WO2023178517A1

WO2023178517A1 - Optical modulator, emission apparatus, communication system, and modulation method

Info

Publication number: WO2023178517A1
Application number: PCT/CN2022/082288
Authority: WO
Inventors: 秦扬; 吴阳博
Original assignee: 华为技术有限公司
Priority date: 2022-03-22
Filing date: 2022-03-22
Publication date: 2023-09-28
Also published as: CN118575127A

Abstract

An optical modulator, an emission apparatus, a communication system, and a modulation method. The optical modulator comprises an optical splitter, a first electro-optical phase shifter, a second electro-optical phase shifter, and a wave combiner, wherein the optical splitter is used for splitting an optical signal into a first optical signal and a second optical signal, and the splitting ratio of the first optical signal to the second optical signal is 1 : m, m being greater than 0 and m not being equal to 1; the first electro-optical phase shifter is connected to a first output end and is used for performing first phase modulation on the first optical signal; the second electro-optical phase shifter is connected to a second output end and is used for performing second phase modulation on the second optical signal; and the wave combiner is used for performing wave combination processing on a modulated first optical signal and a modulated second optical signal, so as to obtain a modulated signal and output same. When the optical modulator is applied to a communication system, even if a dispersion phenomenon occurs after an optical signal enters an optical fiber link and has been transmitted for a long distance, the dispersion can be compensated for by means of the modulation and pre-compensation of the optical modulator for the optical signal, such that high-speed, large-capacity and long-distance communication is realized.

Description

Optical modulator, transmitting device, communication system and modulation method

Technical field

The present application relates to the field of communication technology, and in particular, to an optical modulator, a transmitting device, a communication system and a modulation method.

Background technique

In fiber optic communication systems, signals usually include different frequency components or various mode components. Figure 1 is a schematic diagram of the chirp characteristics of optical signals. As shown in Figure 1, the abscissa represents time changes, and the ordinate represents the frequency of the optical signal. Optical signals will exhibit chirp characteristics during transmission, that is, the instantaneous frequency of the optical signal will change with time. When signals are transmitted over a certain distance in optical fibers, due to different transmission rates, the signals will disperse from each other, resulting in pulse broadening and signal waveform distortion, which is called dispersion. The existence of optical fiber dispersion causes the transmission signal pulse to be distorted, limiting the transmission capacity and transmission bandwidth of the optical fiber. Especially in high-speed optical transmission systems, dispersion will cause inter-code interference, increase the bit error rate, and ultimately lead to a decrease in the transmission capacity of the optical fiber communication system. The chirped characteristics of optical signals can even lead to increased dispersion. Therefore, how to compensate for dispersion is an urgent problem to be solved in optical fiber transmission.

Contents of the invention

This application provides an optical modulator, a transmitting device, a communication system and a modulation method to achieve dispersion compensation, thereby achieving high-speed, large-capacity, and long-distance communications.

In a first aspect, the present application provides an optical modulator. The optical modulator includes an optical splitter, a first electro-optical phase shifter, a second electro-optical phase shifter and a combiner, wherein the first electro-optical phase shifter and the second electro-optical phase shifter are arranged between the optical splitter and the combiner. Specifically, the optical splitter includes a signal input end, a first output end and a second output end. The light splitting ratio between the first output terminal and the second output terminal is 1:m, where m≠1. The combiner includes a first input terminal, a second input terminal and a signal output terminal. The first electro-optical phase shifter can be connected to the first output terminal, and the second electro-optical phase shifter can be connected to the second output terminal.

When the above-mentioned optical modulator is working, the optical splitter receives the optical signal through the signal input end, and divides the optical signal into a first optical signal and a second optical signal according to the above-mentioned splitting ratio. The first optical signal is output from the first output terminal, and the second optical signal is output from the second output terminal. Then, the first electro-optical phase shifter performs first phase modulation on the first optical signal, and the second electro-optical phase shifter performs second phase modulation on the second optical signal. The first optical signal after the first phase modulation enters the combiner through the first input end, and the second optical signal after the second phase modulation enters the combiner through the second input end. The combiner is used for combining the phase-modulated first optical signal and the second optical signal to form a modulated optical signal. Finally, the combiner outputs the modulated optical signal from the signal output end. In this application, the modulated optical signal output by the optical modulator has been phase modulated and pre-compensated. Therefore, even if the modulated optical signal undergoes dispersion during long-distance transmission in the optical fiber link, the phase modulation of the optical signal by the optical modulator and Pre-compensation can also compensate for dispersion, thereby enabling high-speed, large-capacity, and long-distance communications.

The specific type of the above-mentioned spectrometer is not limited. For example, it can be a multi-mode interferometer, a coupler or a Mach-Zehnder interferometer.

In a specific technical solution, the optical splitter may be a coupler. The type of coupler is not limited, for example, it can be a Y-type coupler or a directional coupler.

In addition, the spectrometer may also be a Mach-Zehnder interferometer. Specifically, the number of Mach-Zehnder interferometers is not limited. For example, in a specific technical solution, the light modulator may include at least two Mach-Zehnder interferometers connected in series.

The light splitting ratio of the above-mentioned Mach-Zehnder interferometer may be adjustable. For example, a Mach-Zehnder interferometer may be of the thermally tuned type. In this technical solution, the light modulator also includes a heater, and the heater is arranged corresponding to the Mach-Zehnder interferometer. The heater is used to heat the Mach-Zehnder interferometer, so that the spectroscopic ratio of the Mach-Zehnder interferometer changes with temperature. Alternatively, the Mach-Zehnder interferometer can be of the electrically modulated type. By applying different voltages or currents to the Mach-Zehnder interferometer, the concentration of carriers in the Mach-Zehnder interferometer can be changed, thereby changing the refraction of the optical signal, thereby adjusting the light splitting ratio.

In the above combiner, the splitting ratio between the first input terminal and the second input terminal may be 1:n. In this application, since the value of the splitting ratio of the combiner will not affect the phase modulation and pre-compensation of the optical signal, the specific value of n is not limited. For example, n can be equal to m, or n can also be equal to 1.

The first electro-optical phase shifter and the second electro-optical phase shifter can be arranged in parallel, which can reduce the size of the first electro-optical phase shifter and the second electro-optical phase shifter, which is beneficial to the miniaturization of the optical modulator.

In a second aspect, this application provides a launching device. The transmitting device includes a housing, a circuit board and the light modulator of the first aspect. The light modulator and the circuit board are arranged in the housing, and the light modulator is arranged on the circuit board. In the transmitting device, the optical splitter divides the input optical signal into a first optical signal and a second optical signal, the first electro-optical phase shifter performs first phase modulation on the first optical signal, and the second electro-optical phase shifter performs first phase modulation on the first optical signal. The two optical signals undergo second phase modulation. Since the first optical signal and the second optical signal are not in equal proportions, after the phase-modulated first optical signal and the second optical signal are combined in the combiner, the phase shift of the first optical signal is different from that of the second optical signal. The phase shifts will not completely cancel out. Therefore, compared with the input optical signal, the final output modulated optical signal will be superimposed with additional phase modulation, thereby achieving pre-compensation. When the modulated optical signal emitted by the transmitting device undergoes dispersion through the optical fiber link, the modulation of the optical signal by the optical modulator can compensate for the dispersion, so that the quality of the modulated optical signal received by the receiving device is better, thereby achieving high speed and large capacity. , long-distance communication.

In a third aspect, this application provides a communication system. The communication system includes a receiving device, an optical fiber link and a transmitting device of the second aspect, and the optical fiber link connects the transmitting device and the receiving device. In this communication system, the modulated optical signal emitted by the transmitting device will undergo dispersion after long-distance transmission in the optical fiber link. The pre-compensation of the optical signal by the optical modulator can compensate for the dispersion, thereby making the receiving The quality of the modulated optical signal received by the device is better, enabling high-speed, large-capacity, and long-distance communications.

In a fourth aspect, the present application provides a modulation method. The modulation method is performed using the optical modulator of the first aspect. Specifically, modulation methods include:

The optical splitter receives the optical signal from the signal input end;

The optical splitter divides the optical signal into a first optical signal and a second optical signal, and the splitting ratio of the first optical signal and the second optical signal is 1:m, where m>0 and m≠1;

The first electro-optical phase shifter performs first phase modulation on the first optical signal;

The second electro-optical phase shifter performs second phase modulation on the second optical signal;

The combiner performs multiplexing processing on the first optical signal modulated by the first phase and the second optical signal modulated by the second phase to obtain the modulated optical signal and output it.

Through the above modulation method, the optical signal is phase modulated and pre-compensated before entering the fiber link. Therefore, even in long-distance transmission scenarios of optical fiber links, dispersion can be compensated to achieve high-speed, large-capacity, and long-distance communications.

Description of the drawings

Figure 1 is a schematic diagram of the chirp characteristics of optical signals;

Figure 2 is a schematic structural diagram of an optical modulator in an embodiment of the present application;

Figure 3 is another structural schematic diagram of an optical modulator in an embodiment of the present application;

Figure 4 is another structural schematic diagram of an optical modulator in an embodiment of the present application;

Figure 5 is another structural schematic diagram of an optical modulator in an embodiment of the present application;

Figure 6 is another structural schematic diagram of an optical modulator in an embodiment of the present application;

Figure 7 is a schematic structural diagram of a transmitting device in an embodiment of the present application;

Figure 8 is a schematic structural diagram of a communication system in an embodiment of the present application;

Figure 9 is a schematic flowchart of the modulation method in the embodiment of the present application.

Reference signs:

10-Light modulator;

11-Spectroscope;

12-The first electro-optical phase shifter;

13-Second electro-optical phase shifter;

14-Combiner;

70-Launching device;

71-shell;

72-circuit board;

80-Communication systems;

81-Fiber optic link;

82-receiving device;

111-signal input terminal;

112-First output terminal;

113-Second output terminal;

141-First input terminal;

142-Second input terminal;

143-Signal output terminal.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below in conjunction with the accompanying drawings.

Currently, dispersion compensation technologies commonly used in optical fiber transmission mainly include optical domain dispersion compensation and electrical domain dispersion compensation. Among them, optical domain dispersion compensation usually uses dispersion compensation optical fiber. Dispersion compensating fiber is a fiber with negative dispersion. It can be added to the existing G652 standard optical fiber to compensate for the dispersion in the G652 standard optical fiber to ensure that the total dispersion of the entire optical fiber line is approximately zero. In other words, using this method, different lengths of dispersion compensation fibers must be added according to the different lengths of the G652 standard fiber. Therefore, the optical fiber deployment of the existing network must be modified, resulting in increased network deployment costs and link insertion loss.

Electrical domain dispersion compensation mainly uses equalization technology to increase the falling edge of the signal spectrum, amplify the signal in a specific frequency band, thereby broadening the receivable spectrum range, thereby compensating for the bandline filtering effect caused by dispersion, and thus improving the quality of the signal after dispersion. 3dB bandwidth value. However, electrical domain dispersion compensation requires the use of an Optical Digital Signal Processor (ODSP) in the transceiver, which increases the cost compared to the commonly used clock data recovery (Clock Data Recovery, CDR) solution. Moreover, the dispersion compensation function will increase the power consumption of the optical digital signal processor, resulting in an increase in the overall power consumption of the optical module. In addition, if compensation is performed at the receiving end, since the signal has experienced the dispersion effect of the long-distance optical fiber, part of the frequency band information has been filtered out by the dispersion and cannot be compensated in an equalized manner. Therefore, the compensation effect of electrical domain dispersion compensation is limited.

To this end, this application provides an optical modulator, a transmitting device, a communication system and a modulation method to achieve dispersion compensation, thereby achieving high-speed, large-capacity, and long-distance communications.

Figure 2 is a schematic structural diagram of an optical modulator in an embodiment of the present application. As shown in FIG. 2 , the optical modulator 10 includes a beam splitter 11 , a first electro-optical phase shifter 12 , a second electro-optical phase shifter 13 and a combiner 14 , wherein the first electro-optical phase shifter 12 and the second electro-optical phase shifter The detector 13 is arranged between the optical splitter 11 and the combiner 14. In this application, the light modulator 10 can be fabricated on a chip, or can also be directly assembled in the light processing module. The optical modulator 10 can be applied in long-distance transmission scenarios of wireless fronthaul, mid-backhaul, data center, access network or backbone network and other networks. When applied, the optical modulator 10 can perform phase modulation on the input optical signal, thereby realizing pre-compensation of the optical signal. Specifically, for example, when the optical modulator 10 is used in a communication system, the optical modulator 10 can be disposed on a transmitting device, so that the optical signal can be phase modulated and pre-compensated before the optical signal enters the optical fiber link. Therefore, even if the optical signal output by the optical modulator 10 occurs dispersion after long-distance transmission in the optical fiber link, the modulated optical signal received by the receiving device has been compensated for the dispersion and has better quality. Therefore, the optical modulator 10 of the present application can perform dispersion compensation on optical signals, thereby achieving high-speed, large-capacity, and long-distance communications.

Figure 3 is another structural schematic diagram of an optical modulator in an embodiment of the present application. As shown in FIG. 3 , when the above-mentioned optical modulator 10 is specifically configured, the optical splitter 11 may include a signal input terminal 111 , a first output terminal 112 and a second output terminal 113 . The signal input terminal 111 can be used as an input port of the optical modulator 10 , and the optical splitter 11 receives the optical signal through the signal input terminal 111 . The optical splitter 11 is used to divide the optical signal into a first optical signal and a second optical signal, and output the first optical signal from the first output terminal 112 and the second optical signal from the second output terminal 113 . In the above-mentioned optical splitter 11, the splitting ratio of the first output terminal 112 and the second output terminal 113 is assumed to be 1:m, and m>0 and m≠1. That is to say, the beam splitter 11 is a non-equal-proportion beam splitter. In this way, after subsequent phase modulation of the first optical signal and the second optical signal respectively, since the first optical signal and the second optical signal are not in equal proportions, after the first optical signal and the second optical signal are combined, the first optical signal The phase shift of the signal will not completely cancel out the phase shift of the second optical signal. Therefore, compared with the input optical signal, the final output optical signal will be superimposed with additional phase modulation, thereby achieving pre-compensation.

It should be noted that the pre-compensation described in the embodiments of this application occurs before the optical fiber link, that is to say, the optical signal has been modulated before dispersion occurs, such as phase modulation on the transmitting device side. Therefore, the optical signal output by the optical modulator 10 cannot reflect the effect of dispersion compensation before entering the optical fiber link. Only when the optical signal is dispersed in the optical fiber link, the optical signal received by the receiving device can reflect the pre-compensation effect of the optical modulator 10 on the optical signal.

In the above embodiment, the specific type of the optical splitter 11 is not limited. As shown in Figure 3, in some embodiments, the spectrometer 11 may be a multi-mode interferometer (Multi-mode Interferometer, MMI). The multi-mode interferometer divides the input optical signal into a first optical signal and a second optical signal according to a split ratio of 1:m, and outputs the first optical signal to the first electro-optical phase shifter 12 through the first output terminal 112, and through The second output terminal 113 outputs a second optical signal to the second electro-optical phase shifter 13 .

Figure 4 is another structural schematic diagram of an optical modulator in an embodiment of the present application. As shown in Figure 4, in other embodiments, the optical splitter 11 can also be a coupler. Specifically, in one embodiment, the optical splitter 11 may be a Y-type coupler. Figure 5 is another structural schematic diagram of an optical modulator in an embodiment of the present application. As shown in FIG. 5 , in another embodiment, the optical splitter 11 may also be a directional coupler. Of course, the above-mentioned optical splitter 11 is not limited to these two types of couplers, and other types of couplers will not be described in detail in this application.

Figure 6 is another structural schematic diagram of an optical modulator in an embodiment of the present application. As shown in Figure 6, the spectrometer 11 may be a Mach-Zehnder Interferometer (MZI). When the optical modulator 10 is operating, the Mach-Zehnder interferometer can also perform low-speed phase shifting on the first optical signal and the second optical signal. In this embodiment, the specific number of optical splitters 11 is not limited, and may be 1, 2 or 4, for example. In some embodiments, light modulator 10 may package at least two Mach-Zehnder interferometers. The above-mentioned at least two Mach-Zehnder interferometers can be connected in series, so that the splitting ratio of the first optical signal and the second optical signal finally output is 1:m. Of course, these Mach-Zehnder interferometers can also be arranged in other ways, such as in a matrix distribution.

Of course, the above-mentioned Mach-Zehnder interferometer can also be set to be adjustable to achieve adjustment of the light splitting ratio. For example, in one specific embodiment, the Mach-Zehnder interferometer may be thermally tuned. Specifically, the light modulator 10 may also include a heater provided corresponding to the Mach-Zehnder interferometer. The heater is used to heat the Mach-Zehnder interferometer. When the light modulator 10 is working, the heater can heat the Mach-Zehnder interferometer, so that the spectroscopic ratio of the Mach-Zehnder interferometer changes with changes in temperature, thereby changing the spectroscopic ratio of the Mach-Zehnder interferometer. Therefore, in practical applications, different splitting ratios can be set based on factors such as optical fiber links and transmission distances. Alternatively, in another specific embodiment, the Mach-Zehnder interferometer may also be electrically adjustable. By applying different voltages or currents to the Mach-Zehnder interferometer, the motion of carriers in the Mach-Zehnder interferometer can be changed, thereby changing the concentration of carriers. Since carriers of different concentrations have different refractive indexes, they refract light signals differently, so that the spectroscopic ratio of the Mach-Zehnder interferometer can be adjusted.

In the above-mentioned optical modulator 10, after the optical splitter 11 splits the input optical signal, the electro-optical phase shifter is used to phase-modulate the optical signal. Specifically, the first electro-optical phase shifter 12 is connected to the first output terminal 112 of the optical splitter 11 , and the first optical signal is output from the first output terminal 112 and then enters the first electro-optical phase shifter 12 . The first electro-optical phase shifter 12 may apply a first high-speed electrical signal to perform first phase modulation on the first optical signal. The second electro-optical phase shifter 13 is connected to the second output terminal 113 of the spectrometer 11 , and the second optical signal is output from the second output terminal 113 and then enters the second electro-optical phase shifter 13 . The second electro-optical phase shifter 13 may apply a second high-speed electrical signal, thereby performing second phase modulation on the second optical signal. It should be noted that the first phase modulation and the second phase modulation may be the same or different. In practical applications, the first phase modulation and the second phase modulation can also be set according to factors such as the optical fiber link, transmission distance, etc., so that the quality of the optical signal received by the receiving device is better.

The above-mentioned first electro-optical phase shifter 12 and second electro-optical phase shifter 13 can be arranged in parallel between the spectrometer 11 and the combiner 14, which can reduce the The size is beneficial to the miniaturization of the light modulator 10. Of course, the first electro-optical phase shifter 12 and the second electro-optical phase shifter 13 may not be arranged in parallel, and are not specifically limited in the embodiments of this application.

Please continue to refer to FIG. 3 . After that, the phase-modulated first optical signal and the second optical signal enter the combiner 14 . The combiner 14 includes a first input terminal 141 , a second input terminal 142 and a signal output terminal 143 . The first optical signal is output from the first electro-optical phase shifter 12 and enters the combiner 14 from the first input terminal 141 . The second optical signal is output from the second electro-optical phase shifter 13 and enters the combiner 14 from the second input terminal 142 . The combiner 14 combines the modulated first optical signal and the second optical signal to obtain a modulated optical signal, and outputs the modulated optical signal from the signal output terminal 143 . The type of the combiner 14 is not specifically limited. For example, it may be a coupler-based combiner, or it may be a multi-mode interferometer-based combiner, or it may also be a coupler-based combiner. In this application, in the same optical modulator 10, various types of optical splitters 11 can be paired with different types of combiners 14 without specific limitations.

In the above-mentioned combiner 14, the splitting ratio of the first input terminal 141 and the second input terminal 142 may be 1:n. In the embodiment of the present application, since the combiner 14 performs multiplexing processing on the first optical signal and the second optical signal, it has an impact on the intensity of the final modulated optical signal, while the first optical signal and the second optical signal are The phase modulation of the signal does not have much impact. Therefore, n can be equal to m, or n can be equal to 1. That is to say, the splitting ratios of the combiner 14 may be equal proportions, or may be non-equal proportions. For example, when n=1, the intensity of the modulated optical signal output by the combiner 14 is better.

The dispersion compensation of the optical signal by the optical modulator 10 of the present application will be described in detail below using mathematical derivation.

In the optical modulator 10 of the present application, the electric field of the first optical signal is:

E ₁ =Ae ^ix(t) (1)

The electric field of the second optical signal is:

E ₂ =Be ^-ix(t) (2)

Among them, x(t) represents the composite signal. In the optical modulator 10 of the present application, x(t) represents the composite signal of the real signal s(t) and the DC bias b, that is:

x(t)＝s(t)+b (3)

In the above formulas (1) and (2), A is the optical signal component output by the first output terminal 112 of the optical splitter 11 , and B is the optical signal component output by the second output terminal 113 of the optical splitter 11 . A, B and m satisfy: A:B=1:m. When m=1, A=B. In addition, A and B also satisfy:

A ² +B ² =1 (4)

According to the above formulas (1), (2), (3) and (4), the electric field after combining the first optical signal and the second optical signal is:

E＝E ₁ +E ₂ =(A+B)cosx(t)+i(AB)sinx(t) (5)

Since the offset point is selected in the linear region, the above formula (5) can be approximated as:

E＝(A+B)x(t)+i(A-B)x(t) (6)

When the optical modulator 10 is applied to a communication system, the optical signal is transmitted in a 10km long optical fiber link as an example. Assuming that the transfer function generated by the dispersion effect is h, then the electric field of the optical signal received by the receiving device is:

According to the above formula (7), the intensity of the optical signal received by the receiving device is:

Ignoring the constant term in the above formula (8), we can get:

In the above formula (9), since the higher-order term is an error caused by the approximation of the previous term, it can be ignored. Therefore, perform Fast Fourier Transform (FFT) on I(t) and bring it into the following formula:

H(ω)＝cos(ω ² βL/2)+isin(ω ² βL/2) (10)

Available:

I(ω)＝8ABb*S(ω)*cos(ω ² βL/2)+4(A ² -B ² )b*S(ω)*sin(ω ² βL/2) (11)

When the splitting ratio of the spectroscope 11 is 1, m=1 and A=B, then I(ω)=8ABb*S(ω)*cos(ω ² βL/2), the optical signal will experience distortion caused by dispersion. cos filtering effect.

When the splitting ratio of the spectrometer 11 is not equal to 1, m≠1, that is, A≠B. At this time, the 4(A ² -B ² )b*S(ω)*sin(ω ² βL/2) part in I(ω) is not zero, dispersion compensation can be achieved, and according to the relative sizes of A and B , you can control the positive or negative compensation direction of the optical signal.

Figure 7 is a schematic structural diagram of a transmitting device in an embodiment of the present application. As shown in FIG. 7 , the transmitting device 70 includes a housing 71 , a circuit board 72 and the light modulator 10 of the above embodiments. The optical modulator 10 and the circuit board 72 are arranged in the housing 71 , and the optical modulator 10 is arranged on the circuit board 72 . In the transmitting device 70, the optical splitter 11 divides the input optical signal into a first optical signal and a second optical signal, and the splitting ratio of the first optical signal and the second optical signal is 1:m, where m>0 and m≠1. Then the first electro-optical phase shifter 12 performs first phase modulation on the first optical signal, and the second electro-optical phase shifter 13 performs second phase modulation on the second optical signal. Since the first optical signal and the second optical signal are not in equal proportions, after the first optical signal and the second optical signal are combined, the phase offset of the first optical signal and the phase offset of the second optical signal will not completely cancel out. Therefore, compared with the input optical signal, the final output modulated optical signal will be superimposed with additional phase modulation, thereby achieving pre-compensation. Finally, when the modulated optical signal emitted by the transmitting device 70 undergoes dispersion through the optical fiber link, the modulation of the optical signal by the optical modulator 10 can compensate for the dispersion, so that the quality of the optical signal received by the receiving device is better.

Figure 8 is a schematic structural diagram of a communication system in an embodiment of the present application. As shown in FIG. 8 , the communication system 80 includes a transmitting device 70 , an optical fiber link 81 and a receiving device 82 . Among them, the optical fiber link 81 connects the transmitting device 70 and the receiving device 82. In this communication system 80, the modulated optical signal emitted by the transmitting device 70 will undergo dispersion after long-distance transmission in the optical fiber link 81, and the pre-compensation of the optical signal by the optical modulator 10 can compensate for the dispersion. As a result, the quality of the optical signal received by the receiving device 82 is better, thereby achieving high-speed, large-capacity, and long-distance communication.

Figure 9 is a schematic flowchart of the modulation method in the embodiment of the present application. As shown in FIG. 9 , in the embodiment of the present application, the optical modulator 10 of the above embodiment is used to perform the modulation method on the optical signal. Specifically, modulation methods include:

Step S901: The optical splitter receives the optical signal from the signal input end. The signal input end 111 of the optical splitter 11 can be used as an input port of the optical modulator 10 , and the optical signal enters the optical splitter 11 from the signal input end 111 .

Step S902: The optical splitter divides the optical signal into a first optical signal and a second optical signal. The splitting ratio of the first optical signal and the second optical signal is 1:m, where m>0 and m≠1.

In the optical splitter 11, the optical signal is divided into a first optical signal and a second optical signal, so that the first optical signal is subsequently input to the first electro-optical phase shifter 12, and the second optical signal is input to the second electro-optical phase shifter 12. 13 performs modulation respectively.

Step S903: The first electro-optical phase shifter performs first phase modulation on the first optical signal.

Step S904: The second electro-optical phase shifter performs second phase modulation on the second optical signal.

Since the first optical signal and the second optical signal are not split equally proportionally, the phase modulations of the modulated first optical signal and the second optical signal will not completely cancel each other.

Step S905: The combiner performs multiplexing processing on the first optical signal modulated by the first phase and the second optical signal modulated by the second phase to obtain a modulated optical signal and output it.

Compared with the optical signal input from the signal input terminal 111, the combined modulated optical signal is superimposed with additional phase modulation. The modulated optical signal will undergo dispersion during the long-distance transmission of the optical fiber link 81, but the superimposed phase modulation can compensate for the dispersion, so that it can be transmitted in high-speed, large-capacity, and long-distance communications.

The terminology used in the above embodiments is only for the purpose of describing specific embodiments and is not intended to limit the application. As used in the specification and appended claims of this application, the singular expressions "a", "an", "said", "above", "the" and "the" are intended to also Expressions such as "one or more" are included unless the context clearly indicates otherwise.

Reference in this specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, the phrases "in one embodiment," "in another embodiment," "in some embodiments," "in other embodiments," "in "In some other embodiments" does not necessarily refer to the same embodiment, but means "one or more but not all embodiments" unless otherwise specifically emphasized. The terms “including,” “includes,” “having,” and variations thereof all mean “including but not limited to,” unless otherwise specifically emphasized.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present application, and all of them should be covered. within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

An optical modulator, characterized in that it includes a spectrometer, a first electro-optical phase shifter, a second electro-optical phase shifter and a combiner, the first electro-optical phase shifter and the second electro-optical phase shifter are arranged on Between the optical splitter and the combiner, where:

The optical splitter includes a signal input end, a first output end and a second output end, and the light splitting ratio between the first output end and the second output end is 1:m, where m>0 and m≠1; Optical splitter, configured to receive an optical signal through the signal input end and divide the optical signal into a first optical signal and a second optical signal according to the light splitting ratio of the first output end and the second output end, and Output the first optical signal through the first output terminal, and output the second optical signal through the second output terminal;

The first electro-optical phase shifter is connected to the first output terminal and is used to perform first phase modulation on the first optical signal output by the first output terminal;

The second electro-optical phase shifter is connected to the second output terminal and is used to perform second phase modulation on the second optical signal output by the second output terminal;

The combiner includes a first input terminal, a second input terminal and a signal output terminal. The first input terminal is connected to the first electro-optical phase shifter, and the second input terminal is connected to the second electro-optical phase shifter. device; the combiner is configured to receive a first phase-modulated first optical signal through the first input end, and receive a second phase-modulated second optical signal through the second input end, and convert the phase The modulated first optical signal and the second optical signal are combined and processed to form a modulated optical signal, and the modulated optical signal is output from the signal output end.
The optical modulator of claim 1, wherein the optical splitter is a multi-mode interferometer, a coupler, or a Mach-Zehnder interferometer.
The optical modulator of claim 2, wherein the coupler includes a Y-type coupler or a directional coupler.
The optical modulator of claim 2, wherein the optical modulator includes at least two of the optical splitters connected in series, and the optical splitters are Mach-Zehnder interferometers.
The light modulator according to claim 4, characterized in that the light modulator further includes a heater provided corresponding to the Mach-Zehnder interferometer, and the heater is used to conduct the processing of the Mach-Zehnder interferometer. heating.
The optical modulator according to any one of claims 1 to 5, wherein the light splitting ratio between the first input terminal and the second input terminal is 1:n, where n=m or n=1.
The optical modulator according to any one of claims 1 to 6, characterized in that the first electro-optical phase shifter and the second electro-optical phase shifter are arranged in parallel.
A transmitting device, characterized in that it includes a housing, a circuit board and the light modulator according to any one of claims 1 to 7, the light modulator and the circuit board being arranged in the housing, The light modulator is provided on the circuit board.
A communication system, characterized by comprising a receiving device, an optical fiber link and a transmitting device as claimed in claim 8, the optical fiber link connecting the transmitting device and the receiving device.
A modulation method, characterized in that the modulation method is performed using the optical modulator according to any one of claims 1 to 7, wherein the modulation method includes:

The optical splitter receives an optical signal from the signal input end;

The optical splitter divides the optical signal into a first optical signal and a second optical signal, and the splitting ratio of the first optical signal and the second optical signal is 1:m, where m>0 and m≠1 ;

The first electro-optical phase shifter performs first phase modulation on the first optical signal;

The second electro-optical phase shifter performs second phase modulation on the second optical signal;

The combiner performs multiplexing processing on the first optical signal after first phase modulation and the second optical signal after second phase modulation to obtain a modulated optical signal and output it.