption module 2, a first dispersion part 201 in the signal encryption module 2 scrambles the light intensity of the optical signal and transmits the scrambled optical signal to a first phase modulator 202, the first phase modulator 202 performs phase encryption on the input optical signal according to an encryption key at a driving end and then outputs the phase-encrypted optical signal, and the phase-encrypted optical signal is transmitted to a first optical coupler 203;

the first optical coupler 203 sends out a part of optical signals through a first output end of the first optical coupler 203, the optical signals output by the first output end of the first optical coupler 203 reach a second input end of the first arithmetic unit 211 through the first encryption branch 21, and the first optical coupler 203 sends the rest optical signals to the second optical coupler 206 through a second output end of the first optical coupler 203;

the second optical coupler 206 sends out a part of optical signals through a first output end of the second optical coupler 206, an optical signal output by a first output end of the second optical coupler 206 reaches a first input end of the first arithmetic unit 211, the first arithmetic unit 211 superposes the two paths of input signals to obtain an encryption key, and the encryption key is output to a drive end of the first phase modulator 202; the second output end of the second optical coupler 206 outputs the remaining optical signal, and the optical signal is sent to the third optical coupler 401 in the signal decryption module 4 through the optical fiber transmission module 3;

the third optical coupler 401 sends out a part of optical signals through a first output terminal of the third optical coupler 401, the optical signals output by the first output terminal of the third optical coupler 401 pass through the first decryption branch 41 to reach a first input terminal of the second arithmetic unit 409, and the third optical coupler 401 sends the rest optical signals to the fourth optical coupler 404 through a second output terminal of the third optical coupler 401;

the fourth optical coupler 404 transmits a part of the optical signal through the first output end, the optical signal output by the first output end of the fourth optical coupler 404 reaches the second input end of the second arithmetic unit 409 through the second decryption branch 42, the second arithmetic unit 409 superposes the two paths of input signals to obtain a decryption key, and the decryption key is output to the drive end of the second phase modulator 411; the second output terminal of the fourth optical coupler 404 inputs the remaining optical signal to the second phase modulator 411, the second phase modulator 411 decrypts the optical signal according to the decryption key at the driving terminal, the decrypted optical signal is input to the second dispersion unit 412, the second dispersion unit 412 performs optical intensity recovery on the optical signal, and then transmits the optical signal after optical intensity recovery to the optical demodulator 5, and the optical demodulator 5 converts the received optical signal into an electrical signal.

The embodiment distorts the intensity of an optical signal through a dispersive component, the phase modulator encrypts the phase of the optical signal according to an encryption key, the optical signal output by the phase modulator generates the encryption key through two encryption branches and then returns to the phase modulator for encrypting the phase of the subsequent optical signal, and the two encryption branches can obtain the encryption key with high security, thereby ensuring the confidentiality of the system, being compatible with the existing optical fiber network system by using the existing commercial devices and optical fiber channels, and realizing high-speed data transmission on the premise of ensuring the data security.

Example 2

Fig. 1 is a schematic diagram of a hardware secure communication system based on dispersion-double loop self-phase encryption. As can be seen from fig. 1, the system comprises: the device comprises a signal generation module 1, a signal encryption module 2, an optical fiber transmission module 3, a signal decryption module 4 and an optical demodulator 5;

the signal generation module 1 includes: an external cavity semiconductor laser 101, a Mach-Zehnder modulator 102, and a data generation module 103; optionally, the data generating module 103 is an arbitrary waveform generator.

The signal encryption module 2 includes: a first dispersion unit 201, a first phase modulator 202, a first optical coupler 203, a second optical coupler 206, a first encryption branch 21, a second encryption branch 22, and a first arithmetic unit 211;

the optical fiber transmission module 3 includes: a single mode fiber 301, a dispersion compensating fiber 302, an optical amplifier 303;

the signal decryption module 4 includes: a third optical coupler 401, a fourth optical coupler 404, a first decryption branch 41, a second decryption branch 42, a second operator 409, a second phase modulator 411, and a second dispersion unit 412;

the signal generation module 1, the signal encryption module 2, the optical fiber transmission module 3, the signal decryption module 4 and the optical demodulator 5 are connected in sequence, specifically:

the output end of the external-cavity semiconductor laser 101 is connected with the first input end of the mach-zehnder modulator 102, the output end of the data generation module 103 is connected with the second input end of the mach-zehnder modulator 102, the data generation module 103 generates a driving signal, the external-cavity semiconductor laser 101 emits an optical carrier for carrying the driving signal, the mach-zehnder modulator 102 modulates the driving signal to the optical carrier to generate a high-order modulation signal, and the output end of the mach-zehnder modulator 102 is the output end of the signal generation module 1.

The signal generation module 1 generates an optical signal to be encrypted and sends the optical signal to the signal encryption module 2, a first dispersion part 201 in the signal encryption module 2 scrambles the light intensity of the optical signal and transmits the scrambled optical signal to a first phase modulator 202, the first phase modulator 202 encrypts the phase of the input optical signal according to an encryption key at a driving end and then outputs the optical signal after phase encryption, and the optical signal after phase encryption is transmitted to a first optical coupler 203;

the signal emitted by the signal generating module 1 may be an optical signal in any modulation format, such as a four-level pulse modulation PAM4 signal, an eight-level pulse amplitude modulation PAM8, quadrature phase shift keying QPSK, hexadecimal quadrature amplitude modulation 16QAM, and the like.

The first optical coupler 203 sends out a part of optical signals through a first output end of the first optical coupler 203, the optical signals output by the first output end of the first optical coupler 203 pass through the first encryption branch 21 to reach a second input end of the first arithmetic unit 211, and the first optical coupler 203 sends the rest optical signals to the second optical coupler 206 through a second output end of the first optical coupler 203;

the first encryption branch 21 comprises: the optical fiber delay line detection circuit comprises a first adjustable optical fiber delay line 204, a first adjustable optical attenuator 205 and a first photoelectric detector 209, wherein the first adjustable optical fiber delay line 204, the first adjustable optical attenuator 205 and the first photoelectric detector 209 are sequentially connected, the input end of the first adjustable optical fiber delay line 204 is connected with the first output end of the first optical coupler 203, the output end of the first photoelectric detector 209 is connected with the second input end of a first arithmetic unit 211, and the first photoelectric detector 209 converts an optical signal into an electric signal;

the second optical coupler 206 sends out a part of optical signals through the first output end, the second encryption branch 22 of the optical signals output by the first output end of the second optical coupler 206 reaches the first input end of the first arithmetic unit 211, the first arithmetic unit 211 superposes the two paths of input signals to obtain an encryption key, and the encryption key is output to the drive end of the first phase modulator 202; a second output terminal of the second optical coupler 206 outputs the remaining optical signal; the optical signal enters a transmission link composed of a single-mode optical fiber 301 and a dispersion compensation optical fiber 302 matched with the dispersion value of the single-mode optical fiber 301 for transmission, then the optical amplifier 303 is used for carrying out power amplification on the transmitted optical signal, and then the optical signal is transmitted to a decryption module 4 at a receiving end;

the second encryption branch 22 comprises: the optical fiber delay line is connected with the first adjustable optical fiber delay line 207, the second adjustable optical attenuator 208 and the second photoelectric detector 210 in sequence, the input end of the second adjustable optical fiber delay line 207 is connected with the first output end of the second optical coupler 206, the output end of the second photoelectric detector 210 is connected with the first input end of the first arithmetic unit 211, and the second photoelectric detector 210 converts an optical signal into an electrical signal;

the two encryption branches and the first phase modulator 202 form a double-loop self-phase structure, and an optical signal generated by the signal generation module 1 passes through the first dispersion component 201 to broaden optical pulses, so that the purpose of optical intensity distortion is achieved, and the first disturbance of the optical signal is realized. The double-ring phase structure randomly modulates the optical phase of the signal after the first dispersion component 201 is disturbed, so as to realize secondary disturbance of the optical signal, different key parameters are set for the first optical fiber delay line 204, the first optical attenuator 205, the second optical fiber delay line 207 and the second optical attenuator 208 in the two loops, the combination of the different parameters further increases the key space, increases the difficulty of decoding by an eavesdropper, then the first photoelectric detector 209 and the second photoelectric detector 210 are respectively used for performing photoelectric conversion of two paths, the first arithmetic unit 211 is used for realizing superposition of two paths of electric signals, and the first radio frequency amplifier 212 is used for driving the first phase modulator 202 to realize random modulation of the optical phase. Under the combined action of dispersion and dual-loop self-phase, the optical signal is encrypted in both amplitude and phase.

A third optical coupler 401 in the decryption module 4 sends out a part of optical signals through a first output terminal of the third optical coupler 401, optical signals output by a first output terminal of the third optical coupler 401 pass through the first decryption branch 41 to reach a first input terminal of the second arithmetic unit 409, and the third optical coupler 401 sends the remaining optical signals to the fourth optical coupler 404 through a second output terminal of the third optical coupler 401;

the first decryption branch 41 comprises: a third adjustable optical fiber delay line 402, a third adjustable optical attenuator 403, and a third photodetector 407, where the third adjustable optical fiber delay line 402, the third adjustable optical attenuator 403, and the third photodetector 407 are sequentially connected, an input end of the third adjustable optical fiber delay line 402 is connected to a first output end of the third optical coupler 401, an output end of the third photodetector 407 is connected to a first input end of the second arithmetic unit 409, and the third photodetector 407 converts an optical signal into an electrical signal;

the fourth optical coupler 404 transmits a part of optical signals through the first output end of the fourth optical coupler 404, the optical signals output by the first output end of the fourth optical coupler 404 reach the second input end of the second arithmetic unit 409 through the second decryption branch 42, the second arithmetic unit 409 superposes the two paths of input signals to obtain a decryption key, and the decryption key is output to the drive end of the second phase modulator 411; a second output end of the fourth optical coupler 404 inputs the remaining optical signal to the second phase modulator 411, the second phase modulator 411 decrypts the optical signal according to the decryption key at the driving end, the decrypted optical signal is input to the second dispersion part 412, the second dispersion part 412 performs light intensity recovery on the optical signal, then the optical signal with the recovered light intensity is transmitted to the optical demodulator 5, and the optical demodulator 5 converts the received optical signal into an electrical signal;

the second decryption branch 42 comprises: the fourth adjustable optical fiber delay line 405, the fourth adjustable optical attenuator 406, and the fourth photodetector 408 are sequentially connected, an input end of the fourth adjustable optical fiber delay line 405 is connected to a first output end of the fourth optical coupler 404, an output end of the fourth photodetector 408 is connected to a second input end of the second arithmetic unit 409, and the fourth photodetector 408 converts an optical signal into an electrical signal.

If the high-order modulation signal sent by the signal generating module 1 is a high-order phase modulation signal, the connection sequence of the dispersion component and the double rings cannot be changed; if the high-order modulation signal is a high-order intensity modulation signal or a 16QAM signal, the connection order of the dispersion element and the double loop can be changed. Namely: in this embodiment, the optical signal in the signal encryption module 2 is sequentially encrypted by the first dispersion component 201 and the double ring including the two encryption branches, and the optical signal in the signal decryption module 4 is sequentially decrypted by the double ring including the two decryption branches and the second dispersion component 412; in other embodiments, if the high-order modulation signal sent by the signal generating module 1 is a high-order intensity modulation signal or a 16QAM signal, a structure in which chromatic dispersion and double-loop connection are sequentially exchanged may also be selected, that is: in the decryption module, the input signal sequentially passes through the dispersion component and the double ring comprising the two decryption branches.

In this embodiment, the optical amplifier 303 is an erbium-doped fiber amplifier. The single mode optical fiber 301 and the dispersion compensating optical fiber 302 are dispersion value matched, and the first dispersion member 201 and the second dispersion member 412 are dispersion value matched. The first dispersion member 201 and the second dispersion member 412 each employ a chirped fiber grating. In other embodiments of the present invention, the first dispersive component 201 and the second dispersive component 412 may also adopt dispersive optical fibers, the external-cavity semiconductor laser 101 may be replaced by a CW continuous-wavelength laser, in other embodiments, different modulators are selected according to modulation formats, and optionally, the mach-zehnder modulator 102 in this embodiment may be replaced by an intensity modulator, a phase modulator, a cascaded mach-zehnder modulator, and a parallel mach-zehnder modulator according to modulation formats.

In this embodiment, the two encryption branches and the first phase modulator 202 form a double-ring self-phase structure, and realize encryption of information under the combined action of the dispersion component and the double-ring self-phase structure, and the symmetric decryption modules are used for decrypting signals, so that not only the same structure as that of the encryption module at the transmitting end needs to be built for signal decryption, but also six keys of matched dispersion, two delays, two attenuations and modulation depth need to be set for signal decryption, and by setting different key parameter combinations, the confidentiality of the system is greatly enhanced, and the system can be compatible with the existing optical fiber network system by using the existing commercial devices and optical fiber channels. The modulation depth refers to a ratio of a peak-to-peak value of the amplified output electrical signal by the first rf amplifier 212 to a half-wave voltage of the first phase modulator 202. The peak-to-peak value of the output electric signal can be changed by changing the gain of the radio frequency amplifier, so that the purpose of changing the modulation depth is achieved, and the signal reaching the driving end b through the double rings can be correctly restored only when the transmitting end and the receiving end are matched with the same modulation depth, so that the encryption effect of the double rings can be eliminated by setting the modulation depths with equal values and opposite signs during decryption.

Example 3

The embodiment discloses a hardware secret communication method based on dispersion-double-loop self-phase encryption, which comprises the following steps:

s1, modulating an electric signal to an optical carrier to generate an optical signal to be encrypted;

s2, disturbing the light intensity of the optical signal and outputting the optical signal;

s3, phase encryption is carried out on the optical signal according to the encryption key, and the encrypted optical signal is output;

s4, generating an encryption key by a part of the encrypted optical signals through a double-ring self-phase structure, encrypting the newly received optical signals, and outputting the rest encrypted optical signals;

s5, receiving the encrypted optical signal and decrypting the encrypted optical signal;

s6, generating a decryption key by a part of the encrypted optical signals through a double-ring self-phase structure, carrying out phase decryption on the rest optical signals according to the decryption key, and outputting the optical signals after the phase decryption;

s7, restoring the light intensity of the optical signal after the phase decryption, and outputting the decrypted optical signal;

and S8, demodulating the decrypted optical signal into an electric signal to complete data transmission.

Claims (10)

1. A hardware secure communication system based on dispersion-dual loop self-phase encryption, the system comprising: the device comprises a signal generation module (1), a signal encryption module (2), an optical fiber transmission module (3), a signal decryption module (4) and an optical demodulator (5);

the signal encryption module (2) comprises a first dispersion component (201); the signal decryption module (4) comprises a second dispersion component (412);

the signal encryption method comprises the following steps that a signal generation module (1) generates an optical signal to be encrypted and sends the optical signal to a signal encryption module (2), a first dispersion part (201) in the signal encryption module (2) scrambles the light intensity of the optical signal, then the signal encryption module (2) conducts phase encryption on the optical signal with the scrambled light intensity through a double-ring self-phase structure to obtain an encrypted optical signal, and the optical signal is sent to a signal decryption module (4) through an optical fiber transmission module (3);

the signal decryption module (4) decrypts the phase of the optical signal through a double-ring self-phase structure, and then a second dispersion component (412) in the signal decryption module (4) recovers the light intensity of the optical signal after the phase decryption to obtain a decrypted optical signal;

the signal decryption module (4) transmits the optical signal after the light intensity is restored to the optical demodulator (5), and the optical demodulator (5) converts the received optical signal into an electric signal.

2. A hardware secure communication system based on chromatic dispersion-double loop self-phase encryption according to claim 1, characterized in that the signal generation module (1) comprises: an external cavity semiconductor laser (101), a Mach-Zehnder modulator (102), and a data generation module (103); the output end of the external-cavity semiconductor laser (101) is connected with the first input end of the Mach-Zehnder modulator (102), the output end of the data generation module (103) is connected with the second input end of the Mach-Zehnder modulator (102), the data generation module (103) generates a driving signal, the external-cavity semiconductor laser (101) sends an optical carrier for carrying the driving signal, the Mach-Zehnder modulator (102) modulates the driving signal to the optical carrier to generate a high-order modulation signal, the output end of the Mach-Zehnder modulator (102) is the output end of the signal generation module (1), and the output end of the signal generation module (1) outputs an optical signal to be encrypted and sends the optical signal to the signal encryption module (2).

3. A hardware secure communication system based on chromatic dispersion-double-loop self-phase encryption according to claim 1, characterized in that the double-loop self-phase structure in the signal encryption module (2) comprises: a first phase modulator (202), a first optical coupler (203), a second optical coupler (206), a first encryption branch (21), a second encryption branch (22), and a first arithmetic unit (211);

the double-loop self-phase structure in the signal decryption module (4) comprises: a third optical coupler (401), a fourth optical coupler (404), a first decryption branch (41), a second decryption branch (42), a second arithmetic unit (409) and a second phase modulator (411);

the first dispersion part (201) transmits the optical signal with the disturbed optical intensity to a first phase modulator (202), the first phase modulator (202) performs phase encryption on the input optical signal according to an encryption key at the driving end and then outputs the optical signal with the encrypted phase, and the optical signal with the encrypted phase is transmitted to a first optical coupler (203);

the first optical coupler (203) sends out a part of optical signals through a first output end of the first optical coupler (203), the optical signals output by the first output end of the first optical coupler (203) reach a second input end of the first arithmetic unit (211) through a first encryption branch (21), and the first optical coupler (203) sends the rest optical signals to the second optical coupler (206) through a second output end of the first optical coupler (203);

a second optical coupler (206) sends out a part of optical signals through a first output end of the second optical coupler (206), the optical signals output by a first output end of the second optical coupler (206) reach a first input end of a first arithmetic unit (211) through a second encryption branch (22), the first arithmetic unit (211) superposes the two paths of input signals to obtain an encryption key, and the encryption key is output to a drive end of a first phase modulator (202); a second output end of the second optical coupler (206) outputs the rest optical signal, and the optical signal is sent to a third optical coupler (401) in the signal decryption module (4) through the optical fiber transmission module (3);

the third optical coupler (401) sends out a part of optical signals through a first output end of the third optical coupler (401), the optical signals output by a first output end of the third optical coupler (401) reach a first input end of a second arithmetic unit (409) through a first decryption branch (41), and the third optical coupler (401) sends the rest optical signals to a fourth optical coupler (404) through a second output end of the third optical coupler (401);

a fourth optical coupler (404) sends out a part of optical signals through a first output end of the fourth optical coupler (404), the optical signals output by the first output end of the fourth optical coupler (404) reach a second input end of a second arithmetic unit (409) through a second decryption branch (42), the second arithmetic unit (409) superposes the two paths of input signals to obtain a decryption key, and the decryption key is output to a drive end of a second phase modulator (411); the second output end of the fourth optical coupler (404) inputs the rest optical signal to the second phase modulator (411), the second phase modulator (411) decrypts the optical signal according to the decryption key of the driving end, the decrypted optical signal is input to the second dispersion part (412), and the second dispersion part (412) restores the intensity of the optical signal.

4. A hardware secure communication system based on chromatic dispersion-double loop self-phase encryption according to claim 1, characterized in that the optical fiber transmission module (3) comprises: a single-mode fiber (301), a dispersion compensating fiber (302), and an optical amplifier (303);

the encrypted optical signal enters a transmission link consisting of a single-mode optical fiber (301) and a dispersion compensation optical fiber (302) matched with the dispersion value of the single-mode optical fiber (301) for transmission, and then an optical amplifier (303) is used for carrying out power amplification on the transmitted optical signal and transmitting the amplified optical signal to the input end of a third optical coupler (401).

5. A hardware secure communication system based on chromatic dispersion-double loop self-phase encryption according to claim 3, characterized in that the signal encryption module (2) further comprises a first rf amplifier (212), an input end of the first rf amplifier (212) is connected to an output end of the first operator (211), an output end of the first rf amplifier (212) is connected to a driving end of the first phase modulator (202), and the first rf amplifier (212) amplifies the electrical signal; the signal decryption module (4) further comprises a second radio frequency amplifier (410), the input end of the second radio frequency amplifier (410) is connected with the output end of the second arithmetic unit (409), the output end of the second radio frequency amplifier (410) is connected with the driving end of the second phase modulator (411), and the second radio frequency amplifier (410) amplifies the electric signal.

6. A hardware secure communication system based on chromatic dispersion-double loop self-phase encryption according to claim 3, characterized in that said first encryption branch (21) comprises: the optical fiber delay line optical coupler comprises a first adjustable optical fiber delay line (204), a first adjustable optical attenuator (205) and a first photoelectric detector (209), wherein the first adjustable optical fiber delay line (204), the first adjustable optical attenuator (205) and the first photoelectric detector (209) are sequentially connected, the input end of the first adjustable optical fiber delay line (204) is connected with the first output end of a first optical coupler (203), the output end of the first photoelectric detector (209) is connected with the second input end of a first arithmetic unit (211), and the first photoelectric detector (209) converts an optical signal into an electrical signal;

the second encryption branch (22) comprises: the optical fiber delay line circuit comprises a second adjustable optical fiber delay line (207), a second adjustable optical attenuator (208) and a second photoelectric detector (210), wherein the second adjustable optical fiber delay line (207), the second adjustable optical attenuator (208) and the second photoelectric detector (210) are sequentially connected, the input end of the second adjustable optical fiber delay line (207) is connected with the first output end of a second optical coupler (206), the output end of the second photoelectric detector (210) is connected with the first input end of a first arithmetic unit (211), and the second photoelectric detector (210) converts an optical signal into an electrical signal;

the first decryption branch (41) comprises: the optical fiber delay line circuit comprises a third adjustable optical fiber delay line (402), a third adjustable optical attenuator (403) and a third photoelectric detector (407), wherein the third adjustable optical fiber delay line (402), the third adjustable optical attenuator (403) and the third photoelectric detector (407) are sequentially connected, the input end of the third adjustable optical fiber delay line (402) is connected with the first output end of a third optical coupler (401), the output end of the third photoelectric detector (407) is connected with the first input end of a second arithmetic unit (409), and the third photoelectric detector (407) converts an optical signal into an electrical signal;

the second decryption branch (42) comprises: the optical fiber delay line optical attenuator comprises a fourth adjustable optical fiber delay line (405), a fourth adjustable optical attenuator (406) and a fourth photoelectric detector (408), wherein the fourth adjustable optical fiber delay line (405), the fourth adjustable optical attenuator (406) and the fourth photoelectric detector (408) are sequentially connected, the input end of the fourth adjustable optical fiber delay line (405) is connected with the first output end of the fourth optical coupler (404), the output end of the fourth photoelectric detector (408) is connected with the second input end of a second arithmetic unit (409), and the fourth photoelectric detector (408) converts an optical signal into an electrical signal.

7. A dispersion-double loop self-phase encryption based hardware secure communication system according to claim 4, characterized in that said optical amplifier (303) is an erbium doped fiber amplifier.

8. A dispersion-double loop self-phase encryption based hardware secret communication system according to any one of claim 4, characterized in that the dispersion values of the single mode fiber (301) and the dispersion compensation fiber (302) are matched, and the dispersion values of the first dispersion element (201) and the second dispersion element (412) are matched.

9. A dispersion-double loop self-phase encryption based hardware secure communication system according to claim 1, characterized in that the first dispersion element (201) and the second dispersion element (412) both use chirped fiber gratings.

10. A hardware secret communication method based on dispersion-double loop self-phase encryption is characterized by comprising the following steps:

s1, modulating an electric signal to an optical carrier to generate an optical signal to be encrypted;

s2, disturbing the light intensity of the optical signal and outputting the optical signal;

s3, phase encryption is carried out on the optical signal according to the encryption key, and the encrypted optical signal is output;

s4, generating an encryption key by a part of the encrypted optical signals through a double-ring self-phase structure, encrypting the newly received optical signals and outputting the rest encrypted optical signals;

s5, receiving the encrypted optical signal, and decrypting;

s6, generating a decryption key by a part of the encrypted optical signals through a double-ring self-phase structure, carrying out phase decryption on the rest optical signals according to the decryption key, and outputting the optical signals after the phase decryption;

s7, restoring the light intensity of the optical signal after the phase decryption, and outputting the decrypted optical signal;

and S8, demodulating the decrypted optical signal into an electric signal to complete data transmission.

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