CN108566250B - Modulation and demodulation method and system based on carrier quadrature bias single sideband signal - Google Patents
Modulation and demodulation method and system based on carrier quadrature bias single sideband signal Download PDFInfo
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Abstract
The invention discloses a modulation method, a demodulation method and a system based on a carrier quadrature bias single-sideband signal. The transmitting end determines the guard interval between the baseband signal on the X polarization and the X polarization virtual carrier and the guard interval between the baseband signal on the Y polarization and the Y polarization virtual carrier according to the slope of an optical filter of the receiving end; and driving a dual-polarization IQ modulator according to an X-polarization signal and a Y-polarization signal of information to be transmitted, which are generated on a digital domain, respectively generating two polarized optical signals and synthesizing the two polarized optical signals into a polarization multiplexing single-sideband optical signal. The receiving end optical filter module can remove the virtual carrier component on the Y polarization when receiving the X polarization signal and can filter the virtual carrier component on the X polarization when receiving the Y polarization signal; and then, performing beat frequency damage compensation and down conversion on the signals to obtain X-polarization baseband signals and Y-polarization baseband signals. The invention can realize the direct detection of the polarization multiplexing signal in the Jones space by a simpler system structure.
Description
Technical Field
The invention relates to the field of optical communication transmission, in particular to a transmitting end modulation method based on a carrier orthogonal bias polarization multiplexing single-sideband signal, a receiving end demodulation method based on an optical filter and a corresponding system.
Background
Compared with a coherent detection optical communication system, the direct detection optical communication system has the advantages of low cost, low complexity and easy integration, and is an important solution for the current medium-short distance optical fiber communication transmission system. In order to meet the continuously upgraded traffic demand of the data center, the introduction of the polarization multiplexing technology into the direct detection system becomes a next research hotspot.
For a coherent detection system, because the local oscillator laser is placed at the receiving end, the polarization state of the local oscillator light can be well controlled and averagely divided into two polarization states of the signal light for frequency mixing. In contrast, in a direct detection system, an optical carrier needs to be added to a transmitting end to replace the function of local oscillation light. Thus, after undergoing random polarization rotation in the optical fiber transmission process, it is difficult to effectively control the polarization state of the optical carrier at the receiving end, and thus the problem of optical carrier fading occurs in a certain polarization direction.
Currently, there are two main methods for implementing polarization multiplexing in a direct detection system, one is to use a stokes receiver, and the other is to use a polarization rotator for an optical carrier. Both methods enable polarization multiplexing.
1) A stokes receiver. The method requires a polarization beam splitter, a 90-degree optical mixer, 4 Photodetectors (PD) and 4 analog-to-digital converters (ADC) at the receiving end for detecting the complete Stokes vector, and can process any polarization rotation. The disadvantages are that the four electrical signals need to be aligned in time delay, and 4 × 2 joint equalization is performed in Digital Signal Processing (DSP), so that the hardware requirement and the computational complexity are high.
2) A polarization rotator is used for the optical carrier. The method divides a received signal into two paths, wherein one path extracts an optical carrier through an optical filter, and the optical carrier is rotated by 90 degrees by using a polarization rotator. Thus, a pair of optical carriers with orthogonal polarization states can be obtained for signal detection of two polarizations. The disadvantage of this scheme is that the typically static polarization rotator cannot rotate the optical carrier for all polarization states by 90 °.
Disclosure of Invention
The invention provides a polarization multiplexing single-sideband modulation mode based on carrier orthogonal bias, a receiving end demodulation method based on an optical filter and a system for realizing the method, which can realize direct detection of polarization multiplexing signals in Jones space by a simpler system structure and approach the spectrum efficiency of coherent detection.
In order to achieve the purpose, the invention adopts the following technical scheme:
a polarization multiplexing single sideband modulation and demodulation method based on carrier orthogonal bias comprises the following steps:
the first step is as follows: determining the baud rate of the modulation signal according to the bandwidth of each device of the system; determining a protection interval between baseband signals on X polarization and Y polarization and a virtual carrier according to the slope of an optical filter of a receiving end, so that the optical filter module of the receiving end can remove the virtual carrier component on the Y polarization when receiving the X polarization signal and can filter the virtual carrier component on the X polarization when receiving the Y polarization signal;
the second step is that: an X-polarized signal and a Y-polarized signal are generated in the digital domain. The main content comprises mapping from a binary information sequence to be transmitted to a constellation diagram symbol, adding a frame leader sequence and Nyquist shaping filtering to respectively generate X/Y polarization baseband signals, then adding a virtual carrier to the left side of the frequency spectrum of the X polarization baseband signals to generate X polarization signals, and adding a virtual carrier to the right side of the frequency spectrum of the Y polarization baseband signals to generate Y polarization signals;
the third step: and generating a polarization multiplexing single-sideband optical signal with orthogonal carrier bias. Sending the X polarization signal and the Y polarization signal generated on the digital domain to a digital-to-analog converter (DAC), further driving a dual-polarization IQ modulator to respectively generate two polarized optical signals, and synthesizing a polarization multiplexing single-sideband optical signal in the modulator;
further, the signal at the transmitting end is preprocessed before entering a communication channel, wherein the preprocessing comprises modulator nonlinear precompensation, dispersion precompensation or fiber Kerr nonlinear precompensation.
Further, such a polarization multiplexing single sideband structure with orthogonal carrier offset is not limited to a spectrum structure generated by a single laser generating an imaginary carrier in the digital domain, but may also be a spectrum structure in which a plurality of independent lasers or optical frequency combs are respectively recombined as optical carriers in the X/Y polarization. A single sideband polarization multiplexed spectral structure with orthogonal carrier biasing embodies that X and Y polarized signals overlap spectrally, but the X and Y polarized virtual carriers are on different sides of the signal.
The fourth step: and the right/left virtual carrier components are respectively filtered by an optical filter at a receiving end, and the X polarization electric signals and the Y polarization electric signals are obtained after the detection of a photoelectric detector.
The fifth step: and performing combined signal-signal beat frequency damage compensation on the X-polarization electric signals and the Y-polarization electric signals, wherein the compensated signals are linearly proportional to the transmitted X-polarization signals and the transmitted Y-polarization signals. The X/Y polarized electrical signals synchronized at the moment are sent together to the joint signal-signal beat frequency damage compensation, and an iterative negative feedback improvement algorithm is adopted, as shown in fig. 4.
And a sixth step: and performing down-conversion on the X-polarization electric signals and the Y-polarization electric signals subjected to the joint signal-signal beat frequency damage compensation to obtain X-polarization baseband signals and Y-polarization baseband signals.
A polarization multiplexing single-sideband direct detection system based on carrier orthogonal bias for realizing the method comprises a transmitting end and a receiving end,
the transmitting end includes:
the transmitting terminal Nyquist filtering module is used for carrying out spectrum compression on the X polarization baseband signal and the Y polarization baseband signal and improving the spectrum utilization rate;
the virtual carrier module is connected with the transmitting end Nyquist filtering module and is used for adding a digital virtual carrier to the left side or the right side of the frequency spectrum of the X or Y polarization baseband signal to generate an X or Y polarization signal;
the polarization beam combination module is used for combining the X polarization optical signal and the Y polarization optical signal into a polarization multiplexing single sideband optical signal and then sending the polarization multiplexing single sideband optical signal to a communication channel;
the receiving end includes:
the optical filter module is used for filtering an X polarization virtual carrier component of the polarization multiplexing single-sideband optical signal to obtain a Y polarization optical signal; filtering out Y polarization virtual carrier component of the polarization multiplexing single-side band optical signal to obtain an X polarization optical signal, and realizing polarization demultiplexing;
the photoelectric detector module is connected with the optical filter module and used for converting the X polarized light signal and the Y polarized light signal into corresponding electric signals to obtain an X polarized electric signal and a Y polarized electric signal;
a combined signal-signal beat frequency interference compensation module connected with the photoelectric detector module and used for simultaneously compensating signal-signal beat frequency interference (SSBI) in polarization and between polarizations for the X-polarization electric signals and the Y-polarization electric signals;
the down-conversion module is connected with the combined signal-signal beat frequency interference compensation module and is used for converting the electric signal received by the Photoelectric Detector (PD) into a baseband signal to obtain an X-polarization baseband signal and a Y-polarization baseband signal;
and the receiving end Nyquist filtering module is connected with the down-conversion module and is used for eliminating intersymbol interference (ISI) and improving the signal-to-noise ratio.
Further, still include:
and the transmitting end modulation module is used for carrying out quadrature amplitude phase modulation (QAM) format mapping on a binary information sequence to be transmitted, inserting the synchronization series and the training sequence as a frame structure leader sequence and generating an X or Y polarization baseband signal.
And the transmitting terminal preprocessing module is used for respectively performing pre-compensation processing on the X or Y polarized signals of the transmitting terminal and then sending the signals to the polarization beam combination module.
And the receiving end demodulation module is used for carrying out optimal sampling point optimization and channel equalization on the sequence after the receiving end matched filtering and judging and demodulating the sequence back to a binary sequence.
Further, the pre-compensation processing performed by the front-end data processing module includes: nonlinear compensation of a modulator, dispersion pre-compensation and Kerr nonlinear compensation of optical fibers.
Compared with the prior art, the invention has the following positive effects:
in the method, under the condition of polarization multiplexing single sideband modulation signals, virtual carriers are added to the left side of the frequency spectrum of an X polarization baseband signal, and the virtual carriers are added to the right side of the frequency spectrum of a Y polarization baseband signal to generate polarization multiplexing single sideband signals with orthogonal carrier bias after polarization combination. The scheme can utilize an optical filter at a receiving end to filter carrier components which do not need polarization, thereby realizing the separation of two polarization signals and simplifying the system structure. In the digital signal processing, the invention designs a combined signal-signal beat frequency damage compensation algorithm, and can realize the linear reception of two polarization signals in the Jones space.
Drawings
Fig. 1 is a flowchart of a digital signal processing method for polarization-multiplexed single-sideband signals based on carrier quadrature bias according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a signal spectrum structure according to an embodiment of the present invention.
Fig. 3 is a schematic structural diagram of a polarization multiplexing single-sideband modulation system based on carrier quadrature bias according to an embodiment of the present invention.
FIG. 4 is a flow chart of a joint signal-signal beat impairment compensation algorithm according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below with reference to specific examples and the accompanying drawings.
The following describes the implementation of the technical solution in detail with reference to the algorithm flowchart 1 of this embodiment, and the part shown by the dashed box at the right side in fig. 1 is the main content of the solution of the present invention.
The first step is as follows: and determining the baud rate B of the signal according to the bandwidth of the system device. And determining a guard interval F based on the slope of the edge of the optical filtergapIn general, in order to make the carrier power rejection ratio before and after filtering 20dB or more, a typical value of the guard interval needs to be set to 5 GHz. Note that here the guard interval size is determined only by the optical filter, independent of the signal rate, and the spectral cost is constant.
The second step is that: nyquist filtering with roll-off coefficient alpha is carried out at the transmitting end, the purpose is to compress the signal frequency spectrum into an approximate square, and generally, alpha can be ensured to be 0.01.
Then adding the virtual carrier to the left side of the X-polarized baseband signal, adding the virtual carrier to the right side of the Y-polarized baseband signal, and assuming that the X-polarized baseband signal is s1(t), the baseband signal on the Y polarization is s2(t) the baud rate is B. After adding the virtual carrier, the signals are respectively
And
the up-conversion in the digital domain can be expressed as:
wherein the constant C represents the magnitude of the virtual carrier,satisfies the minimum phase condition | C | > max (| S)1| C | > max (| S)2|), j represents an imaginary unit.
Before a signal is transmitted over an optical fiber link, the signal is typically dispersion pre-compensated in the frequency domain:
Spre(f)＝S(f)·exp(-β2Lω2/2)
wherein S ispre(f) Is frequency domain data after pre-compensation, S (f) is frequency domain data before pre-compensation, beta2For group velocity dispersion coefficient, L is the fiber length and ω is the angular frequency relative to the carrier.
The third step: and respectively receiving the X/Y polarized signals at a receiving end through optical filtering. The received optical signal is first passed through 50: the 50 coupler is divided into two beams, one for filtering the carrier on the right side with an optical filter and the other for filtering the carrier on the left side with an optical filter.
Then, in a Digital Signal Processing (DSP) stage, inter-polarization joint signal-signal beat interference compensation is first performed:
wherein r isi(t) respectively represent the X/Y polarized received signal, and λ is the carrier-to-signal power ratio (CSPR) and the received power of the signal with an amplitude factor dependent on the signal. This process can be iterated many times to gradually improve the performance, and generally it is stable after 4 times. Since this process does not involve decision demodulation, the computational complexity is low.
Then, down-converting the X/Y polarization signals respectively:
the signal after down conversion is then nyquist matched filtered.
And finally, carrying out receiving end demodulation, including optimal sampling point optimization, linear equalization, judgment and demodulation.
Fig. 2 shows the spectrum structure of a signal, which comprises four components, from left to right and from top to bottom: an X-polarized virtual carrier, an X-polarized signal, a Y-polarized signal, and a Y-polarized virtual carrier. The width of each sideband and the spacing parameters are selected as given in the above step.
The spectral structure is not limited to being generated by a single laser, but can be generated by a plurality of lasers and optical frequency combs, and then the parts are combined together through an optical coupler and a polarization-maintaining beam combiner.
Fig. 3 is a schematic diagram of a single-sideband polarization multiplexing direct detection system based on carrier quadrature bias corresponding to the method, including a transmitting end and a receiving end.
The transmitting end includes: the transmitting terminal modulation module is used for carrying out quadrature amplitude phase modulation (QAM) format mapping on a binary sequence to be transmitted and inserting a synchronous series and a training sequence as a frame structure leader sequence; the transmitting end Nyquist filtering module is connected with the transmitting end modulating module and used for compressing the frequency spectrum to be close to a square under the condition of ensuring that the receiving end does not have intersymbol interference (ISI); the virtual carrier module is connected with the transmitting end Nyquist filtering module and is used for adding digital virtual carriers to the left side or the right side of the frequency spectrum of the baseband signal; and the transmitting terminal preprocessing module is connected with the virtual carrier module and used for preprocessing the transmitting terminal signal and then transmitting the signal to a communication channel.
The receiving end includes: the optical filter module is used for filtering the carrier component on the other polarization; the photoelectric detector module is connected with the optical filter module and is used for converting the optical signal into an electric signal; a combined signal-signal beat frequency interference compensation module connected with the photoelectric detector module and used for compensating signal-signal beat frequency interference (SSBI) between polarizations and in the polarizations; the down-conversion module is connected with the combined signal-signal beat frequency interference compensation module and is used for converting the electric signal received by the Photoelectric Detector (PD) into a baseband signal; the receiving end Nyquist filtering module is connected with the down-conversion module and used for eliminating intersymbol interference (ISI) and improving the signal-to-noise ratio; and the receiving end demodulation module is connected with the receiving end Nyquist filtering module and used for carrying out optimal sampling point optimization and channel equalization on the sequence after the receiving end matched filtering and judging and demodulating the sequence back to a binary sequence.
FIG. 4 is a flow chart of a joint signal-signal beat damage compensation algorithm designed by the present invention. The algorithm needs synchronous input of X and Y polarized electric signals at a receiving end, and simulates the physical process of a single-sideband signal passing through a photoelectric detector through a digital Hilbert filter and a modulus square operation, so that a signal-signal beat frequency damage component in the X and Y polarized signals is estimated and removed. This process can improve the estimation accuracy of the beat frequency impairment of the signal-signal by iteration, and is generally stable after 4 times. This process does not involve decision demodulation and therefore the computational complexity is low.
The above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person skilled in the art can modify the technical solution of the present invention or substitute the same without departing from the spirit and scope of the present invention, and the scope of the present invention should be determined by the claims.
Claims (8)
1. A modulation method based on carrier quadrature bias single sideband signal comprises the following steps:
1) determining a guard interval between a baseband signal on X polarization and an X polarization virtual carrier and a guard interval between a baseband signal on Y polarization and a Y polarization virtual carrier according to the slope of an optical filter of a receiving end;
2) generating an X-polarized signal and a Y-polarized signal of information to be transmitted in a digital domain; the method for generating the X-polarization signal and the Y-polarization signal comprises the following steps: firstly, respectively generating an X polarization baseband signal and a Y polarization baseband signal of information to be transmitted, wherein the X polarization baseband signal and the Y polarization baseband signal are overlapped on a frequency spectrum; then according to the guard interval determined in the step 1), adding an X polarization virtual carrier to the left side of the frequency spectrum of the X polarization baseband signal to generate an X polarization signal, and adding a Y polarization virtual carrier to the right side of the frequency spectrum of the Y polarization baseband signal to generate a Y polarization signal, wherein the X polarization virtual carrier and the Y polarization virtual carrier are positioned on different sides of the signal;
3) and driving a dual-polarization IQ modulator according to the X-polarization signal and the Y-polarization signal generated on the digital domain, respectively generating two polarized optical signals and synthesizing the two polarized optical signals into a polarization multiplexing single-sideband optical signal.
2. A method for demodulating a polarization-multiplexed single-sideband optical signal modulated by the modulation method of claim 1, comprising the steps of:
1) the receiving end filters the Y polarization virtual carrier component of the received polarization multiplexing single-sideband optical signal, and then the Y polarization virtual carrier component is detected by a photoelectric detector to obtain an X polarization electric signal; the receiving end filters the X polarization virtual carrier component of the received polarization multiplexing single-sideband optical signal, and then the Y polarization virtual carrier component is detected by a photoelectric detector to obtain a Y polarization electric signal;
2) performing combined signal-signal beat frequency damage compensation on the X-polarization electric signal and the Y-polarization electric signal by adopting an iterative negative feedback improvement algorithm; the method comprises the following steps: respectively inputting the X polarization electric signal and the Y polarization electric signal into a digital Hilbert filter, simulating the physical process of the single-side band signal passing through a photoelectric detector through the digital Hilbert filter and a modulus square operation, estimating a signal-signal beat frequency damage component in the X polarization signal, removing the signal-signal beat frequency damage component, estimating a signal-signal beat frequency damage component in the Y polarization signal, and removing the signal-signal beat frequency damage component;
3) and performing down-conversion on the X-polarization electric signal and the Y-polarization electric signal subjected to the joint signal-signal beat frequency damage compensation to obtain an X-polarization baseband signal and a Y-polarization baseband signal.
3. A modulation and demodulation system based on a carrier orthogonal bias single sideband signal is characterized by comprising a transmitting end and a receiving end; wherein,
the transmitting end includes:
the transmitting end Nyquist filtering module is used for carrying out spectrum compression on the X polarization baseband signal and the Y polarization baseband signal;
the virtual carrier module is used for generating an X polarization signal and a Y polarization signal on a digital domain according to the determined guard interval; determining a guard interval between a baseband signal on X polarization and an X polarization virtual carrier and a guard interval between a baseband signal on Y polarization and a Y polarization virtual carrier according to the slope of an optical filter of a receiving end, wherein virtual carrier components on the X polarization and the Y polarization are positioned on different sides of the baseband signal; the method for generating the X-polarization signal and the Y-polarization signal comprises the following steps: firstly, respectively generating an X polarization baseband signal and a Y polarization baseband signal of information to be transmitted, wherein the X polarization baseband signal and the Y polarization baseband signal are overlapped on a frequency spectrum; then according to the determined guard interval, adding an X polarization virtual carrier to the left side of the frequency spectrum of the X polarization baseband signal to generate an X polarization signal, and adding a Y polarization virtual carrier to the right side of the frequency spectrum of the Y polarization baseband signal to generate a Y polarization signal, wherein the X polarization virtual carrier and the Y polarization virtual carrier are positioned on different sides of the signal;
the polarization beam combination module is used for combining the X polarization optical signal and the Y polarization optical signal into a polarization multiplexing single sideband optical signal and then sending the polarization multiplexing single sideband optical signal to a communication channel;
the receiving end includes:
the optical filter module is used for filtering an X polarization virtual carrier component of the polarization multiplexing single-sideband optical signal to obtain a Y polarization optical signal; filtering out Y polarization virtual carrier component of the polarization multiplexing single-sideband optical signal to obtain an X polarization optical signal;
the photoelectric detector module is used for converting the X polarized light signal and the Y polarized light signal into corresponding electric signals to obtain an X polarized electric signal and a Y polarized electric signal;
the combined signal-signal beat frequency interference compensation module is used for performing combined signal-signal beat frequency damage compensation on the X-polarization electric signal and the Y-polarization electric signal by adopting an iterative negative feedback improvement algorithm; the method comprises the following steps: respectively inputting the X polarization electric signal and the Y polarization electric signal into a digital Hilbert filter, simulating the physical process of the single-side band signal passing through a photoelectric detector through the digital Hilbert filter and a modulus square operation, estimating a signal-signal beat frequency damage component in the X polarization signal, removing the signal-signal beat frequency damage component, estimating a signal-signal beat frequency damage component in the Y polarization signal, and removing the signal-signal beat frequency damage component;
and the down-conversion module is used for performing down-conversion on the X-polarization electric signal and the Y-polarization electric signal subjected to the joint signal-signal beat frequency damage compensation to obtain an X-polarization baseband signal and a Y-polarization baseband signal.
4. The system of claim 3, wherein the transmitting end further comprises a modulation module for performing quadrature amplitude phase modulation format mapping on the binary information sequence to be transmitted, and inserting the synchronization series and the training sequence as a frame structure preamble sequence to generate an X-polarization baseband signal and a Y-polarization baseband signal.
5. The system of claim 3, wherein the transmitting end further comprises a pre-processing module for pre-compensating the X-polarized light signal or the Y-polarized light signal, respectively, and then sending the pre-compensated signals to the polarization beam combining module.
6. The system of claim 5, wherein the pre-compensation process comprises: nonlinear compensation of a modulator, dispersion pre-compensation and Kerr nonlinear compensation of optical fibers.
7. The system of claim 3, wherein the receiving end further comprises a Nyquist filter module for filtering the signal output from the down-conversion module to eliminate intersymbol interference.
8. The system of claim 7, wherein the receiving end further comprises a demodulation module for performing optimal sample point optimization, channel equalization, and decision demodulation of the nyquist filtering module matched filtered signal back to the binary sequence.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101465692A (en) * | 2009-01-07 | 2009-06-24 | 北京邮电大学 | Modulation method and transmission device for single sideband optical signal of optical OFDM system |
| CN102833206A (en) * | 2012-09-13 | 2012-12-19 | 电子科技大学 | Polarization multiplexing band interpolation based OFDMA-PON (orthogonal frequency division multiple access-passive optical network) system |
| CN104393917A (en) * | 2014-10-31 | 2015-03-04 | 哈尔滨工业大学深圳研究生院 | Polarization state rapid tracking monitoring method based on Kalman filtering |
| CN106301588A (en) * | 2016-09-28 | 2017-01-04 | 北京科技大学 | A kind of single-side belt palarization multiplexing direct detecting method and system |
| CN106533573A (en) * | 2016-10-26 | 2017-03-22 | 北京大学 | Asymmetric twin single-sideband modulation/ demodulation method and system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8295373B2 (en) * | 2008-09-30 | 2012-10-23 | Intel Corporation | Virtual multicarrier design for orthogonal frequency division multiple access communications |
| CN104410462B (en) * | 2014-12-25 | 2017-04-12 | 武汉邮电科学研究院 | Polarization-multiplexing-based method and device for modulating and directly detecting optical signals |
| CN107395288B (en) * | 2017-07-24 | 2020-05-01 | 北京大学 | Polarization diversity optical heterodyne coherent receiving method and system |
-
2018
- 2018-03-02 CN CN201810174933.0A patent/CN108566250B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101465692A (en) * | 2009-01-07 | 2009-06-24 | 北京邮电大学 | Modulation method and transmission device for single sideband optical signal of optical OFDM system |
| CN102833206A (en) * | 2012-09-13 | 2012-12-19 | 电子科技大学 | Polarization multiplexing band interpolation based OFDMA-PON (orthogonal frequency division multiple access-passive optical network) system |
| CN104393917A (en) * | 2014-10-31 | 2015-03-04 | 哈尔滨工业大学深圳研究生院 | Polarization state rapid tracking monitoring method based on Kalman filtering |
| CN106301588A (en) * | 2016-09-28 | 2017-01-04 | 北京科技大学 | A kind of single-side belt palarization multiplexing direct detecting method and system |
| CN106533573A (en) * | 2016-10-26 | 2017-03-22 | 北京大学 | Asymmetric twin single-sideband modulation/ demodulation method and system |
Non-Patent Citations (2)
| Title |
|---|
| Direct detection of polarization multiplexed single sideband signals with orthogonal offset carriers;YIXIAO ZHU,etal.;《optics express》;20180611;第15887-15898页 * |
| High Granularity Multiband OFDM Virtual Carrier-Assisted Direct-Detection Metro Networks;Tiago M.F.Alves,etal.;《JOURNAL OF LIGHTWAVE TECHNOLOGY》;20150101;第42-54页 * |
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