CN116260521B - Optical Domain Signal Equalization Device and Method - Google Patents

Abstract

The present application provides an optical domain signal equalization device and a method thereof. The device includes an optical splitting delay module, a nonlinear modulation module, an optical beam combining module, an optical detection module and an electrical control module, wherein the optical splitting delay module is used to divide the input optical signal into several optical signals with delays between them and input them to the non-linear In the linear modulation module; the nonlinear modulation module includes a first-order modulation module and a second-order modulation module. The first-order modulation module and the second-order modulation module are used to modulate the intensity of several optical signals respectively; The optical signals modulated by the modulation module and the second-order modulation module are grouped; the optical detection module is used to convert the grouped optical signals into corresponding electrical signals; and the electrical control module is used to judge and calculate the bit error rate based on the electrical signals. Adjust the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm. The present application can not only compensate the linear damage of the optical signal but also compensate the nonlinear damage.

Description

Optical Domain Signal Equalization Device and Method

technical field

The present application relates to the technical field of optical communication, and in particular to an optical domain signal equalization device and method thereof.

Background technique

In recent years, new applications such as the Internet of Things, augmented virtual reality, cloud computing, cloud storage, and other software services have driven the growth of global IP data traffic, thus placing higher speed and lower latency application requirements in the field of optical communications .

For this kind of high-speed and low-latency optical communication system, if traditional digital signal processing technology is used to compensate signal impairment, it will bring high delay and cannot meet the needs of current real-time applications. To solve this problem, optical domain equalization technology came into being, but the optical domain equalization technology proposed by researchers can only compensate the linear damage of the signal, and still needs to be combined with digital signal processing to compensate the nonlinear damage of the signal, which cannot fundamentally Solve the delay problem caused by digital signal processing.

Contents of the invention

The purpose of the present application is to provide an optical domain signal equalization device and method thereof, which can compensate both linear damage and nonlinear damage of optical signals.

One aspect of the present application provides an optical domain signal equalization device. The optical domain signal equalization device includes an optical division delay module, a nonlinear modulation module, an optical beam combination module, an optical detection module and an electrical control module, wherein the optical division delay module is used to divide the input optical signal into several delays between each other The optical signal is input into the nonlinear modulation module; the nonlinear modulation module includes a first-order modulation module and a second-order modulation module, and the first-order modulation module and the second-order modulation module are respectively used for several The optical signal is subjected to intensity modulation; the optical beam combining module is used to group the optical signals modulated by the first-order modulation module and the second-order modulation module; the light detection module is used to group the grouped light The signal is converted into a corresponding electrical signal; and the electrical control module is used to perform judgment and bit error rate calculation based on the electrical signal to adjust the intensity modulation of the first-order modulation module and the second-order modulation module in the equalization algorithm coefficient.

Further, the optical beam combining module includes a first optical beam combiner and a second optical beam combiner, and in the equalization algorithm, the optical signals with positive intensity modulation coefficients are divided into one group and input to the first optical beam combiner, The first optical beam combiner is combined into a positive modulation coefficient optical signal; in the equalization algorithm, the optical signals with a negative intensity modulation coefficient are divided into a group and input to the second optical beam combiner, and the The second optical beam combiner combines beams into one channel of negative modulation coefficient optical signals.

Further, the light detection module includes a first photodetector and a second photodetector, the first photodetector is used to detect the positive modulation coefficient optical signal input by the first optical beam combiner to generate the first light current; the second photodetector is used to detect the negative modulation coefficient optical signal input by the second optical beam combiner to generate a second photocurrent, wherein the electrical control module is used to generate a second photocurrent based on the first photocurrent and The difference after the subtraction of the second photocurrent is used for judgment and bit error rate calculation.

Further, the anode of the first photodetector is connected to the cathode of the second photodetector, the cathode of the first photodetector is connected to the first voltage source, and the cathode of the second photodetector The anode is connected to a second voltage source, the voltage of the first voltage source is higher than the voltage of the second voltage source, wherein the electrical control module is connected between the anode of the first photodetector and the second photodetector Between the cathodes of the device, it is used to receive the difference electric signal after subtracting the first photocurrent and the second photocurrent.

Further, the electrical control module includes an analog-to-digital converter, a digital-to-analog converter, and a central control chip, the analog-to-digital converter is used to convert the difference electrical signal into a digital signal; the central control chip is used to The digital signal is used for judgment and bit error rate calculation to obtain the weight coefficients of the first-order modulation module and the second-order modulation module, and the digital signal containing the weight coefficients is sent to the digital-to-analog converter ; The digital-to-analog converter is used to convert the digital signal of the weight coefficient into an analog signal, and send it to the first-order modulation module and the second-order modulation module in the nonlinear modulation module respectively, as Intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm.

Further, the optical splitting delay module includes a first optical beam splitter and an optical delayer, the first optical beam splitter is used to divide the input optical signal into M sub-signals with equal power; the optical delayer is used for The M molecular signals are delayed with respect to each other.

Further, the optical delays include M-1, wherein the M-1 optical delays respectively generate different signal delays for the corresponding M-1 sub-signals.

Further, the M sub-signals have equal time delays among each other, and the time delay is equal to the symbol period of the input optical signal or a multiple of the symbol period of the input optical signal.

Further, the first-order modulation module includes M second optical beam splitters and M first optical modulators, and the M second optical beam splitters are respectively used for correspondingly receiving the M sub-signals, each of the second optical beam splitters is used to divide the corresponding sub-signals into M+2 sub-signals to obtain M×(M+2) sub-signals in total, and the M first sub-signals The light modulators are respectively used to correspondingly receive one of the M+2 parts of the M sub-signals and perform intensity modulation on them, and the intensity modulation coefficient of the first-order modulation module includes M pieces of the first light The first-order weight coefficients of the modulator taps; wherein, the remaining M×(M+1) unmodulated sub-signals are input into the second-order modulation module.

Further, the second-order modulation module includes M×(M+1)/2 optical mixers and M×(M+1)/2 second optical modulators, M×(M+1)/2 The optical mixers are respectively used to mix the M×(M+1) sub-signals input by the second optical beam splitter in pairs to generate M×(M+1)/2 sub-signals after mixing The sub-signals are respectively input to the M×(M+1)/2 second optical modulators; the M×(M+1)/2 second optical modulators are respectively used for M×(M +1)/2 the frequency-mixed sub-signals are subjected to corresponding intensity modulation, and the intensity modulation coefficient of the second-order modulation module includes M×(M+1)/2 taps of the second optical modulator Second-order weight coefficients.

Another aspect of the present application provides an optical domain signal equalization method. The optical domain signal equalization method includes: dividing the input optical signal into several optical signals with delays between each other through an optical splitting delay module; The intensity modulation of the optical signal is performed; the optical signals modulated by the first-order modulation module and the second-order modulation module are grouped by the optical beam combining module; the grouped optical signals are converted into corresponding electrical signals by the optical detection module signal; and based on the electrical signal, the electrical control module performs judgment and bit error rate calculation to adjust the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm.

Further, the optical splitting delay module includes a first optical beam splitter and M-1 optical delayers, and dividing the input optical signal into several optical signals with delays between each other through the optical splitting delay module includes: passing through the optical splitting delay module The first optical beam splitter divides the input optical signal into M sub-signals with equal power; and the M-1 optical delayers generate different signal delays for the corresponding M-1 sub-signals so that all The M molecular signals are delayed among each other.

Further, the M sub-signals have equal time delays among each other, and the time delay is equal to the symbol period of the input optical signal or a multiple of the symbol period of the input optical signal.

Further, the first-order modulation module includes M second optical beam splitters and M first optical modulators, and the first-order modulation module and the second-order modulation module in the non-linear modulation module respectively The intensity modulation of the optical signal includes: correspondingly input one of the M+2 parts of the M sub-signals into the M first optical modulators, and the M first optical modulators Intensity modulation is performed on them respectively, wherein the intensity modulation coefficient of the first-order modulation module includes M first-order weight coefficients of the taps of the first optical modulator; and the remaining M×(M+1) parts are not The modulated sub-signals are input to the second-order modulation module, and the second-order modulation module performs intensity modulation on them respectively.

Further, the second-order modulation module includes M×(M+1)/2 optical mixers and M×(M+1)/2 second optical modulators, and the non-linear modulation module The first-order modulation module and the second-order modulation module respectively performing intensity modulation on several optical signals further include: correspondingly dividing each of the M sub-signals into M sub-signals through M second optical beam splitters. +2 copies; the M×(M+1) sub-signals input by the second optical beam splitter are mixed in pairs by M×(M+1)/2 optical mixers to generate M ×(M+1)/2 mixed sub-signals are respectively input to the M×(M+1)/2 second optical modulators; the M×(M+1)/2 The second optical modulator performs corresponding intensity modulation on the M×(M+1)/2 frequency-mixed sub-signals, and the intensity modulation coefficient of the second-order modulation module includes M×(M+1)/ Second-order weight coefficients of the two taps of the second optical modulator.

Further, the optical beam combining module includes a first optical beam combiner and a second optical beam combiner, and grouping the optical signals modulated by the first-order modulation module and the second-order modulation module through the optical beam combining module includes: In the equalization algorithm, the optical signals whose intensity modulation coefficients are positive are divided into a group and input to the first optical beam combiner, and the first optical beam combiner is combined into one optical signal with a positive modulation coefficient; In the equalization algorithm, the optical signals with negative intensity modulation coefficients are divided into one group and input to the second optical beam combiner, and are combined by the second optical beam combiner into one optical signal with negative modulation coefficient.

Further, the photodetection module includes a first photodetector and a second photodetector, and converting the grouped optical signal into a corresponding electrical signal through the photodetection module includes: using the first photodetector The detector detects the positive modulation coefficient optical signal input by the first optical beam combiner to generate the first photocurrent; and the second photodetector detects the negative modulation coefficient optical signal input by the second optical beam combiner to generate the first photocurrent; A second photocurrent is generated, wherein judgment and bit error rate calculation are performed based on a subtracted difference between the first photocurrent and the second photocurrent.

Further, said adjusting the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm based on the electrical signal by the electrical control module to determine and calculate the bit error rate includes: A difference electrical signal after subtracting the photocurrent and the second photocurrent is converted into a digital signal; judgment and bit error rate calculation are performed based on the digital signal to obtain the first-order modulation module and the second-order modulation The weight coefficient of the module; convert the digital signal containing the weight coefficient into an analog signal, and send it to the first-order modulation module and the second-order modulation module in the nonlinear modulation module respectively, as the Intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm.

The optical domain signal equalization device and method thereof of the present application have at least the following beneficial technical effects:

(1) This application can directly compensate the linear damage and nonlinear damage in the optical communication system in the optical domain, without additional digital signal processing modules, eliminating the digital signal processing process at the receiving end, and greatly reducing the signal processing delay , which can meet more and more real-time application requirements.

(2) In this application, the electrical control module can update the equalization weight, which can meet the needs of optical communication systems with different requirements. It has extremely high flexibility and can adapt to various application scenarios.

Description of drawings

FIG. 1 is a schematic diagram of an overall structure of an optical domain signal equalization device according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of an optical splitting delay module in an optical domain signal equalization device according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a nonlinear modulation module in an optical domain signal equalization device according to an embodiment of the present application.

Fig. 4 is a schematic structural diagram of an optical beam combining module in an optical domain signal equalization device according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of an optical detection module in an optical domain signal equalization device according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of an electrical control module in an optical domain signal equalization device according to an embodiment of the present application.

Fig. 7 is a flow chart of a method for equalizing an optical domain signal according to an embodiment of the present application.

Detailed ways

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of means consistent with aspects of the present application as recited in the appended claims.

The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application shall have the usual meanings understood by those skilled in the art to which the present application belongs. As used in the specification and appended claims of this application, the singular forms "a", "the" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

The present application provides an optical domain signal equalization device. Fig. 1 discloses a schematic diagram of an overall structure of an optical domain signal equalization device 100 according to an embodiment of the present application. As shown in FIG. 1 , an optical domain signal equalization device 100 according to an embodiment of the present application includes an optical splitting delay module 110 , a nonlinear modulation module 120 , an optical beam combining module 130 , an optical detection module 140 and an electrical control module 150 . Wherein, the optical splitting and delaying module 110 can be used to receive an input optical signal, divide the input optical signal into several optical signals with delays between them, and input them to the nonlinear modulation module 120 . The nonlinear modulation module 120 includes a first-order modulation module and a second-order modulation module, and the first-order modulation module and the second-order modulation module can be used to respectively perform intensity modulation on several optical signals. The optical beam combining module 130 can group the optical signals modulated by the first-order modulation module and the second-order modulation module. The optical detection module 140 may convert the grouped optical signals into corresponding electrical signals. The electrical control module 150 can perform judgment and bit error rate calculation based on the electrical signal to adjust the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm.

The structures of the five modules in the optical domain signal equalization device 100 will be described in detail below in sequence with reference to the accompanying drawings.

FIG. 2 discloses a schematic structural diagram of an optical splitting delay module 110 in an optical domain signal equalization device 100 according to an embodiment of the present application. As shown in FIG. 2 , the optical splitting and delaying module 110 may include a first optical beam splitter 111 and an optical delayer 112 . The first optical beam splitter 111 can divide the input optical signal into M sub-signals with equal power, namely x(k), x(k-1), x(k-2), ..., x(k-M+ 1). Then, the M sub-signals pass through the optical delayer 112 , and the M sub-signals can be delayed by the optical delayer 112 .

In the embodiment shown in FIG. 2 , the optical splitting and delaying module 110 includes M-1 optical delayers 112 , and the M-1 optical delayers 112 can respectively generate different signal delays for the corresponding M-1 component signals. Wherein, the first optical signal does not pass through the optical delayer 112, that is, the delay t 0 of the sub-signal x(k) is considered to be ₀ = 0; the second optical signal passes through the optical delayer 112 (such as delay line 1) to generate a delay T ₁ , That is, the delay t ₁ =T ₁ of the sub-signal x(k-1) is considered; the third optical signal passes through the optical delayer 112 (such as delay line 2) to generate a delay of T ₂ , that is, the delay of the sub-signal x(k-2) is considered Delay t ₂ =T ₂ ; by analogy, the M-th optical signal passes through the optical delayer 112 (such as delay line M-1) to generate a delay T _M-1 , that is, the delay t _m of x(k-M+1) _-1 =TM _-1 . Finally, the M optical signals with a certain delay are input into the nonlinear modulation module 120 .

In one embodiment, the M sub-signals have an equal time delay among each other, and the time delay is equal to the symbol period of the input optical signal, that is, Δt=t ₁ -t ₀ =t ₂ -t ₁ =...=t _m-1 -t _m-2 =T, T is the symbol period of the input optical signal. In another embodiment, the M sub-signals have an equal time delay between each other, and the time delay is equal to a multiple of the symbol period T of the input optical signal, which can be adjusted according to the signal processing accuracy requirements of the optical communication system . Of course, the present application is not limited thereto. In other embodiments, the M sub-signals may also generate time delays with unequal intervals, which can be adjusted according to the specific conditions of the optical communication system where they are located, and there is no limitation here.

Fig. 3 discloses a schematic structural diagram of the nonlinear modulation module 120 in the optical domain signal equalization device 100 according to an embodiment of the present application. As shown in FIG. 3 , the first-order modulation module in the nonlinear modulation module 120 includes M second optical beam splitters 121 and M first optical modulators 122 . The M sub-signals input to the non-linear modulation module 120 by the optical splitting delay module 110, first, M second optical beam splitters 121 correspondingly receive M sub-signals with delays between each other, each second optical beam splitter 121 can further divide the corresponding sub-signal into M+2 sub-signals, therefore, M×(M+2) sub-signals can be obtained in total. Then, one of the M+2 shares of the M sub-signals is correspondingly sent to the M first optical modulators 122, and the M first optical modulators 122 can respectively receive one of the M+2 shares of the M sub-signals. One of them and intensity modulated on it. Wherein, the intensity modulation coefficient of the first-order modulation module includes M first-order weight coefficients of taps of the first optical modulator 122, and there are M first-order weight coefficients in total, namely , so that M first-order modulated sub-signals can be generated, namely .

Then, the remaining M×(M+1) unmodulated sub-signals are input into the second-order modulation module. Continuing to refer to FIG. 3 , in some embodiments, the second-order modulation module may include M×(M+1)/2 optical mixers 123 and M×(M+1)/2 second optical modulators 124 . First, the M×(M+1) sub-signals input by the second optical beam splitter 121 in the first-order modulation module are mixed in pairs by M×(M+1)/2 optical mixers 123, Generate M×(M+1)/2 mixed sub-signals ; Then, M×(M+1)/2 mixed sub-signals are respectively input to M×(M+1)/2 second optical modulators 124 in the second-order modulation module, by M The ×(M+1)/2 second light modulators 124 respectively perform corresponding intensity modulation on the M×(M+1)/2 mixed sub-signals. Wherein, the intensity modulation coefficient of the second-order modulation module includes M×(M+1)/2 second-order weight coefficients of the 124 taps of the second optical modulator, and there are M×(M+1)/2 second-order weight coefficients in total, Right now , so that M×(M+1)/2 mixed and modulated sub-signals can be generated, namely .

Finally, the M first-order modulated sub-signals and M×(M+1)/2 second-order modulated sub-signals are sent to the optical beam combining module 130 together.

Preferably, the first light modulator 122 and the second light modulator 124 can use an electro-absorption tuner that is insensitive to the polarization state of the light for intensity modulation, but it is not limited to select electro-optical, acoustic and other factors due to factors such as cost and control difficulty. light and other light modulators.

Fig. 4 discloses a schematic structural diagram of the optical beam combining module 130 in the optical domain signal equalization device 100 according to an embodiment of the present application. As shown in FIG. 4 , the optical beam combiner 130 includes a first optical beam combiner 131 and a second optical beam combiner 132 . The M first-order modulated sub-signals and the M×(M+1)/2 second-order modulated sub-signals input to the optical beam combining module 130 by the nonlinear modulation module 120 above will be divided into In the equalization algorithm, the sub-signals with positive intensity modulation coefficients are divided into one group and input to the first optical beam combiner 131, and the first optical beam combiner 131 combines them into one optical signal, which is called here as Make a positive modulation coefficient optical signal. In addition, in the equalization algorithm, the optical signals with negative intensity modulation coefficients are divided into one group and input to the second optical beam combiner 132, and the second optical beam combiner 132 combines them into one optical signal, which is called a negative modulation coefficient here. light signal.

The equalization algorithm described in this application is a signal damage compensation algorithm customized for the optical communication system, and there is no limitation in this application, that is, which sub-signals have positive intensity modulation coefficients and which sub-signals have negative intensity modulation coefficients It can be switched according to the change of the actual application scenario, and the connection mode shown in FIG. 4 is only for illustration, and not as a limitation to the present application.

Therefore, through the optical beam combining module 130, the optical beam combining module 130 is responsible for combining a total of M first-order modulated sub-signals input by the first-order modulation module with a total of M×(M+1)/2 sub-signals input by the second-order modulation module. The second-order modulated sub-signals are grouped and combined into two optical signals according to equalization requirements, that is, an optical signal with a positive modulation coefficient and an optical signal with a negative modulation coefficient, and the two optical signals are respectively input to the optical detection module 140 .

FIG. 5 discloses a schematic structural diagram of the optical detection module 140 in the optical domain signal equalization device 100 according to an embodiment of the present application. As shown in FIG. 5 , the light detection module 140 includes a first photodetector PD1 and a second photodetector PD2 . The above-mentioned positive modulation coefficient optical signal and negative modulation optical signal input to the light detection module 140 by the light combining module 130 are respectively detected by the two photodetectors. Among them, the first photodetector PD1 can detect the positive modulation coefficient optical signal input by the first optical beam combiner 131 to generate the first photocurrent I1; the second photodetector PD2 can detect the negative modulation coefficient input by the second optical beam combiner 132. The coefficient light signal is modulated to generate a second photocurrent I2.

Wherein, the electrical control module 150 can perform judgment and bit error rate calculation based on the difference between the subtraction of the first photocurrent I1 and the second photocurrent I2.

In some embodiments, the anode of the first photodetector PD1 is connected to the cathode of the second photodetector PD2, the cathode of the first photodetector PD1 is connected to the first voltage source V _PD1 , and the second photodetector PD2 The anode of the anode is connected to the second voltage source V _PD2 , the voltage of the first voltage source V _PD1 is higher than the voltage of the second voltage source V _PD2 , that is, the cathode of the first photodetector PD1 is connected to the high voltage signal source, and the second photodetector The anode of PD2 is connected to a low voltage voltage source. In this way, the direction of the photocurrent obtained is shown in Figure 5, and the direction of flowing to the node P is opposite, that is, △I=I1-I2. The electrical control module 150 is connected between the anode of the first photodetector PD1 and the cathode of the second photodetector PD2, and can be used to receive the difference between the subtraction of the first photocurrent and the second photocurrent input by the photodetection module. Value electrical signal △I.

For example, the first photodetector PD1 and the second photodetector PD2 may include but not limited to photosensitive diodes, avalanche photodiodes, phototransistors, etc., as long as the conversion from optical signals to electrical signals can be realized, this application does not make any limit.

FIG. 6 discloses a schematic structural diagram of the electrical control module 150 in the optical domain signal equalization device 100 according to an embodiment of the present application. As shown in FIG. 6 , the electrical control module 150 includes an analog-to-digital converter (ADC, Analog-to-Digital Converter) 151 , a digital-to-analog converter (DAC, Digital-to-Analog Converter) 153 and a central control chip 152 . First, the difference electrical signal ΔI is converted into a digital signal by the analog-to-digital converter 151 . Then, the central control chip 152 will judge and calculate the bit error rate based on the digital signal, so as to obtain the weight coefficients of the first-order modulation module and the second-order modulation module, and send the digital signal containing the weight coefficients to the digital-to-analog conversion device 153. The digital signal of the weight coefficient is converted into an analog signal by the digital-to-analog converter 153, and is delivered to the first-order modulation module and the second-order modulation module in the nonlinear modulation module 120 respectively, and then can be used as the first-order modulation module and the second-order modulation module. The intensity modulation coefficient of the modulation module in the equalization algorithm, that is, the first-order weight coefficient mentioned above and the second-order weight coefficient . Therefore, the equalized optical signal can be recovered.

Preferably, the central control chip 152 in the electrical control module 150 may include but not limited to chips such as a programmable logic array (Field Programmable Gate Array, FPGA), a microcontroller (Mirco Controller Unit, MCU), and the specification of the chip depends on It is based on the signal processing requirements of the optical communication system.

Preferably, the digital-to-analog converter 153 in the electrical control module 150 can use a high-precision digital-to-analog converter with more than 12 bits to report the photocurrent generated by the detection signal, thereby ensuring higher signal processing accuracy. In addition, the number of digital-to-analog converters 153 shown in FIG. 6 is only used as an example to facilitate graphical expression, and is not intended to limit the application. In fact, the number of digital-to-analog converters 153 in the electrical control module 150 of the application One or more channels may be included, as long as the total number of channels of the digital-to-analog converter 153 is not less than the sum of the first-order weight coefficients and the second-order weight coefficients.

The optical domain signal equalization device 100 of the present application at least has the following beneficial technical effects:

(1) The optical domain signal equalization device 100 of the present application can directly compensate the linear damage and nonlinear damage in the optical communication system in the optical domain, without the need for an additional digital signal processing module and the digital signal processing process at the receiving end, The signal processing delay is greatly reduced, which can meet more and more real-time application requirements.

(2) The optical domain signal equalization device 100 of this application can update the equalization weight by the electrical control module 150, which can meet different requirements of optical communication systems, has high flexibility, and can adapt to various application scenarios.

The present application also provides an optical domain signal equalization method. Fig. 7 discloses a flowchart of a method for equalizing an optical domain signal according to an embodiment of the present application. As shown in FIG. 7 , an optical domain signal equalization method according to an embodiment of the present application may include steps S1 to S5.

In step S1, the input optical signal may be divided into several optical signals with delays between them by the optical splitting delay module 110 .

In step S2, the intensity modulation of several optical signals may be performed by the first-order modulation module and the second-order modulation module in the nonlinear modulation module 120, respectively.

In step S3, the optical signals modulated by the first-order modulation module and the second-order modulation module may be grouped by the optical beam combining module 130 .

In step S4, the grouped optical signals may be converted into corresponding electrical signals by the optical detection module 140 .

In step S5, based on the electrical signal, the electrical control module 150 performs judgment and bit error rate calculation to adjust the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm.

In some embodiments, the optical splitting and delaying module 110 may include a first optical beam splitter 111 and M−1 optical delayers 112 . Step S1 may include step S11 and step S12. In step S11, the input optical signal is divided into M sub-signals with equal power by the first optical beam splitter 111 . In step S12 , M−1 optical delayers 112 are used to generate different signal delays for the corresponding M−1 sub-signals so that there is a delay between the M sub-signals.

Optionally, the M sub-signals have equal time delays among each other, and the time delay is equal to the symbol period T of the input optical signal or a multiple of the symbol period T of the input optical signal, which can be specifically processed according to the optical communication system Accuracy needs to be adjusted.

In some embodiments, the first-order modulation module in the nonlinear modulation module 120 may include M second optical beam splitters 121 and M first optical modulators 122 . Step S2 may include step S21 and step S22. In step S21, one of the M+2 parts of the M sub-signals is correspondingly input into the M first light modulators 122, and the M first light modulators 122 respectively perform intensity modulation on them, wherein, The intensity modulation coefficients of the first-order modulation module include first-order weight coefficients of the taps of the M first light modulators 122 . In step S22, the remaining M×(M+1) unmodulated sub-signals are input to the second-order modulation module, and the second-order modulation module performs intensity modulation on them respectively.

In some embodiments, the second-order modulation module in the nonlinear modulation module 120 may include M×(M+1)/2 optical mixers 123 and M×(M+1)/2 second optical modulators 124. Step S2 also includes step S23 to step S25. In step S23, each of the M sub-signals is subdivided into M+2 sub-signals by M second beam splitters. In step S24, the M×(M+1) sub-signals input by the second optical beam splitter 121 are mixed in pairs by M×(M+1)/2 optical mixers 123 to generate M× (M+1)/2 mixed sub-signals are input to M×(M+1)/2 second optical modulators 124 respectively. In step S25, M×(M+1)/2 second optical modulators 124 respectively perform corresponding intensity modulation on M×(M+1)/2 sub-signals after frequency mixing, and the second-order modulation module The intensity modulation coefficients include M×(M+1)/2 second-order weight coefficients of the taps of the second light modulator 124 .

In some embodiments, the light combining module 130 may include a first light combiner 131 and a second light combiner 132 . Step S3 may include step S31 and step S32. In step S31 , the optical signals with positive intensity modulation coefficients in the equalization algorithm are divided into one group and input to the first optical beam combiner 131 , and the first optical beam combiner 131 combines them into one optical signal with positive modulation coefficients. In step S32, the optical signals with negative intensity modulation coefficients in the equalization algorithm are divided into one group and input to the second optical beam combiner 132, and the second optical beam combiner 132 combines them into one optical signal with negative modulation coefficients.

In some embodiments, the light detection module 140 may include a first photodetector PD1 and a second photodetector PD2. Step S4 may include step S41 and step S42. In step S41 , the positive modulation coefficient optical signal input by the first optical beam combiner 131 is detected by the first photodetector PD1 to generate a first photocurrent. In step S42 , the negative modulation coefficient optical signal input by the second optical beam combiner 132 is detected by the second photodetector PD2 to generate a second photocurrent. Wherein, in step S5, judgment and bit error rate calculation may be performed based on the subtracted difference between the first photocurrent generated in step S41 and the second photocurrent generated in step S42.

In some embodiments, step S5 may include step S51 to step S53. In step S51, the electrical difference signal after subtracting the first photocurrent and the second photocurrent is converted into a digital signal. In step S52, the decision and bit error rate calculation are performed based on the digital signal to obtain the weight coefficients of the first-order modulation module and the second-order modulation module. In step S53, the digital signal containing the weight coefficient is converted into an analog signal, and is respectively delivered to the first-order modulation module and the second-order modulation module in the nonlinear modulation module 120, as the first-order modulation module and the second-order modulation module The intensity modulation factor of the module in the equalization algorithm.

The optical domain signal equalization method of the present application can compensate both the linear damage and the nonlinear damage of the optical signal, thereby completely eliminating the digital signal processing process at the receiving end, greatly reducing the signal processing delay, and meeting the current needs of more and more real-time application requirements.

The optical domain signal equalization method of the present application can meet optical communication systems with different requirements, has extremely high flexibility, and can be adapted to various application scenarios.

The optical domain signal equalization device and method thereof provided in the embodiments of the present application have been introduced in detail above. This article uses specific examples to illustrate the optical domain signal equalization device and method of the embodiments of the present application. The description of the above embodiments is only used to help understand the core idea of the present application, and is not intended to limit the present application. It should be pointed out that for those skilled in the art, without departing from the spirit and principle of the application, some improvements and modifications can also be made to the application, and these improvements and modifications should also fall into the scope of the appended documents of the application. within the scope of protection of the claims.

Claims (12)

1. An optical domain signal equalization device, characterized in that: comprising an optical delay module, a nonlinear modulation module, an optical beam combining module, an optical detection module and an electrical control module, wherein, The optical splitting delay module is used to divide the input optical signal into several optical signals with delays between them and input them into the nonlinear modulation module; The nonlinear modulation module includes a first-order modulation module and a second-order modulation module, and the first-order modulation module and the second-order modulation module are respectively used to perform intensity modulation on several optical signals; The optical beam combining module is used to group the optical signals modulated by the first-order modulation module and the second-order modulation module; The optical detection module is used to convert the grouped optical signals into corresponding electrical signals; and The electrical control module is used to perform judgment and bit error rate calculation based on the electrical signal to adjust the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm, The optical splitting delay module includes a first optical beam splitter and an optical delayer, the first optical beam splitter is used to divide the input optical signal into M sub-signals with equal power; the optical delayer is used to make the M molecular signals are delayed with each other, The first-order modulation module includes M second optical beam splitters and M first optical modulators, and the M second optical beam splitters are respectively used to receive the M sub-signals with delays between each other. , each of the second optical beam splitters is used to divide the corresponding sub-signal into M+2 sub-signals to obtain M×(M+2) sub-signals in total, and the M first optical modulators Respectively used to receive one of the M+2 shares of the M sub-signals and perform intensity modulation on them, the intensity modulation coefficient of the first-order modulation module includes M taps of the first optical modulator The first-order weight coefficient; wherein, the remaining M×(M+1) unmodulated sub-signals are input into the second-order modulation module, The second-order modulation module includes M×(M+1)/2 optical mixers and M×(M+1)/2 second optical modulators, M×(M+1)/2 said The optical mixer is respectively used to mix the M×(M+1) sub-signals input by the second optical beam splitter in pairs to generate M×(M+1)/2 mixed sub-signals and respectively input to M×(M+1)/2 said second light modulators; M×(M+1)/2 said second light modulators are respectively used for M×(M+1) /2 said frequency-mixed sub-signals are subjected to corresponding intensity modulation, and the intensity modulation coefficient of said second-order modulation module includes M×(M+1)/2 second-order weights of taps of said second optical modulator coefficient. 2. The optical domain signal equalization device according to claim 1, wherein the optical beam combining module comprises a first optical beam combiner and a second optical beam combiner, In the equalization algorithm, the optical signals with positive intensity modulation coefficients are divided into one group and input to the first optical beam combiner, and are combined by the first optical beam combiner into one optical signal with positive modulation coefficient; In the equalization algorithm, the optical signals with negative intensity modulation coefficients are divided into one group and input to the second optical beam combiner, and are combined by the second optical beam combiner into one optical signal with negative modulation coefficient. 3. The optical domain signal equalization device according to claim 2, wherein the optical detection module comprises a first photodetector and a second photodetector, The first photodetector is used to detect a positive modulation coefficient optical signal input by the first optical beam combiner to generate a first photocurrent; The second photodetector is used to detect the negative modulation coefficient optical signal input by the second optical beam combiner to generate a second photocurrent, Wherein, the electrical control module is configured to perform judgment and bit error rate calculation based on a subtracted difference between the first photocurrent and the second photocurrent. 4. The optical domain signal equalization device according to claim 3, characterized in that: the anode of the first photodetector is connected to the cathode of the second photodetector, and the anode of the first photodetector The cathode is connected to a first voltage source, the anode of the second photodetector is connected to a second voltage source, the voltage of the first voltage source is higher than the voltage of the second voltage source, Wherein, the electrical control module is connected between the anode of the first photodetector and the cathode of the second photodetector, and is used to receive the difference between the subtraction of the first photocurrent and the second photocurrent Value electrical signal. 5. The optical domain signal equalization device according to claim 4, characterized in that: the electrical control module includes an analog-to-digital converter, a digital-to-analog converter and a central control chip, The analog-to-digital converter is used to convert the difference electrical signal into a digital signal; The central control chip is used to perform judgment and bit error rate calculation based on the digital signal to obtain the weight coefficients of the first-order modulation module and the second-order modulation module, and convert the digital signal containing the weight coefficients to delivered to said digital-to-analog converter; The digital-to-analog converter is used to convert the digital signal of the weight coefficient into an analog signal, which is respectively sent to the first-order modulation module and the second-order modulation module in the nonlinear modulation module, as the Intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm. 6. The optical domain signal equalization device according to claim 1, characterized in that: the optical splitting delay module includes M-1 optical delayers, wherein the M-1 optical delayers are respectively corresponding to M-1 molecular signals produce different signal delays. 7. The optical domain signal equalization device according to claim 1, characterized in that: the M sub-signals have equal time delays between each other, and the time delay is equal to the symbol period of the input optical signal or the Integer multiples of the symbol period of the input optical signal. 8. A method for optical domain signal equalization, characterized in that: comprising: The input optical signal is divided into several optical signals with delays between each other through the optical splitting delay module; Intensity modulation is performed on several of the optical signals through the first-order modulation module and the second-order modulation module in the nonlinear modulation module; grouping the optical signals modulated by the first-order modulation module and the second-order modulation module through the optical beam combining module; converting the grouped optical signal into a corresponding electrical signal through the optical detection module; and Based on the electrical signal, the electrical control module performs judgment and bit error rate calculation to adjust the intensity modulation coefficients of the first-order modulation module and the second-order modulation module in the equalization algorithm, The optical splitting and delaying module includes a first optical beam splitter and M-1 optical delayers, and dividing the input optical signal into several optical signals with delays between each other through the optical splitting and delaying module includes: passing through the first optical The beam splitter divides the input optical signal into M sub-signals with equal power; and the M-1 optical delayers generate different signal delays for the corresponding M-1 sub-signals so that the M Signals are delayed from each other; The first-order modulation module includes M second optical beam splitters and M first optical modulators, and the first-order modulation module and the second-order modulation module in the non-linear modulation module respectively process several optical signals Performing intensity modulation includes: correspondingly dividing each of the M sub-signals into M+2 parts through M second optical beam splitters; dividing the M+2 parts of the M sub-signals into One of them is correspondingly input to the M first light modulators, and the intensity modulation is performed by the M first light modulators respectively, wherein the intensity modulation coefficient of the first-order modulation module includes M The first-order weight coefficient of the tap of the first optical modulator; and input the remaining M×(M+1) unmodulated sub-signals into the second-order modulation module, and the second-order modulation module Intensity modulation is performed on them respectively; The second-order modulation module includes M×(M+1)/2 optical mixers and M×(M+1)/2 second optical modulators, and the first-order modulation in the nonlinear modulation module The module and the second-order modulation module respectively perform intensity modulation on several optical signals and further include: respectively inputting M ×(M+1) sub-signals are mixed in pairs to generate M×(M+1)/2 mixed sub-signals and input them to the M×(M+1)/2 second optical Modulator: the M×(M+1)/2 second optical modulators respectively perform corresponding intensity modulation on the M×(M+1)/2 mixed sub-signals, and the two The intensity modulation coefficient of the order modulation module includes M×(M+1)/2 second-order weight coefficients of taps of the second optical modulator. 9. The optical domain signal equalization method according to claim 8, characterized in that: said M sub-signals generate equal time delays between each other, and said time delays are equal to the symbol period of said input optical signal or the Integer multiples of the symbol period of the input optical signal. 10. The optical domain signal equalization method according to claim 8, characterized in that: the optical beam combining module includes a first optical beam combiner and a second optical beam combiner, and the first-order modulation module is combined by the optical beam combining module Grouping the optical signal modulated by the second-order modulation module includes: dividing the optical signals whose intensity modulation coefficients are positive in the equalization algorithm into a group and inputting them to the first optical beam combiner, and combining them into one optical signal with positive modulation coefficients by the first optical beam combiner; The optical signals with negative intensity modulation coefficients in the equalization algorithm are divided into one group and input to the second optical beam combiner, and the second optical beam combiner combines them into one optical signal with negative modulation coefficients. 11. The optical domain signal equalization method according to claim 10, characterized in that: the light detection module includes a first photodetector and a second photodetector, and the grouped light through the light detection module Signal conversion to corresponding electrical signals includes: detecting a positive modulation coefficient optical signal input by the first optical beam combiner by the first photodetector to generate a first photocurrent; and detecting the negative modulation coefficient optical signal input by the second optical beam combiner by the second photodetector to generate a second photocurrent, Wherein, the judgment and bit error rate calculation are performed based on a difference value after subtraction of the first photocurrent and the second photocurrent. 12. The optical domain signal equalization method according to claim 11, characterized in that: the electrical control module performs judgment and bit error rate calculation based on the electrical signal to adjust the first-order modulation module and the second-order modulation module. The intensity modulation coefficients of the modulation module in the equalization algorithm include: converting the difference electrical signal obtained by subtracting the first photocurrent and the second photocurrent into a digital signal; performing judgment and bit error rate calculation based on the digital signal to obtain weight coefficients of the first-order modulation module and the second-order modulation module; converting the digital signal containing the weight coefficients into an analog signal, and sending them to the first-order modulation module and the second-order modulation module in the nonlinear modulation module respectively, as the first-order modulation module and the intensity modulation coefficient of the second-order modulation module in the equalization algorithm.