A photon-assisted terahertz signal transmission system and method

Abstract

The application discloses a kind of photonic-assisted terahertz signal transmission system and method, including the terahertz signal photon generation module, transmission module and photoelectric conversion module connected in turn;The terahertz signal photon generation module is used to generate the optical signal containing terahertz signal;The transmission module is used to transmit the optical signal containing terahertz signal at different distances, and send it into photoelectric conversion module;The photoelectric conversion module is used to convert the received optical signal containing terahertz signal into terahertz signal.Setting a laser realizes multiple multi-band signal generation, avoids using external cavity laser to reduce the phase noise of generated signal, in addition, long-distance transmission is carried out using optical fiber, solve the technical problem that prior art cannot realize long-distance communication.

Description

Technical Field

[0001] This invention belongs to the field of terahertz communication and relates to terahertz signal generation and transmission systems, specifically a photon-assisted terahertz signal transmission system and method. Background Technology

[0002] With the rapid development of mobile communications and the advent of the 6G era, various smart products and big data platforms are emerging in large numbers, leading to ever-increasing demands for data rates and capacity. Data transmission methods are also gradually moving towards wireless and broadband technologies. Achieving ultra-high-speed wireless signals has become a pressing problem. It is well known that fiber optic communication can provide enormous transmission capacity and ultra-long transmission distances, but its location is fixed and it cannot provide comprehensive coverage to any arbitrary location. While wireless communication technology can ideally cover all locations, its spectrum resources are limited, and it suffers from many losses during transmission. Therefore, this communication method has a shorter transmission distance and cannot meet the needs of long-distance transmission. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a photon-assisted terahertz signal transmission system and method to solve the technical problems that the existing technology cannot achieve long-distance communication and has low transmission stability.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A photon-assisted terahertz signal transmission system includes a terahertz signal photon generation module, a transmission module, and a photoelectric conversion module connected in sequence.

[0006] The terahertz signal photon generation module is used to generate an optical signal containing a terahertz signal;

[0007] The transmission module is used to transmit optical signals containing terahertz signals over different distances and send them to the photoelectric conversion module.

[0008] The photoelectric conversion module is used to convert the received optical signal containing terahertz signals into terahertz signals.

[0009] This invention also includes the following technical features:

[0010] The terahertz signal photon generation module includes a laser source, a MAZ modulator, an erbium-doped fiber amplifier, and a dense wavelength division multiplexer connected in sequence. The first output terminal of the dense wavelength division multiplexer is connected to an IQ modulator, the output terminal of the IQ modulator is connected to an optical coupler, and the optical coupler is connected to the second output terminal of the dense wavelength division multiplexer.

[0011] The transmission module includes an optical splitter connected to an optical coupler, and the two outputs of the optical splitter are respectively connected to two optical fibers.

[0012] The photoelectric conversion module includes two optical amplifiers connected to two optical fibers respectively, and each optical amplifier is connected to a photodiode.

[0013] A method for transmitting photon-assisted terahertz signals, based on the photon-assisted terahertz signal transmission system, specifically includes the following steps:

[0014] Step 1: The laser source outputs optical signal E(t) and local oscillator signal E... Lo (t) and communication signal E s (t);

[0015] E(t) = E0exp(j2πf c t) (1)

[0016] E Lo (t)=V Lo sin(2πf Lo t) (2)

[0017] E s (t)=V s sin(2πf s t) (3)

[0018] in:

[0019] E0 is the electric field amplitude of the output optical signal from the laser source;

[0020] f c The frequency of the optical signal;

[0021] V Lo It is the amplitude of the local oscillator signal;

[0022] f Lo It is the frequency of the local oscillator signal;

[0023] V s It is the amplitude of the communication signal;

[0024] f s The frequency of the communication signal;

[0025] j represents an imaginary number;

[0026] t represents time;

[0027] Step 2, the optical signal E(t) is transmitted through the local oscillator signal E... Lo After modulation by (t) and the Maximizer modulator, the modulated optical signal E is obtained. MZM (t);

[0028]

[0029] in:

[0030] m is the modulation index;

[0031] J0(m) represents the expansion coefficients of the 0th-order Bessel function;

[0032] J1(m) represents the expansion coefficients of the first-order Bessel function;

[0033] J2(m) represents the expansion coefficients of the second-order Bessel function;

[0034] exp represents the exponential function;

[0035] Step 3, modulate the optical signal E obtained in Step 2. MZM (t) Power compensation is performed on the input erbium-doped fiber amplifier, and the compensated optical signal is input to the dense wavelength division multiplexer to obtain the first optical signal E. DWDM1 (t) and the second optical signal E DWDM2 (t);

[0036]

[0037] Step four, convert the first optical signal E obtained in step three into a signal that is... DWDM1 (t) is transmitted to the IQ modulator, using the communication signal E obtained in step one. s (t) for the first optical signal E DWDM1 (t) is modulated to obtain the modulated first optical signal E. IQMZM (t);

[0038]

[0039] V s (t) represents the amplitude of the communication signal at time t;

[0040] Step 5, modulate the first optical signal E obtained in step 4. IQMZM (t) and the second optical signal E obtained in step three DWDM2 (t) is coupled into a single optical signal via an optical coupler, and then split into optical signals E via a splitter. OS1 (t) and optical signal E OS2 (t);

[0041]

[0042] Step six, convert the signal E obtained in step five into a signal... OS1 (t) and signal E OS2 (t) After passing through the corresponding optical fiber and optical amplifier respectively, the two photodiodes output current i respectively. channel1(t) and current i channel2 (t), that is, the terahertz signal is obtained;

[0043] i channel1 (t)∝V s (t)cos(2π4f Lo t) (9)

[0044] i channel2 (t)∝V s (t)cos(2π3f Lo t) (10).

[0045] Compared with the prior art, the beneficial technical effects of this invention are:

[0046] (I) Compared to most optical terahertz signal generation methods that require expensive external cavity lasers, or complex optical synchronization techniques to eliminate phase differences between different lasers, or some multi-band signal generation techniques that require multiple lasers and modulators, this application uses only one laser to achieve multi-channel multi-band signal generation, avoiding the use of external cavity lasers to reduce phase noise of the generated signals. In addition, the use of optical fiber for long-distance transmission solves the technical problem that existing technologies cannot achieve long-distance communication.

[0047] (II) This invention uses a high-symmetry MAZ modulator and IQ modulator to realize a high-speed and stable terahertz communication signal transmission system, thereby improving the stability of the communication system. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the system of the present invention;

[0049] Figure 2 The terahertz single-tone signal obtained from the simulation in Example 1;

[0050] Figure 3 This is the constellation diagram of the terahertz 16QAM communication signal obtained from the simulation in Example 2.

[0051] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0052] It should be noted that, unless otherwise specified, all components in this invention are those known in the art.

[0053] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0054] This invention provides a photon-assisted terahertz signal transmission system, comprising a terahertz signal photon generation module, a transmission module, and a photoelectric conversion module connected in sequence.

[0055] The terahertz signal photon generation module is used to generate optical signals containing terahertz signals;

[0056] The transmission module is used to transmit optical signals containing terahertz signals over different distances and send them to the photoelectric conversion module;

[0057] The photoelectric conversion module is used to convert received optical signals containing terahertz signals into terahertz signals.

[0058] In the above technical solution, an optical signal containing terahertz signals is generated by a terahertz signal photon generation module, then transmitted over long distances by a transmission module, and finally converted into a terahertz signal by a photoelectric conversion module, thus solving the technical problem that existing technologies cannot achieve long-distance communication.

[0059] The terahertz signal photon generation module includes a laser source, a MAZ modulator, an erbium-doped fiber amplifier, and a dense wavelength division multiplexer connected in sequence. The first output terminal of the dense wavelength division multiplexer is connected to an IQ modulator, the output terminal of the IQ modulator is connected to an optical coupler, and the optical coupler is connected to the second output terminal of the dense wavelength division multiplexer.

[0060] In the above technical solution, compared with most optical terahertz signal generation methods that require the use of expensive external cavity lasers, or complex optical synchronization technology to eliminate the phase difference between different lasers, or some multi-band signal generation technologies that require multiple lasers and modulators, this solution uses only one laser to realize the generation of multiple multi-band signals, avoiding the use of external cavity lasers to reduce the phase noise of the generated signals. In addition, the use of optical fiber for long-distance transmission solves the technical problem that existing technologies cannot achieve long-distance communication.

[0061] By employing a high-symmetry MAZ modulator and IQ modulator, a high-speed and stable terahertz communication signal transmission system was realized, improving the stability of the communication system.

[0062] The transmission module includes an optical splitter connected to an optical coupler, and the two outputs of the optical splitter are respectively connected to two optical fibers.

[0063] In the above technical solution, multiple signals are realized by setting up an optical splitter connected by an optical coupler, and long-distance transmission is realized by setting up an optical fiber.

[0064] The photoelectric conversion module includes two optical amplifiers connected to two optical fibers respectively, and each optical amplifier is connected to a photodiode.

[0065] In the above technical solution, the optical signal is amplified by setting an optical amplifier, and the optical signal is converted into a terahertz signal by a photodiode, thus realizing the generation of the terahertz signal.

[0066] A photon-assisted terahertz signal transmission method, based on a photon-assisted terahertz signal transmission system, specifically includes the following steps:

[0067] Step 1: The laser source outputs optical signal E(t) and local oscillator signal E... Lo (t) and communication signal E s (t);

[0068] E(t)=E0 exp(j2πf c t) (1)

[0069] E Lo (t)=V Lo sin(2πf Lo t) (2)

[0070] E s (t)=V s sin(2πf s t) (3)

[0071] in:

[0072] E0 is the electric field amplitude of the output optical signal from the laser source;

[0073] f c The frequency of the optical signal;

[0074] V Lo It is the amplitude of the local oscillator signal;

[0075] f Lo It is the frequency of the local oscillator signal;

[0076] V s It is the amplitude of the communication signal;

[0077] f s The frequency of the communication signal;

[0078] j represents an imaginary number;

[0079] t represents time;

[0080] Step 2, the optical signal E(t) is transmitted through the local oscillator signal E... Lo After modulation by (t) and the Maximizer modulator, the modulated optical signal E is obtained. MZM (t);

[0081]

[0082] in:

[0083] m is the modulation index;

[0084] J0(m) represents the expansion coefficients of the 0th-order Bessel function;

[0085] J1(m) represents the expansion coefficients of the first-order Bessel function;

[0086] J2(m) represents the expansion coefficients of the second-order Bessel function;

[0087] exp represents the exponential function;

[0088] Step 3, modulate the optical signal E obtained in Step 2. MZM (t) Power compensation is performed on the input erbium-doped fiber amplifier, and the compensated optical signal is input to the dense wavelength division multiplexer to obtain the first optical signal E. DWDM1 (t) and the second optical signal E DWDM2 (t);

[0089]

[0090] Step four, convert the first optical signal E obtained in step three into a signal that is... DWDM1 (t) is transmitted to the IQ modulator, using the communication signal E obtained in step one. s (t) for the first optical signal E DWDM1 (t) is modulated to obtain the modulated first optical signal E. IQMZM (t);

[0091]

[0092] V s (t) represents the amplitude of the communication signal at time t;

[0093] Step 5, modulate the first optical signal E obtained in step 4. IQMZM (t) and the second optical signal E obtained in step three DWDM2 (t) is coupled into a single optical signal via an optical coupler, and then split into optical signals E via a splitter. OS1 (t) and optical signal E OS2 (t);

[0094]

[0095] Step six, convert the signal E obtained in step five into a signal... OS1 (t) and signal E OS2 (t) After passing through the corresponding optical fiber and optical amplifier respectively, the two photodiodes output current i respectively. channel1 (t) and current i channel2 (t), that is, the terahertz signal is obtained;

[0096] i channel1 (t)∝V s (t)cos(2π4f Lo t) (9)

[0097] i channel2 (t)∝V s (t)cos(2π3f Lo t) (10).

[0098] Example 1:

[0099] This embodiment presents a photon-assisted terahertz signal transmission system, wherein the selection of various components is as follows:

[0100] The system includes a laser (generating an optical carrier with a wavelength of 1549.9 nm and an optical power of 12 dBm), a MAZM modulator (half-wave voltage of 3.5 V and extinction ratio of 32 dB), an erbium-doped fiber amplifier, a dense wavelength division multiplexer (two channels with a center wavelength of 1549.9 nm, a channel bandwidth of 100 GHz, and crosstalk between adjacent channels of 32 dB), two optical fibers (20 km and 40 km in length, respectively), and a photodiode (responsivity of 0.8 A / W).

[0101] A microwave signal source generates a 40GHz local oscillator signal with a power of 12dBm. This local oscillator signal is then passed through a Markov modulator to generate a five-line optical comb. An erbium-doped fiber amplifier (in automatic power control mode) outputs a 10dBm optical signal. The output voltage of a DC voltage source is adjusted to make the amplitudes of the carrier wave, ±1st-order sideband, and ±2nd-order sideband of the optical signal equal. After photodetection, 120GHz and 160GHz single-tone terahertz signals are generated, and their spectra are shown below. Figure 2 As shown, the generation and transmission of a single-tone terahertz signal were realized.

[0102] Example 2:

[0103] This embodiment presents a photon-assisted terahertz signal transmission system, wherein the selection of various components is as follows:

[0104] The system includes a laser (generating an optical carrier with a wavelength of 1549.9 nm and an optical power of 12 dBm), a MAZM modulator (half-wave voltage of 3.5 V and extinction ratio of 32 dB), an erbium-doped fiber amplifier, a dense wavelength division multiplexer (two channels with a center wavelength of 1549.9 nm, a channel bandwidth of 100 GHz, and crosstalk between adjacent channels of 32 dB), two optical fibers (20 km and 40 km in length, respectively), and a photodiode (responsivity of 0.8 A / W).

[0105] A microwave signal source generates a 40GHz local oscillator signal with a power of 12dBm. A communication signal source generates a 4GHz bandwidth, 16QAM modulation baseband signal. The local oscillator signal is passed through a Markov modulator to generate a five-line optical comb. An erbium-doped fiber amplifier outputs a 10dBm optical signal in automatic power control mode. The output voltage of a DC voltage source is adjusted to make the amplitudes of the carrier wave, ±1st-order sideband, and ±2nd-order sideband of the optical signal equal. After photodetection, two communication signals with center frequencies of 120GHz and 160GHz are generated, respectively. The constellation diagram and EVM (error vector magnitude) of the two communication signals are shown below. Figure 3 The 16QAM communication signals with carrier frequencies of 120GHz and 160GHz have EVM values ​​of 8.6% and 8.3% respectively, realizing the generation and transmission of terahertz communication signals.

Claims

1. A photon-assisted terahertz signal transmission system, characterized in that, It includes a terahertz signal photon generation module, a transmission module, and a photoelectric conversion module connected in sequence; The terahertz signal photon generation module is used to generate an optical signal containing a terahertz signal; The transmission module is used to transmit optical signals containing terahertz signals over different distances and send them to the photoelectric conversion module. The photoelectric conversion module is used to convert the received optical signal containing terahertz signals into terahertz signals. The terahertz signal photon generation module includes a laser source, a MAZ modulator, an erbium-doped fiber amplifier, and a dense wavelength division multiplexer connected in sequence. The first output terminal of the dense wavelength division multiplexer is connected to an IQ modulator, the output terminal of the IQ modulator is connected to an optical coupler, and the optical coupler is connected to the second output terminal of the dense wavelength division multiplexer. The transmission module includes an optical splitter connected to an optical coupler, and the two outputs of the optical splitter are respectively connected to two optical fibers; The photoelectric conversion module includes two optical amplifiers connected to two optical fibers respectively, and each optical amplifier is connected to a photodiode.

2. A method for transmitting photon-assisted terahertz signals, characterized in that, The photon-assisted terahertz signal transmission system based on claim 1 specifically includes the following steps: Step 1: The laser source outputs an optical signal. , local oscillator signal and communication signals ; （1） （2） （3） in: The electric field amplitude of the output optical signal from the laser source; The frequency of the optical signal; It is the amplitude of the local oscillator signal; It is the frequency of the local oscillator signal; It is the amplitude of the communication signal; The frequency of the communication signal; Imaginary numbers; t represents time; Step 2, optical signal Through local oscillator signal After modulation by the modulator, a modulated optical signal is obtained. ; （4） in: m is the modulation index; Represents the expansion coefficients of the 0th-order Bessel function; Represents the expansion coefficients of a first-order Bessel function; Represents the expansion coefficients of the second-order Bessel function; exp represents the exponential function; Step 3: Modulate the optical signal obtained in Step 2. The erbium-doped fiber amplifier performs power compensation, and the compensated optical signal is then input into a dense wavelength division multiplexer to obtain the first optical signal. Second optical signal ; （5） （6） Step four, take the first optical signal obtained in step three. The signal is transmitted to the IQ modulator and uses the communication signal obtained in step one. For the first optical signal Modulation is performed to obtain the modulated first optical signal. ; （7） This represents the amplitude of the communication signal at time t; Step 5: Modulate the first optical signal obtained in Step 4. and the second optical signal obtained in step three The optical signal is coupled into a single optical signal by an optical coupler, and then split into multiple optical signals by a splitter. and light signal ; （8） Step six, take the signal obtained in step five. and signal After passing through corresponding optical fibers and optical amplifiers, the two photodiodes output current respectively. and current That is, the terahertz signal is obtained; （9） （10）。

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