A carrier-suppressed based optical frequency hopping communication system and method

Abstract

The present disclosure provides a carrier suppression-based optical frequency hopping communication system, characterized in that comprising: a transmitter, configured to carrier suppression modulate a laser signal to generate two frequency signals with different frequencies, output the two frequency signals on two links alternately based on a frequency hopping sequence to generate two carrier signals, modulate two user data on the two carrier signals respectively to generate two modulated carrier signals, and couple the two modulated carrier signals as a transmission signal for transmission; and a receiver, configured to receive the transmission signal, separate the two frequency signals based on different frequencies, output the two frequency signals on two links alternately based on the frequency hopping sequence to recover the two modulated carrier signals, and demodulate the two modulated carrier signals respectively to obtain the two user data. By loading user data on carrier signals with random frequency hopping, the data is effectively hidden to prevent eavesdropping by illegal third parties.

Description

Technical Field

[0001] This disclosure relates to the field of optical communication, specifically to an optical frequency hopping communication system and method based on carrier suppression. Background Technology

[0002] Fiber optic communication technology has developed rapidly in recent years, greatly promoting social progress and economic development. However, with the frequent occurrence of user information leaks around the world in recent years, the risk of user data being stolen by illegal third parties during transmission is increasing, and optical communication security technology is receiving increasing attention.

[0003] In existing secure communication mechanisms, encrypting user data using algorithms at the software layer is the most common method. However, with the tremendous increase in computing power, the security of this method has begun to be threatened. Therefore, more and more researchers are turning their attention to physical layer security technologies. Physical layer security technologies utilize the physical characteristics of communication channels to enhance communication security through appropriate encoding and processing of signals. Summary of the Invention

[0004] In view of this, the present disclosure proposes an optical frequency hopping communication system based on carrier suppression, characterized in that it includes: a transmitter, used to perform carrier suppression modulation on a laser signal to generate two frequency signals with different frequencies, and based on a frequency hopping sequence, alternately output the two frequency signals on two links to generate two carrier signals, and modulate two user data signals onto the two carrier signals respectively to generate two modulated carrier signals, and couple them into a transmit signal for transmission; and a receiver, used to receive the transmit signal, separate the two frequency signals based on different frequencies, and based on the frequency hopping sequence, alternately output the two frequency signals on two links to recover the two modulated carrier signals, and demodulate the two modulated carrier signals respectively to obtain two user data signals.

[0005] Optionally, the transmitter includes: a carrier suppression module for carrier-suppressed modulation of the laser signal to generate a modulated signal with positive and negative first-order sidebands; a first filtering module for filtering out the positive and negative first-order sidebands of the modulated signal to obtain two frequency signals; a carrier modulation module for alternately outputting the two frequency signals on two links based on the frequency hopping sequence to generate two carrier signals; a data modulation module for modulating two user data streams onto the two carrier signals to generate two modulated carrier signals; and a transmission signal generation module for coupling the two modulated carrier signals into a transmission signal.

[0006] Optionally, the receiver comprises: a second filtering module, configured to generate two paths of the frequency signals based on frequency separation of the transmitting signals; a modulated carrier wave recovery module, configured to output the two paths of the frequency signals on two links alternately based on the frequency hopping sequence, so as to recover two paths of the modulated carrier wave signals; and a signal demodulation module, configured to demodulate the two paths of the modulated carrier wave signals respectively, so as to obtain the user data.

[0007] Optionally, the carrier wave suppression module comprises: a laser generator, connected to the modulator, and configured to generate the laser signal; a radio frequency signal generator, connected to the modulator, and configured to generate a radio frequency signal; and a modulator, configured to modulate the radio frequency signal on the laser signal, so as to realize carrier wave suppression of the laser signal.

[0008] Optionally, the carrier wave modulation module comprises: a first frequency hopping sequence generator, configured to generate the frequency hopping sequence; and a first 2*2 optical switch, with a voltage control end connected to the first frequency hopping sequence generator, and configured to control a connection state between an input end and an output end based on the frequency hopping sequence, so as to output the two paths of the frequency signals on the two links alternately based on the frequency hopping sequence, and form the carrier wave signal.

[0009] Optionally, the data modulation module further comprises: a pre-processing encryption unit, configured to perform data encryption on the user data.

[0010] Optionally, the modulated carrier wave recovery module comprises: a second frequency hopping sequence generator, configured to generate the frequency hopping sequence; and a second 2*2 optical switch, with a voltage control end connected to the second frequency hopping sequence generator, and configured to control a connection state between an input end and an output end based on the frequency hopping sequence, so as to output the two paths of the frequency signals on the two links alternately based on the frequency hopping sequence, and recover the two paths of the modulated carrier wave signals.

[0011] Optionally, the signal demodulation module comprises: a local oscillator light generator, configured to generate local oscillator light with the same frequency as the laser; two couplers, configured to mix the two paths of the modulated carrier wave signals with the local oscillator light respectively, so as to generate mixed signals; and two balanced detectors, configured to perform heterodyne detection on the two paths of the mixed signals respectively, so as to obtain the user data.

[0012] Optionally, the frequency hopping sequence is one of an m sequence, an M sequence, a Gold sequence, and an RS sequence.

[0013] A carrier suppression based optical frequency hopping communication method, characterized in that, comprising: two frequency signals obtained by carrier suppression modulating laser signals, based on a frequency hopping sequence, generating two carrier signals, modulating two user data on two carrier signals respectively, generating two modulated carrier signals, and coupling into a transmission signal for transmission; receiving the transmission signal, based on the frequency hopping sequence, restoring two modulated carrier signals from two frequency signals separated from the transmission signal, and demodulating two modulated carrier signals respectively to obtain two user data.

[0014] The present disclosure provides a carrier suppression based optical frequency hopping communication system, the transmitter obtains two frequency signals with different frequencies by carrier suppression modulation method, and under the control of the frequency hopping sequence, two frequency signals are alternately output on two links, generating two carrier signals with opposite frequency hopping rules and complementary wavelengths. Two user data are loaded on the above two carrier signals respectively, and coupled into a transmission signal, so that the user data is transmitted by different physical channels in the transmission process, so that the data can be effectively hidden to prevent illegal third parties from eavesdropping, thereby improving the security of data transmission. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1 A block diagram of a carrier suppression based optical frequency hopping communication system according to an embodiment of the present disclosure is schematically shown;

[0017] Figure 2 A device schematic diagram of a carrier suppression based optical frequency hopping communication system according to an embodiment of the present disclosure is schematically shown;

[0018] Figure 3 A carrier suppression based optical frequency hopping communication method according to an embodiment of the present disclosure is schematically shown;

[0019] Figure 4 A schematic diagram of two frequency signals separated after carrier suppression of a laser signal according to an embodiment of the present disclosure is schematically shown;

[0020] Figure 5 Two carrier signals generated based on a frequency hopping sequence according to an embodiment of the present disclosure are schematically shown; and

[0021] Figure 6 The distribution of two user data after the frequency separation of the transmission signal into two frequency signals according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It is to be understood, however, that the description is merely exemplary and is intended to provide a thorough understanding of the present disclosure. In the following detailed description of embodiments of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it would be apparent to those skilled in the art that the present disclosure can be practiced without these specific details. In other instances, well-known structures and functions have not been described in detail in order to avoid obscuring the concepts of the present disclosure.

[0023] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the term "includes" and tautological expressions thereof, such as "including," "includes," "include," "contains," "containing," and so forth, mean the term "comprises," as long as the above-mentioned terms do not exclude the existence or addition of one or more other features, steps, operations, and / or components.

[0024] All terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having meanings consistent with the context of the present specification, and should not be interpreted in an idealized or excessively formal manner.

[0025] In the case of using expressions similar to "at least one of A, B, and C, etc.", it should generally be interpreted to include one or more of the items enumerated in the list of A, B, and C, etc. For example, "a system having at least one of A, B, and C" should be interpreted to include a system having A alone, a system having B alone, a system having C alone, a system having both A and B, a system having both A and C, a system having both B and C, and / or a system having A, B, and C, etc.

[0026] A carrier-suppressed optical frequency hopping communication system according to an embodiment of the present disclosure includes a transmitter 100 and a receiver 200. The transmitter 100 is configured to carrier-suppress modulate a laser signal to generate two frequency signals having different frequencies, output the two frequency signals alternately on two links based on a frequency hopping sequence to generate two carrier signals, modulate two user data on the two carrier signals, respectively, to generate two modulated carrier signals, and couple the two modulated carrier signals to generate a transmission signal. The receiver 200 is configured to receive the transmission signal, separate the two frequency signals based on different frequencies, output the two frequency signals alternately on the two links based on the frequency hopping sequence, recover the two modulated carrier signals, and demodulate the two modulated carrier signals, respectively, to obtain the two user data.

[0027] Figure 1 A block diagram of a carrier-suppressed optical frequency hopping communication system according to an embodiment of the present disclosure is schematically shown.

[0028] According to an embodiment of the present disclosure, as Figure 1As shown, the transmitter 100 of the optical frequency hopping communication system based on carrier suppression comprises a carrier suppression module 110, a first filtering module 120, a carrier modulation module 130, a data modulation module 140 and a transmitting signal forming module 150. The receiver 200 of the optical frequency hopping communication system based on carrier suppression comprises a second filtering module 210, a modulated carrier recovery module 220 and a signal demodulation module 230.

[0029] According to the embodiment of the present disclosure, the carrier suppression module 110 is configured to perform carrier suppression modulation on the laser signal to generate a modulated signal having positive and negative first-order sidebands. As shown in the figure, Figure 2 The carrier suppression module 110 comprises a laser generator 111, a radio frequency signal generator 112 and a modulator 113. The laser generator 111 is connected to the modulator 113 and configured to generate a laser signal. The radio frequency signal generator 112 is connected to the modulator 113 and configured to generate a radio frequency signal. The modulator 113 is configured to modulate the radio frequency signal on the laser signal to realize carrier suppression of the laser signal.

[0030] It can be understood that the modulator 113 can be a Mach-Zehnder modulator, an intensity modulator, an electro-absorption modulator and a phase modulator, and those skilled in the art can select a modulator for carrier suppression modulation according to actual conditions.

[0031] When the frequency of the laser signal is ω c , the frequency of the radio frequency signal is ω m , and the modulator 113 is a Mach-Zehnder modulator. By setting the bias voltage of the Mach-Zehnder modulator, the phase difference on the two arms of the Mach-Zehnder modulator is π, so that the radio frequency signal is modulated on the laser signal by the Mach-Zehnder modulator, and the generated modulated signal has positive and negative first-order sidebands ω c -ω m and ω c +ω m , and the phases of the two sidebands are the same.

[0032] According to the embodiment of the present disclosure, the first filtering module 120 is configured to filter out the positive and negative first-order sidebands of the modulated signal respectively to obtain two frequency signals. As shown in the figure, Figure 4 When the frequency of the laser signal is ω c , the frequency of the radio frequency signal is ω m , the positive and negative first-order frequencies of the modulated signal are ω c -ω m and ω c +ω m , and the frequencies of the two filtered frequency signals are ω c -ω m and ω c +ω mIt is understandable that the filter in the first filtering module 120 can be as follows: Figure 2 The first array waveguide grating 121 shown can also be two carrier frequencies ω. c -ω m and ω c +ω m An optical notch filter. Those skilled in the art can select the appropriate filter based on the specific circumstances.

[0033] According to an embodiment of this disclosure, the carrier modulation module 130 is used to generate two carrier signals by alternately outputting two frequency signals on two links based on a frequency hopping sequence. For example... Figure 2 The carrier modulation module 130 shown includes a first frequency hopping sequence generator 131 and a first 2×2 optical switch 132. The first frequency hopping sequence generator 131 is used to generate a frequency hopping sequence. The voltage control terminal of the first 2×2 optical switch 132 is connected to the first frequency hopping sequence generator 131, and is used to control the connection state between its input and output terminals based on the frequency hopping sequence, so as to realize the alternating output of two frequency signals on two links based on the frequency hopping sequence to form a carrier signal.

[0034] The frequency hopping sequence generated by the first frequency hopping sequence generator 131 can be a frequency hopping sequence code based on pseudo-random sequences, such as m-sequence, M-sequence, Gold sequence, etc., or it can be a frequency hopping sequence code based on number theory, such as RS code.

[0035] The first 2×2 optical switch 132 receives one frequency signal at each of its two input terminals and outputs one carrier signal at each of its two output terminals. By controlling the voltage applied to the voltage control terminal of the first 2×2 optical switch 132, the connection state between the two input terminals and the two output terminals can be controlled. That is, when the voltage is high, input terminal 1 and output terminal 1 are connected, input terminal 2 and output terminal 2 are connected, and output terminal 1 outputs a frequency of ω. c -ω m The signal output at output terminal 2 has a frequency of ω. c +ω m The signal; when the voltage is low, input terminal 1 and output terminal 2 are connected, input terminal 2 and output terminal 1 are connected, and output terminal 1 outputs a frequency of ω. c +ω m The signal output at output terminal 2 has a frequency of ω. c -ω m The signal. In this embodiment of the disclosure, the voltage control terminal of the first 2×2 optical switch 132 is connected to the first frequency hopping sequence generator 131, so that the voltage of its voltage control terminal changes with the changes of 0 and 1 in the frequency hopping sequence. Figure 5As shown, because the input terminals of the first 2×2 optical switch 132 are two frequency signals with different frequencies but the same phase, the wavelengths of the two carrier signals output from its output terminal are complementary, and their frequencies jump between the two frequencies with the frequency hopping sequence. Furthermore, at the same moment, the frequency of one carrier signal is ω. c -ω m At that time, the frequency of the other carrier signal is ω c +ω m .

[0036] According to an embodiment of this disclosure, the data modulation module 140 is used to modulate two channels of user data onto two carrier signals respectively, generating two modulated carrier signals. For example... Figure 2 As shown, the data modulation module 140 may include two IQ modulators 141. User data DATA1 and user data DATA2 are modulated onto each carrier signal by the two IQ modulators 141. User data DATA1 may be confidential information, and user data DATA2 may be non-confidential information. In this embodiment, the transmitter 100 loads the two user data onto the two carrier signals whose frequencies change according to the frequency hopping sequence, so that if the receiver 200 does not know the frequency hopping sequence, it cannot perform frequency hopping recovery, thereby achieving secure signal transmission. Simultaneously, if user data DATA1 is confidential information and user data DATA2 is non-confidential information, then the confidential user data DATA1 is hidden within a large amount of cluttered information, achieving greater confidentiality.

[0037] According to an embodiment of this disclosure, the data modulation module 140 further includes a preprocessing encryption unit for encrypting user data from each channel, thereby further improving the reliability of data transmission.

[0038] According to an embodiment of this disclosure, the transmit signal generation module 150 is used to couple two modulated carrier signals into a transmit signal. For example... Figure 2 As shown, the transmission signal generation module 150 includes a coupler 151. Using the coupler 151, the upper and lower modulation carrier signals are coupled into a single transmission signal, which is then transmitted through an optical fiber.

[0039] According to embodiments of this disclosure, the transmitter 200 further includes an amplifier for amplifying the transmitted signal after receiving it, to facilitate subsequent operations. The amplifier can be of the following types: Figure 2 The erbium-doped fiber amplifier shown can also be other types of amplifiers such as Raman amplifiers.

[0040] According to an embodiment of this disclosure, the second filtering module 210 is used to generate two frequency signals based on frequency separation of the transmitted signal. For example... Figure 2As shown, the second filtering module 210 can be an arrayed waveguide grating 211 or other filters. The frequencies of the two frequency signals are ω and ω', respectively. c -ω m and ω c +ω m . Figure 6 The diagram illustrates the distribution of user data DATA1 and user data DATA2 on the two frequency signals at this time.

[0041] According to an embodiment of this disclosure, the modulation carrier recovery module 220 is used to alternately output the two frequency signals on two links based on the frequency hopping sequence, so as to recover the two modulation carrier signals. Figure 2 As shown, the modulation carrier recovery module 220 includes a second frequency hopping sequence generator (221) for generating the frequency hopping sequence. A second 2×2 optical switch (222), whose voltage control terminal is connected to the second frequency hopping sequence generator (221), is used to control the connection state between its input and output terminals based on the frequency hopping sequence, so as to realize the alternating output of the two frequency signals on two links based on the frequency hopping sequence, thus restoring the two modulation carrier signals.

[0042] According to an embodiment of this disclosure, the signal demodulation module 230 is used to demodulate two modulated carrier signals respectively to obtain user data for each channel. For example... Figure 2 As shown, the signal demodulation module 230 includes a local oscillator generator 231, two couplers 232, and two balanced detectors 233. The local oscillator generator 231 generates local oscillator light with the same frequency as the laser. The two couplers 232 mix the two modulated carrier signals with the local oscillator light respectively to generate a mixed signal. The two balanced detectors 233 perform heterodyne detection on the two mixed signals respectively to obtain two channels of user data.

[0043] According to an embodiment of this disclosure, the signal demodulation module 230 further includes a decryption module unit for decrypting user data from various channels based on the encryption method of the preprocessing module 150.

[0044] The embodiment of the present disclosure provides a carrier suppression-based optical frequency hopping communication system. A transmitter 100 obtains two frequency signals with different frequencies through a carrier suppression modulation method, and alternately outputs the two frequency signals on two links under the control of a frequency hopping sequence, to generate two carrier signals with opposite frequency hopping rules and complementary wavelengths. Two user data are loaded on the two carrier signals respectively, and coupled into a transmission signal, so that the user data are transmitted through different physical channels in the transmission process, and the data can be effectively hidden. A receiver 200 restores the modulation carrier signals through the same frequency hopping sequence as the transmitter 100. When an illegal third party eavesdrops, the corresponding frequency hopping sequence cannot be obtained, so the modulation carrier signals cannot be restored, the user data are effectively hidden, and the security of data transmission is improved.

[0045] Figure 3 A carrier suppression-based optical frequency hopping communication method of the present disclosure is schematically shown.

[0046] S301, a laser signal is carrier suppression modulated to generate two frequency signals with different frequencies, the two frequency signals are alternately output on two links based on a frequency hopping sequence, two carrier signals are generated, two user data are modulated on the two carrier signals respectively to generate two modulation carrier signals, and the two modulation carrier signals are coupled into a transmission signal for transmission.

[0047] S302, a transmission signal is received, two frequency signals are separated based on different frequencies, the two frequency signals are alternately output on two links based on a frequency hopping sequence, two modulation carrier signals are restored, and two user data are obtained by demodulating the two modulation carrier signals respectively.

[0048] Those skilled in the art can understand that the features described in various embodiments and / or claims of the present disclosure can be combined or / and integrated in various combinations, even if such combinations are not explicitly described in the present disclosure. In particular, the features described in various embodiments and / or claims of the present disclosure can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present disclosure. All these combinations and / or integrations fall within the scope of the present disclosure.

[0049] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be advantageously combined. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which all fall within the scope of the present disclosure.

Claims

1. An optical frequency hopping communication system based on carrier suppression, characterized in that, include: Transmitter (100) is used to perform carrier suppression modulation on laser signals to generate two frequency signals with different frequencies. Based on the frequency hopping sequence, the two frequency signals are alternately output on two links to generate two carrier signals. Two user data are modulated onto the two carrier signals respectively to generate two modulated carrier signals, and coupled into a transmission signal for transmission. The receiver (200) is used to receive the transmitted signal, separate two frequency signals based on different frequencies, output the two frequency signals alternately on two links based on the frequency hopping sequence, recover the two modulated carrier signals, and demodulate the two modulated carrier signals respectively to obtain two user data. The transmitter (100) includes: The carrier suppression module (110) is used to perform carrier suppression modulation on the laser signal to generate a modulation signal with positive and negative first-order sidebands; The first filtering module (120) is used to filter out the positive and negative first-order sidebands of the modulation signal to obtain two frequency signals; The carrier modulation module (130) is used to alternately output the two frequency signals on two links based on the frequency hopping sequence to generate two carrier signals; The data modulation module (140) is used to modulate the two channels of user data onto the two channels of carrier signals respectively, thereby generating the two channels of modulated carrier signals; A transmit signal generation module (150) is used to couple the two modulated carrier signals into a transmit signal; The carrier suppression module (110) includes: A laser generator (111) is connected to a modulator (113) for generating the laser signal; A radio frequency signal generator (112) is connected to a modulator (113) and is used to generate radio frequency signals; The modulator (113) is used to modulate the radio frequency signal onto the laser signal to achieve carrier suppression of the laser signal.

2. The optical frequency hopping communication system based on carrier suppression according to claim 1, characterized in that, The receiver (200) includes: The second filtering module (210) is used to separate the transmitted signal based on frequency and generate two frequency signals; The modulation carrier recovery module (220) is used to alternately output the two frequency signals on two links based on the frequency hopping sequence to recover the two modulation carrier signals; The signal demodulation module (230) is used to demodulate the two modulated carrier signals respectively to obtain the user data of each channel.

3. The optical frequency hopping communication system based on carrier suppression according to claim 1, characterized in that, The carrier modulation module (130) includes: A first frequency hopping sequence generator (131) is used to generate the frequency hopping sequence; First The optical switch (132) has its voltage control terminal connected to the first frequency hopping sequence generator (131) and is used to control the connection state between its input terminal and output terminal based on the frequency hopping sequence, so as to realize the alternating output of the two frequency signals on the two links based on the frequency hopping sequence to form the carrier signal.

4. The optical frequency hopping communication system according to claim 1, characterized in that, The data modulation module (140) further includes: The preprocessing encryption unit is used to encrypt the user data from each channel.

5. The optical frequency hopping communication system based on carrier suppression according to claim 2, characterized in that, The modulation carrier recovery module (220) includes: A second frequency hopping sequence generator (221) is used to generate the frequency hopping sequence; second The optical switch (222) has its voltage control terminal connected to the second frequency hopping sequence generator (221) and is used to control the connection state between its input terminal and output terminal based on the frequency hopping sequence, so as to realize the alternating output of the two frequency signals on the two links based on the frequency hopping sequence, and restore the two modulation carrier signals.

6. The optical frequency hopping communication system based on carrier suppression according to claim 2, characterized in that, The signal demodulation module (230) includes: Local oscillator light generator (231) is used to generate local oscillator light with the same frequency as the laser. Two couplers (232) are used to mix the two modulated carrier signals with the local oscillator light respectively to generate a mixed signal; Two balanced detectors (233) are used to perform heterodyne detection on the two mixed signals respectively to obtain two user data.

7. The optical frequency hopping communication system based on carrier suppression according to claim 1, characterized in that, The frequency hopping sequence is one of the following: m sequence, M sequence, Gold sequence, and RS sequence.

8. An optical frequency hopping communication method based on carrier suppression, characterized in that, include: Two frequency signals obtained by carrier suppression modulation of the laser signal are used to generate two carrier signals based on a frequency hopping sequence. Two user data streams are modulated onto the two carrier signals respectively to generate two modulated carrier signals, which are then coupled into a transmission signal for transmission. Upon receiving the transmitted signal, based on the frequency hopping sequence, two modulated carrier signals are recovered from the two frequency signals separated from the transmitted signal, and the two modulated carrier signals are demodulated respectively to obtain two user data streams.

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