CN113541798A - Multi-band optical transmission system based on super-Nyquist transmission technology - Google Patents
Multi-band optical transmission system based on super-Nyquist transmission technology Download PDFInfo
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- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/25—Arrangements specific to fibre transmission
- H04B10/2507—Arrangements specific to fibre transmission for the reduction or elimination of distortion or dispersion
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/50—Transmitters
- H04B10/501—Structural aspects
- H04B10/506—Multiwavelength transmitters
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- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
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- H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
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- H04L25/03834—Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties using pulse shaping
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Abstract
The invention relates to a multiband optical transmission system based on a super-Nyquist transmission technology, which is characterized by comprising the following components: the system comprises a transmitting end, a multiplexing system and a receiving end; the transmitting terminal is used for generating a super-Nyquist signal; the multiplexing system is used for generating a frequency domain multiplexing signal according to the super-Nyquist signal; and the receiving end is used for generating multiband optical transmission data according to the frequency domain multiplexing signals. The invention effectively realizes the capacity expansion of the transmission system by utilizing the ultra-wideband wavelength division multiplexing transmission system, compresses the signal frequency spectrum of each wave band by combining the super-Nyquist technology, further improves the frequency spectrum efficiency and realizes better capacity expansion effect.
Description
Technical Field
The invention relates to the technical field of digital communication, in particular to a multiband optical transmission system based on a super-Nyquist transmission technology.
Background
The research and development of optical fiber transmission systems face two fundamental challenges: increasing fiber capacity and extending transmission distances. At present, high-efficiency optical transmission using a high-order modulation format and a Wavelength Division Multiplexing (WDM) technology is an important way to realize large-capacity optical communication. In addition, the super-Nyquist optical transmission technology reviews the channel bandwidth, the symbol rate, the spectrum efficiency and the detection mode again, and breaks through the original constraint relation. Under the non-orthogonalization transmission condition, the symbol rate can exceed the Nyquist rate, the wavelength division channel interval is allowed to be lower than the symbol rate, and the frequency spectrum efficiency is improved by 2 bits/s/Hz without depending on the modulation order. Therefore, the super-Nyquist optical transmission technology provides a new mechanism for improving the system spectrum efficiency, and can be combined with the technologies such as a high-order modulation format and high-order coding error correction to deeply mine spectrum resources.
Mazo's laboratory in 1975 first proposed a faster than nyquist communication theory, suggesting that the system bit error rate does not degrade when the channel rate is greater than within 25% of the nyquist rate. In the field of optical communication, Tyco corporation of america proposed in 2011 the possibility of implementing a faster than nyquist wavelength division multiplexing system by spectrum compression in the field of optical fiber communication. Since 2011, a lot of research and research make internal disorder or usurp have been obtained worldwide from the beginning of the super-nyquist optical communication, international conferences such as ECOC2015, OFC2016 and ECOC2016 all set up research topics about super-nyquist, and it is marked that the super-nyquist technology becomes a research hotspot in the field of large-capacity high-speed optical communication. The world has conducted intensive research on the aspects of coding, modulation format, digital signal processing architecture, damage compensation model and the like of the super-nyquist transmission system.
On the other hand, in optical communications, as it becomes more and more difficult to increase the transmission capacity of a single optical fiber within a conventional limited bandwidth, an ultra-wideband Wavelength Division Multiplexing (WDM) transmission system receives a wide attention. Expanding the wavelength of an ultra-wideband wavelength division multiplexing system from the widely used C or L band to the additional S, E and O bands can effectively achieve expansion of the transmission system. In the process of implementing capacity expansion of a transmission system, the prior art generally performs an optimal modulation format suitable for a different band by using an elastic optical network technology, but the euclidean distance of a high-order signal is relatively small, which may cause a sharp decrease in the narrow-band filtering resistance of the signal, and further cause an intersymbol interference model of the high-order signal to be more complex, and have a higher requirement on the processing capability of a rear-end algorithm, thereby causing problems of low spectrum utilization rate, poor capacity expansion stability effect, and the like.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a multiband optical transmission system based on the super-nyquist transmission technology.
In order to achieve the purpose, the invention provides the following scheme:
a multi-band optical transmission system based on the super-nyquist transmission technique, comprising: the system comprises a transmitting end, a multiplexing system and a receiving end;
the transmitting terminal is used for generating a super-Nyquist signal; the multiplexing system is used for generating a frequency domain multiplexing signal according to the super-Nyquist signal; and the receiving end is used for generating multiband optical transmission data according to the frequency domain multiplexing signals.
Preferably, the transmitting end includes: the device comprises a laser generator, an IQ modulation unit, a super-Nyquist modulation unit and a first amplification unit;
the IQ modulation unit includes: QPSK modulator, 16QAM modulator and 64QAM modulator;
the first amplification unit includes: the optical fiber amplifier comprises a first praseodymium-doped optical fiber amplifier, a first semiconductor optical amplifier, a first thulium-doped optical fiber amplifier and a first erbium-doped optical fiber amplifier;
the input end of the QPSK modulator, the input end of the 16QAM modulator and the input end of the 64QAM modulator are connected with the laser generator; the output end of the QPSK modulator, the output end of the 16QAM modulator and the output end of the 64QAM modulator are connected with the input end of the super-Nyquist modulation unit; the output end of the super-Nyquist modulation unit is respectively connected with the input end of the first praseodymium-doped optical fiber amplifier, the input end of the first semiconductor optical amplifier, the input end of the first thulium-doped optical fiber amplifier and the input end of the first erbium-doped optical fiber amplifier; the output end of the first praseodymium-doped optical fiber amplifier, the output end of the first semiconductor optical amplifier, the output end of the first thulium-doped optical fiber amplifier and the output end of the first erbium-doped optical fiber amplifier are all connected with the multiplexing system.
Preferably, the super-nyquist modulation unit includes a plurality of differential encoders.
Preferably, the multiplexing system comprises a wavelength division multiplexer, a coupler and an output port;
the input end of the wavelength division multiplexer is connected with the output end of the first praseodymium-doped optical fiber amplifier, the output end of the first thulium-doped optical fiber amplifier and the output end of the first erbium-doped optical fiber amplifier; the input end of the first coupler is connected with the output end of the first semiconductor optical amplifier and the output end of the first erbium-doped fiber amplifier; and the output end of the wavelength division multiplexer and the output end of the first coupler are both connected with the output port.
Preferably, the receiving end includes: the device comprises a receiving port, a wavelength division demultiplexer, a second coupler, a second amplifying unit, a first filtering unit and a super-Nyquist demodulating unit;
the receiving port is connected with the output port; the input end of the wavelength division demultiplexer and the input end of the second coupler are both connected with the receiving port; the output end of the wavelength division demultiplexer and the output end of the second coupler are connected with the input end of the second amplifying unit; the output end of the second amplifying unit is connected with the input end of the first filtering unit; the output end of the first filtering unit is connected with the input end of the super-Nyquist demodulation unit; and the output end of the super-Nyquist demodulation unit outputs optical signal data of different wave bands.
Preferably, the second amplification unit includes: a second praseodymium-doped optical fiber amplifier, a second semiconductor optical amplifier, a second thulium-doped optical fiber amplifier and a second erbium-doped optical fiber amplifier;
the output end of the wavelength division demultiplexer is connected with the input end of the second praseodymium-doped optical fiber amplifier, the input end of the second thulium-doped optical fiber amplifier and the input end of the second erbium-doped optical fiber amplifier; the output end of the second coupler is connected with the input end of the second semiconductor optical amplifier and the input end of the second erbium-doped optical fiber amplifier; the output end of the second praseodymium-doped optical fiber amplifier, the output end of the second semiconductor optical amplifier, the output end of the second thulium-doped optical fiber amplifier and the output end of the second erbium-doped optical fiber amplifier are connected with the input end of the first filtering unit.
Preferably, the first filtering unit includes a plurality of low pass filters or a plurality of optical band pass filters.
Preferably, the transmitting end includes: a second filtering unit;
the input end of the second filtering unit is connected with the output end of the IQ modulation unit; and the output end of the second filtering unit is connected with the input end of the super-Nyquist modulation unit.
Preferably, the second filtering unit is a low-pass filter or an optical band-pass filter;
and the bandwidth of the low-pass filter or the bandwidth of the optical band-pass filter is smaller than the Nyquist signal.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
according to the multiband optical transmission system based on the super-Nyquist transmission technology, the capacity expansion of the transmission system is effectively realized by utilizing the ultra-wideband wavelength division multiplexing transmission system, the super-Nyquist technology is combined, the signal spectrum of each band is compressed, the spectrum efficiency is further improved, and a better capacity expansion effect is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a schematic structural diagram of a multiband optical transmission system based on the super-nyquist transmission technology provided by the present invention;
FIG. 2 is a graph of pulse period comparisons of a non-orthogonalized overlapping signal and an orthogonalized overlapping signal according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a transmitting end using an O-band as a main channel according to an embodiment of the present invention;
fig. 4 is a schematic diagram of transmission and reception at a faster than nyquist rate in a transmitter and a receiver, for example, in a C-band, according to an embodiment of the present invention;
FIG. 5 is a spectral diagram of a five-band WDM system with a transmitter according to an embodiment of the present invention;
fig. 6 is a flowchart illustrating a method for implementing QPSK modulation using a duobinary modulation scheme according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention aims to provide a multiband optical transmission system based on a super-Nyquist transmission technology, which can improve the utilization rate of a frequency spectrum and realize a better capacity expansion effect.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1, the multi-band optical transmission system based on the super-nyquist transmission technology provided by the present invention includes: the system comprises a transmitting end, a multiplexing system and a receiving end.
And the transmitting end is used for generating a super-Nyquist signal. The multiplexing system is configured to generate a frequency domain multiplexed signal from the faster-than-nyquist signal. And the receiving end is used for generating multiband optical transmission data according to the frequency domain multiplexing signals.
Wherein, the transmitting terminal includes: the device comprises a laser generator, an IQ modulation unit, a super-Nyquist modulation unit and a first amplification unit. The super-nyquist modulation unit includes a plurality of differential encoders.
The IQ modulation unit includes: QPSK modulator, 16QAM modulator, and 64QAM modulator.
The first amplification unit includes: the optical fiber amplifier comprises a first praseodymium-doped optical fiber amplifier, a first semiconductor optical amplifier, a first thulium-doped optical fiber amplifier and a first erbium-doped optical fiber amplifier.
The input end of the QPSK modulator, the input end of the 16QAM modulator and the input end of the 64QAM modulator are connected with the laser generator. The output end of the QPSK modulator, the output end of the 16QAM modulator and the output end of the 64QAM modulator are connected with the input end of the super-Nyquist modulation unit. The output end of the super-Nyquist modulation unit is respectively connected with the input end of the first praseodymium-doped optical fiber amplifier, the input end of the first semiconductor optical amplifier, the input end of the first thulium-doped optical fiber amplifier and the input end of the first erbium-doped optical fiber amplifier. The output end of the first praseodymium-doped optical fiber amplifier, the output end of the first semiconductor optical amplifier, the output end of the first thulium-doped optical fiber amplifier and the output end of the first erbium-doped optical fiber amplifier are all connected with the multiplexing system.
The multiplexing system adopted above comprises a wavelength division multiplexer, a coupler and an output port.
The input end of the wavelength division multiplexer is connected with the output end of the first praseodymium-doped optical fiber amplifier, the output end of the first thulium-doped optical fiber amplifier and the output end of the first erbium-doped optical fiber amplifier. The input end of the first coupler is connected with the output end of the first semiconductor optical amplifier and the output end of the first erbium-doped fiber amplifier. The output end of the wavelength division multiplexer and the output end of the first coupler are connected with the output port.
The receiving end of the above-mentioned adoption includes: the device comprises a receiving port, a wavelength division demultiplexer, a second coupler, a second amplifying unit, a first filtering unit and a super-Nyquist demodulating unit.
The receiving port is connected with the output port. The input end of the wavelength division demultiplexer and the input end of the second coupler are connected with the receiving port. The output end of the wavelength division demultiplexer and the output end of the second coupler are connected with the input end of the second amplifying unit. The output end of the second amplifying unit is connected with the input end of the first filtering unit. The output end of the first filtering unit is connected with the input end of the super-Nyquist demodulation unit. And the output end of the super-Nyquist demodulation unit outputs optical signal data of different wave bands.
The first filtering unit employed above preferably comprises a plurality of low-pass filters or a plurality of optical band-pass filters. The second amplification unit preferably includes: a second praseodymium-doped optical fiber amplifier, a second semiconductor optical amplifier, a second thulium-doped optical fiber amplifier and a second erbium-doped optical fiber amplifier.
Specifically, the output end of the wavelength division demultiplexer is connected with the input end of a second praseodymium-doped optical fiber amplifier, the input end of a second thulium-doped optical fiber amplifier and the input end of a second erbium-doped optical fiber amplifier. The output end of the second coupler is connected with the input end of the second semiconductor optical amplifier and the input end of the second erbium-doped optical fiber amplifier. The output end of the second praseodymium-doped optical fiber amplifier, the output end of the second semiconductor optical amplifier, the output end of the second thulium-doped optical fiber amplifier and the output end of the second erbium-doped optical fiber amplifier are connected with the input end of the first filtering unit.
Further, the generation of the super-nyquist signal may be achieved by filtering the transmission signal using a low pass filter having a bandwidth less than the nyquist transmission, or by adding an optical bandpass filter less than the nyquist after the output of the optical domain modulator. Referring to fig. 1, after the super-nyquist filtering, the binary signal may become a duobinary signal, the constellation diagram of a Quadrature Phase Shift Keying (QPSK) modulation signal may become 9 constellation points from 4 points, that is, a quadrature amplitude modulation (9QAM) signal similar to 9 symbols, and 16 points of a quadrature amplitude modulation (16QAM) signal of 16 symbols may become 49 constellation points, that is, a quadrature amplitude modulation (49QAM) similar to 49 symbols. Based on this, the transmitting end adopted in the present invention may further include: and a second filtering unit. The input end of the second filtering unit is connected with the output end of the IQ modulation unit. And the output end of the second filtering unit is connected with the input end of the super-Nyquist modulation unit. The second filtering unit is preferably a low-pass filter or an optical band-pass filter. Wherein, the bandwidth of the low-pass filter or the bandwidth of the optical band-pass filter is smaller than the Nyquist signal.
Similarly, corresponding differential decoding is needed at the receiving end, and after all recovery flows process hard decisions, the differential decoding process can successfully realize the reception of the super-nyquist signal.
Based on the structure, the multi-band optical transmission system based on the super-Nyquist transmission technology provided by the invention expands the wavelength from the widely used C or L band to the additional S, E and O bands, and can effectively realize the expansion of the transmission system. According to the existing research, the optimal modulation format suitable for the band can be carried out in different bands through the elastic optical network technology, but the Euclidean distance of a high-order signal is relatively small, so that the narrow-band filtering resistance of the signal is sharply reduced, an intersymbol interference model of the high-order signal is more complex, and the requirement on the processing capacity of a back-end algorithm is higher.
The method comprises the steps of expanding the channel bandwidth through a multiband optical transmission technology to improve the transmission capacity of the system, modulating all channels of each waveband by using a lower-order modulation format, reducing the inter-channel interval by using a super-Nyquist wavelength division multiplexing technology, introducing controllable inter-symbol interference (ISI) and inter-carrier interference (ICI), recovering original signals by using a Digital Signal Processing (DSP) technology at a receiving end, and further improving the utilization rate of frequency spectrum resources.
The following is a description of a specific implementation process of the multi-band optical transmission system based on the super-nyquist transmission technology provided in the present invention, so as to more prominently describe the advantages of the present invention.
First, the most suitable modulation format is selected according to the band, and in the conventional system design, all channels of 5 bands are modulated by the same low-order modulation format, and the use of QPSK in each band is determined by the O band with the worst transmission performance. In designing a system, the present invention selects an appropriate modulation format according to the overall transmission performance of the system, for example, 16QAM is allocated in the E and S bands and 64QAM is allocated in the C and L bands. In this way, the total capacity of each fiber in an ultra-wideband wavelength division multiplexing system can be effectively increased.
At a transmitting end of the multi-band transmission system, transmitting signals in different channels of each band are mapped into QPSK, 16QAM or 64QAM signals, differential coding is carried out on I-path signals and Q-path signals respectively, the I-path signals and the Q-path signals are recombined into a number of signals after differential coding, and then the Nyquist signal of each band is obtained through a delay addition module.
And the super-Nyquist signal passes through a wavelength division multiplexer, and the non-orthogonalized and overlapped optical signals of each waveband are subjected to frequency domain multiplexing to generate a frequency domain multiplexing signal. After being transmitted by the optical channel, the digital signals are respectively processed in each wave band by the wavelength division demultiplexer. The receiving end in a single band needs to perform differential decoding of response, and the differential decoding process performs demodulation processing on an I path and a Q path of a recovered signal (i.e., a signal after the hard decision after the differential decoding) after all recovery processes finish the hard decision. The invention effectively realizes the capacity expansion of the transmission system by utilizing the ultra-wideband wavelength division multiplexing transmission system, compresses the signal frequency spectrum of each wave band by combining the super-Nyquist technology, further improves the frequency spectrum efficiency and realizes better capacity expansion effect.
The following further describes an implementation and a specific operation process of the multi-band optical transmission system based on the super-nyquist transmission technology provided by the present invention by way of specific embodiments.
As shown in fig. 2, the 3 stages of the transition from the orthogonalization mode to the non-orthogonalization mode of the pulse time domain multiplexing are: in the first stage, the pulses do not overlap each other, so as to avoid introducing intersymbol interference, which represents the techniques such as traditional non-return-to-zero (NRZ) and return-to-zero (RZ) modulation. Both NRZ and RZ technologies realize pulse orthogonalization transmission through a mode with a simple structure, the transmission efficiency is not fully paid attention to while the transmission performance is ensured, and the code element rate is lower than the Nyquist rate; in the second stage, the pulses are overlapped, but the pulse waveform is designed to realize the transmission without intersymbol interference. Typical techniques such as time division multiplexing based on nyquist waveforms; in the third stage, non-orthogonal overlapping between pulses allows the presence of intersymbol interference, and the symbol rate can exceed the nyquist rate. At a transmitting end, the super-Nyquist system does not need pulse shaping, and can compensate intersymbol interference by DSP processing at a receiving end by utilizing physically realizable pulse waveforms.
As shown in fig. 3, in the 5-band multiplexing multi-band optical transmission system, a transmitter uses O, E, S, C and L-band laser transmission, a tunable laser is placed in each band, the laser of each band outputs signals into an IQ modulator of the band, the IQ modulator is driven by an arbitrary waveform generator in each band, and QPSK, 16QAM or 64QAM signals are generated according to the band of the signals. The modulated signals pass through a corresponding amplifier after the super-Nyquist rate transmission of a super-Nyquist (FTN) modulation unit is realized. The O-band is amplified using a Praseodymium Doped Fiber Amplifier (PDFA), the E-band is amplified using a Semiconductor Optical Amplifier (SOA), the S-band is amplified using a Thulium Doped Fiber Amplifier (TDFA), and the C-and L-bands are amplified using an Erbium Doped Fiber Amplifier (EDFA). The amplified 5-band signals are multiplexed by a multiplexer (namely, a wavelength division multiplexer), the multiplexed signals are demultiplexed to each band by the wavelength division demultiplexer after being transmitted by optical fibers, and the demultiplexed signals of each band are amplified by PDFA, SOA, TDFA and EDFA. After passing through the band-pass filter, the output signals of each waveband are obtained through FTN demodulation.
The way to realize the transmission at the super-nyquist rate inside the transmitter is shown in fig. 4, taking signal transmission in the C-band as an example, the transmission at the super-nyquist rate is realized by the super-nyquist modulation after the IQ modulator. The transmitter selects the appropriate modulation format within each band taking into account transmission loss according to the spectral plots of the different band optical signals shown in figure 5. Wherein, the wavelength of each channel is 1310nm at O wave band, 1430nm at E wave band, 1475nm at S wave band, 1547.7nm at C wave band and 1590nm at L wave band. The transmitter has the worst signal-to-noise ratio in the S-band and the best signal-to-noise ratio in the C-band. The signal-to-noise ratio of each wave band of the transmitter is respectively 27.5dB, 30.2dB, 26.1dB, 36.0dB and 30.1 dB. QPSK is allocated in O-band, 16QAM is allocated in E and S-band, and 64QAM is allocated in C and L-band. And after mapping, carrying out differential coding on the I path signals or the Q path signals respectively, recombining the I path signals or the Q path signals into a number of signals after the differential coding, and obtaining the super-Nyquist signal of each wave band through a delay addition module.
The generation of the super-nyquist signal by differential coding between different channels in each band is based on a duo-binary delay-sum filter, and the implementation principle and effect of the filter exemplified by QPSK modulation are shown in fig. 4. In duobinary shaping, the present symbol is added with a symbol delayed by one symbol period. It can be described by a rectangular nyquist-shaped double tap FIR filter. The impulse response is:
where t is time and B is the signal baud rate.
The impulse response consists of two rectangular nyquist-shaped delay impulse responses as shown in figure 6. The amplitude spectrum of the signal after duobinary shaping is represented as:
the frequency spectrum of the signal after the duobinary shaping is in a cosine shape, and the bandwidth is 1/2 of the original signal. The above-mentioned duobinary shaping should be maintained for the overall transfer function consisting of the transmit end, the receive end and the transmit channel. In addition, the matched filter configuration achieves the best bit error rate under additive white gaussian noise.
The constellation diagram of the signal after the super-nyquist filtering changes as shown in fig. 6, and 4 points of the QPSK signal become 9 constellation points, i.e. similar to 9QAM signal. From the radius of the generated signal, the four constellation points of QPSK are located on a circle of the same radius, and the duobinary QPSK (9QAM) is located on 3 circles of different radii. The more signal layers, the higher the resolution required on the signal and the more stringent the signal-to-noise ratio requirements on the system.
As shown in fig. 4, the specific operation of the FTN demodulation module inside the receiver is that the receiving end in each band detects the receiving center channel through the homodyne, after the operation of removing the cyclic prefix from the received signal, down-sampling and frequency domain post-equalization are performed, and the corresponding differential decoding process performs the modulo M processing on the I path and the Q path of the recovered signal after all the recovery processes have finished hard decision, so as to successfully receive the super-nyquist signal in the band.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (9)
1. A multi-band optical transmission system based on the super-nyquist transmission technique, comprising: the system comprises a transmitting end, a multiplexing system and a receiving end;
the transmitting terminal is used for generating a super-Nyquist signal; the multiplexing system is used for generating a frequency domain multiplexing signal according to the super-Nyquist signal; and the receiving end is used for generating multiband optical transmission data according to the frequency domain multiplexing signals.
2. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 1, wherein the transmitting end includes: the device comprises a laser generator, an IQ modulation unit, a super-Nyquist modulation unit and a first amplification unit;
the IQ modulation unit includes: QPSK modulator, 16QAM modulator and 64QAM modulator;
the first amplification unit includes: the optical fiber amplifier comprises a first praseodymium-doped optical fiber amplifier, a first semiconductor optical amplifier, a first thulium-doped optical fiber amplifier and a first erbium-doped optical fiber amplifier;
the input end of the QPSK modulator, the input end of the 16QAM modulator and the input end of the 64QAM modulator are connected with the laser generator; the output end of the QPSK modulator, the output end of the 16QAM modulator and the output end of the 64QAM modulator are connected with the input end of the super-Nyquist modulation unit; the output end of the super-Nyquist modulation unit is respectively connected with the input end of the first praseodymium-doped optical fiber amplifier, the input end of the first semiconductor optical amplifier, the input end of the first thulium-doped optical fiber amplifier and the input end of the first erbium-doped optical fiber amplifier; the output end of the first praseodymium-doped optical fiber amplifier, the output end of the first semiconductor optical amplifier, the output end of the first thulium-doped optical fiber amplifier and the output end of the first erbium-doped optical fiber amplifier are all connected with the multiplexing system.
3. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 2, wherein the super-nyquist modulation unit includes a plurality of differential encoders.
4. The multi-band optical transmission system based on the super-nyquist transmission technique of claim 2, wherein the multiplexing system includes a wavelength division multiplexer, a coupler, and an output port;
the input end of the wavelength division multiplexer is connected with the output end of the first praseodymium-doped optical fiber amplifier, the output end of the first thulium-doped optical fiber amplifier and the output end of the first erbium-doped optical fiber amplifier; the input end of the first coupler is connected with the output end of the first semiconductor optical amplifier and the output end of the first erbium-doped fiber amplifier; and the output end of the wavelength division multiplexer and the output end of the first coupler are both connected with the output port.
5. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 3, wherein the receiving end includes: the device comprises a receiving port, a wavelength division demultiplexer, a second coupler, a second amplifying unit, a first filtering unit and a super-Nyquist demodulating unit;
the receiving port is connected with the output port; the input end of the wavelength division demultiplexer and the input end of the second coupler are both connected with the receiving port; the output end of the wavelength division demultiplexer and the output end of the second coupler are connected with the input end of the second amplifying unit; the output end of the second amplifying unit is connected with the input end of the first filtering unit; the output end of the first filtering unit is connected with the input end of the super-Nyquist demodulation unit; and the output end of the super-Nyquist demodulation unit outputs optical signal data of different wave bands.
6. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 5, wherein the second amplification unit includes: a second praseodymium-doped optical fiber amplifier, a second semiconductor optical amplifier, a second thulium-doped optical fiber amplifier and a second erbium-doped optical fiber amplifier;
the output end of the wavelength division demultiplexer is connected with the input end of the second praseodymium-doped optical fiber amplifier, the input end of the second thulium-doped optical fiber amplifier and the input end of the second erbium-doped optical fiber amplifier; the output end of the second coupler is connected with the input end of the second semiconductor optical amplifier and the input end of the second erbium-doped optical fiber amplifier; the output end of the second praseodymium-doped optical fiber amplifier, the output end of the second semiconductor optical amplifier, the output end of the second thulium-doped optical fiber amplifier and the output end of the second erbium-doped optical fiber amplifier are connected with the input end of the first filtering unit.
7. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 4, wherein the first filtering unit includes a plurality of low-pass filters or a plurality of optical band-pass filters.
8. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 2, wherein the transmitting end includes: a second filtering unit;
the input end of the second filtering unit is connected with the output end of the IQ modulation unit; and the output end of the second filtering unit is connected with the input end of the super-Nyquist modulation unit.
9. The multi-band optical transmission system based on the super-nyquist transmission technique as claimed in claim 8, wherein the second filtering unit is a low-pass filter or an optical band-pass filter;
and the bandwidth of the low-pass filter or the bandwidth of the optical band-pass filter is smaller than the Nyquist signal.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105610516A (en) * | 2015-12-24 | 2016-05-25 | 湖北工业大学 | Optical modulation method based on ultra-Nyquist system and corresponding demodulation method thereof |
| CN106100730A (en) * | 2016-06-02 | 2016-11-09 | 复旦大学 | Carrierless amplitude phase modulating system based on super Nyquist precoding and modulator approach |
| CN106533643A (en) * | 2015-09-15 | 2017-03-22 | 清华大学 | Method and system for adjusting bandwidth of optical modulator |
| CN108600127A (en) * | 2018-02-28 | 2018-09-28 | 北京邮电大学 | A kind of communication system and method for the super Nyquist overlapped based on pulse |
| CN111431607A (en) * | 2020-04-14 | 2020-07-17 | 兰州理工大学 | Block matrix interference elimination method in WO-FTN transmission system |
-
2021
- 2021-07-12 CN CN202110782849.9A patent/CN113541798A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106533643A (en) * | 2015-09-15 | 2017-03-22 | 清华大学 | Method and system for adjusting bandwidth of optical modulator |
| CN105610516A (en) * | 2015-12-24 | 2016-05-25 | 湖北工业大学 | Optical modulation method based on ultra-Nyquist system and corresponding demodulation method thereof |
| CN106100730A (en) * | 2016-06-02 | 2016-11-09 | 复旦大学 | Carrierless amplitude phase modulating system based on super Nyquist precoding and modulator approach |
| CN108600127A (en) * | 2018-02-28 | 2018-09-28 | 北京邮电大学 | A kind of communication system and method for the super Nyquist overlapped based on pulse |
| CN111431607A (en) * | 2020-04-14 | 2020-07-17 | 兰州理工大学 | Block matrix interference elimination method in WO-FTN transmission system |
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