WO2022001546A1

WO2022001546A1 - Signal transmission method and apparatus, and network device

Info

Publication number: WO2022001546A1
Application number: PCT/CN2021/097400
Authority: WO
Inventors: 范忱
Original assignee: 中兴通讯股份有限公司
Priority date: 2020-06-29
Filing date: 2021-05-31
Publication date: 2022-01-06
Also published as: CN113938204A

Abstract

The embodiments of the present application relate to the technical field of communications. Disclosed are a signal transmission method and apparatus, and a network device. The signal transmission method comprises: acquiring a first electrical signal and a second electrical signal; performing polarization separation on an optical signal emitted by a laser, so as to acquire signal light and local-oscillation light; modulating the first electrical signal onto a first sideband of the signal light, and modulating the second electrical signal onto a second sideband of the signal light, so as to acquire modulated signal light; and combining the modulated signal light and the local-oscillation light into emitted light for transmission.

Description

Signal transmission method, device and network equipment

cross reference

This application is based on the Chinese patent application with the application number "202010606768.9" and the application date is June 29, 2020, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated by reference. Apply.

technical field

The embodiments of the present application relate to the field of communication technologies, and in particular, to a signal transmission method, an apparatus, and a network device.

Background technique

With the commercialization of 5G, the base station density of the network will be higher. Therefore, for the base station, lighter weight, smaller size and lower power consumption are the first considerations in designing a communication system, and the optical carrier radio frequency technology can well solve the above problems.

Coherent optical carrier radio frequency technology is the key technology of next-generation optical communication. Compared with the traditional direct detection scheme, coherent optical carrier transmission technology has higher sensitivity, which can generally be improved by 10-20dB. It can also be improved by 3dB compared with the heterodyne coherent technology. The principle of coherent communication is to add a local oscillator light with the same frequency, phase, and polarization direction to the received signal light, and the two beams of light undergo interference mixing. The application of higher-order modulation formats enables coherent optical communication to have higher spectral utilization of single-wavelength channels. In some cases, the light source (including the local oscillator light and the signal light) at the transmitting end of the self-homodyne coherent optical carrier microwave transmission method comes from the same laser, but it needs to be transmitted through two channels respectively, and the coherence of the two channels of light changes during the transmission process. Poor, the receiving end needs to use a DSP (Digital Signal Processing, digital signal processing) circuit to perform relevant signal compensation on the received signal in order to reconstruct the signal.

However, in the process of implementing the embodiments of the present application, the inventor found that since the traditional coherent receiving end needs to rely on high-speed digital signal processing technology to perform relevant signal compensation on the received signal, the signal can be reconstructed and distortion compensation can be realized, while The DSP circuit that realizes high-speed signal processing technology needs to include digital processing, mixer and clock circuits, and its volume, weight and power consumption are large, which increases the hardware (Active Antenna Unit, AAU) / radio frequency The size, weight and power consumption of the design of the remote function (Radio Remote Unit, RRU).

SUMMARY OF THE INVENTION

An embodiment of the present application provides a signal transmission method, including: obtaining a first electrical signal and a second electrical signal; performing polarization separation on an optical signal emitted by a laser to obtain signal light and local oscillator light; converting the first electrical signal The modulated signal light is modulated onto the first sideband of the signal light, the second electrical signal is modulated onto the second sideband of the signal light, and the modulated signal light is obtained; the modulated signal light and the The local oscillator light is combined into emitted light for transmission.

Embodiments of the present application further provide a signal transmission method, including: receiving emitted light, where the emitted light includes signal light and local oscillator light; performing optical filtering processing on the emitted light to obtain first sideband light and a second sideband light, wherein the first sideband light includes a first sideband of the signal light and the local oscillator light, and the second sideband light includes a second sideband of the signal light and the local oscillator light; demodulate the first sideband light and the second sideband light respectively to obtain a first electrical signal and a second electrical signal.

The embodiments of the present application also provide a signal transmission device, including: a laser, a polarization beam splitter, an IQM modulator, a phase delayer, and a beam combiner; wherein the laser is used to transmit an optical signal; the polarization beam The beam splitter is used for polarization separation of the optical signal to obtain signal light and local oscillator light; the IQM modulator is used for modulating the received first electrical signal to the first sideband of the signal light , modulate the received second electrical signal on the second sideband of the signal light to obtain the modulated signal light; the phase delayer is used to perform phase correction on the local oscillator light to obtain The corrected local oscillator light; the beam combiner is configured to perform beam combining processing on the corrected local oscillator light and the modulated signal light to generate and transmit the emitted light.

Embodiments of the present application also provide a signal transmission device, comprising: a first optical filter, a second optical filter, a first photodetector, and a second photodetector; wherein, the first optical filter, is used for filtering the received emitted light to obtain first sideband light, wherein the first sideband light includes the first sideband of the signal light and the local oscillator light; the second light a filter, used for filtering the received emitted light to obtain second sideband light, wherein the second sideband light includes the second sideband of the signal light and the local oscillator light; the The first photodetector is used to demodulate the first sideband light to obtain a first electrical signal; the second photodetector is used to demodulate the second sideband light to obtain the first electrical signal. Two electrical signals.

Embodiments of the present application also provide a network device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores data that can be executed by the at least one processor The instructions are executed by the at least one processor to enable the at least one processor to perform the signal transmission method described above.

Description of drawings

One or more embodiments are exemplified by the pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments.

1 is a flowchart of a signal transmission method provided by a first embodiment of the present application;

2 is a flowchart of a signal transmission method provided by a second embodiment of the present application;

3 is a flowchart of a signal transmission method provided by a third embodiment of the present application;

4 is a flowchart of a signal transmission method provided by a fourth embodiment of the present application;

5 is a schematic diagram of a signal transmission apparatus provided by a fifth embodiment of the present application;

Fig. 6 is the schematic diagram of the spectrum of the corresponding node in Fig. 5;

FIG. 7 is a schematic diagram of double SSB signal generation in some cases;

8 is a schematic diagram of a signal transmission apparatus provided by a sixth embodiment of the present application;

Fig. 9 is the schematic diagram of the spectrum of the corresponding node in Fig. 7;

FIG. 10 is a schematic diagram of a network device provided by a seventh embodiment of the present application.

detailed description

In order to make the objectives, technical solutions and advantages of the embodiments of the present application more clear, each embodiment of the present application will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that, in each embodiment of the present application, many technical details are provided for the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be realized. The following division of each embodiment is for the convenience of description, and should not constitute any limitation to the specific implementation of the present application, and each embodiment may be combined with each other and referenced on the premise of not contradicting each other.

The purpose of the embodiments of the present application is to provide a signal transmission method, apparatus, and network device, in which hardware design does not require a digital signal processing circuit, and can reduce the volume, weight, and power consumption of hardware design.

The first embodiment of the present application relates to a signal transmission method, see FIG. 1 , and includes the following steps.

Step S101, acquiring a first electrical signal and a second electrical signal.

Specifically, the first electrical signal and the second electrical signal are baseband signals. After frequency conversion processing and Hilbert change, the real part and the imaginary part of the complex signal are converted according to the addition characteristic of the Fourier transform. The parts are separated and used as I/Q signals to drive the IQ modulator respectively. This part of the content will be described in detail later, but this is just a brief introduction.

In step S102, the optical signal emitted by the laser is subjected to polarization separation to obtain signal light and local oscillator light.

Specifically, the optical signal emitted by the laser is separated into X-polarized light and Y-polarized light by a polarization beam splitter (PBS), and the frequencies of the two are the same, wherein the X-polarization is used as the signal light for modulation, and the Y-polarization is used as the coherent light. Receive the required LO light.

Step S103, modulate the first electrical signal on the first sideband of the signal light, modulate the second electrical signal on the second sideband of the signal light, and obtain modulated signal light.

Specifically, the first electrical signal and the second electrical signal are modulated onto the two sidebands of the signal light, specifically, the first electrical signal and the second electrical signal are passed through an in-phase/quadrature-phase modulator (In-phase/Quadrature-phase Modulator, IQM) is modulated to the upper and lower sidebands of the X polarization state, so that there is no interference between the two electrical signals.

Step S104, combining the modulated signal light and the local oscillator light into emission light for transmission.

Specifically, the modulated signal light and the local oscillator light are combined by a beam combiner (Optical Combiner, OC) for transmission through an optical fiber, which can ensure a strong phase correlation between the two signal lights.

In this embodiment of the present application, the first electrical signal is modulated onto the first sideband of the signal light, the second electrical signal is modulated onto the second sideband of the signal light, and the modulated signal is obtained light; the modulated signal light and the local oscillator light are combined into emission light for transmission, and the first electrical signal and the second electrical signal can be modulated onto the two sidebands of the signal light through single sideband processing. , there is no interference between the two electrical signals, and the optical phase correlation between the two signals is guaranteed to be strong through combined transmission. Since there is no interference between the two electrical signals and the correlation is strong, the receiving end does not need to monitor the two electrical signals. For compensation, the digital signal processing (Digital Signal Processing, DSP) circuit that needs to be used for compensation is omitted, which can reduce the size, weight and power consumption of hardware design.

The second embodiment of the present application relates to a signal transmission method. The second embodiment is substantially the same as the first embodiment, and the differences are as follows.

Referring to FIG. 2 , in the second embodiment, step S104 , combining the modulated signal light and the local oscillator light into emission light for transmission, includes the following steps.

Step S1041, performing phase correction on the local oscillator light to obtain the corrected local oscillator light.

Specifically, to perform phase correction on the local oscillator light (Y polarized light) is to perform phase correction through a phase delay device (Phase Delay Time, TOD).

Step S1042, performing beam combining processing on the corrected local oscillator light and the modulated signal light to generate and transmit emitted light.

Specifically, the phase-corrected X-polarized signal light and the Y-polarized local oscillator light are combined by a polarization beam combiner (Polarization Beam Combiner, PBC), and then transmitted through an optical fiber.

In addition, in the second embodiment, in step S1041, the phase correction is performed on the local oscillator light, and after the corrected local oscillator light is obtained, in step S1042, the corrected local oscillator light and the modulated light are obtained in step S1042. After the signal light is combined, the emitted light is generated and sent, and it also includes:

Step S1043: Perform polarization rotation on the corrected local oscillator light to obtain the rotated local oscillator light, wherein the rotated local oscillator light is consistent with the polarization state of the modulated signal light.

Specifically, the polarization rotation of the local oscillator light (Y-polarized light) is performed through a Faraday Rotator Mirror (FRM), so that the polarization states of the rotated local oscillator light and the modulated signal light are consistent.

Step S1042, performing beam combination processing on the corrected local oscillator light and the modulated signal light to generate and transmit emitted light is specifically: combining the rotated local oscillator light and the modulated signal light. The signal light undergoes beam combining processing to generate emitted light and send it.

Specifically, after phase correction and polarization rotation, there is no difference in polarization state and phase between the local oscillator light and the signal light, and the two are combined with each other, and the generated emission light is transmitted through the optical fiber.

In this embodiment, by performing phase correction and polarization rotation on the local oscillator light, there is no difference in polarization state and phase between the local oscillator light and the signal light. Therefore, the demodulated signal can be directly connected to the wave control board , greatly reducing the complexity of hardware design, as well as weight, size and power consumption.

The third embodiment of the present application relates to a signal transmission method, see FIG. 3 , and includes the following steps.

Step S201, receiving emitted light, wherein the emitted light includes signal light and local oscillator light.

Specifically, the emitted light is received after being transmitted by an optical fiber, and the emitted light includes signal light and local oscillator light. The signal light is a modulated signal light, and the upper and lower sidebands are modulated with a first electrical signal and a second electrical signal respectively.

Step S202, performing optical filtering processing on the emitted light to obtain first sideband light and second sideband light, wherein the first sideband light includes the first sideband of the signal light and the local oscillator light, the second sideband light includes a second sideband of the signal light and the local oscillator light.

Specifically, the emitted light is subjected to optical filtering processing by an optical filter (Optical Band Pass Filter, OBPF) to obtain the first sideband (corresponding to the first electrical signal) and the local oscillator light of the signal light, and the second sideband respectively. band (corresponding to the first electrical signal) and local oscillator light.

Step S203, demodulate the first sideband light and the second sideband light respectively to obtain a first electrical signal and a second electrical signal.

Specifically, the required first electrical signal and the second electrical signal can be obtained by performing homodyne beat frequency with the first sideband and the second sideband respectively by the local oscillator light.

In this embodiment, light filtering processing is performed on the emitted light to obtain first sideband light and second sideband light, wherein the first sideband light includes the first sideband of the signal light and the Local oscillator light, the second sideband light includes the second sideband of the signal light and the local oscillator light, respectively demodulate the first sideband light and the second sideband light to obtain The first electrical signal and the second electrical signal are processed by SSB and sent together. Therefore, after the receiving end demodulates the first electrical signal and the second electrical signal, it is not necessary to perform the SSB processing on the two electrical signals. Compensation can save the DSP circuit that needs to be used for compensation, which can reduce the size, weight and power consumption of hardware design.

The fourth embodiment of the present application relates to a signal transmission method. The fourth embodiment is substantially the same as the third embodiment, and the differences are as follows.

Referring to FIG. 4 , in step S201 , after receiving the emitted light, in step S202 , before performing optical filtering processing on the emitted light to obtain the first sideband light and the second sideband light, the following steps are further included.

Step S204, performing branch processing on the emitted light to obtain the signal light and the local oscillator light.

Specifically, a wavelength division module (Wavelength Division Module, WDM) can realize the split processing of the emitted light to obtain signal light and local oscillator light. The signal light is the modulated signal light, and the upper and lower sidebands are modulated with a first electrical signal and a second electrical signal.

Step S205, performing polarization rotation on the local oscillator light to obtain the rotated local oscillator light.

Specifically, the polarization rotation of the local oscillator light is performed by the Faraday rotating mirror FRM to make it consistent with the polarization of the sideband light signal.

Step S206 , the signal light is reflected to obtain the reflected signal light, wherein the rotated local oscillator light is in phase with the reflected signal light.

Specifically, the signal light is reflected by a Faraday Mirror (FM) to ensure that the phase of the local oscillator light with Y polarization is consistent.

Step S207, combining the reflected signal light and the rotated local oscillator light to generate the emission light to be processed.

Specifically, the emitted light to be processed includes the reflected signal light with the same phase and polarization state and the rotated local oscillator light. After the combined processing, the optical filtering processing and the demodulation processing are performed subsequently.

In addition, in the fourth embodiment, in step S202, performing optical filtering processing on the emitted light to obtain the first sideband light and the second sideband light, specifically: performing optical filtering on the emitted light to be processed. Filter processing to obtain the first sideband light and the second sideband light.

Specifically, the emitted light to be processed obtains the first sideband light and the second sideband light through the optical filter OBPF.

In this embodiment, by adjusting the phase and polarization rotation of the local oscillator light, there is no polarization state and phase difference between the local oscillator light and the signal light. Therefore, the demodulated signal can be directly connected to the wave control board, greatly reducing the Reduce hardware design complexity, as well as weight, size and power consumption.

The fifth embodiment of the present application relates to a signal transmission device, including a transmitting end and a receiving end, and the transmitting end includes: a laser, a polarization beam splitter, an IQM modulator, a phase delayer, and a beam combiner; wherein, the laser , used to transmit an optical signal; the polarization beam splitter is used to polarize the optical signal to obtain signal light and local oscillator light; the IQM modulator is used to modulate the received first electrical signal to the first sideband of the signal light, modulate the received second electrical signal on the second sideband of the signal light, and obtain the modulated signal light; the phase delay device is used to The local oscillator light is phase-corrected to obtain the corrected local oscillator light; the beam combiner is used for combining the corrected local oscillator light and the modulated signal light to generate emission light and send.

The receiving end includes: a first optical filter, a second optical filter, a first photodetector and a second photodetector; wherein the first optical filter is used to filter the received emitted light processing to obtain first sideband light, wherein the first sideband light includes the first sideband of the signal light and the local oscillator light; the second optical filter is used for the received emission The light is filtered to obtain a second sideband light, wherein the second sideband light includes the second sideband of the signal light and the local oscillator light; the first photodetector is used to The first sideband light is demodulated to obtain a first electrical signal; the second photodetector is used to demodulate the second sideband light to obtain a second electrical signal.

The receiving end further includes: a wavelength division module, a Faraday rotating mirror and a Faraday reflector; wherein the wavelength division module is used to perform branch processing on the emitted light to obtain the signal light and the local oscillator light The Faraday rotating mirror is used for polarizing and rotating the local oscillator light to obtain the rotated local oscillator light; the Faraday mirror is used for reflecting the signal light to obtain the reflected signal light, Wherein, the rotated local oscillator light is in phase with the reflected signal light; then the first optical filter is also used for filtering the emitted light to be processed to obtain the first sideband light, wherein , the first sideband light includes the first sideband of the signal light and the local oscillator light, and the emitted light to be processed is generated by combining the reflected signal light and the rotated local oscillator light The second optical filter is also used for filtering the emitted light to be processed to obtain a second sideband light, wherein the second sideband light includes the second sideband of the signal light and the Local oscillator light, the emission light to be processed is generated by combining the reflected signal light and the rotated local oscillator light.

5 and 6 are used as examples to describe the above-mentioned signal transmission device. Please refer to FIG. 5 and FIG. 6. The signal transmission device includes a transmitting end and a receiving end, and the transmitting end includes: a laser 1, a polarization beam splitter PBS2, an IQM Modulator 3, phase delay device TOD4, polarization beam combiner PBC5; the receiving end includes: circulator C1, wavelength division module WDM6, Faraday rotating mirror FRM7, Faraday mirror FM8, optical filter OBPF 9, 10 and photodetector PD 11, 12.

In FIG. 5, the light emitted by the laser 1 is polarized and separated by the polarization beam splitter PBS2, the X polarized light is modulated as the signal light, and the Y polarized light is used as the local oscillator light required for coherent reception. The electrical signal is subjected to single-sideband modulation (corresponding to the a signal) to the signal light through the IQM modulator 3, and this modulation method makes the signals S1 and S2 respectively on the two sidebands of the X-polarized light. The Y-polarized light is phase-corrected by the phase delay device TOD4 (corresponding to the b signal), and then the X-polarized signal light and the Y-polarized local oscillator light are combined by the polarization beam combiner PBC5 (corresponding to the c signal), and then passed through the polarization beam combiner PBC5. Optical fiber transmission, and then enter from port 1 of the circulator C1 and exit from port 2. The sideband optical signal and the Y-polarized local oscillator light are split through the wavelength division module WDM6, and the Y-polarized local oscillator light then passes through the Faraday rotator FRM7. The polarization rotation is performed to make it consistent with the polarization of the sideband optical signal, and the sideband light passes through the Faraday mirror FM8 to ensure that the phase of the Y-polarized local oscillator light is consistent, and finally the sideband optical signal and the local oscillator light are recombined. , enters port 2 of circulator C1, and then exits port 3 (corresponding to the d signal). Through the optical filters OBPF 9, 10, the two sideband lights (corresponding to the e, f signals) containing the local oscillator light are filtered out respectively, and then the signals S1 and S2 are demodulated by the photodetectors PD 11, 12, and then the signals S1 and S2 can be demodulated. Connect to the wave control board for signal transmission. The schematic diagrams of the spectra corresponding to the a, b, c, d, e, and f signals in the figure are shown in Fig. 6 .

Figure 7 shows the principle of double-sideband optical signal generation. Here a single polarization state enables 2-dimensional signal transmission. Suppose two independent signals to be transmitted are denoted as S ₁ (t) and S ₂ (t), respectively. Both of these signals are baseband signals, the spectrum of which is shown in Figure 7. After up-conversion by a frequency source with a frequency of f _{s, it becomes a radio frequency signal.} The up-converted real-numbered radio frequency signal is processed by single-sideband filtering to become a complex single-sideband signal. The single sideband filter is shown in Fig. 7, including the Hilbert transform and the complex number j. The single sideband signal of the upper sideband or the lower sideband can be obtained by adjusting the positive or negative value of j. The spectrum of the resulting SSB signals a(t) and b(t) are shown in the figure. a(t) and b(t) can be expressed as:

a(t)=S ₁ (t)·cos(2π·fst)+j·HT(S ₁ (t)·cos(2π·fst))

b(t)=S ₂ (t)·cos(2π·fst)-j·HT(S ₂ (t)·cos(2π·fst))

where HT(·) represents the Hilbert transform. Finally, according to the additive characteristic of Fourier transform, that is, F(a(t)+b(t))=F(a(t))+F(b(t)), a(t)+b(t) ), the real part of the complex signal is separated from the imaginary part and used as I/Q signals to drive the IQ modulator respectively. It should be noted here that the bias point of the I/Q modulator is located at the NULL point. It can be clearly seen that the signals S ₁ (t) and S ₂ (t) are distributed on the left and right sides of the optical carrier fc, respectively. When receiving, an optical filter is used to filter out a sideband signal and carrier to be detected, so that the detection without crosstalk between signals can be realized. The single-sideband modulation method can avoid the phase noise introduced by IQM and the IQ mismatch problem of traditional coherent reception Hybrid.

The sixth embodiment of the present application relates to a signal transmission device, including a transmitting end and a receiving end, and the transmitting end includes: a laser, a polarization beam splitter, an IQM modulator, a phase delayer, and a beam combiner; wherein, the laser , used to transmit an optical signal; the polarization beam splitter is used to polarize the optical signal to obtain signal light and local oscillator light; the IQM modulator is used to modulate the received first electrical signal to the first sideband of the signal light, modulate the received second electrical signal on the second sideband of the signal light, and obtain the modulated signal light; the phase delay device is used to The local oscillator light is phase-corrected to obtain the corrected local oscillator light; the beam combiner is used for combining the corrected local oscillator light and the modulated signal light to generate emission light and send.

The transmitting end further includes: a Faraday rotating mirror; wherein, the Faraday rotating mirror is used to perform polarization rotation on the corrected local oscillator light to obtain the rotated local oscillator light, wherein the rotated local oscillator light is obtained. The polarization state of the vibrating light is the same as that of the modulated signal light; the beam combiner is also used to combine the rotated local oscillator light and the modulated signal light to generate emitted light and transmit it .

8 and 9 are used as examples to describe the above signal transmission device. Specifically, please refer to FIGS. 8 and 9. The transmitting end includes: a laser 1, a polarization beam splitter PBS2, an IQM modulator 3, and a beam combiner OC4, circulator C1, phase delay device TOD5, Faraday rotating mirror FRM6; the receiving end includes:

optical filter OBPF

7, 8, photodetector PD 9, 10.

In Figure 8, the light emitted by the laser 1 on the left side is polarized and separated by the polarization beam splitter PBS2, the X polarized light is modulated as the signal light, and the Y polarized light is used as the local oscillator light required for coherent reception. The electrical signal is subjected to single-sideband modulation (corresponding to a signal) to the signal light through the IQM modulator 3. This modulation method makes the signals S1 and S2 on the two sidebands of the X-polarized light respectively, and the local oscillator light of the Y-polarized light (corresponding to b signal), it enters through port 1 of circulator C1, and exits through port 2, and then performs phase correction through phase delay device TOD5, and then performs polarization rotation through Faraday rotator FRM6 to make the polarization state of Y-polarized local oscillator light. It is consistent with the signal light of the polarization state of the X-polarized light. After reflection, it enters from port 2 of the circulator C1 and exits from port 3 (corresponding to the c signal), and then combines the signal light and the local oscillator light through the beam combiner OC4 (corresponding to d). signal), and then transmitted through the optical fiber, and then passed through the optical filters OBPF 7, 8 to filter out the two sideband lights (corresponding to the e, f signals) containing the local oscillator light respectively, and then passed the photodetectors PD 9, 10 The signal S1 and S2 are demodulated, and then can be connected to the wave control board in the current technology for signal transmission. The schematic diagrams of the spectra corresponding to a, b, c, d, e, and f in the figure are shown in Figure 9.

It should be noted that the circulators in the fifth embodiment and the sixth embodiment can also be implemented by other circuit structures, for example, a multiplexer, etc., as long as the input and output of signals can be realized.

In the fifth and sixth embodiments of the present application, the mode, frequency, and bandwidth of the signal to be modulated can be changed according to the needs of the user, and the coherent optical carrier transmission that can realize multi-mode and multi-frequency fusion of high and low frequencies can be realized, because there is no traditional The digital processing module, frequency conversion module and clock of the base station greatly reduce the complexity of the structure, reduce the cost, and solve its size, weight and power consumption problems. In addition, the IQ mismatch of the Hybrid used in traditional coherent reception can also be effectively avoided, and the phase noise introduced by this mismatch can be eliminated.

The present application is not limited to the transmission applied to the base station, and can also be applied to the fields using coherent transmission such as data centers.

The seventh embodiment of the present application relates to a network device, as shown in FIG. 10 , comprising: at least one processor 1001 ; and a memory 1002 communicatively connected to the at least one processor 1001 ; wherein the memory 1002 stores Instructions executable by the at least one processor, the instructions are executed by the at least one processor 1001, so that the at least one processor 1001 can execute the signal transmission method provided by the above embodiments of the present application.

The memory and the processor are connected by a bus, and the bus may include any number of interconnected buses and bridges, and the bus connects one or more processors and various circuits of the memory. The bus may also connect together various other circuits, such as peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. The bus interface provides the interface between the bus and the transceiver. A transceiver may be a single element or multiple elements, such as multiple receivers and transmitters, providing a means for communicating with various other devices over a transmission medium. The data processed by the processor is transmitted on the wireless medium through the antenna, and further, the antenna also receives the data and transmits the data to the processor.

The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interface, voltage regulation, power management, and other control functions. Instead, memory may be used to store data used by the processor in performing operations.

Those of ordinary skill in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the present application, and in practical applications, various changes in form and details can be made without departing from the spirit and the spirit of the present application. Scope.

Claims

A signal transmission method, comprising:

obtaining the first electrical signal and the second electrical signal;

The optical signal emitted by the laser is polarized and separated to obtain the signal light and the local oscillator light;

modulating the first electrical signal on the first sideband of the signal light, modulating the second electrical signal on the second sideband of the signal light, and obtaining the modulated signal light;

The modulated signal light and the local oscillator light are combined into emission light for transmission.
The method according to claim 1, wherein the combining the modulated signal light and the local oscillator light into emission light for transmission comprises:

performing phase correction on the local oscillator light to obtain the corrected local oscillator light;

The corrected local oscillator light and the modulated signal light are subjected to beam combining processing to generate and transmit emitted light.
The method according to claim 2, wherein the phase correction is performed on the local oscillator light, and after the corrected local oscillator light is obtained, the corrected local oscillator light and the modulated signal are obtained. The light is combined and processed, before generating the emitted light and sending it, it also includes:

performing polarization rotation on the corrected local oscillator light to obtain the rotated local oscillator light, wherein the rotated local oscillator light is consistent with the polarization state of the modulated signal light;

The process of combining the corrected local oscillator light and the modulated signal light to generate and transmit the emitted light is as follows:

The rotated local oscillator light and the modulated signal light are subjected to beam combining processing to generate and transmit emitted light.
A signal transmission method, comprising:

receiving emitted light, wherein the emitted light includes signal light and local oscillator light;

Perform optical filtering processing on the emitted light to obtain first sideband light and second sideband light, wherein the first sideband light includes the first sideband of the signal light and the local oscillator light, so the second sideband light includes the second sideband of the signal light and the local oscillator light;

The first sideband light and the second sideband light are demodulated respectively to obtain a first electrical signal and a second electrical signal.
The method according to claim 4, wherein after the receiving the emitted light, the performing optical filtering processing on the emitted light and before acquiring the first sideband light and the second sideband light, further comprising:

performing branch processing on the emitted light to obtain the signal light and the local oscillator light;

performing polarization rotation on the local oscillator light to obtain the rotated local oscillator light;

Reflecting the signal light to obtain the reflected signal light, wherein the rotated local oscillator light is in phase with the reflected signal light;

combining the reflected signal light and the rotated local oscillator light to generate the emitted light to be processed;

The performing optical filtering processing on the emitted light to obtain the first sideband light and the second sideband light is specifically:

Perform light filtering processing on the emitted light to be processed to obtain the first sideband light and the second sideband light.
A signal transmission device, comprising: a laser, a polarization beam splitter, an IQM modulator, a phase delayer and a beam combiner; wherein,

the laser, for emitting an optical signal;

The polarization beam splitter is used for polarization separation of the optical signal to obtain signal light and local oscillator light;

The in-phase quadrature modulator IQM is used to modulate the received first electrical signal on the first sideband of the signal light, and modulate the received second electrical signal on the second side of the signal light On the band, obtain the modulated signal light;

The phase delayer is used to perform phase correction on the local oscillator light to obtain the corrected local oscillator light;

The beam combiner is configured to perform beam combining processing on the corrected local oscillator light and the modulated signal light to generate and transmit emitted light.
The apparatus of claim 6, further comprising: a Faraday rotation mirror; wherein,

The Faraday rotating mirror is used to perform polarization rotation on the corrected local oscillator light to obtain the rotated local oscillator light, wherein the rotated local oscillator light is consistent with the polarization state of the modulated signal light ;

The beam combiner is further configured to perform beam combining processing on the rotated local oscillator light and the modulated signal light to generate and transmit emitted light.
A signal transmission device, comprising: a first optical filter, a second optical filter, a first photodetector and a second photodetector; wherein,

The first optical filter is used for filtering the received emitted light to obtain first sideband light, wherein the first sideband light includes the first sideband of the signal light and the original sideband light. vibrating light;

The second optical filter is used for filtering the received emitted light to obtain a second sideband light, wherein the second sideband light includes the second sideband of the signal light and the original light. vibrating light;

the first photodetector for demodulating the first sideband light to obtain a first electrical signal;

The second photodetector is used for demodulating the second sideband light to obtain a second electrical signal.
The device according to claim 8, further comprising: a wavelength division module, a Faraday rotating mirror and a Faraday mirror; wherein,

the wavelength division module, configured to perform branch processing on the emitted light to obtain the signal light and the local oscillator light;

The Faraday rotating mirror is used for polarizing and rotating the local oscillator light to obtain the rotated local oscillator light;

the Faraday mirror is used for reflecting the signal light to obtain the reflected signal light, wherein the rotated local oscillator light is in phase with the reflected signal light;

Then the first optical filter is further configured to filter the emitted light to be processed to obtain first sideband light, wherein the first sideband light includes the first sideband of the signal light and the Local oscillator light, the emission light to be processed is generated by combining the reflected signal light and the rotated local oscillator light;

The second optical filter is further configured to perform filtering processing on the emitted light to be processed to obtain a second sideband light, wherein the second sideband light includes the second sideband of the signal light and the source light. The emitted light to be processed is generated by combining the reflected signal light and the rotated local oscillator light.
A network device comprising:

at least one processor; and,

a memory communicatively coupled to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the execution of any one of claims 1 to 3 The signal transmission method described above, or the signal transmission method described in claim 4 or 5.