Harmonic generators, harmonic modulation components, optical modules and optical communication equipment

Abstract

The present application provides a harmonic generator, which is applied to the field of optical communications. The first output port of the first beam splitter is connected to the first input port of the first optical coupler through the first optical transmission path. The second output port of the first beam splitter is connected to the second input port of the first optical coupler through the second optical transmission path. An inhibitor is arranged on the first optical transmission path. The inhibitor is used to obtain a harmonic beam by modulating a carrier beam, and suppress the carrier and even harmonics in the harmonic beam. A first phase shifter is connected to an output port of the first optical coupler. The first phase shifter is used to output the first light beam. Another output port of the first optical coupler is used to output the second light beam. The carriers in the first light beam and the second light beam are in phase, and the odd harmonics are in reverse phase. In the present application, the power of the even harmonics can be suppressed by the inhibitor, thereby improving the signal-to-noise ratio of the subsequent modulated optical signal.

Description

Technical Field

[0001] The present application relates to the field of optical communications, and in particular to a harmonic generator, a harmonic modulation component, an optical module and an optical communication device. Background Art

[0002] In the field of optical communications, the bandwidth of many devices restricts the improvement of transmission rate. For example, the bandwidth of complementary metal oxide semiconductor digital analog converter (CMOS DAC) is generally below 100 GHz.

[0003] To this end, the bandwidth requirements of the device can be reduced through optical domain spectrum splicing technology. Figure 1 Figure 1 is a schematic diagram of the structure of an optical communication device. Figure 1 As shown, the optical communication device includes a light source 101, a harmonic generator 102, a modulator group 103 and a beam combiner 110. The optical communication device is used to divide the electrical signal to be modulated into a first electrical signal and a second electrical signal. The spectrum range of the first electrical signal and the second electrical signal is half of the spectrum range of the electrical signal to be modulated. The bandwidths of the first electrical signal and the second electrical signal are the same and are both smaller than the bandwidth of the electrical signal to be modulated. The light source 101 is used to output a light beam. The harmonic generator 102 includes a beam splitter 104, a modulator 105, a phase shifter (PS) 106 and an optical coupler 107. The beam splitter 104 is used to divide the light beam into a light beam 1 and a light beam 2. The modulator 105 is used to modulate the light beam 1 according to the first drive signal. The modulator 105 is also used to modulate the light beam 2 according to the second drive signal. The first drive signal and the second drive signal are complementary. The first drive signal and the second drive signal are clock signals. The frequency of the clock signal is greater than or equal to half of the bandwidth of the electrical signal to be modulated. PS 106 is used to change the phase of the light beam 1. The optical coupler 107 is used to couple the light beam 1 and the light beam 2, and output the first light beam and the second light beam. The carrier waves of the first light beam and the second light beam are in phase, and the first harmonics are in reverse phase. The modulator group 103 includes a modulator 108 and a modulator 109. The modulator 108 is used to modulate the first light beam according to the first electrical signal to obtain a modulated optical signal 1. The modulator 109 is used to modulate the second light beam according to the second electrical signal to obtain a modulated optical signal 2. The combiner 110 is used to combine the modulated optical signal 1 and the modulated optical signal 2 to obtain a modulated optical signal. Through the optical domain spectrum splicing technology, a high baud rate optical modulated signal can be generated by low-bandwidth optoelectronic devices. For example, the bandwidth of the modulator 108 and the modulator 109 can be half of the spectrum of the signal to be modulated. Similarly, the bandwidth of other devices can also be half of the spectrum of the signal to be modulated. For example, a DAC that performs digital-to-analog conversion on the first electrical signal and a driver that amplifies the first electrical signal.

[0004] However, the modulator 105 will generate even harmonics with the same phase. For example, the second harmonic. Therefore, the first light beam and the second light beam will also carry the second harmonic. For example, when phi = π / 2, S = m*π / 4*cos(2*pi*BW*t), Figure 1 The optical equations of the first light beam (Esout1) and the second light beam (Esout2) output by the optical coupler 107 are as follows.

[0005]

[0006]

[0007] Wherein, “*” indicates the multiplication of two values. phi is the phase shift value of the phase shifter 106. phi can be adjusted by a DC bias voltage. BW is the frequency of the first drive signal and the second drive signal. t is time. m is the modulation depth, which is set to 1 here. is the coefficient of the Bessel expansion. It can be seen from formulas 1 and 2 that, in addition to the carrier and the first harmonic component, there is also a second harmonic component in the first light beam and the second light beam output by 107. In the modulation process of the subsequent modulator group 103, the second harmonic with the same phase will introduce noise, thereby reducing the signal-to-noise ratio of the modulated optical signal. Summary of the invention

[0008] The present application provides a harmonic generator, a harmonic modulation component, an optical module and an optical communication device. In the present application, the power of even-order harmonics in the first light beam and the second light beam can be reduced by a suppressor, thereby improving the signal-to-noise ratio of the subsequent modulated optical signal.

[0009] The first aspect of the present application provides a harmonic generator. The harmonic generator includes a first beam splitter, an inhibitor, a first optical coupler and a first phase shifter. The first output port of the first beam splitter is connected to the first input port of the first optical coupler through a first optical transmission path. The second output port of the first beam splitter is connected to the second input port of the first optical coupler through a second optical transmission path. The first beam splitter is used to receive a light beam and divide the light beam into two sub-beams. The two sub-beams do not carry harmonics or the power of the harmonics is very small. Therefore, the two sub-beams are also called two carrier beams. An inhibitor is provided on the first optical transmission path. The inhibitor is used to receive a carrier beam and modulate the carrier beam according to a driving signal to obtain a harmonic beam. The harmonic beam carries a carrier and harmonics. The inhibitor is also used to suppress the carrier and even harmonics in the harmonic beam. When the power of the carrier and the even harmonics is ignored, the inhibitor is used to output odd harmonics. The first input port of the first optical coupler is used to receive odd harmonics. The second input port of the first optical coupler is used to receive a carrier. The first optical coupler is used to couple odd harmonics and a carrier. The first optical coupler includes two output ports. One of the two output ports is connected to a first phase shifter. The first phase shifter is used to output a first light beam. The other of the two output ports is used to output a second light beam. The first phase shifter is used to change the phase of the light beam so that the carrier of the first light beam and the carrier of the second light beam are in phase, and the odd harmonics of the first light beam and the odd harmonics of the second light beam are in opposite phases.

[0010] In the present application, the suppressor can suppress even harmonics in the carrier and harmonics, thereby obtaining relatively pure odd harmonics. Then, through the first optical coupler and the first phase shifter, the first light beam and the second light beam with the same phase of the carrier and the reverse phase of the odd harmonics can be obtained. Therefore, the present application can reduce the power of the second harmonic in the first light beam and the second light beam, thereby improving the signal-to-noise ratio of the subsequent modulated optical signal.

[0011] In an optional manner of the first aspect, the harmonic generator also includes a power regulator. A power regulator is provided on the first optical transmission path or the second optical transmission path. The power regulator is used to adjust the power of the light beam. Among them, the power ratio of the carrier and the first harmonic in the first light beam or the second light beam is related to the signal-to-noise ratio of the modulated optical signal. Specifically, it is assumed that the power ratio of the first harmonic and the carrier is R. When the noise of the electrical signal of the subsequent modulator group is large, the larger R value will increase the noise of the modulated optical signal, thereby reducing the signal-to-noise ratio of the modulated optical signal. During the preprocessing process, the smaller R value will reduce the power of the effective electrical signal, thereby also reducing the signal-to-noise ratio of the modulated optical signal. Therefore, after adding the power regulator, the present application can improve the signal-to-noise ratio of the modulated optical signal by adjusting the power ratio.

[0012] In an optional manner of the first aspect, the harmonic generator further includes a second phase shifter. The second phase shifter is provided on the first optical transmission path or the second optical transmission path. The second phase shifter is used to change the phase of the light beam. The lengths of the first optical transmission path and the second optical transmission path may be different, thereby generating a phase difference between the carrier and the odd harmonics. When there is a phase difference between the carrier and the odd harmonics, the signal-to-noise ratio of the modulated optical signal is reduced. Therefore, by adding the second phase shifter, the phase difference can be compensated, thereby improving the signal-to-noise ratio of the modulated optical signal.

[0013] In an optional manner of the first aspect, the splitting ratio of the first optical coupler is a:1-a. The value range of a is between 0.4 and 0.6. Among them, when the difference between the value of a and 0.5 is too large, the power difference of the carrier in the first light beam and the second light beam will become larger, and the power difference of the first harmonic will also become larger. After the first light beam and the second light beam are subsequently modulated by the modulator group, the spectrum splicing noise generated by the two output optical signals generated by the modulator group after coupling increases, thereby affecting the signal-to-noise ratio of the modulated optical signal. Therefore, the present application can improve the signal-to-noise ratio of the modulated optical signal.

[0014] In an optional manner of the first aspect, the suppressor is a Mach-Zehnder modulator (MZM). The MZM includes a second beam splitter, an upper modulator, a lower modulator, a third phase shifter and a second optical coupler. The input port of the second beam splitter is connected to the first output port of the first beam splitter. The first output port of the second beam splitter is connected to the first input port of the second optical coupler through a third optical transmission path. The second output port of the second beam splitter is connected to the second input port of the second optical coupler through a fourth optical transmission path. An upper modulator is provided on the third optical transmission path. A lower modulator is provided on the fourth optical transmission path. The upper modulator and the lower modulator are used to receive a differential clock drive signal, and modulate the carrier beam according to the differential clock drive signal to obtain a harmonic beam. The harmonic beam carries a carrier and harmonics. A third phase shifter is provided on the third optical transmission path or the fourth optical transmission path. The third phase shifter is used to generate a phase difference between the light beams transmitted in the third optical transmission path and the fourth optical transmission path. The second optical coupler is used to suppress the carrier and even harmonics in the harmonic beam according to the phase difference. The second optical coupler is used to output odd harmonics. The cost of the harmonic generator can be reduced by using the MZM as a suppressor.

[0015] In an optional manner of the first aspect, the suppressor is a linearized optical modulator. Wherein, by using a linearized optical modulator, the power ratio of high-frequency harmonics to low-frequency harmonics can be reduced. For example, the power ratio of the third harmonic to the first harmonic can be reduced. In the subsequent modulation of the first light beam and the second light beam, the present application mainly relies on low-frequency harmonics. The power of the high-frequency harmonics is lost as loss. Therefore, by reducing the power ratio of the high-frequency harmonics to the low-frequency harmonics, the loss of the harmonic generator can be reduced.

[0016] In an optional manner of the first aspect, the linearized optical modulator includes a first MZM, a second MZM, a second optical coupler and a third phase shifter. The input port of the first MZM is connected to the first output port of the first beam splitter. The first output port of the first MZM is connected to the first input port of the second optical coupler through a third optical transmission path. The second output port of the first MZM is connected to the second input port of the second optical coupler through a fourth optical transmission path. The second MZM is arranged on the third optical transmission path. The third phase shifter is arranged on the third optical transmission path or the fourth optical transmission path.

[0017] In an optional manner of the first aspect, the linearized optical modulator includes a first MZM, a reflector, a second optical coupler and a third phase shifter. The first input port of the first MZM is connected to the first output port of the first beam splitter. The first output port of the first MZM is connected to the reflector. The second output port of the first MZM is connected to the first input port of the second optical coupler through a third optical transmission path. The second input port of the first MZM is connected to the second input port of the second optical coupler through a fourth optical transmission path. A third phase shifter is provided on the third optical transmission path or the fourth optical transmission path. Among them, by adding a reflector, the number of MZMs can be reduced, thereby reducing the cost of the harmonic generator.

[0018] In an optional manner of the first aspect, the splitting ratio of the second optical coupler is r: 1-r. The value range of r is 0.02 to 0.2. Among them, in the light beam output by the linearized optical modulator, the power ratio of high-frequency harmonics to low-frequency harmonics is related to the linearity of the linearized optical modulator. The better the linearity, the lower the power ratio. Linearity is related to the value of r. When the value range of r is 0.02 to 0.2, the linearized optical modulator has better linearity. Therefore, the present application can reduce the power ratio of high-frequency harmonics to low-frequency harmonics, thereby reducing the loss of the harmonic generator.

[0019] In an optional manner of the first aspect, the second optical coupler is an adjustable optical coupler. When the splitting ratio of the first MZM output is 0.5:0.5 and r is 0.02 to 0.2, the linearized optical modulator has better linearity. However, the optical path losses in the third optical transmission path and the fourth optical transmission path may be different. Different optical path losses will change the optimal value range of r. When the second optical coupler is an adjustable optical coupler, the r value can be changed by the adjustable optical coupler, thereby reducing the power ratio of high-frequency harmonics and low-frequency harmonics and reducing the loss of the harmonic generator.

[0020] The second aspect of the present application provides a harmonic modulation component. The harmonic modulation component includes a modulator group, a beam combiner, and the harmonic generator described in the first aspect or any one of the first aspects. The modulator group includes a first modulator and a second modulator. An output port of the harmonic generator is connected to the first modulator. Another output port of the harmonic generator is connected to the second modulator. The output end of the first modulator is connected to the first input end of the beam combiner. The output end of the second modulator is connected to the second input end of the beam combiner.

[0021] In an optional manner of the second aspect, the first modulator and the second modulator are intensity modulators.

[0022] In an optional manner of the second aspect, the first modulator and the second modulator are IQ modulators.

[0023] In an optional manner of the second aspect, the harmonic modulation component also includes a polarization splitter, another modulator group, another beam combiner, a polarization combiner, and another harmonic generator described in the first aspect or any one of the first aspects. The first output port of the polarization splitter is connected to the input port of the harmonic generator. The second output port of the polarization splitter is connected to the input port of another harmonic generator. The other modulator group includes a third modulator and a fourth modulator. An output port of another harmonic generator is connected to the third modulator. Another output port of another harmonic generator is connected to the fourth modulator. The output port of the third modulator is connected to the first input port of another beam combiner. The output port of the fourth modulator is connected to the second input port of another beam combiner. The output port of the beam combiner is connected to the first input port of the polarization combiner. The output port of the other beam combiner is connected to the second input port of the polarization combiner.

[0024] In an optional manner of the second aspect, the first modulator and the second modulator are linearized optical modulators, wherein the linearized optical modulator reduces the nonlinearity of the modulator, thereby reducing the in-band noise caused by the high-order harmonic components, and can further improve the signal-to-noise ratio of the modulated optical signal.

[0025] The third aspect of the present application provides an optical module. The optical module includes a light source and the harmonic modulation component described in the second aspect or any one of the second aspects. The light source is used to generate a light beam and transmit the light beam to the harmonic modulation component. The harmonic modulation component is used to modulate the light beam to obtain a modulated light signal.

[0026] The fourth aspect of the present application provides an optical communication device. The optical communication device includes a processor and the optical module described in the third aspect. The processor is used to divide the electrical signal to be modulated into a first electrical signal and a second electrical signal. The bandwidths of the first electrical signal and the second electrical signal are the same and both are smaller than the bandwidth of the electrical signal to be modulated. The processor is also used to transmit the first electrical signal and the second electrical signal to the optical module. The optical module is used to generate a light beam, and the first light beam and the second light beam are obtained according to the light beam. The carrier of the first light beam and the carrier of the second light beam are in phase. The odd harmonics of the first light beam and the odd harmonics of the second light beam are in reverse. The optical module is also used to modulate the first light beam by the first electrical signal to obtain a first modulated optical signal. The optical module is also used to modulate the second light beam by the second electrical signal to obtain a second modulated optical signal. The optical module is also used to combine the first modulated optical signal and the second modulated optical signal to obtain a modulated optical signal.

[0027] The fifth aspect of the present application provides a harmonic generation method. The harmonic generation method comprises the following steps: a carrier beam is split into two carrier beams by a beam splitter. One of the two carrier beams is modulated to obtain a harmonic beam. The harmonic beam includes a carrier and harmonics. The carrier and even-order harmonics in the harmonic beam are suppressed to obtain an odd-order harmonic beam. The odd-order harmonic beam is coupled with another carrier beam of the two carrier beams to obtain two beams. The phase of one of the two beams is changed by a phase shifter so that the carriers of the two beams are in phase and the odd-order harmonics are in opposite directions.

[0028] In an optional manner of the fifth aspect, the harmonic generation method further includes the following steps: adjusting the power of the one carrier beam, the other carrier beam, or the odd-order harmonic beam by a power regulator.

[0029] In an optional manner of the fifth aspect, the harmonic generation method further includes the following steps: changing the phase of the one carrier beam, the other carrier beam, or the odd-order harmonic beam by a phase shifter. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of an optical communication device;

[0031] Figure 2 This is a first structural schematic diagram of a harmonic generator provided in an embodiment of the present application;

[0032] Figure 3aA schematic diagram of the distribution of the carrier wave and the harmonic wave of the first light beam provided in an embodiment of the present application;

[0033] Figure 3b A schematic diagram of the distribution of the carrier wave and the harmonic wave of the second light beam provided in an embodiment of the present application;

[0034] Figure 4a This is a first structural schematic diagram of the suppressor provided in an embodiment of the present application;

[0035] Figure 4b A second structural diagram of the harmonic generator provided in the embodiment of the present application

[0036] Figure 5 This is a second structural schematic diagram of the suppressor provided in an embodiment of the present application;

[0037] Figure 6 This is a third structural schematic diagram of the suppressor provided in the embodiment of the present application;

[0038] Figure 7 This is a third structural schematic diagram of the harmonic generator provided in the embodiment of the present application;

[0039] Figure 8 A schematic diagram of the structure of a power regulator provided in an embodiment of the present application;

[0040] Fig. 9 This is a first structural schematic diagram of a harmonic modulation component provided in an embodiment of the present application;

[0041] Fig.10 A second structural schematic diagram of a harmonic modulation component provided in an embodiment of the present application;

[0042] Fig.11 This is a schematic diagram of the structure of the optical module provided in the embodiment of the present application;

[0043] Fig.12 A schematic diagram of the structure of an optical communication device provided in an embodiment of the present application;

[0044] Fig.13 This is a schematic diagram of the structure of the optical communication system provided in this application. DETAILED DESCRIPTION

[0045] The present application provides a harmonic generator, a harmonic modulation component, an optical module and an optical communication device. In the present application, the suppressor can suppress even harmonics in the carrier and the harmonics. Therefore, the present application can reduce the power of the second harmonic in the first light beam and the second light beam, thereby improving the signal-to-noise ratio of the subsequent modulated optical signal. It should be understood that the "first", "second", "target", etc. used in the present application are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, for simplicity and clarity, reference numbers and / or letters are repeated in multiple figures of the present application. Repetition does not indicate a strict limiting relationship between various embodiments and / or configurations.

[0046] The harmonic generator in this application is applied to the field of optical communication. In the field of optical communication, the bandwidth of the device restricts the transmission rate. Therefore, the bandwidth requirement of the device can be reduced by optical domain spectrum splicing technology. Figure 1 In the embodiment, the first light beam and the second light beam output by the harmonic generator 102 carry even-order harmonics. The second harmonic in the even-order harmonics will introduce spectral splicing noise. The beam combiner 110 cannot eliminate the noise caused by the second harmonic. In subsequent processing, the noise will reduce the signal-to-noise ratio of the modulated optical signal.

[0047] To this end, the present application provides a harmonic generator. Figure 2 This is a first structural diagram of the harmonic generator provided in the embodiment of the present application. Figure 2 As shown, the harmonic generator 200 includes a beam splitter 201 , a suppressor 202 , a first optical coupler 204 and a first phase shifter (PS) 203 .

[0048] The first output port of the beam splitter 201 is connected to the first input port of the first optical coupler 204 through the first optical transmission path. The second output port of the beam splitter 201 is connected to the second input port of the first optical coupler 204 through the second optical transmission path. The beam splitter 201 is used to receive a light beam and split the light beam into two light beams. The light beam is a continuous light signal. The two light beams include light beam 1 and light beam 2. The first optical transmission path is used to transmit light beam 1. The second optical transmission path is used to transmit light beam 2. An inhibitor 202 is provided on the first optical transmission path. The inhibitor 202 is used to modulate the light beam 1 according to the driving signal to obtain the modulated light beam 1. The driving signal of the inhibitor 202 can be a clock signal or a periodic signal with a duty cycle of fifty percent. Light beam 1 is also called a carrier beam, and the modulated light beam 1 is also called a harmonic beam. The carrier beam carries a carrier. The harmonic beam carries a carrier and harmonics. The frequency of the carrier is the same as the frequency of the light beam received by the beam splitter 201. Harmonics include even harmonics and odd harmonics. Even harmonics include second harmonics, fourth harmonics, etc. Odd harmonics include first harmonics, third harmonics, etc. The suppressor 202 is also used to suppress the carrier and even harmonics in the harmonic beam. After suppressing the carrier and even harmonics, the power of the carrier and even harmonics can be ignored. At this time, the suppressor 202 is used to transmit odd harmonics to the first optical coupler 204. The first optical coupler 204 is used to receive odd harmonics from the suppressor 202. The first optical coupler 204 is used to receive the carrier from the beam splitter 201. The first optical coupler 204 is used to optically couple the odd harmonics and the carrier. An output port of the first optical coupler 204 is connected to the first phase shifter 203. The first phase shifter 203 is a 90° phase shifter. In practical applications, the phase shift value of the first phase shifter 203 may differ from 90°. The difference is used to compensate for the optical path difference between the first light beam and the second light beam on the optical transmission path after the optical coupler 204 outputs. The first phase shifter 203 is used to change the phase of the light beam and output the first light beam. Another output port of the first optical coupler 204 is used to output a second light beam.

[0049] The phases of the carrier wave of the first light beam and the carrier wave of the second light beam are the same (referred to as in-phase). The phases of the odd harmonics of the first light beam and the odd harmonics of the second light beam are opposite (referred to as anti-phase). Figure 3a Schematic diagram of the distribution of the carrier and harmonics of the first light beam provided in the embodiment of the present application. Figure 3a As shown, the horizontal axis is frequency and the vertical axis represents amplitude. The first light beam includes a carrier f0 and a first harmonic f11. The amplitude of the carrier f0 is higher than the amplitude of the first harmonic f11. In practical applications, the amplitude of the carrier f0 can be equal to or less than the amplitude of the first harmonic f11. The frequency difference between the carrier f0 and the first harmonic f11 is equal to the frequency of the driving signal. The frequency of the driving signal can be equal to half of the bandwidth of the subsequent electrical signal to be modulated. Figure 3bSchematic diagram of the distribution of the carrier and harmonic waves of the second light beam provided in the embodiment of the present application. Figure 3b As shown, the second light beam includes a carrier f0 and a first harmonic f12. The carrier f0 of the second light beam is in phase with the carrier f0 of the first light beam. The first harmonic f12 and the first harmonic f11 are in opposite directions. The power of the carrier f0 of the second light beam is the same as that of the carrier f0 of the first light beam. The power of the first harmonic f12 and the first harmonic f11 are the same. Among them, the high-frequency harmonics in the odd-order harmonics have little effect on noise, so the third harmonic and above high-frequency harmonics can be ignored here. After the suppressor 202 suppresses the even-order harmonics, the even-order harmonics can also be ignored here.

[0050] In the present application, the suppressor 202 can suppress the carrier and even-order harmonics in the harmonic light beam, thereby obtaining relatively pure odd-order harmonics. Then, through the first optical coupler and the first phase shifter, the first light beam and the second light beam with the same phase of the carrier and the reverse phase of the odd-order harmonics can be obtained. In practical applications, the second harmonic in the even-order harmonics is the main cause of noise. Therefore, the present application can reduce the power of the second harmonic in the first light beam and the second light beam, thereby improving the signal-to-noise ratio of the subsequent modulated optical signal.

[0051] It should be understood that in practical applications, due to manufacturing errors of the device, there may be some deviation between the phase of the carrier of the first light beam and the carrier of the second light beam. Similarly, there may be some deviation between the phase difference of the odd harmonics of the first light beam and the odd harmonics of the second light beam and 180°.

[0052] It should be understood that Figure 2 In the embodiment, the first phase shifter 203 is connected to the first output port of the first optical coupler 204. In practical applications, the first phase shifter 203 can be connected to the second output port of the first optical coupler 204. In this case, the first phase shifter 203 is used to change the phase of the second light beam. Alternatively, the harmonic generator 200 includes two first phase shifters 203. One first phase shifter 203 is connected to the first output port of the first optical coupler 204. Another first phase shifter 203 is connected to the second output port of the first optical coupler 204. One of the first phase shifters 203 is a 90° phase shifter. Another first phase shifter 203 is a 180° phase shifter.

[0053] The splitting ratio of the first optical coupler 204 affects the power difference between the carrier in the first light beam and the second light beam, and also affects the power difference between the first harmonic in the first light beam and the second light beam. The splitting ratio of the first optical coupler can be a:1-a. The value range of a is between 0.4 and 0.6. When the difference between the value of a and 0.5 is too large, the power difference between the carrier in the first light beam and the second light beam will become larger, and the power difference between the first harmonic will also become larger. After the first light beam and the second light beam are modulated by the modulator group, the spectrum splicing noise generated by the coupling of the two optical signals increases, thereby affecting the signal-to-noise ratio of the modulated optical signal. Therefore, the present application can improve the signal-to-noise ratio of the modulated optical signal. The structure of the suppressor 202 provided in the present application is described below. Figure 4a This is a first structural diagram of the suppressor provided in the embodiment of the present application. Figure 4a As shown, the suppressor 202 includes a second beam splitter 401, an upper modulator 402, a lower modulator 403, a third phase shifter 404 and a second optical coupler 405. The input port of the second beam splitter 401 is connected to the first beam splitter ( Figure 4a The first output port of the optical beam 1 is not shown in the figure. The second beam splitter 401 is used to receive the light beam 1 and split the light beam 1 into a light beam 11 and a light beam 12. The first output port of the second beam splitter 401 is connected to the first input port of the second optical coupler 405 through a third optical transmission path. The second output port of the second beam splitter 401 is connected to the second input port of the second optical coupler 405 through a fourth optical transmission path. An upper modulator 402 is arranged on the third optical transmission path. A lower modulator 403 is arranged on the fourth optical transmission path. The upper modulator 402 is used to receive the first drive signal, and modulate the light beam 11 according to the first drive signal to obtain the light beam 21. The lower modulator 403 is used to receive the second drive signal, and modulate the light beam 12 according to the first drive signal to obtain the light beam 22. The first drive signal and the second drive signal are differential clock drive signals. The voltages of the second drive signal and the first drive signal are opposite. After modulation, the light beams 21 and 22 carry carriers and harmonics. A third phase shifter 404 is arranged on the third optical transmission path. The third phase shifter 404 is used to change the phase of the light beam 21 so that there is a phase difference between the light beam 21 and the light beam 22. The second optical coupler 405 is used to couple the light beam 21 and the light beam 22. Since there is a certain phase difference between the light beam 21 and the light beam 22, the second optical coupler 405 can suppress even harmonics and carrier waves during the coupling process. The second optical coupler 405 is used to output odd harmonics.

[0054] Figure 4b This is a second structural diagram of the harmonic generator provided in the embodiment of the present application. Figure 4b As shown, when using Figure 4aAs shown in the suppressor, the harmonic generator 200 includes a beam splitter 201, a suppressor 202, a first optical coupler 204 and a first phase shifter 203. The beam splitter 201 is used to split the light beam into two light beams. The two light beams include a light beam 1 and a light beam 2. The light beam 1 and the light beam 2 are also called carrier beams. The suppressor 202 is arranged on the first optical transmission path. The structure of the suppressor 202 is as shown in FIG. Figure 4a As shown. The suppressor 202 is used to modulate the light beam 1 to obtain the modulated light beam 1. The modulated light beam 1 includes a carrier and harmonics. The suppressor 202 is also used to suppress the carrier and even-order harmonics in the modulated light beam 1, and output odd-order harmonics. The first optical coupler 204 is used to receive odd-order harmonics from the suppressor 202 and to receive the carrier from the beam splitter 201. The first optical coupler 204 is used to optically couple the odd-order harmonics and the carrier. The harmonic generator 200 is used to output a first light beam and a second light beam. The first phase shifter 203 is used to change the phase of the light beam so that the carrier of the second light beam is in phase with the carrier of the first light beam, and the odd-order harmonics of the second light beam are opposite to the odd-order harmonics of the first light beam. Figure 4a The suppressor 202 in is a nonlinear optical modulator. At this time, in the odd-order harmonics, the power ratio of high-order harmonics to low-order harmonics is higher. In subsequent processing, the power of high-order harmonics will be used as loss. In order to reduce the loss, the suppressor 202 can be a linearized optical modulator. When there is an approximate linear relationship between the input and output of the linearized optical modulator, the power of the high-order harmonics carried in the light beam output by the linearized optical modulator is small. When there is a linear relationship between the input and output of the linearized optical modulator, the light beam output by the linearized optical modulator does not carry high-order harmonics. Assume that the output Eout(t) of the linearized optical modulator is equal to Formula 3.

[0055]

[0056] At this time, the first light beam output1 and the second light beam output2 output by the harmonic generator 200 can be expressed by the following formula.

[0057]

[0058] Wherein, "*" indicates the multiplication of two values. OC is the light intensity amplitude of the input light beam of the harmonic generator 200. Substituting Formula 3 into Formula 4, Formulas 5 and 6 are obtained.

[0059]

[0060]

[0061] In Formula 5 and Formula 6, the function of the first phase shifter 203 is not calculated. At this time, there is an additional phase difference j between the first light beam and the second light beam. The phase difference between the first light beam and the second light beam can be eliminated by the first phase shifter 203. After eliminating the phase difference, according to Formula 5 and Formula 6, when there is a linear relationship between the input and output of the linearized optical modulator, the output of the harmonic generator 200 does not carry high-frequency, odd-order harmonics of the third harmonic and above. Therefore, the present application can reduce losses.

[0062] According to the above description, when the suppressor 202 is a linear optical modulator, the loss can be reduced. In practical applications, the linear optical modulator can have different structures. The linear optical modulator in this application is described below by taking two different structures as examples.

[0063] Figure 5 This is a second schematic diagram of the structure of the suppressor provided in the embodiment of the present application. Figure 5 As shown, the suppressor 202 includes a first MZM, a second MZM, a second optical coupler 502 and a third phase shifter 501. The input port of the first MZM is used to communicate with the first beam splitter ( Figure 5 The first MZM is connected to the first output port of the second optical coupler 502 (not shown). The input port of the first MZM is used to receive the light beam 1. The first MZM is used to modulate the light beam 1 according to the first drive signal to obtain the light beam 11 and the light beam 12. The first MZM includes an optical coupler 503. The splitting ratio of the optical coupler 503 is 0.5:0.5. The optical coupler 503 is used to optically couple the light beam 11 and the light beam 12 to obtain the light beam 21 and the light beam 22. Among them, the light beam 22 is a light beam in which the carrier and the even harmonics are suppressed. The light beam 21 is a light beam carrying the carrier and the even harmonics. The first output port of the first MZM is connected to the first input port of the second optical coupler 502 through the third optical transmission path. The second output port of the first MZM is connected to the second input port of the second optical coupler 502 through the fourth optical transmission path. The first MZM is used to output the light beam 21 through the first output port. The first MZM is used to output the light beam 22 through the second output port.

[0064] A second MZM is arranged on the third optical transmission path. The second MZM is used to modulate the light beam 21 according to the second drive signal, and convert the carrier and even harmonics carried in the light beam 21 into odd harmonics. The second MZM outputs odd harmonics. The first drive signal and the second drive signal are differential clock drive signals. The voltages of the second drive signal and the first drive signal are opposite. A third phase shifter 501 is arranged on the fourth optical transmission path. The third phase shifter 501 is used to compensate for the optical path difference between the third optical transmission path and the fourth optical transmission path. In practical applications, the optical path difference can also be compensated by adjusting the length of the fourth optical transmission path. The second optical coupler 502 is used to receive the light beam 21 and the light beam 22. During the coupling process, high-frequency harmonics can be suppressed by adjusting the splitting ratio of the second optical coupler 502. The second optical coupler 502 is used to output odd-numbered harmonics and the energy of the high-frequency harmonics is suppressed.

[0065] Figure 5 The light field of the linearized light modulator in can be expressed as the following formula.

[0066]

[0067] Wherein, Eout(t) is an odd harmonic. The power ratio of the modulated light beam 21 and the light beam 22 is 1-r∶r. 1-r∶r can also be called the splitting ratio of the second optical coupler 502. Vπ is the half-wave voltage of the first MZM and the second MZM. V(t) is the absolute value of the driving voltage of the first MZM and the second MZM.

[0068] make |x|≤1. Formula 7 is simplified into the following formula.

[0069]

[0070] The Taylor expansion of the sine function is shown in Formula 9. Since the absolute value of x is less than 1, it only needs to be expanded to the fifth power, and the influence of higher orders is very small. Therefore, in Formula 9, (x 5 ) represents a higher power. The coefficient of a higher power is represented by O.

[0071]

[0072] Substitute Formula 9 into Formula 8. When r=0.112, Formula 10 can be obtained.

[0073] Eout(t)≈0.98x(t) Formula 10

[0074] The driving voltage V(t) is less than the half-wave voltage Vπ. Therefore, Formula 10 can be further simplified to obtain the aforementioned Formula 3.

[0075]

[0076] From the normalized Taylor formula expansion of formula 8, it can be seen that the nonlinearity of the first term of the light field can be compensated by the nonlinearity of the second term. Better linearity can be obtained by adjusting the coefficient r. Through numerical simulation, it can be seen that when r is in the range of 0.02 to 0.2, the linearized light modulator has a certain linearity. The value range of r includes 0.02 or 0.2. Moreover, when r is 0.112, the linearized light modulator has good linearity.

[0077] Figure 6 This is a third structural diagram of the suppressor provided in the embodiment of the present application. Figure 6 As shown, the suppressor 202 includes a first MZM, a reflector 601, a second optical coupler 603 and a third phase shifter 602. The first input port of the first MZM is used to communicate with the first beam splitter ( Figure 6 The first MZM is connected to the first output port of the first MZM (not shown). The first input port of the first MZM is used to receive the light beam 1. The first MZM is used to divide the light beam 1 into a light beam 11 and a light beam 12. The first MZM is used to modulate the light beam 11 and the light beam 12 according to the driving signal. The first MZM is also used to couple the light beam 11 and the light beam 12 to obtain the light beam 21 and the light beam 22. Among them, the light beam 22 is a light beam in which the carrier and the even harmonics are suppressed. The light beam 21 is a light beam carrying the carrier and the even harmonics. The light beam 21 and the light beam 22 are complementary. The first output port of the first MZM is connected to the reflector 601. The first output port of the first MZM is used to output the light beam 21. The reflector 601 is used to reflect the light beam 21. The reflected light beam 21 enters the first MZM through the first output port of the first MZM. The first MZM is used to modulate the reflected light beam 21 according to the driving signal, and convert the carrier and the even harmonics carried in the light beam 21 into odd harmonics. The first MZM is used to output the modulated light beam 21 through the second input port. The modulated light beam 21 carries odd-order harmonics.

[0078] The second output port of the first MZM is connected to the first input port of the second optical coupler 603 through the third optical transmission path. The second output port of the first MZM is used to transmit the light beam 22 to the second optical coupler 603. The second input port of the first MZM is connected to the second input port of the second optical coupler 603 through the fourth optical transmission path. The second input port of the first MZM is used to transmit the modulated light beam 21 to the second optical coupler 603. A third phase shifter 602 is provided on the third optical transmission path. The third phase shifter 602 is used to compensate for the optical path difference between the third optical transmission path and the fourth optical transmission path. The second optical coupler 603 is used to couple the light beam 21 and the light beam 22. During the coupling process, high-frequency harmonics can be suppressed by adjusting the splitting ratio of the second optical coupler 603. The second optical coupler 603 is used to output odd-order harmonics and the energy of the high-frequency harmonics is suppressed.

[0079] exist Figure 6 In the example, one MZM realizes the functions of two MZMs. Figure 5 , this solution can reduce the cost or volume of the harmonic generator. The light beam 21 (E2) and the light beam 22 (E1) can be expressed by the following formula.

[0080]

[0081]

[0082] The light beam 21 returns along the original path after passing through the reflective sheet 601. At this time, the reflected light beam 21 is used as the input light beam of the first MZM (ignoring the path delay of the light). The first MZM modulates the reflected light beam 21 according to the driving signal. The modulated light beam 21 (E3) can be expressed by the following formula.

[0083]

[0084] After passing through the third phase shifter 602, the second optical coupler 603 obtains odd harmonics according to the light beam 22 (E1) and the modulated light beam 21 (E3). The odd harmonics can be expressed by the following formula.

[0085]

[0086] Wherein, Eout(t) is an odd harmonic. The power ratio of the modulated light beam 21 and the light beam 22 is 1-r∶r. 1-r∶r can also be called the splitting ratio of the second optical coupler 603. Vπ is the half-wave voltage of the first MZM. V(t) is the driving voltage of the first MZM. Formula 14 is the same as Formula 7. Formula 3 can be obtained by simplifying Formula 14 in the manner of simplifying Formula 7 as described above. In addition, the linearity of the linearized optical modulator can also be adjusted by adjusting the value of r.

[0087] It should be understood that Figure 5 , the third phase shifter 501 is arranged in the fourth optical transmission path. The third phase shifter 501 is used to change the phase of the light beam 22. In practical applications, the third phase shifter can also be arranged in the third optical transmission path. The third phase shifter 501 is used to change the phase of the modulated light beam 21. Similarly, in Figure 6 In the embodiment, the third phase shifter 602 is arranged in the third optical transmission path. The third phase shifter 602 is used to change the phase of the light beam 22. In practical applications, the third phase shifter 602 may also be arranged in the fourth optical transmission path. The third phase shifter 602 is used to change the phase of the modulated light beam 21.

[0088] According to the aforementioned Figure 5It can be seen from the description that when the splitting ratio of the optical coupler 503 is 0.5:0.5 and r is 0.02 to 0.2, the linearized optical modulator has better linearity. However, the optical path losses in the third optical transmission path and the fourth optical transmission path may be different. Different optical path losses will change the optimal value range of r. When the second optical coupler is an adjustable optical coupler, the r value can be changed by the adjustable optical coupler, thereby reducing the power ratio of high-frequency harmonics and low-frequency harmonics and reducing the loss of the harmonic generator.

[0089] exist Figure 2 In the embodiment, the lengths of the first optical transmission path and the second optical transmission path may be different. Different lengths will produce phase differences. When there is a large phase difference between the carrier and the odd harmonics, the signal-to-noise ratio of the subsequent modulated optical signal will be reduced. To this end, the harmonic generator may also include a second phase shifter. The second phase shifter is used to compensate for the optical path difference caused by the different lengths of the optical transmission paths. For example, Figure 7 This is a third structural diagram of the harmonic generator provided in the embodiment of the present application. Figure 7 As shown, in Figure 2 On the basis of, the harmonic generator further includes a second phase shifter 702. The second phase shifter 702 is arranged in the second optical transmission path. The second phase shifter 702 is used to change the phase of the light beam 2. It should be understood that in practical applications, the second phase shifter 702 can also be arranged in the first optical transmission path.

[0090] exist Figure 2 In the embodiment, when the splitting ratio of the first optical splitter 201 changes, the power ratio of the carrier and the odd harmonics in the first light beam or the second light beam changes. The power ratio is related to the signal-to-noise ratio of the modulated optical signal. Therefore, the first optical splitter 201 can be an adjustable beam splitter. The signal-to-noise ratio of the modulated optical signal is adjusted by adjusting the splitting ratio of the optical splitter 201. Alternatively, the harmonic generator also includes a power regulator. The power regulator is used to adjust the power of the carrier or the odd harmonics. For example, Figure 7 As shown, in Figure 2 On the basis of, the harmonic generator also includes a power regulator 701. The power regulator 701 is arranged on the second optical transmission path. The power regulator 701 is used to adjust the power of the power beam 2. When the power of the beam 2 changes, the power of the carrier in the first beam or the second beam changes, thereby adjusting the power ratio of the carrier and the odd harmonics in the first beam or the second beam. It should be understood that in practical applications, the power regulator 701 can also be arranged on the first optical transmission path. At this time, the power regulator 701 is used to adjust the power of the odd harmonics.

[0091] Figure 8 Schematic diagram of the structure of the power regulator provided in the embodiment of the present application. Figure 8As shown, the power regulator 701 includes a beam splitter 801, a phase shifter 802 and an optical coupler 803. The beam splitter 801 is used to split the light beam 2 into two light beams. The first output port of the beam splitter 801 is connected to the first input port of the optical coupler 803 through the optical transmission path 1. The second output port of the beam splitter 801 is connected to the second input port of the optical coupler 803 through the optical transmission path 2. A phase shifter 802 is provided on the optical transmission path 1. The phase shifter 802 is used to change the phase of the light beam. The optical coupler 803 is used to optically couple the two light beams and output the light beam 2 after power adjustment. By controlling the phase shifter 802, the power of the light beam 2 can be adjusted.

[0092] The harmonic generator provided in the present application is described above, and the harmonic modulation component provided in the present application is described below. Fig. 9 This is a first structural diagram of the harmonic modulation component provided in the embodiment of the present application. Fig. 9 The harmonic modulation component 900 includes a harmonic generator 200 , a modulator group 904 and a beam combiner 903 .

[0093] For the description of the harmonic generator 200, please refer to the aforementioned Figure 2-8 The harmonic generator 200 is used to receive a light beam, and obtain a first light beam and a second light beam according to a driving signal and the light beam. The carrier of the first light beam and the carrier of the second light beam are in phase. The odd harmonics of the first light beam and the odd harmonics of the second light beam are in opposite directions. The harmonic generator 200 is used to transmit the first light beam and the second light beam to the modulator group 904.

[0094] The modulator group 904 includes a first modulator 901 and a second modulator 902. The first modulator 901 and the second modulator 902 can be intensity modulators or IQ modulators. The first modulator 901 is used to receive a first light beam. The first modulator 901 is used to modulate the first light beam according to the first electrical signal to obtain a first modulated optical signal. The second modulator 902 is used to receive a second light beam. The second modulator 902 is used to modulate the second light beam according to the second electrical signal to obtain a second modulated optical signal. Among them, the first electrical signal and the second electrical signal are obtained according to the electrical signal to be modulated. The bandwidths of the first electrical signal and the second electrical signal are the same and are both smaller than the bandwidth of the electrical signal to be modulated. For example, the frequency spectrum of the electrical signal to be modulated ranges from 0 to 2B. Two electrical signals with a bandwidth of B are generated by a digital signal preprocessing (DSP) module. The two electrical signals with a bandwidth of B are the first electrical signal and the second electrical signal, respectively.

[0095] The first input end of the beam combiner 903 is connected to the output end of the first modulator 901. The second input end of the beam combiner 903 is connected to the output end of the second modulator 902. The beam combiner 903 is used to combine the first modulated optical signal and the second modulated optical signal to obtain a modulated optical signal. During the beam combining process, the first modulated optical signal and the second modulated optical signal interfere with each other to achieve spectrum splicing.

[0096] Fig.10 FIG. 2 is a second structural diagram of the harmonic modulation component provided in the embodiment of the present application. Fig.10 As shown. The harmonic modulation component 1000 includes a polarization splitter 1001 and a polarization combiner 1005. The polarization splitter 1001 is used to receive a light beam and split the light beam into an X-polarized light beam and a Y-polarized light beam. The first output port of the polarization splitter 1001 is connected to the first input port of the polarization combiner 1005 through an optical transmission path 3. The second output port of the polarization splitter 1001 is connected to the second input port of the polarization combiner 1005 through an optical transmission path 4.

[0097] The first output port of the polarization splitter 1001 is used to output an X-polarized light beam. A harmonic generator 200, a modulator group 904, and a beam combiner 903 are arranged on the optical transmission path 3. For a description of the harmonic generator 200, the modulator group 904, and the beam combiner 903, please refer to Fig. 9 The harmonic modulation component 900 is described in detail in FIG. The harmonic modulation component 900 is used to output an X-polarized modulated light beam.

[0098] The second output port of the polarization splitter 1001 is used to output a Y polarized light beam. A harmonic generator 1002, a modulator group 1003 and a beam combiner 1004 are arranged on the optical transmission path 4. The harmonic generator 1002 is used to receive the Y polarized light beam, and obtain the third light beam and the fourth light beam according to the driving signal and the Y polarized light beam. The carriers in the third light beam and the fourth light beam are in phase, and the odd harmonics are reversed. The harmonic generator 1002 is used to transmit the third light beam and the fourth light beam to the modulator group 1003. The modulator group 1003 includes a third modulator and a fourth modulator. The third modulator is used to receive the third light beam, modulate the first light beam according to the first electrical signal, and obtain a third modulated light signal. The fourth modulator is used to receive the fourth light beam, modulate the fourth light beam according to the fourth electrical signal, and obtain a fourth modulated light signal. Among them, the third electrical signal and the fourth electrical signal are obtained according to the Y polarized electrical signal to be modulated. The bandwidths of the third electrical signal and the fourth electrical signal are the same, and are both smaller than the bandwidth of the electrical signal to be modulated. The beam combiner 1004 is used to receive the third modulated light signal and the fourth modulated light signal. The beam combiner 1004 is used to combine the third modulated optical signal and the fourth modulated optical signal to obtain a Y-polarized modulated optical signal. It should be understood that the description of the optical transmission path 4 can refer to the description of the optical transmission path 3 above.

[0099] The first input port of the polarization combiner 1005 is connected to the output port of the beam combiner 903. The polarization combiner 1005 is used to receive the X polarization modulated optical signal from the beam combiner 903. The second input port of the polarization combiner 1005 is connected to the output port of the beam combiner 1004. The polarization combiner 1005 is used to receive the Y polarization modulated optical signal from the beam combiner 1004. The polarization combiner 1005 is used to combine the Y polarization modulated optical signal and the X polarization modulated optical signal to obtain a target optical signal.

[0100] The above describes the harmonic modulation component in the present application, and the following describes the optical module provided in the present application. Fig.11 Schematic diagram of the structure of the optical module provided in the embodiment of the present application. Fig.11 The optical module 1100 includes a light source 1101 and a harmonic modulation component 1102. The light source 1101 is used to generate a light beam and transmit the light beam to the harmonic modulation component 1102. For the description of the harmonic modulation component 1102, please refer to the aforementioned Fig. 9 or Fig.10 Related description of the harmonic modulation component. The harmonic modulation component 1102 is used to modulate the light beam according to the electrical signal to obtain a modulated light signal.

[0101] The optical module in the present application is described above, and the optical communication device provided in the present application is described below. Fig.12 Schematic diagram of the structure of the optical communication device provided in the embodiment of the present application. Fig.12 As shown, the optical communication device 1200 includes a processor 1201 and an optical module 1100 .

[0102] The processor 1201 may be a central processing unit (CPU), a network processor (NP) or a combination of a CPU and a NP. The processor 1201 may further include a hardware chip or other general-purpose processor. The above-mentioned hardware chip may be an application specific integrated circuit (ASIC), a programmable logic device (PLD) or a combination thereof. Specifically, the processor 1201 may be an optical digital signal processing (oDSP) chip. The oDSP chip may include a DSP module.

[0103] The processor 1201 is used to obtain a first electrical signal and a second electrical signal according to the electrical signal to be modulated. The bandwidths of the first electrical signal and the second electrical signal are the same and are both smaller than the bandwidth of the electrical signal to be modulated. In addition, the processor 1201 can also perform modulation format mapping, shaping, filtering, or link pre-compensation on the electrical signal to be modulated. The processor 1201 is used to transmit the first electrical signal and the second electrical signal to the optical module 1100. In practical applications, the optical communication device 1200 may also include two DACs and two electrical drivers. The two DACs are used to perform digital-to-analog conversion on the first electrical signal and the second electrical signal, respectively. The two electrical drivers are used to power amplify the first electrical signal and the second electrical signal, respectively.

[0104] The optical module 1100 is used to receive the first electrical signal and the second electrical signal. Fig.11 . The optical module 1100 is used to generate a light beam, and a first light beam and a second light beam are obtained according to the light beam. The carrier waves of the first light beam and the second light beam are in phase, and the odd harmonics are in reverse phase. The optical module 1100 is used to modulate the first optical signal by a first electrical signal to obtain a first modulated optical signal. The optical module 1100 is also used to modulate the second optical signal by a second electrical signal to obtain a second modulated optical signal. The optical module 1100 is used to combine the first modulated optical signal and the second modulated optical signal to obtain a modulated optical signal. The bandwidth of the modulated optical signal is the same as the bandwidth of the electrical signal to be modulated.

[0105] In other embodiments, the optical communication device 1200 may further include a memory. The memory is used to store the electrical signal to be modulated. The memory may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), or a flash memory. The volatile memory may be a random access memory (RAM).

[0106] The optical communication device provided in the present application is described above, and the optical communication system provided in the present application is described below. Fig.13 Schematic diagram of the structure of the optical communication system provided in this application. Fig.13 As shown, the optical communication system includes an optical communication device 1200 and an optical network device 1301 .

[0107] For the description of the optical communication device 1200, reference can be made to the aforementioned Fig.12Related descriptions. The optical communication device 1200 is used to obtain a first electrical signal and a second electrical signal according to the electrical signal to be modulated. The bandwidths of the first electrical signal and the second electrical signal are the same, and both are smaller than the bandwidth of the electrical signal to be modulated. The optical communication device 1200 is used to obtain a first light beam and a second light beam according to a light beam. The carriers of the first light beam and the second light beam are in phase, and the odd harmonics are in reverse phases. The optical communication device 1200 is used to modulate the first light beam according to the first electrical signal to obtain a first modulated light signal. The optical communication device 1200 is also used to modulate the second light beam according to the second electrical signal to obtain a second modulated light signal. The optical communication device 1200 is also used to combine the first modulated light signal and the second modulated light signal to obtain a modulated light signal. The optical communication device 1200 is used to transmit the modulated light signal to the optical network device 1301.

[0108] The optical network device 1301 is used to receive modulated optical signals, demodulate the modulated optical signals, and obtain electrical signals. In practical applications, the optical network device 1301 can also transmit optical signals to the optical communication device 1200. The method for the optical network device 1201 to obtain optical signals can refer to the related description of the optical communication device 1200 obtaining modulated optical signals.

[0109] In other embodiments, the optical communication system may further include a multiplexer (MUX) and a demultiplexer (DEMUX). The MUX connects N optical communication devices 1200. N is an integer greater than 0. Each optical communication device 1200 is used to transmit modulated optical signals of different wavelengths to the MUX. The MUX is used to combine N modulated optical signals of different wavelengths to obtain an optical signal with N wavelengths. The MUX is used to transmit an optical signal with N wavelengths to the DEMUX. The DEMUX is used to demultiplex an optical signal with N wavelengths to obtain N modulated optical signals with different wavelengths. The DEMUX is connected to N optical network devices 1301. The DEMUX is used to transmit a modulated optical signal carrying one wavelength to each optical network device 1301.

[0110] The present application also provides a harmonic generation method. The harmonic generation method includes the following steps: splitting a carrier beam into two carrier beams by a beam splitter. Modulating one of the two carrier beams to obtain a harmonic beam. The harmonic beam includes a carrier and harmonics. Suppressing the carrier and even-order harmonics in the harmonic beam to obtain an odd-order harmonic beam. Coupling the odd-order harmonic beam and the other carrier beam of the two carrier beams to obtain two beams. Changing the phase of one of the two beams by a phase shifter makes the carriers of the two beams in phase and the odd-order harmonics in opposite directions.

[0111] For the description of the harmonic generation method, reference may be made to the related description of the aforementioned harmonic generator. For example, the two carrier beams are beam 1 and beam 2. The two beams are a first beam and a second beam. For another example, the harmonic generation method includes the following steps: adjusting the power of a carrier beam, another carrier beam, or an odd-order harmonic beam by a power regulator. For another example, the harmonic generation method also includes the following steps: changing the phase of a carrier beam, another carrier beam, or an odd-order harmonic beam by a second phase shifter.

[0112] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A harmonic generator, characterized in that: The invention comprises a first beam splitter, an inhibitor, a first optical coupler and a first phase shifter, wherein: The first output port of the first beam splitter is connected to the first input port of the first optical coupler through a first optical transmission path; The second output port of the first beam splitter is connected to the second input port of the first optical coupler through a second optical transmission path; The suppressor is provided on the first optical transmission path, and is used to obtain a harmonic light beam by modulating a carrier light beam, and suppress the carrier and even-order harmonics in the harmonic light beam; The first optical coupler comprises two output ports, one of the two output ports is connected to the first phase shifter, the first phase shifter is used to output a first light beam, the other of the two output ports is used to output a second light beam, a carrier of the first light beam and a carrier of the second light beam are in phase, and an odd-order harmonic of the first light beam and an odd-order harmonic of the second light beam are in opposite phases; The suppressor includes a second beam splitter, an upper modulator, a lower modulator, a third phase shifter, and a second optical coupler; The input port of the second beam splitter is connected to the first output port of the first beam splitter; The first output port of the second beam splitter is connected to the first input port of the second optical coupler through a third optical transmission path; The second output port of the second beam splitter is connected to the second input port of the second optical coupler through a fourth optical transmission path; The upper modulator is arranged on the third optical transmission path, and the lower modulator is arranged on the fourth optical transmission path, and the upper modulator and the lower modulator are used to receive a differential clock driving signal, and modulate the carrier light beam according to the differential clock driving signal to obtain the harmonic light beam; The third phase shifter is arranged on the third optical transmission path or the fourth optical transmission path, and the third phase shifter is used to generate a phase difference between the light beams transmitted in the third optical transmission path and the fourth optical transmission path, and the second optical coupler is used to suppress the carrier and even harmonics in the harmonic light beam according to the phase difference.

2. The harmonic generator according to claim 1, characterized in that The harmonic generator also includes a power regulator; The power regulator is provided on the first optical transmission path or the second optical transmission path.

3. The harmonic generator according to claim 1 or 2, characterized in that: The harmonic generator also includes a second phase shifter; The second phase shifter is arranged on the first optical transmission path or the second optical transmission path.

4. The harmonic generator according to claim 1 or 2, characterized in that: The splitting ratio of the first optical coupler is a:1-a, and the value range of a is between 0.4 and 0.

6.

5. A harmonic generator, characterized in that: The invention comprises a first beam splitter, an inhibitor, a first optical coupler and a first phase shifter, wherein: The first output port of the first beam splitter is connected to the first input port of the first optical coupler through a first optical transmission path; The second output port of the first beam splitter is connected to the second input port of the first optical coupler through a second optical transmission path; The suppressor is provided on the first optical transmission path, and is used to obtain a harmonic light beam by modulating a carrier light beam, and suppress the carrier and even-order harmonics in the harmonic light beam; The first optical coupler comprises two output ports, one of the two output ports is connected to the first phase shifter, the first phase shifter is used to output a first light beam, the other of the two output ports is used to output a second light beam, a carrier of the first light beam and a carrier of the second light beam are in phase, and an odd-order harmonic of the first light beam and an odd-order harmonic of the second light beam are in opposite phases; The suppressor is a linearized optical modulator; If the linearized optical modulator includes a first Mach-Zehnder modulator MZM, a second MZM, a second optical coupler and a third phase shifter; the input port of the first MZM is connected to the first output port of the first beam splitter; the first output port of the first MZM is connected to the first input port of the second optical coupler through a third optical transmission path; the second output port of the first MZM is connected to the second input port of the second optical coupler through a fourth optical transmission path; the second MZM is arranged on the third optical transmission path; the third optical transmission path or the fourth optical transmission path is provided with the third phase shifter; If the linearized optical modulator includes a first MZM, a reflector, a second optical coupler and a third phase shifter; the first input port of the first MZM is connected to the first output port of the first beam splitter; the first output port of the first MZM is connected to the reflector; the second output port of the first MZM is connected to the first input port of the second optical coupler through a third optical transmission path; the second input port of the first MZM is connected to the second input port of the second optical coupler through a fourth optical transmission path; and the third phase shifter is arranged on the third optical transmission path or the fourth optical transmission path.

6. The harmonic generator according to claim 5, characterized in that The harmonic generator also includes a power regulator; The power regulator is provided on the first optical transmission path or the second optical transmission path.

7. The harmonic generator according to claim 5 or 6, characterized in that: The harmonic generator also includes a second phase shifter; The second phase shifter is arranged on the first optical transmission path or the second optical transmission path.

8. The harmonic generator according to any one of claims 5 to 6, characterized in that: The splitting ratio of the first optical coupler is a:1-a, and the value range of a is between 0.4 and 0.

6.

9. The harmonic generator according to claim 5, characterized in that: The splitting ratio of the second optical coupler is r: 1-r, wherein the value range of r is 0.02 to 0.

2.

10. The harmonic generator according to claim 5 or 9, characterized in that: The second optical coupler is an adjustable optical coupler.

11. A harmonic modulation component, characterized in that: The method comprises a modulator group, a beam combiner and a harmonic generator as claimed in any one of claims 1 to 10, wherein: The modulator group includes a first modulator and a second modulator; An output port of the harmonic generator is connected to the first modulator; Another output port of the harmonic generator is connected to the second modulator; The output end of the first modulator is connected to the first input end of the beam combiner; The output end of the second modulator is connected to the second input end of the beam combiner.

12. The harmonic modulation component according to claim 11, characterized in that: The first modulator and the second modulator are intensity modulators.

13. The harmonic modulation component according to claim 11, characterized in that: The first modulator and the second modulator are IQ modulators.

14. The harmonic modulation component according to claim 13, characterized in that: The harmonic modulation assembly further comprises a polarization splitter, another modulator group, another beam combiner, a polarization combiner and another harmonic generator as claimed in any one of claims 1 to 10; The first output port of the polarization splitter is connected to the input port of the harmonic generator; The second output port of the polarization splitter is connected to the input port of the other harmonic generator; The another modulator group includes a third modulator and a fourth modulator; An output port of the other harmonic generator is connected to the third modulator; Another output port of the another harmonic generator is connected to the fourth modulator; The output port of the third modulator is connected to the first input port of the other beam combiner; The output port of the fourth modulator is connected to the second input port of the other beam combiner; The output port of the beam combiner is connected to the first input port of the polarization combiner; The output port of the other beam combiner is connected to the second input port of the polarization combiner.

15. The harmonic modulation component according to any one of claims 11 to 14, characterized in that: The first modulator and the second modulator are linearized optical modulators.

16. An optical module, characterized in that: A method comprising a light source and a harmonic modulation component as claimed in any one of claims 11 to 15, wherein: The light source is used to generate a light beam, and transmit the light beam to the harmonic modulation component; The harmonic modulation component is used to modulate the light beam to obtain a modulated light signal.

17. An optical communication device, characterized in that: The optical module comprises a processor and the optical module as claimed in claim 16, wherein: The processor is used to divide the electrical signal to be modulated into a first electrical signal and a second electrical signal, the bandwidths of the first electrical signal and the second electrical signal are the same and both are smaller than the bandwidth of the electrical signal to be modulated, and transmit the first electrical signal and the second electrical signal to the optical module; The optical module is used to generate a light beam, and a first light beam and a second light beam are obtained according to the light beam, a carrier of the first light beam and a carrier of the second light beam are in phase, and an odd-order harmonic of the first light beam and an odd-order harmonic of the second light beam are in opposite phases; The optical module is further used to modulate the first light beam by the first electrical signal to obtain a first modulated light signal, and to modulate the second light beam by the second electrical signal to obtain a second modulated light signal; The optical module is further used to combine the first modulated optical signal and the second modulated optical signal to obtain a modulated optical signal.

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