Apparatus and method for real-time monitoring delay skew of sub signal of optical transmitter

Abstract

To provide an apparatus and a method for real-time monitoring a delay difference of a sub-signal of an optical transmitter.SOLUTION: A method includes the steps of: modulating to-be-modulated light and inputting a first input signal to a first electrical / optical conversion unit so as to obtain a first output signal; modulating to-be-modulated light to obtain a second output signal and inputting a second input signal to a second electrical / optical conversion unit so as to obtain a second output signal, the second input signal being a differential signal of the first input signal; executing correlation operation processing on the first output signal and the second output signal to obtain a correlation amount between the first input signal and the second input signal; and determining a delay difference between an output signal of the first electrical / optical conversion unit and an output signal of the second electrical / optical conversion unit on the basis of the correlation amount and a correspondence between a predetermined correlation amount and the delay difference. Accordingly, a delay difference between two high-speed signals can be monitored by using only a low-bandwidth electrical device while avoiding the use of a high-speed device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of optical communication.

Background Art

[0002] In the field of optical communication, in order to achieve a larger communication capacity, a transmitter outputs a very high signal rate of, for example, 100 gigabaud (GBaud). These signals are usually composed of a plurality of sub-signals. For example, a dual-polarization system has two polarization components, x and y. A coherent system has an in-phase component I and a quadrature component Q. In a DAC architecture, PAM8 is a superposition of 0 / 1 sequences of three paths, and the 0 / 1 sequence of each path constitutes a sub-signal. In modulation by a multi-segment, the total signal is a superposition of signals of each segment, and each segment constitutes a sub-signal. In a hardware implementation, these sub-signals are usually generated by different electrical and optical elements. Therefore, different sub-signals have different analog characteristics. For example, there may be different delay skews (also referred to as delay time differences) between different sub-signals. Such a delay difference causes distortion in the output signal, resulting in a degradation of system performance. Currently, in order to reduce the influence of such a delay difference, before using the transmitter, the delays of all sub-signals are corrected. However, even if the delays of all sub-signals are corrected before using the transmitter, due to changes in temperature, environment, etc., there may still be a deviation in the delay between sub-signals again. Therefore, it is necessary to monitor the delay difference of sub-signals in real time without affecting normal communication.

[0003] It should be noted that the above description of the technical background is for the purpose of clearly and completely understanding the technical solution of the present invention and is described to enable those skilled in the art to understand. These technical solutions are only described as the background art part of the present invention and are not well known to those skilled in the art.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the discovery of the inventor of the present invention, in a high-speed optical transmitter having a plurality of sub-signals, as a scheme for adjusting the delay difference of each sub-signal, the quality of the eye diagram on the output side is monitored, and based on the quality of the eye diagram, the delay difference of the sub-signal may be adjusted by the AWG on the transmission side. However, in such a scheme, an expensive real-time signal analysis device is required to obtain the output waveform on the receiving side, so it is difficult to implement in applications. Further, in such a scheme, the delay difference cannot be monitored without affecting normal communication.

[0005] In view of at least one of the above technical problems, embodiments of the present invention utilize the correlation amount between a high-speed sub-signal and other high-speed signals during communication of an optical transmitter to indicate the delay of the optical transmitter or the electrical / optical conversion unit of the optical transmitter, thereby providing a real-time monitoring device and method for the delay difference of sub-signals of an optical transmitter that are simple to implement, have a flexible implementation method, and a wide range of uses.

Means for Solving the Problems

[0006] In one aspect of an embodiment of the present invention, there is provided a real-time monitoring device for the delay difference of sub-signals of an optical transmitter, including: a first signal input unit configured to input the first input signal to a first electrical / optical conversion unit so as to modulate a modulated optical signal based on the first input signal and obtain a first output signal; a second signal input unit configured to input the second input signal to a second electrical / optical conversion unit so as to modulate a modulated optical signal based on the second input signal and obtain a second output signal, wherein the second input signal is a differential signal of the first input signal; a correlation operation unit configured to perform a correlation operation process on the first output signal and the second output signal to obtain a correlation amount between the first input signal and the second input signal; and a delay difference determination unit configured to determine a delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation amount and a correspondence relationship between a predetermined correlation amount and the delay difference.

[0007] In one aspect of an embodiment of the present invention, there is provided a real-time monitoring method for the delay difference of sub-signals of an optical transmitter, including: inputting the first input signal to a first electrical / optical conversion unit so as to modulate a modulated optical signal based on the first input signal and obtain a first output signal; inputting the second input signal to a second electrical / optical conversion unit so as to modulate a modulated optical signal based on the second input signal and obtain a second output signal, wherein the second input signal is a differential signal of the first input signal; performing a correlation operation process on the first output signal and the second output signal to obtain a correlation amount between the first input signal and the second input signal; and determining a delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation amount and a correspondence relationship between a predetermined correlation amount and the delay difference.

[0008] One of the advantageous effects of the embodiments of the present invention is as follows. The present invention can realize real-time monitoring of the delay difference by determining the delay difference using the signal output by the electrical / optical conversion unit of the optical transmitter, and the optical transmitter does not need to transmit a special signal. Further, the present invention can realize monitoring of the delay difference of the sub-signals of the optical transmitter using a low-bandwidth electrical device, avoid the use of high-speed devices, and can be flexibly realized in either an integrated or non-integrated manner. Furthermore, the present invention can be applied to various scenarios and can be applied to monitoring the delay difference of sub-signals in various types of optical transmitters.

[0009] Specific embodiments of the present invention are disclosed in detail as shown in the following description and drawings, showing a manner in which the principles of the present invention can be adopted. It should be noted that the embodiments of the present invention are not limited in scope. The embodiments of the present invention include various changes, modifications, and equivalents within the spirit and scope of the appended claims.

Brief Description of the Drawings

[0010] The drawings included herein are for understanding the embodiments of the present invention, form a part of this specification, and are for exemplifying the embodiments of the present invention, and explain the principles of the present invention in conjunction with the written description. It should be noted that the drawings described herein are only for explaining the embodiments of the present invention, and those skilled in the art can easily obtain other drawings based on these drawings.

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Embodiments for Carrying Out the Invention

[0011] The above and other features of the present invention will become clear from the drawings and the following description. In the specification and the drawings, specific embodiments of the present invention, that is, some embodiments that follow the principles of the present invention are disclosed. Note that the present invention is not limited to the described embodiments, and the present invention includes all modifications, variations, and equivalents within the scope of the claims.

[0012] In the embodiments of the present invention, the terms "first" and "second" are for distinguishing different elements by name, and do not mean the spatial arrangement or temporal order of these elements, etc., and these elements are not limited to these terms. The term "and / or" includes any one or a combination of the recited terms. The terms "include", "comprise", and "have" mean the presence of the described features, elements, elements, or members, but do not exclude the presence or addition of one or more other features, elements, elements, or members.

[0013] In the embodiments of the present invention, the singular forms "a", "the", etc. include the plural form, mean "a kind" or "a category", and are not limited to "one". Also, the term "the foregoing" includes both the singular and plural forms unless clearly indicated otherwise in the context. Also, unless clearly indicated otherwise in the context, the term "according to" means "at least partially according to", and the term "based on" means "at least partially based on".

[0014] Features described and / or illustrated in one embodiment may be used in the same or similar manner in one or more other embodiments, combined with the features in other embodiments, or used instead of the features in other embodiments. The terms "comprising" or "including" mean the presence of the described features, elements, elements or members, but do not exclude the presence or addition of one or more other features, elements, elements or members.

[0015] <Example 1> Embodiments of the present invention provide a method for real-time monitoring of the delay difference of sub-signals of an optical transmitter. FIG. 1 is a schematic diagram of an example of a method for real-time monitoring of the delay difference of sub-signals of an optical transmitter according to an embodiment of the present invention. As shown in FIG. 1, the method includes the following steps.

[0016] Step 101: Input the first input signal to the first electrical / optical conversion unit so that the first electrical / optical conversion unit modulates the modulated light based on the first input signal and obtains a first output signal.

[0017] Step 102: Input the second input signal to the second electrical / optical conversion unit so that the second electrical / optical conversion unit modulates the modulated light based on the second input signal and obtains a second output signal. Here, the second input signal is a differential signal of the first input signal.

[0018] Step 103: Perform a correlation operation process on the first output signal and the second output signal to obtain a correlation amount between the first input signal and the second input signal.

[0019] Step 104: Determine the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation amount and the correspondence relationship between the predetermined correlation amount and the delay difference.

[0020] Note that the above Figure 1 is only a schematic illustration of an embodiment of the present invention, and the present invention is not limited thereto. For example, some of the above steps may be executed simultaneously, sequentially according to a predetermined order, or the execution order of each step may be appropriately adjusted. Also, other steps may be added, or some of the steps may be deleted. Those skilled in the art may make appropriate modifications according to the above content and are not limited to the description content of Figure 1 above.

[0021] In step 101, the first input signal is input to the first electro-optical conversion unit so that the modulated light is modulated based on the first input signal and the first output signal is obtained.

[0022] In some embodiments, the first input signal may be any signal, and in the present invention, it is represented by the first input signal A[n]. The first input signal A[n] may be a discrete symbol sequence or a continuous signal. Here, n represents a time series number. The first electro-optical conversion unit modulates the input modulated light based on the first input signal A[n] and obtains the first output signal. The first output signal is a high-speed signal and an optical signal. The modulated light is, for example, direct current light or an optical signal output by an upper unit connected to the first electro-optical conversion unit.

[0023] In some embodiments, the first electro-optical conversion unit is a unit having a modulation function capable of generating a high-speed signal. For example, the first electro-optical conversion unit is the optical transmitter itself. In this case, the first output signal is the optical signal of the total output of the optical transmitter. The first electro-optical conversion unit may also be a part of the modulation unit of the optical transmitter. In this case, the first output signal is a part of the optical signal of the total output of the optical transmitter, that is, the first output signal is included in the optical signal of the total output of the optical transmitter. Here, the first electro-optical conversion unit includes, but is not limited to, a coherent transmitter, an intensity modulation transmitter, a phase modulator, a composite signal transmitter based on an optical frequency comb, etc.

[0024] FIGS. 2A to 2D are schematic diagrams of a first electrical / optical conversion unit according to an embodiment of the present invention. FIG. 2A shows an IQ modulator having a branching path of a plurality of sub-signals in a coherent transmitter, and both the I path and the Q path of the IQ modulator have a plurality of modulation units. The first electrical / optical conversion unit in FIG. 2A may be any one of the modulation units in the IQ modulator. For example, it may be a modulation unit corresponding to the first symbol sequence A[n] in the I path, that is, a modulation unit to which the first symbol sequence A[n] is input. In FIG. 2B, the first electrical / optical conversion unit is a modulation unit corresponding to the first symbol sequence A[n] in the segmented intensity modulator. In FIG. 2C, the first electrical / optical conversion unit is a modulation unit corresponding to the first symbol sequence A[n] in the segmented phase modulator. In FIG. 2D, the first electrical / optical conversion unit is an EO MOD unit corresponding to the first symbol sequence A[n] in a composite signal transmitter based on an optical frequency comb. The first electrical / optical conversion unit may adopt other configurations other than those shown in FIGS. 2A to 2D, and the present invention is not limited thereto.

[0025] In step 102, the second input signal is input to the second electrical / optical conversion unit so that the modulated light is modulated based on the second input signal and the second output signal is obtained. Here, the second input signal is a differential signal of the first input signal.

[0026] In some embodiments, the second input signal is a differential signal of the first input signal A[n], and in the present invention, it is represented by the second input signal B[n]. Here, n represents a time series number. The second electrical / optical conversion unit modulates the input modulated light based on the second input signal B[n] and obtains the second output signal. The second output signal is also a high-speed signal and an optical signal. The modulated light of the second electrical / optical conversion unit may be the same as or different from the modulated light corresponding to the first electrical / optical conversion unit.

[0027] In some embodiments, the differential signal of the first input signal, i.e., the second input signal, is the difference between the first input signals at two different time points.

[0028] For example, the first input signals A[n] at two different time points are represented as A[n + k1] and A[n + k2] respectively, where k1 and k2 are integers and k1 ≠ k2. In this case, the second input signal B[n] is the difference between A[n + k1] and A[n + k2], i.e., B[n]=A[n + k1] - A[n + k2].

[0029] In some embodiments, the differential signal of the first input signal, i.e., the second input signal, is a symbol sequence of the differences between the first input signals at two different time points.

[0030] For example, the first input signals A[n] at two different time points are represented as A[n + k1] and A[n + k2] respectively, where k1 and k2 are integers and k1 ≠ k2, and the symbol function is sign(). In this case, the second input signal B[n] is a symbol sequence of the difference between A[n + k1] and A[n + k2], i.e., B[n]=sign(A[n + k1] - A[n + k2]).

[0031] In some embodiments, the differential signal of the first input signal, i.e., the second input signal, is the product of a symbol sequence of the differences between the first input signals at two different time points and a random amplitude sequence having finite values.

[0032] For example, the first input signals A[n] at two different time points are represented as A[n + k1] and A[n + k2] respectively, where k1 and k2 are integers and k1 ≠ k2, and the sequence of random amplitudes having finite values is Amp1[n]. In this case, the second input signal B[n] is the product of a symbol sequence of the difference between A[n + k1] and A[n + k2] and Amp1[n], i.e., B[n]=Amp1[n]*sign(A[n + k1] - A[n + k2]). Here, Amp1[n] is, for example, a sequence of random amplitudes of a series of positive values.

[0033] In some embodiments, the differential signal of the first input signal, i.e., the second input signal, is the product of the symbol sequence of the difference between the first input signals at two different times and a random amplitude sequence having an infinite value.

[0034] For example, the first input signals A[n] at two different times are represented as A[n + k1] and A[n + k2] respectively, where k1 and k2 are integers and k1 ≠ k2, and the random amplitude sequence having an infinite value is Amp2[n]. In this case, the second input signal B[n] is the product of the symbol sequence of the difference between A[n + k1] and A[n + k2] and Amp2[n], i.e., B[n] = Amp2[n] * sign(A[n + k1] - A[n + k2]). Here, Amp2[n] is, for example, a random amplitude sequence of a series of positive values.

[0035] In some embodiments, the second input signal operates at intervals. Operating at intervals means that the signal input to the second electro - optical conversion unit is not set to the second input signal B[n] at all times, but is set to the second input signal B[n] at some times. Thus, at a predetermined time, the second input signal B[n] is input to the second electro - optical conversion unit, and at times other than the predetermined time, a 0 signal or a signal not related to the second input signal A[n] is input to the second electro - optical conversion unit.

[0036] In some embodiments, the predetermined time point may be a periodically occurring time point, that is, the second input signal may operate at fixed intervals. FIG. 3 is a schematic diagram of the operation based on the interval of the second input signal according to an embodiment of the present invention. FIG. 3 shows cells in five rows, each cell in each row represents one time point, and a cell with a white background color represents that the signal shown on the left side of the cell in the row is set at the corresponding time point. As shown in FIG. 3, the cells in the first row represent that the first input signal A[n] is input to the first electro-optical conversion unit at all time points, the cells in the second row represent that the second input signal B[n] is input to the second electro-optical conversion unit at all time points, the cells in the third row represent that the second input signal operates at a rate interval of 1 / 2 (Half-assigned B[n]), that is, two time points form one cycle, and at one time point included in each cycle, the second input signal B[n] is input to the second electro-optical conversion unit, the cells in the fourth row represent that the second input signal operates at a rate interval of 1 / 4 (1 / 4-assigned B[n]), that is, four time points form one cycle, and at one time point included in each cycle, the second input signal B[n] is input to the second electro-optical conversion unit, and the cells in the fifth row represent that the second input signal operates at a rate interval of 1 / 8 (1 / 8-assigned B[n]), that is, eight time points form one cycle, and at one time point included in each cycle, the second input signal B[n] is input to the second electro-optical conversion unit.

[0037] In actual applications, the length of the cycle in which the second input signal B[n] operates at intervals is not limited to the above example.

[0038] In some embodiments, the predetermined time point may be a randomly selected time point, that is, the second input signal may operate at random intervals.

[0039] In the above embodiment, by operating the second input signal at intervals, the time point at which the second input signal is input is reduced, and the calculated correlation amount also decreases accordingly. Therefore, the power consumption of the real-time monitoring operation of the delay difference of the sub-signals of the optical transmitter can be reduced.

[0040] In some embodiments, the second electrical / optical conversion unit is a unit having a modulation function capable of generating a high-speed signal. In the present invention, the second electrical / optical conversion unit may be a conventional electrical / optical conversion unit. FIGS. 4A to 4E are schematic diagrams of the second electrical / optical conversion unit according to an embodiment of the present invention. In FIG. 4A, the second electrical / optical conversion unit is a Mach-Zehnder modulator (MZM) having one modulation unit. In FIG. 4B, the second electrical / optical conversion unit is a Mach-Zehnder modulator (MZM) having two equal-length modulation units. In FIG. 4C, the second electrical / optical conversion unit is an electro-absorption modulator (EAM). In FIG. 4D, the second electrical / optical conversion unit is a phase modulator (PM). In FIG. 4E, the second electrical / optical conversion unit has a configuration in which an amplitude modulator (for example, a Mach-Zehnder modulator (MZM) or an electro-absorption modulator (EAM)) and a phase modulator (PM) are connected in series. The second electrical / optical conversion unit may adopt other configurations other than those shown in FIGS. 4A to 4E, and the present invention is not limited thereto.

[0041] In some embodiments, the second output signal output by the second electrical / optical conversion unit is a continuous signal.

[0042] In some embodiments, the second electro - optical conversion unit outputs a finite number of states, that is, the second output signal output by the second electro - optical conversion unit is a discrete signal having a finite number of values. For example, the set of values of the second output signal output by the second electro - optical conversion unit may be {1, - 1}, {1, 0}, or {1, 0, - 1}, etc. For example, for the second electro - optical conversion unit shown in FIG. 4A, the value of the input second input signal B[n] is ± 1, and the value of the output symbol sequence may be {1, - 1}, {1, 0}, or {1, 0, - 1}. For the second electro - optical conversion unit shown in FIG. 4B, the value of the input second input signal B[n] is ± 1, and the value of the output symbol sequence may be {1, 0, - 1}. For the second electro - optical conversion unit shown in FIG. 4C, the values of the input second symbol sequence B[n] are 1 and 0, and the value of the output symbol sequence may be {1, 0}. For the second electro - optical conversion unit shown in FIG. 4D, the value of the input second symbol sequence B[n] is ± 1, and the value of the output symbol sequence may be {1, - 1}. For the second electro - optical conversion unit shown in FIG. 4E, when the configuration is such that an MZ modulator (MZM) and a phase modulator (PM) are connected in series, the value of the second symbol sequence B[n] input to the MZM is ± 1, the value of the second symbol sequence B[n] input to the PM is ± 1, and the symbol sequence output by the second electro - optical conversion unit is {1, 0, - 1}; when the configuration is such that an electro - absorption modulator (EAM) and a phase modulator (PM) are connected in series, the values of the second symbol sequence B[n] input to the EAM are 1 and 0, the value of the second symbol sequence B[n] input to the PM is ± 1, and the value of the symbol sequence output by the second electro - optical conversion unit may be {1, 0}.

[0043] When the second electro - optical conversion unit outputs only a finite number of states, since the second electro - optical conversion unit only requires logical operations, its complexity, cost, and power consumption can be reduced.

[0044] In step 103, a correlation operation process is executed on the first output signal and the second output signal to obtain the correlation amount between the first input signal and the second input signal.

[0045] In some embodiments, the step of executing a correlation operation process on the first output signal and the second output signal includes: executing a multiplication operation on the first output signal and the second output signal to obtain a product signal of the first output signal and the second output signal; and executing an electrical averaging operation on the product signal to obtain the correlation amount between the first input signal and the second input signal.

[0046] In some embodiments, the product signal of the first output signal and the second output signal is determined by an optoelectronic method.

[0047] When the optoelectronic method is adopted, a first electrical / optical conversion unit and a second electrical / optical conversion unit are connected in parallel. In this case, the first electrical / optical conversion unit outputs an optical signal of the first output signal, and the second electrical / optical conversion unit outputs an optical signal of the second output signal. Next, the optical signal of the first output signal and the optical signal of the second output signal are combined into one optical signal, and an electrical / optical conversion and multiplication operation are executed on the combined optical signal to obtain a product signal of the first output signal and the second output signal, and the product signal is an electrical signal.

[0048] In some embodiments, the optoelectronic method is realized by an optoelectronic multiplier, for example, by using an optoelectronic detector, a balanced detector, a coherent detector, etc. to perform electrical / optical conversion and multiplication operations. FIGS. 5A - 5B are schematic diagrams of an optoelectronic multiplier according to an embodiment of the present invention. In FIG. 5A, the optoelectronic multiplier includes a phase shifter (φ), one 90 - degree frequency mixer (90° hybrid), and two balanced detectors (BPD). Here, the phase shifter (φ) is an optional component, that is, FIG. 5A may or may not include a phase shifter. In FIG. 5A, the optoelectronic multiplier has two input signals, namely, signal 1 and signal 2. In the present invention, one of signal 1 and signal 2 is the optical signal of the first output signal output by the first electrical / optical conversion unit, and the other is the optical signal of the second output signal output by the second electrical / optical conversion unit. The output signal of the optoelectronic multiplier includes the product signal of the first output signal and the second output signal.

[0049] In FIG. 5B, the optoelectronic multiplier includes two single detectors (PD) and one multiplier. The input of one of the two PDs is the optical signal of the first output signal output by the first electrical / optical conversion unit, and the output is the electrical signal of the first output signal. The input of the other of the two PDs is the optical signal of the second output signal output by the second electrical / optical conversion unit, and the output is the electrical signal of the second output signal. The multiplier calculates and outputs the product signal of the electrical signal of the first output signal and the electrical signal of the second output signal.

[0050] The optoelectronic multiplier may adopt other configurations other than those shown in FIGS. 5A - 5B, and the present invention is not limited thereto.

[0051] In some embodiments, the product signal of the first output signal and the second output signal is determined by an optical method.

[0052] When adopting an optical method, a first electrical / optical conversion unit and a second electrical / optical conversion unit are connected in series to form an optical multiplier. In order for the optical multiplier to realize the multiplication in the optical domain between the first output signal and the second output signal, the optical multiplier directly outputs an optical signal of the product of the first output signal and the second output signal. Then, electrical / optical conversion is performed on the optical signal of the product to obtain an electrical signal of the product of the first output signal and the second output signal, that is, the above-mentioned product signal.

[0053] In some embodiments, the optical / electrical conversion is realized by an optical / electrical conversion unit. The configuration of the optical / electrical conversion unit is, for example, the same as the configuration of the optoelectronic multiplier shown in FIGS. 5A to 5B. However, as a difference, when using an optical method, the optoelectronic multiplier in FIG. 5A is used as the optical / electrical conversion unit. In this case, one of its two input signals, that is, one of signal 1 and signal 2, is a signal output by connecting the first electrical / optical conversion unit and the second electrical / optical conversion unit in series, that is, an optical signal of the product of the first output signal and the second output signal, and the other is direct current light.

[0054] The optical / electrical conversion unit may adopt other configurations other than the configuration shown in FIG. 5, and the present invention is not limited thereto.

[0055] In some embodiments, an electrical averaging operation is performed on the product signal of the first output signal and the second output signal to obtain a correlation quantity between the first output signal and the second output signal.

[0056] Here, the electrical averaging operation may be realized in the analog domain. For example, the electrical averaging operation on the product signal may be realized by an analog circuit. The electrical averaging operation may also be realized in the digital domain. For example, after performing analog / digital conversion on the product signal, the electrical averaging operation on the digital signal corresponding to the product signal may be realized by a digital circuit.

[0057] In some embodiments, the electrical averaging operation is realized by an electrical averaging unit. For example, the averaging of signals is realized by a low-pass filter or a low-speed DSP. FIGS. 6A to 6B are schematic diagrams of the electrical averaging unit according to embodiments of the present invention. In FIG. 6A, the electrical averaging unit includes two low-pass filters and one low-speed digital signal processor. In FIG. 6B, the electrical averaging unit includes one low-pass filter and one low-speed digital signal processor.

[0058] The electrical averaging unit may adopt other configurations other than those shown in FIGS. 6A to 6B, and the present invention is not limited thereto.

[0059] The above photoelectric multiplier and electrical averaging unit of the present invention constitute a correlation operation unit, or the above photoelectric multiplier, optical / electrical conversion unit and electrical averaging unit constitute a correlation operation unit. The following will exemplarily describe the configuration for determining the correlation amount between the first output signal and the second output signal with reference to embodiments, but the methods for realizing the related operations of the present invention are not limited thereto.

[0060] FIGS. 7 to 10 are schematic diagrams of the hardware configuration for determining the correlation amount according to embodiments of the present invention. Here, the hardware configurations shown in FIGS. 7, 9 and 10 include a first electrical / optical conversion unit, a second electrical / optical conversion unit, a photoelectric multiplier and an electrical averaging unit, and the hardware configuration shown in FIG. 8 includes a first electrical / optical conversion unit, a second electrical / optical conversion unit, an optical / electrical conversion unit and an electrical averaging unit. Also, the first electrical / optical conversion unit may be any one of the first electrical / optical conversion units shown in FIGS. 2A to 2D or other configurations, the second electrical / optical conversion unit may be any one of the second electrical / optical conversion units shown in FIGS. 4A to 4E or other configurations, the photoelectric multiplier or the optical / electrical conversion unit may be any one of the photoelectric multipliers shown in FIGS. 5A to 5B or other configurations, and the electrical averaging unit may be any one of the electrical averaging units shown in FIGS. 6A to 6B or other configurations.

[0061] For example, in the hardware configuration shown in FIG. 7, the first electrical / optical conversion unit shown in FIG. 2A, the second electrical / optical conversion unit shown in FIG. 4A, the optoelectronic multiplier shown in FIG. 5A, and the electrical averaging unit shown in FIG. 6A are adopted. In FIG. 7, the first electrical / optical conversion unit and the second electrical / optical conversion unit are connected in parallel, and the modulated light of the first electrical / optical conversion unit and the modulated light of the second electrical / optical conversion unit are DC lights output by the same laser. Before the modulator, a part of the DC light (for example, 95%) is supplied to the first electrical / optical conversion unit, and the other part (for example, 5%) is supplied to the second electrical / optical conversion unit. Here, since the coherent transmitter has a plurality of output ports, the first output signal output is included in the output signal I + jQ of the I + jQ detection port, or included in the output signal I - jQ of the I - jQ detection port, or included in the output signals of other detection branches. The acquisition of the first output signal may be realized by a beam splitter. For example, a part (for example, 5%) of the output signal corresponding to the branch is separated by a beam splitter and applied to the present invention as the first output signal. For details, reference may be made to the prior art. FIG. 7 shows an example in which the first output signal is included in the output signal I - jQ of the I - jQ detection port, but the present invention is not limited thereto.

[0062] The input of the optoelectronic multiplier is the first output signal output by the first electrical / optical conversion unit and the second output signal output by the second electrical / optical conversion unit, and the output of the optoelectronic multiplier is two electrical signals in the in-phase path and the quadrature path. The low-pass filtering of the electrical signal and the low-speed DSP constitute the electrical averaging unit, and the electrical averaging operation may be realized in the analog domain or the digital domain.

[0063] Also, for example, in the hardware configuration shown in FIG. 8, the first electro-optical conversion unit shown in FIG. 2A, the second electro-optical conversion unit shown in FIG. 4A, the optical / electrical conversion unit shown in FIG. 5A, and the electrical averaging unit shown in FIG. 6A are adopted. In FIG. 8, the first electro-optical conversion unit and the second electro-optical conversion unit are connected in series to form an optical multiplier, realizing multiplication in the optical domain between the first output signal and the second output signal. Before the modulator, a part (e.g., 95%) of the DC light output by the laser is supplied to the first electro-optical conversion unit, and the first electro-optical conversion unit forms the first output signal. The first output signal is included in the output signal of the output port of the coherent transmitter (e.g., I + jQ detection port or I - jQ detection port or other detection ports). The input port of the second electro-optical conversion unit is connected to the corresponding output port of the coherent transmitter, modulates the input signal including the first output signal, and outputs the product in the optical domain between the first output signal and the second output signal.

[0064] The two inputs of the optical / electrical conversion unit are, respectively, the product in the optical domain between the first output signal and the second output signal, and a separated part (e.g., 5%) of the DC light.

[0065] Also, for example, in the hardware configuration shown in FIG. 9, the first electro-optical conversion unit shown in FIG. 2A, the second electro-optical conversion unit shown in FIG. 4A, the optical / electrical conversion unit shown in FIG. 5B, and the electrical averaging unit shown in FIG. 6B are adopted. In FIG. 9, the first electro-optical conversion unit and the second electro-optical conversion unit are connected in parallel, and the modulated light of the first electro-optical conversion unit and the modulated light of the second electro-optical conversion unit are DC lights output by the same or different lasers. The first output signal of the first electro-optical conversion unit and the second output signal of the second electro-optical conversion unit are respectively detected by one PD, then electrically multiplied by a multiplier, and electrically averaged by the electrical averaging unit to obtain the correlation amount between the first output signal and the second output signal.

[0066] In some embodiments, in the process of performing the correlation operation, it further includes a square-wave multiplication frequency shift operation. Specifically, multiply the second input signal by a low-frequency square wave, and input the product of the second input signal and the low-frequency square wave into the second electrical / optical conversion unit. Accordingly, in the correlation operation process, multiply the product signal of the first output signal of the first electrical / optical conversion unit and the second output signal of the second electrical / optical conversion unit by the low-frequency square wave, and then perform an electrical averaging operation on the product of the product signal and the low-frequency square wave to obtain the correlation amount between the first output signal and the second output signal.

[0067] In FIG. 10, based on the hardware configuration shown in FIG. 7, a multiplier is provided before the input of the second electrical / optical conversion unit to realize the multiplication of the second input signal and the low-frequency square wave, and a multiplier is provided between the low-pass filter and the low-speed digital signal processor (Low-speed DSP) of the electrical averaging unit to realize the multiplication of the product signal of the first output signal and the second output signal and the low-frequency square wave. Also, based on the hardware configurations shown in FIGS. 8 and 9 and other hardware configurations capable of realizing correlation operations, a square-wave multiplication frequency shift operation may be added, and the present invention is not limited thereto.

[0068] According to the above embodiments, the present invention adds a step of square-wave multiplication frequency shift to the real-time monitoring method for the delay difference of the sub-signals of the optical transmitter, that is, uses the product of the low-frequency square wave and the second input signal as the input of the second electrical / optical conversion unit, and performs an electrical averaging operation on the product of the product signal of the first output signal and the second output signal and the low-frequency square wave in the electrical averaging operation to obtain the correlation amount between the first output signal and the second output signal. By adding the operation of square-wave multiplication frequency shift, the calculated correlation amount can be shifted from DC to the frequency of the low-frequency square wave, so that the 1 / f noise near DC can be avoided.

[0069] In step 104, based on the correlation amount between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit and the correspondence between a predetermined correlation amount and a delay difference, the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit is determined.

[0070] In some embodiments, a first input signal is input to a first electrical / optical conversion unit, the first electrical / optical conversion unit outputs a first output signal, a second input signal is input to a second electrical / optical conversion unit, and the second electrical / optical conversion unit outputs a second output signal. The correlation amount between the first output signal and the second output signal indicates the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit. The correspondence between the correlation amount and the delay difference is that the sum of the delay difference and a constant is proportional to the correlation amount. Here, the constant is related to the second input signal. As described above, the second input signal is a difference signal of the first input signal at two different time points, and the constant is related to the selection of "two different time points".

[0071] For example, the first input signal is A[n], the second input signal is a difference signal between the first input signal A[n + k1] and A[n + k2] at two different time points, k1 and k2 are integers, and k1 ≠ k2. In this case, the correspondence between the correlation amount and the delay difference is expressed as follows: S = k*(τ + (k1 + k2)T / 2) Here, S is the correlation amount between the first output signal and the second output signal, τ is the delay difference between the first electrical / optical conversion unit and the second electrical / optical conversion unit, T is the unit time length corresponding to the time series number n, k1 and k2 are integers, and k1 ≠ k2, and k is a known quantity related to k1 and k2.

[0072] As can be seen from the above, the above constant is (k1 + k2)T / 2. When the selected "two different time points" are different, k1 and k2 are different, and (k1 + k2) may be different. Therefore, the above constant, that is, (k1 + k2)T / 2, may also be different.

[0073] Figures 11A to 11C are schematic diagrams of the correspondence relationship between the correlation quantity and the delay difference according to an embodiment of the present invention. Figure 11A shows the case where the values of k1 and k2 are (-1,0), (-1,1), (-3,0), and (-3,1) respectively. In actual applications, k1 and k2 may be other different combinations, and the present invention is not limited thereto.

[0074] In the present invention, the "correspondence relationship between the correlation quantity and the delay difference" corresponding to different combinations of k1 and k2 may be pre-stored in a memory. In the process of real-time monitoring of the delay difference, when the values of k1 and k2 are given, based on the values of k1 and k2, a predetermined correspondence relationship between the correlation quantity and the delay difference is obtained by searching, and based on the correlation quantity between the first output signal of the first electrical / optical conversion unit and the second output signal of the second electrical / optical conversion unit and the obtained correspondence relationship, the value of (τ + (k1 + k2)T / 2) may be determined, and the delay difference τ may be obtained.

[0075] In Figure 11A, an example is the difference between the first input signals at two different time points of the second input signal. The above-mentioned correspondence relationship between the correlation quantity and the delay difference may be similarly applied when it is the symbol sequence of the difference between the first input signals at two different time points of the second input signal, or the product of the symbol sequence of the difference between the first input signals at two different time points and a random amplitude function having a finite value, or the product of the symbol sequence of the difference between the first input signals at two different time points and a random amplitude function having an infinite value.

[0076] For example, FIG. 11B shows the correspondence between the correlation amount and the delay difference when the second input signal adopts a differential signal of a different form from the first input signal, where the values of k1 and k2 are (-1, 0), respectively. In FIG. 11B, curve S0 shows the correspondence between the correlation amount between the first output signal and the second output signal and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal B[n] = A[n + k1] - A[n + k2]. Curve S1 shows the correspondence between the correlation amount between the first output signal and the second output signal and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal B[n] = sign(A[n + k1] - A[n + k2]). Curve S2 shows the correspondence between the correlation amount between the first output signal and the second output signal and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal B[n] = Amp1[n] * sign(A[n + k1] - A[n + k2]) and Amp1[n] is a random amplitude sequence with finite values. Curve S3 shows the correspondence between the correlation amount between the first output signal and the second output signal and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal B[n] = Amp2[n] * sign(A[n + k1] - A[n + k2]) and Amp2[n] is a random amplitude sequence with infinite values.

[0077] Also, the above correspondence between the correlation amount and the delay difference may be similarly applied to the second input signal operating at intervals.

[0078] For example, FIG. 11C shows the correspondence between the correlation amount and the delay difference when operating in different ways for the same second input signal B[n]. In FIG. 11C, the curve Full shows the correlation amount between the first output signal and the second output signal, and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal operates with values set at all time points (corresponding to the cell in the second row of FIG. 3). The curve Half-assigned B[n] shows the correlation amount between the first output signal and the second output signal, and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal operates at a 1 / 2 rate interval (corresponding to the cell in the third row of FIG. 3). The curve 1 / 4-assigned B[n] shows the correlation amount between the first output signal and the second output signal, and the delay difference between the output signal of the first electro-optical conversion unit and the output signal of the second electro-optical conversion unit when the second input signal operates at a 1 / 4 rate interval (corresponding to the cell in the fourth row of FIG. 3).

[0079] In FIGS. 11A to 11C, the unit of the correlation amount is millivolt (mV) and the unit of the delay difference is picosecond (ps). However, in actual applications, the units of the correlation amount and the delay difference may be different from these. Accordingly, the slope of the corresponding curve may be different, but the present invention is not limited thereto.

[0080] In some embodiments, when the responses of the first electro-optical conversion unit and the second electro-optical conversion unit are the same and the correlation amount between the first output signal of the first electro-optical conversion unit and the second output signal of the second electro-optical conversion unit is 0, the delays of the output signals of the first electro-optical conversion unit and the second electro-optical conversion unit are aligned.

[0081] In the process of real-time monitoring, since the second input signal of the second electrical / optical conversion unit is the differential signal of the first output signal of the first electrical / optical conversion unit, even if the delays of the output signal of the first electrical / optical conversion unit and the output signal of the second conversion unit are matched, the delay difference obtained by the above steps is not necessarily zero. For example, in FIG. 11A, when the values of k1 and k2 are (-1, 1) respectively, the responses of the first electrical / optical conversion unit and the second electrical / optical conversion unit are the same, and the correlation amount between the first output signal of the first electrical / optical conversion unit and the second output signal of the second electrical / optical conversion unit is 0, the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit is matched. In this case, the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit obtained by the above steps is 0. On the other hand, when the values of k1 and k2 are (-1, 0) respectively, the responses of the first electrical / optical conversion unit and the second electrical / optical conversion unit are the same, and the correlation amount between the first output signal of the first electrical / optical conversion unit and the second output signal of the second electrical / optical conversion unit is 0, the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit is matched. In this case, the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit obtained by the above steps is T / 2 picoseconds.

[0082] In some embodiments, the real-time monitoring method for the delay difference of the sub-signals of the optical transmitter further includes the following steps.

[0083] Based on the correlation amounts between the first output signals of a plurality of different first electrical / optical conversion units and the second output signal of the same second electrical / optical conversion unit, and the corresponding relationship between the correlation amounts and the delay differences, determine the delay differences between the output signals of the plurality of first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit respectively. Correct the delays between the plurality of first electrical / optical conversion units based on each of the delay differences.

[0084] In some embodiments, the step of correcting the delays between the plurality of first electrical / optical conversion units based on each of the delay differences includes the following steps.

[0085] Determine a reference delay difference between the output signals of the second electro-optical conversion units that are the same as each of the first electro-optical conversion units. Here, the reference delay difference is the value of the delay difference when the correlation amount is 0 in the correspondence relationship between the corresponding correlation amount and the delay difference.

[0086] Determine the difference between each of the delay differences and the corresponding reference delay difference.

[0087] Based on the difference, correct the delay between the corresponding first electro-optical conversion unit and the second electro-optical conversion unit.

[0088] When the correlation amount is 0, since the delays of the output signals of the corresponding first electro-optical conversion unit and the output signals of the second electro-optical conversion unit are aligned, when correcting the delay of the output signal of the corresponding first electro-optical conversion unit based on the difference, the delays of the output signals of each first electro-optical conversion unit and the output signals of the second electro-optical conversion unit are aligned, and the delay difference of the output signals of each first electro-optical conversion unit becomes 0.

[0089] For example, assume that N different first electrical / optical conversion units are Tx11, Tx12, …, Tx1N, and the second electrical / optical conversion unit is Tx2. According to steps 101 to 104 of the present invention, the delays of the output signals of the N first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit Tx2 are τ11, τ12, …, τ1N respectively, and when it is determined that the reference delay differences of the output signals of the N first electrical / optical conversion units and the second electrical / optical conversion unit Tx2 are τ01, τ02, …, τ0N respectively, the differences between the delay differences corresponding to the N first electrical / optical conversion units and the reference delay differences are (τ11 - τ01), (τ12 - τ02), …, (τ1N - τ0N) respectively. In this case, the delay of the output signal where the first electrical / optical conversion unit is Tx11 is adjusted by [-(τ11 - τ01)], the delay of the output signal where the first electrical / optical conversion unit is Tx12 is adjusted by [-(τ12 - τ02)], …, and the delay of the output signal where the first electrical / optical conversion unit is Tx1N is adjusted by [-(τ1N - τ0N)]. By the above adjustment, the delays of the output signals of these N first electrical / optical conversion units become the same, and the delay difference becomes 0. Thereby, the delay correction for the quality inspection of different first electrical / optical conversion units is realized.

[0090] The above has merely described a part of the real-time monitoring method for the delay difference of the sub-signals of the optical transmitter and the hardware configuration for realizing the method, but the present invention is not limited thereto. The real-time monitoring method for the delay difference of the sub-signals of the optical transmitter may further include other steps or processes, and for the specific contents of these steps or processes, reference may be made to the prior art. Also, the above has merely illustratively described the embodiments of the present invention by taking some structures of article recognition as examples, and the present invention is not limited to these structures, and appropriate modifications may be made to these structures, and these modifications should be included within the scope of the embodiments of the present invention.

[0091] The above embodiments merely illustratively explain the embodiments of the present invention, and the present invention is not limited thereto, and appropriate modifications may be made based on the above various embodiments. For example, each of the above embodiments may be used alone, or one or more of the above embodiments may be combined and used.

[0092] According to an embodiment of the present invention, the present invention can realize real-time monitoring of a delay difference by determining the delay difference using a signal output by an electrical / optical conversion unit of an optical transmitter, and there is no need for the optical transmitter to transmit a special signal. Further, the present invention can realize monitoring of the delay difference of sub-signals of an optical transmitter using a low-bandwidth electrical device, avoid the use of high-speed devices, and can be flexibly realized in either an integrated or non-integrated manner. Furthermore, the present invention can be applied to various scenarios and is applicable to monitoring the delay difference of sub-signals in various types of optical transmitters.

[0093] <Example 2> An embodiment of the present invention provides a real-time monitoring device for the delay difference of sub-signals of an optical transmitter. The description of the same content as in Example 1 is omitted.

[0094] FIG. 12 is a schematic diagram of a real-time monitoring device for the delay difference of sub-signals of an optical transmitter according to an embodiment of the present invention. As shown in FIG. 12, the real-time monitoring device 1200 for the delay difference of sub-signals of the optical transmitter includes the following components.

[0095] The first signal input unit 1201 inputs the first input signal to the first electrical / optical conversion unit so as to modulate the modulated light based on the first input signal by the first electrical / optical conversion unit and obtain a first output signal.

[0096] The second signal input unit 1202 inputs the second input signal to the second electrical / optical conversion unit so as to modulate the modulated light based on the second input signal by the second electrical / optical conversion unit and obtain a second output signal. Here, the second input signal is a differential signal of the first input signal.

[0097] The correlation operation unit 1203 performs a correlation operation process on the first output signal and the second output signal, and obtains a correlation amount between the first input signal and the second input signal.

[0098] The delay difference determination unit 1204 determines the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation quantity and the correspondence between the predetermined correlation quantity and the delay difference.

[0099] In some embodiments, the first electrical / optical conversion unit is part of a transmitter or a modulation unit of a transmitter.

[0100] In some embodiments, the second electrical / optical conversion unit outputs a finite number of states.

[0101] In some embodiments, the differential signal of the first input signal includes the difference between the first input signals at two different time points, or the symbol sequence of the difference between the first input signals at two different time points, or the product of the symbol sequence of the difference between the first input signals at two different time points and a random amplitude sequence having a finite value, or the product of the symbol sequence of the difference between the first input signals at two different time points and a random amplitude sequence having an infinite value.

[0102] In some embodiments, the correlation operation unit 1203 determines the product signal of the first output signal and the second output signal by an optoelectronic method or an optical method, performs an electrical averaging operation on the product signal, and obtains the correlation quantity between the first input signal and the second input signal.

[0103] In some embodiments, the first input signal is A[n], the second input signal is the differential signal between the first input signals A[n + k1] and A[n + k2] at two different time points, k1 and k2 are integers, and k1 ≠ k2. The correspondence between the correlation quantity and the delay difference includes S = k*(τ + (k1 + k2)T / 2), where S is the correlation quantity, τ is the delay difference between the first electrical / optical conversion unit and the second electrical / optical conversion unit, T is the unit time length corresponding to the time series number n, k1 and k2 are integers, and k1 ≠ k2, and k is a known quantity related to k1 and k2.

[0104] In some embodiments, at a predetermined time, the second signal input unit 1202 inputs the second input signal to the second electrical / optical conversion unit, and at a time other than the predetermined time, inputs a signal that has no relation to the first input signal or a zero signal to the second electrical / optical conversion unit.

[0105] In some embodiments, the delay difference determination unit 1204 determines, based on the correlation amount between the output signals of the plurality of first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit, and the correspondence relationship between the corresponding correlation amount and the delay difference, the delay difference between the output signal of each of the first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit, respectively.

[0106] The real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter further includes a delay correction unit 1205 that corrects the delay between the plurality of first electrical / optical conversion units based on each of the delay differences.

[0107] In some embodiments, the modulated light corresponding to the first electrical / optical conversion unit and the modulated light corresponding to the second electrical / optical conversion unit are from the same or different laser light sources.

[0108] Note that the above merely describes each component or module related to the present invention, and the present invention is not limited thereto. The real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter may include other components or modules, and for the specific content of these components or modules, reference may be made to related technologies.

[0109] For simplicity, FIG. 12 merely exemplarily shows the connection relationship or signal direction between each component or module, and it is obvious to those skilled in the art that various related technologies such as bus connection can be used. The above various components or modules may be implemented by hardware devices such as a processor and a memory, and the embodiments of the present invention are not limited thereto.

[0110] Each of the above embodiments is merely an exemplary description of the embodiments of the present invention, and the present invention is not limited thereto, and appropriate modifications may be made based on the various embodiments described above. For example, each of the above embodiments may be used alone, or one or more of the above embodiments may be used in combination.

[0111] According to the embodiments of the present invention, the present invention can realize real-time monitoring of the delay difference by determining the delay difference using the signal output by the electrical / optical conversion unit of the optical transmitter, and there is no need for the optical transmitter to transmit a special signal. Further, the present invention can realize monitoring of the delay difference of the sub-signals of the optical transmitter using a low-bandwidth electrical device, avoid the use of high-speed devices, and can be flexibly realized in either an integrated or non-integrated manner. Furthermore, the present invention can be applied to various scenarios and can be applied to monitoring the delay difference of sub-signals in various types of optical transmitters.

[0112] <Example 3> The embodiments of the present invention provide an electronic device including the real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter described in Example 2, and the content thereof is incorporated herein by reference. The electronic device may be, for example, a computer, a server, a workstation, a laptop computer, a smartphone, etc., but the embodiments of the present invention are not limited thereto.

[0113] FIG. 13 is a schematic diagram of an electronic device according to an embodiment of the present invention. As shown in FIG. 13, the electronic device 1300 includes a processor (e.g., a central processing unit (CPU)) 1310 and a memory 1320. The memory 1320 is connected to the processor 1310. The memory 1320 may store various data and may further store a program 1321 for information processing. The program 1321 is executed under the control of the processor 1310.

[0114] In some aspects, the function of the real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter may be integrated into the processor 1310. Here, the processor 1310 may be configured to implement the real-time monitoring method for the delay difference of the sub-signals of the optical transmitter described in Example 1.

[0115] In some aspects, the real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter may be separately configured with the processor 1310. For example, the real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter is a chip connected to the processor 1310 and may be configured to implement the function of the real-time monitoring device 1200 for the delay difference of the sub-signals of the optical transmitter under the control of the processor 1310.

[0116] For example, the processor 1310 is configured to input the first input signal to the first electrical / optical conversion unit to modulate the modulated light based on the first input signal and obtain a first output signal, and input the second input signal to the second electrical / optical conversion unit to modulate the modulated light based on the second input signal and obtain a second output signal, where the second input signal is a differential signal of the first input signal, and perform a correlation operation process on the first output signal and the second output signal to obtain a correlation quantity between the first input signal and the second input signal, and based on the correlation quantity and the correspondence between the predetermined correlation quantity and the delay difference, determine the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit.

[0117] Also, as shown in FIG. 13, the electronic device 1300 may further include an input / output (I / O) device 1330, a display 1340, etc. Here, the functions of these components are the same as those in the prior art, and the description thereof is omitted here. Note that the electronic device 1300 does not necessarily include all the components shown in FIG. 13. Also, the electronic device 1300 may include components not shown in FIG. 13 and may refer to the prior art.

[0118] An embodiment of the present invention provides a computer-readable program that causes a computer to execute, when executing a program in an electronic device, a real-time monitoring method for the delay difference of sub-signals of the optical transmitter described in Example 1 in the electronic device.

[0119] An embodiment of the present invention further provides a storage medium in which a computer-readable program for causing a computer to execute the real-time monitoring method for the delay difference of sub-signals of the optical transmitter described in Example 1 in an electronic device is stored.

[0120] The above device and method of the present invention may be implemented by hardware, or may be implemented by combining hardware and software. The present invention relates to a computer-readable program, which, when executed by a logic unit, can cause the logic unit to implement the above-described device or component, or cause the logic unit to implement the various methods or steps described above. The present invention relates to a storage medium for storing the above program, such as a hard disk, magnetic disk, optical disk, DVD, flash memory, etc.

[0121] The method / device described with reference to the embodiments of the present invention may be implemented by hardware, a software module executed by a processor, or a combination of both. For example, one or more of the functional block diagrams shown in the drawings, or a combination of one or more of the functional block diagrams, may correspond to each software module of the flow of the computer program, or may correspond to each hardware module. These software modules may respectively correspond to each step shown in the drawings. These hardware modules may be realized by hardware-implementing these software modules using, for example, a field programmable gate array (FPGA).

[0122] The software module may be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium known to those skilled in the art. The storage medium may be connected to the processor so that the processor can read information from the storage medium or write information to the storage medium, or the storage medium may be a component of the processor. The processor and the storage medium are located in an ASIC. The software module may be stored in the memory of the mobile terminal or may be stored in a memory card inserted into the mobile terminal. For example, when a device (such as a mobile terminal) uses a relatively large-capacity MEGA-SIM card or a large-capacity flash memory device, the software module may be stored in the MEGA-SIM card or the large-capacity flash memory device.

[0123] One or more functional blocks described in the drawings and / or one or more combinations of functional blocks may be implemented by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described in the present invention. One or more functional blocks described in the drawings and / or one or more combinations of functional blocks may be implemented, for example, in a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors in combination with DSP communication, or any other configuration.

[0124] The present invention has been described above with reference to specific embodiments, but the above description is merely exemplary and does not limit the scope of protection of the present invention. Without departing from the spirit and principle of the present invention, various modifications and changes may be made to the present invention, and these modifications and changes also belong to the scope of the present invention.

[0125] Furthermore, the following supplementary notes are disclosed regarding the embodiments including the above-described embodiments. (Supplementary Note 1) A method for real-time monitoring of the delay difference of sub-signals of an optical transmitter, comprising: inputting the first input signal into the first electrical / optical conversion unit so as to modulate the light to be modulated based on the first input signal and obtain a first output signal; inputting the second input signal into the second electrical / optical conversion unit so as to modulate the light to be modulated based on the second input signal and obtain a second output signal, wherein the second input signal is a differential signal of the first input signal; performing a correlation operation process on the first output signal and the second output signal to obtain a correlation quantity between the first input signal and the second input signal; determining a delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation quantity and the correspondence relationship between the predetermined correlation quantity and the delay difference. (Supplementary Note 2) The method according to Supplementary Note 1, wherein the first electrical / optical conversion unit is part of a transmitter or a modulation unit of a transmitter. (Supplementary Note 3) The method according to Supplementary Note 1, wherein the second electrical / optical conversion unit outputs a finite number of states. (Supplementary Note 4) The differential signal of the first input signal is the difference between the first input signals at two different times, or the symbol sequence of the difference between the first input signals at two different times, or the product of the symbol sequence of the difference between the first input signals at two different times and a random amplitude sequence having a finite value, or the product of the symbol sequence of the difference between the first input signals at two different times and a random amplitude sequence having an infinite value. (Supplementary Note 5) The step of performing a correlation operation process on the first output signal and the second output signal and obtaining a correlation amount between the first input signal and the second input signal is as follows: determining a product signal of the first output signal and the second output signal by a photoelectric method or an optical method; performing an electrical averaging operation on the product signal and obtaining a correlation amount between the first input signal and the second input signal, which is the method described in Appendix 1. (Appendix 6) The first input signal is A[n], and the second input signal is a difference signal between the first input signals A[n + k1] and A[n + k2] at two different time points, where k1 and k2 are integers and k1 ≠ k2. The correspondence between the correlation amount and the delay difference includes S = k * (τ + (k1 + k2)T / 2). Here, S is the correlation amount, τ is the delay difference between the first electrical / optical conversion unit and the second electrical / optical conversion unit, T is the unit time length corresponding to the time series number n, k1 and k2 are integers and k1 ≠ k2, and k is a known quantity related to k1 and k2, which is the method described in Appendix 1. (Appendix 7) At a predetermined time point, input the second input signal into the second electrical / optical conversion unit, and at time points other than the predetermined time point, input a signal that has no relation with the first input signal or a 0 signal into the second electrical / optical conversion unit, which is the method described in Appendix 1. (Appendix 8) Based on the correlation amounts between the output signals of a plurality of first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit and the corresponding correspondence between the correlation amounts and the delay differences, respectively determining the delay differences between the output signals of each of the first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit; further including the step of correcting the delay between the plurality of first electrical / optical conversion units based on each of the delay differences, which is the method described in Appendix 1. (Appendix 9) The method according to Supplementary Note 1, wherein the modulated light corresponding to the first electro-optical conversion unit and the modulated light corresponding to the second electro-optical conversion unit are from the same or different laser light sources. (Supplementary Note 10) An electronic device including a memory storing a computer program and a processor, wherein the processor is configured to execute the computer program to implement a method for real-time monitoring of the delay difference of sub-signals of an optical transmitter according to any one of Supplementary Notes 1 to 9. (Supplementary Note 11) A storage medium storing a computer-readable program, wherein the computer-readable program causes a computer to execute a method for real-time monitoring of the delay difference of sub-signals of an optical transmitter according to any one of Supplementary Notes 1 to 9 in an electronic device.

Claims

1. A real-time monitoring device for the delay difference of sub-signals of an optical transmitter, comprising: A first signal input unit that inputs the first input signal to the first electrical / optical conversion unit so as to modulate the modulated light based on the first input signal and obtain a first output signal; A second signal input unit that inputs the second input signal to the second electrical / optical conversion unit so as to modulate the modulated light based on the second input signal and obtain a second output signal, wherein the second input signal is a differential signal of the first input signal; A correlation operation unit that performs a correlation operation process on the first output signal and the second output signal and obtains a correlation amount between the first input signal and the second input signal; A delay difference determination unit that determines a delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation amount and the correspondence relationship between the predetermined correlation amount and the delay difference.

2. The device according to claim 1, wherein the first electrical / optical conversion unit is a part of a transmitter or a modulation unit of a transmitter.

3. The device according to claim 1, wherein the second electrical / optical conversion unit outputs a finite number of states.

4. The differential signal of the first input signal is the difference between the first input signals at two different time points, or the symbol sequence of the difference between the first input signals at two different time points, or the product of the symbol sequence of the difference between the first input signals at two different time points and a random amplitude sequence having a finite value, or the product of the symbol sequence of the difference between the first input signals at two different time points and a random amplitude sequence having an infinite value. The device according to claim 1.

5. The correlation operation unit determines a product signal between the first output signal and the second output signal by an optoelectronic method or an optical method, performs an electrical averaging operation on the product signal, and obtains a correlation amount between the first input signal and the second input signal. The device according to claim 1.

6. The first input signal is A[n], and the second input signal is the difference signal between the first input signal A[n + k １ and A[n + k ２ at two different time points, where k １ and k ２ are integers, and k １ ≠ k ２ . The correspondence relationship between the correlation quantity and the delay difference is S = k * (τ + (k １ + k ２ ) T / 2), and includes Here, S is the correlation quantity, τ is the delay difference between the first electro-optical conversion unit and the second electro-optical conversion unit, T is the unit time length corresponding to the time series number n, k １ and k ２ are integers, and k １ ≠ k ２ , k is a known quantity related to k １ and k ２ The apparatus according to claim 1, wherein

7. The second signal input unit inputs the second input signal to the second electrical / optical conversion unit at a predetermined time point, and inputs a signal that has no relation with the first input signal or a 0 signal to the second electrical / optical conversion unit at time points other than the predetermined time point. The device according to claim 1.

8. The delay difference determination unit determines the delay difference between the output signal of each of the plurality of first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit based on the correlation amount between the output signals of the plurality of first electrical / optical conversion units and the output signal of the second electrical / optical conversion unit and the correspondence relationship between the corresponding correlation amount and the delay difference. The apparatus according to claim 1 further includes a delay correction unit that corrects the delay between the plurality of first electrical / optical conversion units based on each of the delay differences.

9. The modulated light corresponding to the first electrical / optical conversion unit and the modulated light corresponding to the second electrical / optical conversion unit are from the same or different laser light sources. The apparatus according to claim 1.

10. A method for real-time monitoring of the delay difference of sub-signals of an optical transmitter, Inputting the first input signal to the first electrical / optical conversion unit so that the first electrical / optical conversion unit modulates the modulated light based on the first input signal and obtains a first output signal. Inputting the second input signal to the second electrical / optical conversion unit so that the second electrical / optical conversion unit modulates the modulated light based on the second input signal and obtains a second output signal, where the second input signal is a differential signal of the first input signal. Performing a correlation operation process on the first output signal and the second output signal to obtain a correlation amount between the first input signal and the second input signal. Determining the delay difference between the output signal of the first electrical / optical conversion unit and the output signal of the second electrical / optical conversion unit based on the correlation amount and the correspondence relationship between a predetermined correlation amount and the delay difference. A method including this step.

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