Signal transmission method and system

Abstract

The invention relates to the technical field of single-fiber signal two-way transmission, and discloses a signal transmission method and system, and the method is applied to a transmitter, and comprises the steps: generating a double-sideband optical modulation signal based on an optical signal and an electric signal; filtering and combining the double-sideband light modulation signal to generate a wavelength division multiplexing single-sideband signal; and sending the wavelength division multiplexing single side band signal to a receiver through an uplink transmission direction or a downlink transmission direction, so that the receiver performs filtering and wave splitting on the wavelength division multiplexing single side band signal to generate a restored electric signal. According to the invention, the number of high-performance filters and signal transmission loss can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of single-fiber signal bidirectional transmission, and in particular to a signal transmission method and system. Background Art

[0002] With the exponential growth of global Internet traffic, current data center interconnection faces unprecedented pressure in meeting the requirements of ultra-large capacity and ultra-low cost. At present, data center interconnection mainly adopts the solution based on intensity modulation / direct detection (IM / DD), but it will become increasingly challenging to further expand the scale to meet the growing capacity demand. The main reason is the low spectrum efficiency of IM / DD and the susceptibility to fiber dispersion. For the 800G / 1.6T module based on four-level pulse intensity modulation (PAM4) technology to be adopted in the future, the line side rate will reach more than 200Gb / s / λ. Under such conditions, even if it can be transmitted in the O band, the transmission distance of coarse wavelength division multiplexing (CWDM) will be limited to less than 4km, which greatly limits the scope of IM / DD solution in data center interconnection. The use of coherent optical communication solution is a technically effective solution. However, based on cost considerations, the coherent optical communication solution is still not suitable for large-scale deployment in data center interconnection.

[0003] The single sideband (SSB) modulation method based on direct detection is currently an effective low-cost solution. By removing one of the redundant sidebands, the spectrum utilization of the SSB signal can be doubled compared to the double sideband (DSB) signal. At the same time, the narrow spectrum characteristics can reduce the influence of frequency selective fading caused by dispersion in the traditional IM / DD system to a certain extent, thereby increasing its transmission distance. There are usually three methods to achieve signal SSB modulation. Method 1: Use direct optical filtering to remove the upper bandwidth or lower sideband optical signal from the original DSB optical signal to achieve SSB modulation. The main disadvantage of this method is that it has strict requirements on the filter. When using the wavelength division multiplexing (WDM) solution, the cost will increase linearly. At the same time, when a non-adjustable filter is used, the system performance will also be affected by the wavelength stability. Method 2 and Method 3, one uses an IQ modulator and the other uses a dual-drive Mach-Zehnder Modulator (MZM). The modulation principles are basically the same, both using a modulation scheme based on Hilbert transform. The advantage of this scheme is that signal generation is not affected by the laser. The disadvantage is that it requires a new transmitter structure and is incompatible with the original system. Therefore, the cost of using a large-scale WDM system is difficult to estimate and upgrading is difficult to achieve. In large-scale data center optical interconnection, in order to save optical link resources, single-fiber bidirectional transmission technology is usually used, that is, bidirectional communication is achieved in the same optical fiber. Such a solution can effectively improve the transmission capacity of the single-fiber system, so that the growing capacity demand can be met while maintaining the original system structure. However, in a single-core bidirectional system, backscattering will inevitably occur. This noise will reduce the signal-to-noise ratio (SNR) of the received signal, causing the performance of the entire system to deteriorate. In order to avoid backscattering, different wavelength uplink and downlink solutions are usually used in single-fiber bidirectional communication. The disadvantage of this method is that it uses more wavelength resources, the signal transmission loss is high, and the spectrum utilization of the system is reduced.

[0004] Therefore, how to effectively reduce the number of high-performance filters and signal transmission losses is a problem that needs to be solved urgently.

[0005] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0006] The main purpose of this application is to provide a signal transmission method and system, aiming to solve the technical problem of how to effectively reduce the number of high-performance filters and signal transmission loss.

[0007] To achieve the above object, the present application proposes a signal transmission method, which is applied to a transmitter, and the method comprises: generating a double-sideband optical modulation signal based on an optical signal and an electrical signal; Filtering and combining the double-sideband optical modulated signal to generate a wavelength division multiplexed single-sideband signal; The wavelength division multiplexing single sideband signal is sent to a receiver via an uplink transmission direction or a downlink transmission direction, so that the receiver filters and demultiplexes the wavelength division multiplexing single sideband signal to generate a restored electrical signal.

[0008] In one embodiment, generating a double-sideband optical modulation signal based on an optical signal and an electrical signal includes: Receive electrical and optical signals; Modulation is performed according to the electrical signal and the optical signal to generate a double-sideband optical modulation signal.

[0009] In one embodiment, the step of performing modulation according to the electrical signal and the optical signal to generate a double-sideband optical modulation signal includes: The electrical signal and the optical signal are input to an intensity modulator, so that the intensity modulator adds the electrical signal to the optical signal to generate a double-sideband optical modulation signal.

[0010] In one embodiment, filtering and combining the double-sideband optical modulation signal to generate a wavelength division multiplexed single-sideband signal includes: filtering the double-sideband optical modulation signal to generate a single-sideband optical modulation signal; The single sideband optical modulation signals are multiplexed to generate wavelength division multiplexed single sideband signals.

[0011] In one embodiment, the combining of the single sideband optical modulation signals to generate wavelength division multiplexed single sideband signals includes: Performing equal-gain amplification on the single-sideband optical modulated signal to obtain an amplified single-sideband optical modulated signal; The amplified single-sideband optical modulation signals are combined to generate wavelength division multiplexed single-sideband signals.

[0012] In one embodiment, the step of sending the wavelength division multiplexed single sideband signal to a receiver via an uplink transmission direction or a downlink transmission direction includes: When the wavelength division multiplexing single sideband signal is an upper sideband signal, sending the upper sideband signal to a receiver via the uplink transmission direction; When the wavelength division multiplexing single sideband signal is a lower sideband signal, the lower sideband signal is sent to a receiver via the downlink transmission direction.

[0013] In addition, to achieve the above-mentioned purpose, the present application also proposes a signal transmission method, which is applied to a receiver, and the method includes: Receive the wavelength division multiplexed single sideband signal sent by the transmitter; The wavelength division multiplexed single sideband signal is filtered and demultiplexed to generate a restored electrical signal.

[0014] In one embodiment, filtering and demultiplexing the wavelength division multiplexed single sideband signal to generate a restored electrical signal includes: Filtering and demultiplexing the wavelength division multiplexing single sideband signal to generate a target single sideband signal; The target single sideband signal is restored to generate a restored electrical signal.

[0015] In one embodiment, filtering and demultiplexing the wavelength division multiplexing single sideband signal to generate a target single sideband signal includes: Filtering the wavelength division multiplexing single sideband signal to obtain a filtered single sideband signal; The filtered single sideband signal is subjected to signal separation to generate a target single sideband signal.

[0016] In one embodiment, performing signal restoration on the target single sideband signal to generate a restored electrical signal includes: The target single sideband signal is sent to a photoelectric detector, so that the photoelectric detector performs photoelectric conversion on the target single sideband signal to generate a restored electrical signal.

[0017] In addition, to achieve the above objectives, the present application also proposes a signal transmission system, which includes a transmitter and a receiver, the transmitter executes the signal transmission method as described above, and the receiver executes the signal transmission method as described above.

[0018] The present application provides a signal transmission method, which is applied to a transmitter. The present application first generates a double-sideband optical modulation signal based on an optical signal and an electrical signal; filters and combines the double-sideband optical modulation signal to generate a wavelength division multiplexing single-sideband signal; and transmits the wavelength division multiplexing single-sideband signal to a receiver via an uplink transmission direction or a downlink transmission direction, so that the receiver filters and demultiplexes the wavelength division multiplexing single-sideband signal to generate a restored electrical signal, thereby effectively reducing the number of high-performance filters and signal transmission losses.

[0019] In summary, the present application effectively improves the spectrum utilization rate by generating a double-sideband optical modulated signal based on an optical signal and an electrical signal, and then filters and combines the double-sideband optical modulated signal, effectively reducing the optical power loss, and then sends the generated wavelength division multiplexed single-sideband signal to the receiver through the uplink transmission direction or the downlink transmission direction for filtering and demultiplexing, so as to realize two-way transmission of the signal and restoration of the electrical signal, overcoming the technical defects of high demand for the number of high-performance filters and high signal transmission loss, and can effectively reduce the number of high-performance filters and signal transmission loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 A schematic diagram of a flow chart provided for a signal transmission method embodiment 1 of the present application applied to a transmitter; Figure 2 A framework diagram of a transmitter provided in Embodiment 1 of the signal transmission method applied to a transmitter of the present application; Figure 3 A schematic diagram of transmission of a wavelength division multiplexed single sideband signal provided in Embodiment 1 of the signal transmission method applied to a transmitter of the present application; Figure 4 A flowchart of a second embodiment of a signal transmission method for a transmitter according to the present application is provided; Figure 5 A flowchart of a signal transmission method for a receiver according to a first embodiment of the present invention; Figure 6 A schematic diagram of a flow chart provided for a signal transmission method embodiment 2 of the present application applied to a receiver; Figure 7 A framework diagram of a receiver provided for Embodiment 2 of the signal transmission method applied to a receiver of the present application.

[0023] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0024] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0025] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0026] The main solution of the embodiment of the present application is: generate a double-sideband optical modulation signal based on an optical signal and an electrical signal; filter and combine the double-sideband optical modulation signal to generate a wavelength division multiplexing single sideband signal; send the wavelength division multiplexing single sideband signal to a receiver via an uplink transmission direction or a downlink transmission direction, so that the receiver filters and demultiplexes the wavelength division multiplexing single sideband signal to generate a restored electrical signal.

[0027] The single sideband (SSB) modulation method based on direct detection is currently an effective low-cost solution. By removing one of the redundant sidebands, the spectrum utilization of the SSB signal can be doubled compared to the double sideband (DSB) signal. At the same time, the narrow spectrum characteristics can reduce the influence of frequency selective fading caused by dispersion in the traditional IM / DD system to a certain extent, thereby increasing its transmission distance. There are usually three methods to achieve signal SSB modulation. Method 1: Use direct optical filtering to remove the upper bandwidth or lower sideband optical signal from the original DSB optical signal to achieve SSB modulation. The main disadvantage of this method is that it has strict requirements on the filter. When using the wavelength division multiplexing (WDM) solution, the cost will increase linearly. At the same time, when a non-adjustable filter is used, the system performance will also be affected by the wavelength stability. Method 2 and Method 3, one uses an IQ modulator and the other uses a dual-drive Mach-Zehnder Modulator (MZM). The modulation principles are basically the same, both using a modulation scheme based on Hilbert transform. The advantage of this scheme is that signal generation is not affected by the laser. The disadvantage is that it requires a new transmitter structure and is incompatible with the original system. Therefore, the cost of using a large-scale WDM system is difficult to estimate and upgrading is difficult to achieve. In large-scale data center optical interconnection, in order to save optical link resources, single-fiber bidirectional transmission technology is usually used, that is, bidirectional communication is achieved in the same optical fiber. Such a solution can effectively improve the transmission capacity of the single-fiber system, so that the growing capacity demand can be met while maintaining the original system structure. However, in a single-core bidirectional system, backscattering will inevitably occur. This noise will reduce the signal-to-noise ratio (SNR) of the received signal, causing the performance of the entire system to deteriorate. In order to avoid backscattering, different wavelength uplink and downlink solutions are usually used in single-fiber bidirectional communication. The disadvantage of this method is that it uses more wavelength resources, the signal transmission loss is high, and the spectrum utilization of the system is reduced. Therefore, how to effectively reduce the number of high-performance filters and signal transmission loss is a problem that needs to be solved urgently.

[0028] The present application effectively improves the spectrum utilization rate by generating a double-sideband optical modulation signal based on an optical signal and an electrical signal, and then filters and combines the double-sideband optical modulation signal, effectively reducing the optical power loss, and then sends the generated wavelength division multiplexed single-sideband signal to the receiver through the uplink transmission direction or the downlink transmission direction for filtering and demultiplexing, so as to realize two-way transmission of the signal and restoration of the electrical signal, overcoming the technical defects of high demand for the number of high-performance filters and high signal transmission loss, and can effectively reduce the number of high-performance filters and signal transmission loss.

[0029] Based on this, the embodiment of the present application provides a signal transmission method, which is applied to a transmitter, referring to Figure 1 , Figure 1 This is a flow chart of a first embodiment of a signal transmission method applied to a transmitter in the present application.

[0030] In this embodiment, the signal transmission method includes steps S10 to S30: Step S10: generating a double-sideband optical modulation signal based on the optical signal and the electrical signal.

[0031] It should be noted that the execution subject of this embodiment is a transmitter, which is a device for generating and transmitting wavelength division multiplexing single sideband signals, and includes but is not limited to key components such as an intensity modulator and a wavelength selection switch. The transmitter in this embodiment is the transmitting end in the traditional optical interconnect transceiver architecture.

[0032] It is understandable that the double-sideband optical modulation signal is an optical signal including an upper sideband and a lower sideband, and its spectrum characteristics are similar to those of a traditional double-sideband (DSB) signal, but it has a higher spectrum utilization rate. In the process of generating the double-sideband optical modulation signal, the transmitter combines the electrical signal with the optical signal through a specific modulation technology, such as intensity modulation or phase modulation, so as to achieve efficient use of the spectrum, and this embodiment does not impose specific restrictions on this.

[0033] In a specific implementation, the transmitter receives an electrical signal from the outside, and then combines it with an optical signal to generate a double-sideband optical modulated signal. The process involves converting the electrical signal into an optical signal and combining the two through modulation technology to form a double-sideband optical modulated signal with specific spectral characteristics.

[0034] In a feasible implementation manner, step S10 may include: receiving an electrical signal and an optical signal; and performing modulation according to the electrical signal and the optical signal to generate a double-sideband optical modulation signal.

[0035] It should be noted that in this embodiment, the transmitter receives multiple electrical signals and optical signals of the same data, for example, receives N electrical signals and N corresponding optical signals, and this embodiment does not impose any specific limitation on this.

[0036] It can be understood that the electrical signal contains different data information, and the optical signal is used as a carrier to transmit this data information. In the modulation process, the transmitter modulates these electrical signals with the optical signal respectively to generate multiple double-sideband optical modulation signals, each of which corresponds to a specific set of data information. The electrical signal and the optical signal can be generated by an electrical signal generator and an optical signal generator respectively.

[0037] It is worth noting that the transmitter may also include one or more signal processing units for preprocessing the input electrical signal, such as filtering, amplifying or shaping, to ensure that the signal quality meets the modulation requirements. The transmitter is also equipped with a wavelength selection switch for selecting a suitable wavelength to meet different transmission requirements.

[0038] In a feasible implementation, the modulating according to the electrical signal and the optical signal to generate a double-sideband optical modulation signal includes: inputting the electrical signal and the optical signal into an intensity modulator so that the intensity modulator loads the electrical signal into the optical signal to generate a double-sideband optical modulation signal.

[0039] It should be noted that the transmitter includes multiple intensity modulators for processing the modulation of multiple electrical signals and optical signals. Each intensity modulator can work independently to ensure accurate modulation and transmission of the signal. The transmitter may also include one or more wavelength selection switches to dynamically adjust the wavelength of the optical signal to adapt to different network environments and transmission requirements.

[0040] It can be understood that the intensity modulator is a key optical modulation technology, which realizes the encoding of data information by changing the intensity of the optical signal. In this embodiment, the intensity modulator can adopt a variety of technologies, such as electro-absorption modulator (EAM) or Mach-Zehnder interferometer (MZI) modulator, etc., to achieve efficient optical signal modulation.

[0041] It can be understood that during the modulation process, each intensity modulator loads the corresponding electrical signal onto the corresponding optical signal, that is, the amplitude change of the electrical signal is converted into a change in the intensity of the optical signal, thereby generating a double-sideband optical modulated signal with specific spectral characteristics. Due to the use of double-sideband optical modulation technology, higher data transmission rates and spectral efficiency can be achieved under the same transmission bandwidth.

[0042] In the specific implementation, the optical signal with wavelength λ1 is loaded onto the optical carrier through the intensity modulator. According to the intensity modulation formula, the output double-sideband optical modulated signal is y1(t) =(A+ x1(t))cos(f1t+ ), where A is the optical carrier amplitude, f1 is the frequency corresponding to the optical signal with wavelength λ1, is the initial phase. According to the Fourier transform formula, the signal spectrum is a double-sideband signal with λ1 as the center and a bandwidth of B above and below. The above operation is performed on all wavelengths to generate a set of central wavelengths of λ1, λ2, ..., λ N Double-sideband optical modulation signal.

[0043] Step S20, filtering and multiplexing the double-sideband optical modulation signal to generate a wavelength division multiplexed single-sideband signal.

[0044] It should be noted that the transmitter also includes a wavelength selective switch (WSS) for filtering and combining. The wavelength selective switch can select different wavelength channels as needed, thereby achieving precise control of the signal. In this embodiment, the wavelength selective switch filters each double-sideband optical modulated signal, removes unnecessary frequency components, and then combines them into a wavelength division multiplexing single-sideband signal.

[0045] It can be understood that the central wavelengths are λ1, λ2, ..., λ N The double-sideband optical modulated signal is input to the wavelength selective switch for filtering and combining. During the filtering process, the wavelength selective switch will select a suitable filter to remove side lobes and noise according to the central wavelength of each double-sideband optical modulated signal to ensure the quality of the output signal. The filtered signal will be combined, that is, multiple single-sideband optical modulated signals of different wavelengths will be combined into one signal for easy transmission, and a wavelength division multiplexed single-sideband signal can be obtained.

[0046] It is worth mentioning that wavelength division multiplexing single sideband signal (WDM-SSB) is an efficient signal transmission method used to improve the transmission efficiency and spectrum utilization of optical fiber communication systems. WDM-SSB combines the advantages of wavelength division multiplexing (WDM) technology and single sideband modulation (SSB) technology, and can achieve efficient data transmission in optical fiber communication systems. Wavelength division multiplexing (WDM) technology allows multiple signals of different wavelengths to be transmitted simultaneously in the same optical fiber, thereby greatly improving the transmission capacity of optical fiber. Single sideband modulation (SSB) is a modulation technology that transmits only one sideband (upper sideband or lower sideband) of the information signal without transmitting the other sideband and the carrier signal, which can save half of the spectrum resources and improve transmission efficiency.

[0047] Step S30, sending the wavelength division multiplexing single sideband signal to a receiver via an uplink transmission direction or a downlink transmission direction, so that the receiver filters and demultiplexes the wavelength division multiplexing single sideband signal to generate a restored electrical signal.

[0048] It should be noted that, in this embodiment, a bidirectional transmission method is adopted in each process of sending the wavelength division multiplexing single sideband signal to the receiver, that is, the wavelength division multiplexing single sideband signal is an upper sideband signal or a lower sideband signal, which can be transmitted through the uplink and downlink respectively, that is, sent to the receiver through the uplink transmission direction or the downlink transmission direction. In the system structure of single-fiber bidirectional transmission, the uplink and downlink use upper sideband and lower sideband transmission respectively, which effectively reduces the impact of backscattering on the performance of the system itself while maintaining the spectrum utilization of the original system, and improves the practicality and reliability of the system.

[0049] It is worth noting that the receiver is used to receive wavelength division multiplexed single sideband signals and filter and demultiplex them to restore the signals and obtain restored electrical signals, and then demodulate the restored electrical signals to extract the original information. The receiver also performs filtering and demultiplexing through a wavelength selective switch (WSS).

[0050] It is worth noting that in this application, a multi-port wavelength selective switch WSS is used to perform single-sideband (SSB) filtering on the traditional double-sideband (DSB) signal of multiple wavelengths, that is, the multi-wavelength DSB signal is input to different ports corresponding to the WSS, and then the signals of different wavelengths are uniformly SSB filtered by the WSS and then combined and output, thereby realizing the generation of WDM-SSB combined signal. Compared with the traditional single-wave filtering solution, the change of the transmitting end structure is reduced, and the demand for the number of high-performance filters is reduced. At the same time, the multi-port WSS synthesis method is used to unify the filtering and combining, reduce the optical loss and complexity of the system, and improve the scalability of the system. Finally, the adjustable WSS method can adjust the filtering range according to the frequency deviation of different wavelengths, which improves the flexibility and practicality of the solution.

[0051] like Figure 2 As shown, Figure 2 The transmitter consists of several intensity modulators and a wavelength selection switch. The wavelengths are λ1, λ2, ..., λ N The optical signal is loaded onto the optical carrier through the intensity modulator to generate a set of central wavelengths λ1, λ2, ..., λ N Each double-sideband optical modulated signal occupies a bandwidth of B, and each double-sideband optical modulated signal is input into a different port corresponding to the wavelength selective switch, filtered and combined by the wavelength selective switch, and finally outputs a wavelength division multiplexed single-sideband signal.

[0052] In a feasible implementation manner, in step S30, "sending the wavelength division multiplexing single sideband signal to the receiver via an uplink transmission direction or a downlink transmission direction" specifically includes: when the wavelength division multiplexing single sideband signal is an upper sideband signal, sending the upper sideband signal to the receiver via the uplink transmission direction; when the wavelength division multiplexing single sideband signal is a lower sideband signal, sending the lower sideband signal to the receiver via the downlink transmission direction.

[0053] It should be noted that when bidirectional transmission is adopted, the wavelength selective switch WSS generates upper sideband signals and lower sideband signals respectively according to different transmission directions. Since the bidirectional transmission signals do not overlap in frequency, the back Rayleigh scattering is almost unaffected, thereby improving the system performance. When bidirectional transmission is adopted, the central wavelength of the signal is the same, resulting in no reduction in wavelength efficiency, thus maintaining the practicality and reliability of the original bidirectional transmission.

[0054] It can be understood that the upper sideband signal is the upper sideband part containing information, while the lower sideband signal is the lower sideband part containing information. By selectively transmitting the upper sideband or lower sideband signal according to the channel direction, interference between signals can be effectively reduced and transmission quality can be improved.

[0055] It is worth noting that when single-fiber bidirectional N-wavelength wavelength division multiplexing (WDM) is used, its spectrum structure is: the lower sideband signal, i.e. the downlink signal, has a central wavelength of f1+B / 2, f2+B / 2, ..., f N +B / 2, a signal with a bandwidth of B; the upper sideband signal is the uplink signal, and the central wavelengths are f1-B / 2, f2-B / 2, ..., f N -B / 2, the bandwidth is B. The uplink and downlink modulation signals do not overlap in the spectrum, only the carrier part has a partial overlap area. Therefore, during bidirectional transmission, even if there is some backscattered optical signal, since the main component of the scattering is the carrier part, it is mainly converted into DC during photoelectric detection. Therefore, it has little impact on the original receiving system. At the same time, the bidirectional transmission method is adopted, which increases the system capacity exponentially without changing the original system structure. This method is almost unaffected by backscattering and can effectively increase the overall capacity of the system.

[0056] like Figure 3 As shown, Figure 3 The transmission diagram of wavelength division multiplexing single sideband signal is as follows: the spectrum structure of the wavelength division multiplexing single sideband signal is as follows: the downlink signals have central wavelengths of f1+B / 2, f2+B / 2, ..., f N +B / 2 and a bandwidth of B; the uplink signals have central wavelengths of f1-B / 2, f2-B / 2, ..., f N-B / 2 and a signal with a bandwidth of B, the downlink signal and the uplink signal are transmitted in the uplink transmission direction and the downlink transmission direction respectively.

[0057] The present embodiment provides a signal transmission method, which is applied to a transmitter. The present embodiment first generates a double-sideband optical modulation signal based on an optical signal and an electrical signal; filters and combines the double-sideband optical modulation signal to generate a wavelength division multiplexing single sideband signal; and transmits the wavelength division multiplexing single sideband signal to a receiver via an uplink transmission direction or a downlink transmission direction, so that the receiver filters and demultiplexes the wavelength division multiplexing single sideband signal to generate a restored electrical signal, thereby effectively reducing the number of high-performance filters and signal transmission losses.

[0058] In summary, this embodiment effectively improves spectrum utilization by generating a double-sideband optical modulated signal based on an optical signal and an electrical signal, and then filters and combines the double-sideband optical modulated signal, effectively reducing optical power loss, and then sends the generated wavelength division multiplexing single-sideband signal to the receiver through the uplink transmission direction or the downlink transmission direction for filtering and demultiplexing, so as to realize two-way transmission of the signal and restoration of the electrical signal, overcoming the technical defects of high demand for the number of high-performance filters and high signal transmission loss, and can effectively reduce the number of high-performance filters and signal transmission loss.

[0059] Based on the first embodiment of the signal transmission method applied to the transmitter of the present application, in the second embodiment of the signal transmission method applied to the transmitter of the present application, the same or similar contents as those in the above-mentioned embodiment 1 can be referred to the above introduction, and will not be repeated in the following. Figure 4 , the step S20 further includes steps S201-S202: Step S201, filtering the double-sideband optical modulation signal to generate a single-sideband optical modulation signal.

[0060] It should be noted that filtering is achieved through a wavelength selective switch WSS, which sets the central wavelengths to λ1, λ2, ..., λ N The double-sideband optical modulation signals with bandwidth B above and below are respectively input to different ports corresponding to the wavelength selective switch WSS. The number of input ports of the wavelength selective switch can be greater than N, so that the number of WDM wavelengths can be flexibly increased, thereby improving the scalability of the system.

[0061] It can be understood that the parameters for filtering the wavelength selective switch WSS are set, that is, the filtering parameters for ports 1, 2, ..., N are set to have center frequencies of f1+B / 2, f2+B / 2, ..., f N+B / 2 and a low-pass filter with a bandwidth of B is used for filtering to generate a single-sideband optical modulation signal, that is, a lower sideband signal. When a high-pass filter is set for filtering, the generated single-sideband optical modulation signal is an upper sideband signal, which is not specifically limited in this embodiment. This embodiment is described by taking filtering with a low-pass filter to generate a lower sideband signal as an example.

[0062] It is worth noting that by filtering the double-sideband optical modulated signal to generate a single-sideband optical modulated signal, the bandwidth requirement of the optical signal can be effectively reduced, thereby reducing the occupation of bandwidth resources during the transmission process. By accurately controlling the filtering parameters, the signal quality can be further optimized to ensure the stability and reliability of the signal during the transmission process.

[0063] It is worth noting that the double-sideband optical modulation signal contains the upper sideband and lower sideband of the information signal, but does not contain the carrier signal. The single-sideband optical modulation signal only contains one sideband of the information signal, usually the upper sideband (USB) or the lower sideband (LSB). The single-sideband optical modulation signal can be obtained by filtering the unnecessary sidebands in the double-sideband optical modulation signal through a filter.

[0064] Step S202, multiplexing the single sideband optical modulation signals to generate wavelength division multiplexed single sideband signals.

[0065] It should be noted that combining is also achieved through the wavelength selective switch WSS, that is, all filtered signals are combined with equal gain to form a wavelength division multiplexed single sideband signal (WDM-SSB) that can be input into the optical fiber for transmission.

[0066] In a feasible implementation, step S202 may include: performing equal-gain amplification on the single-sideband optical modulated signal to obtain an amplified single-sideband optical modulated signal; and performing signal merging on the amplified single-sideband optical modulated signal to generate a wavelength division multiplexed single-sideband signal.

[0067] It should be noted that equal-gain amplification means that during the amplification process, the gains of each signal remain consistent to ensure that different signals have the same power level when combined, avoiding over-amplification of certain signals during combination and causing nonlinear distortion, while ensuring the detectability of weaker signals.

[0068] It can be understood that after equal gain amplification, each single-sideband optical modulated signal is precisely combined together through precise timing control and wavelength selective switch (WSS) configuration to form a wavelength division multiplexed single sideband signal (WDM-SSB) containing all information. The wavelength division multiplexed single sideband signal may include an upper sideband signal or a lower sideband signal, as shown in the following formula: y1(t)= Acos(f1t+ )+ x1(t) cos(f1t+ )+ x1(t) sin(f1t+ ) y1'(t)= Acos(f1t+ )+ x1(t) cos(f1t+ )- x1'(t) sin(f1t+ ) Among them, y1(t) is the lower sideband signal, y1'(t) is the upper sideband signal, A is the optical carrier amplitude, f1 is the frequency corresponding to the optical signal with wavelength λ1, is the initial phase, x1(t) is the electrical signal, and x1'(t) represents the Hilbert change of the electrical signal.

[0069] It is worth mentioning that the advantage of using wavelength selective switch WSS for filtering and combining is that it simplifies the system structure compared to the solution of filtering each wavelength separately. At the same time, WSS can also combine all SSB signals uniformly after filtering. Compared with the traditional solution of combining after filtering, it effectively reduces the loss of system optical power and improves the performance of the system after combining. Usually, due to the need to consider low-cost conditions in the optical interconnection environment of the data center, WSS can adopt a fixed grid structure to achieve low cost. Under conditions that are less cost-sensitive, an adjustable WSS solution can be selected, so that even when the performance of the laser deviates and frequency shifts occur, the position of the filter center wavelength can still be replanned through an adaptive adjustment solution without affecting the implementation of the entire WDM-SSB transmission system.

[0070] In this embodiment, the double-sideband optical modulation signal is filtered and combined by a wavelength selective switch, and the filtering and combining are unified, thereby effectively reducing the optical power loss.

[0071] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the signal transmission method of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0072] The present application also provides a signal transmission method, which is applied to a receiver. Figure 5 , Figure 5 This is a flow chart of a first embodiment of a signal transmission method applied to a receiver according to the present application.

[0073] In this embodiment, the signal transmission method includes steps S10' to S20': Step S10', receiving the wavelength division multiplexed single sideband signal sent by the transmitter.

[0074] It should be noted that the execution subject of this embodiment is a receiver, which is a device for receiving wavelength division multiplexing single sideband signals and performing signal restoration, and the transmitter includes but is not limited to key components such as wavelength selection switches and photodetectors. The receiver in this embodiment is the receiving end in the traditional optical interconnect transceiver architecture.

[0075] It can be understood that the wavelength division multiplexed single sideband signal sent by the transmitter is input into the wavelength selection switch of the receiver for filtering and wavelength division processing after bidirectional transmission.

[0076] It is worth noting that the wavelength division multiplexed single sideband signal sent by the transmitter is obtained by combining multiple single sideband signals, and may include upper sideband signals or lower sideband signals at the same time. Therefore, filtering and demultiplexing are required to ensure that each signal can be correctly restored.

[0077] Step S20', filtering and demultiplexing the wavelength division multiplexed single sideband signal to generate a restored electrical signal.

[0078] It should be noted that filtering and demultiplexing the wavelength division multiplexing single sideband signal is achieved through the wavelength selection switch of the receiver. The double-sideband optical modulation signal and the wavelength division multiplexing single sideband signal in this application are both subjected to single sideband (SSB) filtering through the wavelength selection switch, and the wavelength selection switch includes structures such as liquid crystal on silicon (LCOS), microelectromechanical system (MEMS) and planar light waveguide (Planar Lightwave Circuit, PLC).

[0079] It can be understood that filtering refers to separating the optical signal of a specific wavelength from the mixed signal, that is, filtering the unnecessary sideband in the wavelength division multiplexing single sideband signal, which can be the upper sideband or the lower sideband. This embodiment does not impose specific restrictions on this. This embodiment takes filtering the upper sideband as an example for explanation. At this time, the receiver is a downlink receiver. Wavelength separation is to further distribute the separated signal to different paths. The wavelength selection switch of the receiver performs filtering and wavelength separation operations to ensure that each single sideband signal can be accurately restored to an electrical signal.

[0080] In this embodiment, the wavelength division multiplexing single sideband signal is filtered and demultiplexed by a wavelength selective switch, so that the electrical signal can be accurately restored and the signal transmission loss can be effectively reduced.

[0081] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the signal transmission method of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0082] Based on the first embodiment of the signal transmission method applied to the receiver of the present application, in the second embodiment of the signal transmission method applied to the receiver of the present application, the same or similar contents as those of the above-mentioned embodiment 2 can be referred to the above introduction, and will not be repeated in the following. Figure 6 , the step S20' further comprises steps S201'-S202': Step S201', filtering and demultiplexing the wavelength division multiplexed single sideband signal to generate a target single sideband signal.

[0083] It should be noted that the wavelength division multiplexing single sideband signal is a mixed signal that combines the upper sideband signal or the lower sideband signal. Through the filtering function of the wavelength selective switch, the optical signal of a specific wavelength can be separated, that is, the unnecessary sidebands, such as the upper sideband or the lower sideband, can be filtered out.

[0084] It can be understood that when the receiver is a downlink receiver, the target single sideband signal is the lower sideband signal after signal separation. Through the wavelength selective switch's wave splitting function, the filtered signal is further separated and sent to different paths, ensuring that each single sideband signal can be accurately restored to an electrical signal.

[0085] In a feasible implementation, step S201' may include: filtering the wavelength division multiplexing single sideband signal to obtain a filtered single sideband signal; performing signal separation on the filtered single sideband signal to generate a target single sideband signal.

[0086] It should be noted that when the receiver is a downlink receiver, the wavelength selection switch of the receiver is set to a 1-input N-output multi-port filter structure, wherein from port 1 to port N, they correspond to the same filtering parameters of the wavelength selection switch of the transmitter, that is, the center frequencies are f1+B / 2, f2+B / 2, ..., f N +B / 2 and a low-pass filter with a bandwidth of B, so that single-sideband signals of different wavelengths can be output from ports 1 to N, that is, the filtered single-sideband signal.

[0087] It can be understood that separating the filtered single-sideband signal into multiple signals and performing signal restoration separately can further improve the accuracy and efficiency of signal restoration, wherein signal separation can also be achieved through a filter.

[0088] Step S202', performing signal restoration on the target single sideband signal to generate a restored electrical signal.

[0089] It should be noted that, in this embodiment, signal restoration is accomplished by a photodetector, and the receiver includes a plurality of photodetectors, which convert optical signals into electrical signals. The photodetectors may be PIN diodes or avalanche photodiodes (APDs), which can respond to changes in optical signals and generate corresponding current or voltage signals. In the receiver, the target single-sideband signal is first filtered and demultiplexed by a wavelength selective switch, and then converted into an electrical signal by a photodetector.

[0090] In a feasible implementation manner, step S202' may include: sending the target single sideband signal to a photoelectric detector, so that the photoelectric detector performs photoelectric conversion on the target single sideband signal to generate a restored electrical signal.

[0091] It should be noted that the transmitter includes a photodetector for signal restoration. Each photodetector can work independently to improve the efficiency and reliability of signal restoration. The output electrical signal of the photodetector can then be further processed, for example, by amplification by an amplifier and necessary signal shaping and noise filtering by a subsequent signal processing circuit to ensure the quality of the final output electrical signal.

[0092] It can be understood that the target single-sideband signal is received by a photodetector through a square, that is, the SSB optical signal is converted into an electrical signal by the photodetector, that is, the photodetector converts the received light intensity into a corresponding current output, and the current output by the photodetector is squared, and then the squared signal is restored to the electrical signal input by the transmitter, that is, the restored electrical signal.

[0093] It is worth noting that when the target single-sideband signal is squared and received by the photodetector, the normalized signal output is Z(t) = A 2 +Ax(t)+x 2 (t)+x1' 2 (t), where the last two terms are the self-beating frequency noise of the signal. When the carrier signal power ratio (CSPR) of the signal is large enough, that is, the signal carrier energy is large enough, that is, A is large enough, the noise can be ignored, and the original transmitted signal can be recovered from the SSB signal, that is, the restored electrical signal can be obtained.

[0094] like Figure 7 As shown, Figure 7 The frame diagram of the receiver includes a wavelength selective switch and several photodetectors. The wavelength division multiplexed single sideband signal is filtered and split by the wavelength selective switch to generate a set of central wavelengths λ1, λ2, ..., λ N And the bandwidth is B for the single sideband signal, each single sideband signal is input into the corresponding photoelectric detector for signal restoration.

[0095] In this embodiment, by filtering and demultiplexing the wavelength division multiplexing single sideband signal and then restoring the signal, the input signal can be accurately restored, the loss of signal transmission is effectively reduced, and the accuracy of information restoration is improved.

[0096] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the signal transmission method of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0097] The present application provides a signal transmission system, which includes a transmitter and a receiver. The transmitter executes the signal transmission method as described above, and the receiver executes the signal transmission method as described above.

[0098] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0099] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0100] The readable storage medium provided by the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned signal transmission method, and can solve the technical problem of how to effectively reduce the number of high-performance filters and signal transmission loss. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the present application are the same as the beneficial effects of the signal transmission method provided by the above-mentioned embodiment, and will not be repeated here.

[0101] The present application also provides a computer program product, including a computer program, which implements the steps of the above-mentioned signal transmission method when executed by a processor.

[0102] The computer program product provided by the present application can solve the technical problem of how to effectively reduce the number of high-performance filters and signal transmission loss. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the signal transmission method provided by the above embodiment, which will not be repeated here.

[0103] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A signal transmission method, characterized in that: The signal transmission method is applied to a transmitter, and the method comprises: generating a double-sideband optical modulation signal based on an optical signal and an electrical signal; Filtering and combining the double-sideband optical modulated signal to generate a wavelength division multiplexed single-sideband signal; The wavelength division multiplexing single sideband signal is sent to a receiver via an uplink transmission direction or a downlink transmission direction, so that the receiver filters and demultiplexes the wavelength division multiplexing single sideband signal to generate a restored electrical signal.

2. The method according to claim 1, characterized in that The method of generating a double-sideband optical modulation signal based on an optical signal and an electrical signal comprises: Receive electrical and optical signals; The electrical signal and the optical signal are input to an intensity modulator, so that the intensity modulator adds the electrical signal to the optical signal to generate a double-sideband optical modulation signal.

3. The method according to claim 1, characterized in that The filtering and combining of the double-sideband optical modulation signal to generate a wavelength division multiplexed single-sideband signal includes: filtering the double-sideband optical modulation signal to generate a single-sideband optical modulation signal; The single sideband optical modulation signals are multiplexed to generate wavelength division multiplexed single sideband signals.

4. The method according to claim 3, characterized in that The step of combining the single sideband optical modulation signals to generate a wavelength division multiplexed single sideband signal comprises: Performing equal-gain amplification on the single-sideband optical modulated signal to obtain an amplified single-sideband optical modulated signal; The amplified single-sideband optical modulation signals are combined to generate wavelength division multiplexed single-sideband signals.

5. The method according to claim 1, characterized in that The step of sending the wavelength division multiplexed single sideband signal to a receiver via an uplink transmission direction or a downlink transmission direction comprises: When the wavelength division multiplexing single sideband signal is an upper sideband signal, sending the upper sideband signal to a receiver via the uplink transmission direction; When the wavelength division multiplexing single sideband signal is a lower sideband signal, the lower sideband signal is sent to a receiver via the downlink transmission direction.

6. A signal transmission method, characterized in that: The signal transmission method is applied to a receiver, and the method comprises: Receive the wavelength division multiplexed single sideband signal sent by the transmitter; The wavelength division multiplexed single sideband signal is filtered and demultiplexed to generate a restored electrical signal.

7. The method according to claim 6, characterized in that The filtering and demultiplexing of the wavelength division multiplexing single sideband signal to generate a restored electrical signal includes: Filtering and demultiplexing the wavelength division multiplexing single sideband signal to generate a target single sideband signal; The target single sideband signal is restored to generate a restored electrical signal.

8. The method according to claim 7, characterized in that The filtering and demultiplexing of the wavelength division multiplexing single sideband signal to generate a target single sideband signal includes: Filtering the wavelength division multiplexing single sideband signal to obtain a filtered single sideband signal; The filtered single sideband signal is subjected to signal separation to generate a target single sideband signal.

9. The method according to claim 7, characterized in that The performing signal restoration on the target single sideband signal to generate a restored electrical signal includes: The target single sideband signal is sent to a photoelectric detector, so that the photoelectric detector performs photoelectric conversion on the target single sideband signal to generate a restored electrical signal.

10. A signal transmission system, characterized in that: The signal transmission system comprises a transmitter and a receiver. The transmitter executes the signal transmission method according to any one of claims 1 to 5, and the receiver executes the signal transmission method according to any one of claims 6 to 9.

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