On-chip silicon-based electro-optic modulator

Abstract

This disclosure provides an on-chip silicon-based electro-optic modulator comprising: an input waveguide; a Mach-Zehnder type modulation unit, the input end of which is connected to the input waveguide, the Mach-Zehnder type modulation unit including a modulation arm, the arm length of which is less than 2 mm to increase the bandwidth of the output optical signal; a nonlinear switching unit including: a first 1×2 beam splitter connected to the output end of the Mach-Zehnder type modulation unit; a first power arm connected to one output end of the first 1×2 beam splitter; a second power arm connected to the other output end of the first 1×2 beam splitter, the power of the second power arm being higher than that of the first power arm; and a 2×2 coupler including a first output port and a second output port, the two input ends of the 2×2 coupler being connected to the first power arm and the second power arm respectively, the 2×2 coupler being configured to respond to an increase in the phase difference due to the Kerr effect, thereby increasing the extinction ratio of the modulation signal output from the first output port.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of optical communication technology, and more particularly, to a silicon-based electro-optical modulator on chip. BACKGROUND

[0002] Optical communication technology plays an important role in modern communication, and optical modulators are important elements in optical fiber communication, which can load electrical signals on optical carriers for high-speed transmission through electro-optical modulation. Silicon-based modulators based on complementary metal oxide semiconductor (CMOS) process have advantages of high yield, low cost and large modulation bandwidth. There are three main structures of silicon-based modulators: Mach-Zehnder modulator based on Mach-Zehnder interferometer, micro-ring / micro-disk modulator based on resonant cavity, and waveguide modulator based on electrical absorption. Among them, the most widely used is the Mach-Zehnder interferometer structure modulator. In the design of the modulation region, the length of the traveling wave electrode depends on the length of the modulation region, and the electro-optical bandwidth of the modulator is inversely proportional to the length of the traveling wave electrode. At the same time, the length of the modulation region also needs to be long enough to make the extinction ratio of the modulator meet the requirements.

[0003] At present, the traditional silicon-based electro-optical modulator based on Mach-Zehnder interferometer needs to trade off between electro-optical bandwidth and extinction ratio. This means that when a certain extinction ratio is guaranteed, the electro-optical bandwidth often has a limit. The existing technical solutions have an electro-optical bandwidth bottleneck, which cannot meet the high bandwidth and high extinction ratio requirements of the on-chip optical modulator. SUMMARY

[0004] To solve the at least one of the above and other problems in the prior art, the present disclosure provides a silicon-based electro-optical modulator on chip, which modulates the optical signal by combining a Mach-Zehnder type modulation unit and a nonlinear switch unit, adjusts the arm length of the modulation arm of the Mach-Zehnder type modulation unit to be less than 2mm, and uses the first power arm and the second power arm of the nonlinear switch unit to generate a Kerr effect phase difference to increase the extinction ratio of the modulation signal output through the first output port, thereby increasing the bandwidth of the optical signal while ensuring the extinction ratio of the optical signal.

[0005] The embodiment of the present disclosure provides a silicon-based electro-optical modulator on a chip, which comprises: an input waveguide for inputting an optical signal; a Mach-Zehnder type modulation unit, an input end of which is connected with the input waveguide, the Mach-Zehnder type modulation unit comprising a modulation arm, an arm length of the modulation arm being less than 2 mm to increase a bandwidth of an output optical signal; and a nonlinear switching unit comprising: a first 1*2 beam splitter, an output end of which is connected with an output end of the Mach-Zehnder type modulation unit; a first power arm, one output end of the first 1*2 beam splitter being connected with the first power arm, the first power arm being suitable for suppressing a Kerr effect of a modulated optical signal; a second power arm, the other output end of the first 1*2 beam splitter being connected with the second power arm, a power of the second power arm being higher than that of the first power arm, so that a Kerr effect of the second power arm is greater than that of the first power arm, thereby generating a Kerr effect phase difference; and a 2*2 coupler, comprising a first output port and a second output port, two input ends of the 2*2 coupler being connected with the first power arm and the second power arm respectively, the 2*2 coupler being configured to increase an extinction ratio of a modulation signal output by the first output port in response to an increase of the Kerr effect phase difference.

[0006] According to some embodiments of the present disclosure, the Mach-Zehnder modulation unit further comprises: a second 1*2 beam splitter, an input end of which is connected with the input waveguide, the second 1*2 beam splitter being suitable for splitting the optical signal into two beams; a first modulation arm, an input end of which is connected with a first output end of the second 1*2 beam splitter, the first modulation arm comprising: a thermal tuning region, suitable for modulating one beam of the optical signal by using a thermo-optic effect; and a first modulation region, suitable for electro-optically modulating the optical signal modulated by the thermal tuning region by using a plasmonic dispersion effect; and a second modulation arm, an input end of which is connected with a second output end of the second 1*2 beam splitter, the second modulation arm comprising a second modulation region, the second modulation region being suitable for electro-optically modulating the other beam of the optical signal by using the plasmonic dispersion effect; wherein the first modulation region and the second modulation region have the same doping region cross section and length; and the first modulation region and the second modulation region are respectively driven by using a differential electrical signal through a traveling wave electrode.

[0007] According to some embodiments of the present disclosure, the first modulation arm and the second modulation arm have the same waveguide cross section and arm length to balance a phase difference of the first modulation arm and the second modulation arm except the thermal tuning region, the first modulation region and the second modulation region.

[0008] According to some embodiments of the present disclosure, the Mach-Zehnder modulation unit further comprises a 2x1 combiner, a first input end of the 2x1 combiner is connected with an output end of the first modulation arm, a second input end of the 2x1 combiner is connected with an output end of the second modulation arm, and the 2x1 combiner is used to combine the optical signals of the first modulation arm and the second modulation arm.

[0009] According to some embodiments of the present disclosure, the first power arm comprises a cascaded splitting-combining group, which is used to reduce the optical power of one of the optical signals output by the first 1x2 splitter, so as to reduce the phase shift of the Kerr effect of the first power arm; and a first thermal tuning region, which is adapted to modulate the optical signal output by the cascaded splitting-combining group, so as to compensate for the phase shift caused by manufacturing errors.

[0010] According to some embodiments of the present disclosure, the second power arm comprises a second thermal tuning region, which is adapted to modulate the other optical signal output by the first 1x2 splitter, so as to compensate for the phase shift caused by manufacturing errors; and wherein the voltages of the first thermal tuning region and the second thermal tuning region are adjusted to increase the extinction ratio of the modulation signal output through the first output port.

[0011] According to some embodiments of the present disclosure, the first power arm and the second power arm have the same length, so that the transmission losses are the same and the amplitudes are balanced.

[0012] According to some embodiments of the present disclosure, the cascaded splitting-combining group comprises a plurality of cascaded splitting-combining units, each of which comprises a splitter and a combiner, and at least two waveguides which are arranged in parallel between the splitter and the combiner.

[0013] According to some embodiments of the present disclosure, the 2x2 coupler is a 3dB coupler, and the 2x2 coupler is a splitter based on multimode interference or a 3dB directional coupler based on evanescent wave coupling.

[0014] According to some embodiments of the present disclosure, the electro-optical modulator is configured by photolithography and etching of a top layer of silicon on an insulator.

[0015] The present disclosure provides a silicon-based electro-optical modulator on a chip, which modulates an optical signal by combining a Mach-Zehnder modulation unit and a nonlinear switching unit, adjusts the arm length of the modulation arm of the Mach-Zehnder modulation unit to be less than 2mm, generates a Kerr effect phase difference by using the first power arm and the second power arm of the nonlinear switching unit to increase the extinction ratio of the modulation signal output through the first output port, and increases the extinction ratio by using the small loss of the nonlinear switching unit to increase the electro-optical bandwidth. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structure diagram of a silicon-based electro-optical modulator on chip according to an exemplary embodiment of the present disclosure;

[0017] Figure 2 is a diagram showing the change of the output optical power of a Mach-Zehnder modulation unit according to an exemplary embodiment of the present disclosure;

[0018] In the drawings, the meanings of the reference signs are as follows:

[0019] 100, Mach-Zehnder type modulation unit;

[0020] 101, second 1x2 beam splitter;

[0021] 102, first modulation arm;

[0022] 103, thermal tuning region;

[0023] 104, first modulation region;

[0024] 105, second modulation arm;

[0025] 106, second modulation region;

[0026] 107, 2x1 beam combiner;

[0027] 200, nonlinear switch unit;

[0028] 201, first 1x2 beam splitter;

[0029] 202, first power arm;

[0030] 203, cascaded beam splitting and combining group;

[0031] 204, first thermal tuning region;

[0032] 205, second power arm;

[0033] 206, second thermal tuning region;

[0034] 207, 2x2 coupler;

[0035] 208, first output port;

[0036] 209, second output port;

[0037] 300, input waveguide. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the present disclosure is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the terms "comprises", "comprising", "includes", "including" and the like are, generally used

[0040] All terms used herein including technical and scientific terms have the meanings commonly understood by one of ordinary skill in the art unless otherwise specified. It should be noted that the use of any terms herein should not be interpreted to limit the disclosure in any way unless otherwise explicitly stated.

[0041] In the case of using expressions similar to "at least one of A, B, and C, etc.", it should generally be interpreted to include any of them, to include, for example, a system having at least one of A, a system having at least one of B, a system having at least one of C, a system having at least one of A and B, a system having at least one of A and C, a system having at least one of B and C, and / or a system having at least one of A, B, and C, etc. In the case of using expressions similar to "at least one of A, B, or C, etc.", it should generally be interpreted to include any of them, to include, for example, a system having at least one of A, a system having at least one of B, a system having at least one of C, a system having at least one of A and B, a system having at least one of A and C, a system having at least one of B and C, and / or a system having at least one of A, B, and C, etc.

[0042] For the purpose of making the purposes, technical solutions and advantages of the disclosure more clear, further detailed description of the disclosure is made below in combination with specific embodiments and with reference to the drawings.

[0043] Figure 1 is a structural diagram of a silicon-based electro-optical modulator on chip according to an exemplary embodiment of the disclosure.

[0044] The silicon-based electro-optical modulator on chip provided by the embodiments of the disclosure, as shown in Figure 1 The silicon-based electro-optical modulator on chip includes a Mach-Zehnder type modulation unit 100, a nonlinear switch unit 200, and an input waveguide 300.

[0045] The input waveguide 300 is used for inputting an optical signal; an input end of the Mach-Zehnder type modulation unit 100 is connected with the input waveguide 300, and the Mach-Zehnder type modulation unit 100 includes a modulation arm, and an arm length of the modulation arm is less than 2 mm to increase a bandwidth of an output optical signal.

[0046] The nonlinear switch unit 200 comprises a first 1x2 beam splitter 201, a first power arm 202, a second power arm 205 and a 2x2 coupler 207. The first 1x2 beam splitter 201 is connected with the output end of the Mach-Zehnder modulation unit 100. The first power arm 202 is connected with one output end of the first 1x2 beam splitter 201. The first power arm 202 is adapted to suppress the Kerr effect of the modulated optical signal. The second power arm 205 is connected with the other output end of the first 1x2 beam splitter 201. The power of the second power arm 205 is higher than that of the first power arm 202, so that the Kerr effect of the second power arm 205 is greater than that of the first power arm 202, thereby generating a Kerr effect phase difference. The 2x2 coupler 207 comprises a first output port 208 and a second output port 209. Two input ends of the 2x2 coupler 207 are connected with the first power arm 202 and the second power arm 205 respectively. The 2x2 coupler 207 is configured to increase the extinction ratio of the modulated signal output by the first output port 208 in response to the increase of the Kerr effect phase difference.

[0047] In the embodiment, the Mach-Zehnder modulation unit and the nonlinear switch unit are combined to modulate the optical signal. The arm length of the modulation arm of the Mach-Zehnder modulation unit is adjusted to be less than 2 mm. The Kerr effect phase difference is generated by the first power arm and the second power arm of the nonlinear switch unit to increase the extinction ratio of the modulated signal output by the first output port. The loss of the nonlinear switch unit 200 is small, the electro-optical bandwidth is increased, and the extinction ratio is increased. According to the embodiment of the present disclosure, the electro-optical modulator is configured by photolithography and etching of the top layer silicon of the silicon-on-insulator.

[0048] According to the embodiment of the present disclosure, the electro-optical modulator is implemented based on a silicon-on-insulator (SOI) platform, which is usually implemented by photolithography and etching of the top layer silicon of the SOI. The top layer silicon is etched to form a square waveguide, which can be a strip waveguide or a ridge waveguide. The waveguide is characterized in that the refractive index of the waveguide core (Si) is higher than that of the waveguide cladding (which can be silicon dioxide or air). For a square waveguide, there is a cutoff frequency for a specific electromagnetic wave (light wave), so there are single-mode waveguides and multi-mode waveguides. The cross-sectional dimensions of the waveguide involved in the present disclosure meet the single-mode requirement.

[0049] According to the embodiment of the present disclosure, the 2x2 coupler 207 is a 3dB coupler. The 2x2 coupler 207 is a beam splitter based on multi-mode interference or a 3dB directional coupler based on evanescent wave coupling.

[0050] According to an embodiment of the present disclosure, the 2x2 coupler 207 can also be a 3dB coupler designed reversely. The reverse design is a method of solving the structure of a device reversely by targeting an expected result, relying on an intelligent algorithm and model training, and combining a computer and silicon light.

[0051] According to an embodiment of the present disclosure, the Mach-Zehnder modulation unit 100 further comprises: a second 1x2 beam splitter 101, an input end of which is connected with the input waveguide 300, the second 1x2 beam splitter 101 being adapted to split the optical signal into two beams; a first modulation arm 102, an input end of which is connected with a first output end of the second 1x2 beam splitter 101, the first modulation arm 102 comprising: a thermal tuning region 103 adapted to modulate one of the two beams of optical signal by using the thermo-optic effect; and a first modulation region 104 adapted to perform electro-optic modulation on the optical signal modulated by the thermal tuning region 103 by using the plasmonic dispersion effect; and a second modulation arm 105, an input end of which is connected with a second output end of the second 1x2 beam splitter 101, the second modulation arm 105 comprising a second modulation region 106 adapted to perform electro-optic modulation on the other beam of optical signal by using the plasmonic dispersion effect; wherein the first modulation region 104 and the second modulation region 106 have the same doping region cross section and length; the first modulation region 104 and the second modulation region 106 respectively use one traveling wave electrode, and are differentially driven by using a differential electrical signal.

[0052] According to an embodiment of the present disclosure, the thermal tuning region 103 of the Mach-Zehnder modulation unit 100 utilizes the thermo-optic effect of silicon, and a thermal pole is arranged on the thermal tuning region 103, and the material of the thermal pole can be selected from titanium nitride TiN or metal tungsten and other resistive materials.

[0053] According to an embodiment of the present disclosure, the first modulation region 104 and the second modulation region 106 of the Mach-Zehnder modulation unit 100 utilize the plasmonic dispersion effect of silicon, and the modulation arm structure based on the carrier dispersion effect mainly has three types: carrier accumulation type, carrier injection type, and carrier depletion type. The carrier accumulation type is to build a silicon dioxide barrier layer in the center of the waveguide to form a MOS capacitor, that is, a metal-oxide-semiconductor capacitor, and to change the refractive index in the waveguide by charging and discharging the capacitor to accumulate at the interface between the silicon dioxide and the silicon, thereby achieving modulation of light. The carrier injection type is to change the refractive index of the waveguide by positively injecting carriers into the central waveguide region, which can have the highest modulation efficiency, but due to the characteristics of positive injection (carrier lifetime limitation), it cannot realize high-speed changes in carrier concentration, and the modulation speed is greatly limited, with a modulation rate generally in the order of hundreds of megabits per second. The carrier depletion type is to change the refractive index in the waveguide by changing the carrier concentration near the depletion region by applying a reverse bias to the PN junction. The reverse junction capacitance of the PN junction is relatively small, so its modulation efficiency is the lowest among various structures, but the depletion type modulation is not limited by the lifetime of the carriers, and the drift motion under bias is very fast. An embodiment of the present disclosure adopts the carrier depletion type.

[0054] Figure 2 is a diagram showing the change of the optical power of the Mach-Zehnder modulation unit 100 according to an illustrative embodiment of the present disclosure.

[0055] According to an embodiment of the present disclosure, as shown in Figure 2 , the optical power bias point of the displayed optical signal will change by changing the voltage through the thermo-optic effect of the thermal modulation region 103, and the amplitude of the radio frequency signal is adjusted to adjust the optical power of the optical signal by changing the voltage value through the plasmonic dispersion effect of the first modulation region 104 and the second modulation region 106.

[0056] According to an embodiment of the present disclosure, the Mach-Zehnder modulation unit 100 further comprises a 2x1 combiner 107, a first input end of the 2x1 combiner 107 is connected with an output end of the first modulation arm 102, a second input end of the 2x1 combiner 107 is connected with an output end of the second modulation arm 105, and the 2x1 combiner 107 is used for combining the optical signals of the first modulation arm 102 and the second modulation arm 105.

[0057] According to an embodiment of the present disclosure, the first modulation arm 102 and the second modulation arm 105 have the same waveguide cross section and arm length to balance the phase difference of the first modulation arm 102 and the second modulation arm 105 except for the thermal modulation region 103, the first modulation region 104, and the second modulation region 106.

[0058] According to an embodiment of the present disclosure, the first power arm 202 comprises: a cascaded beam splitting and combining group 203 for reducing the optical power of one of the optical signals output by the first 1x2 beam splitter 201, thereby reducing the phase shift of the Kerr effect of the first power arm 202; and a first thermal tuning region 204 adapted to modulate the optical signal output by the cascaded beam splitting and combining group 203 to compensate for the phase shift caused by manufacturing errors.

[0059] According to an embodiment of the present disclosure, the cascaded beam splitting and combining group 203 comprises a plurality of cascaded beam splitting and combining units, each of which comprises: a beam splitter and a beam combiner; and at least two waveguides arranged in parallel between the beam splitter and the beam combiner.

[0060] According to an embodiment of the present disclosure, the cascaded beam splitting and combining group 203 comprises a plurality of beam splitters, waveguides and a plurality of beam combiners, a 1x2 3dB beam splitter splits the optical signal into two paths, and the optical power of each path is reduced by 3dB. By cascading N 1x2 3dB beam splitters, the optical power of each path can be reduced by 3NdB. Finally, N 2x1 3dB beam combiners are used to combine the signals into one path. This process makes the first power arm 202 have smaller power in the cascaded beam splitting and combining group 203 than the second power arm 205, thereby having smaller phase shift of the Kerr effect than the second power arm 205.

[0061] According to an embodiment of the present disclosure, the second power arm 205 comprises: a second thermal tuning region 206 adapted to modulate the other optical signal output by the first 1x2 beam splitter 201 to compensate for the phase shift caused by manufacturing errors; and wherein the voltages of the first thermal tuning region 204 and the second thermal tuning region 206 are adjusted to increase the extinction ratio of the modulated signal output through the first output port 208.

[0062] According to an embodiment of the present disclosure, the first thermal tuning region 204 and the second thermal tuning region 206 of the nonlinear switch unit 200 utilize the thermo-optic effect of silicon, and a hot pole is arranged on the first thermal tuning region 204 and the second thermal tuning region 206. The material of the hot pole can be selected from titanium nitride TiN or metal tungsten and other resistive materials.

[0063] According to an embodiment of the present disclosure, the first power arm 202 and the second power arm 205 have the same length, so that the transmission loss is the same and the amplitude is balanced.

[0064] According to an embodiment of the present disclosure, the corresponding high and low level powers of the modulated optical signal before entering the nonlinear switch unit 200 are P p1 and P p2 After passing through the first 1x2 beam splitter 201, the modulated optical signal is split into two optical signals with the same amplitude. One path enters the first power arm 202, and the other path enters the second power arm 205. The optical signal of the first power arm 202 is first split into N (for example, N=4) by the cascaded beam splitting units in the cascaded beam splitting and combining group 203, and then the optical signal of each path is reduced by 3NdB (for example, N=4, 3NdB=12dB) by the cascaded beam splitting and combining units in the cascaded beam splitting and combining group 203. Figure 1N paths of light signals, the power of each path of light signal is reduced to 1 / N of the input power arm 202, and the N paths of light signals are again combined into one path of light signal by the cascaded combining unit after a distance in the cascaded beam splitting and combining group 203; and the light signal of the second power arm 205 is transmitted in the second power arm 205 for a length equal to the length of the light signal of the first power arm 202 transmitted in the first power arm 202. Since the modulated light signal has two high and low levels, the Kerr effect phase difference induced in the second power arm 205 and the first power arm 202 in the high level case is:

[0065]

[0066] The Kerr effect phase difference of the second power arm 205 and the first power arm 202 in the low level case is:

[0067]

[0068] wherein, P p1_high (mW) is the high level power value, P p1_low (mW) is the reduced light power value of the high level power value after the cascaded beam splitting, P p2_high (mW) is the low level power value, P p2_low (mW) is the reduced light power value of the low level power value after the cascaded beam splitting, and γ is the nonlinear coefficient of the waveguide cross section, L eff is the length of the first power arm 202 between the cascaded beam splitting and the cascaded combining unit. For the nonlinear switching unit 200, let P in be the light power before the input of the nonlinear switching unit 200, and the phase difference of the first power arm 202 and the second power arm 205 is denoted as The power of the first output port 208 is:

[0069]

[0070] The first thermal adjustment region 204 and the second thermal adjustment region 206 are adjusted so that the light power in the high level case reaches the maximum in the first output port 208:

[0071] P p1_out1 = P p1 (4)

[0072] The voltage of the first thermal adjustment region 204 and the second thermal adjustment region 206 is kept unchanged, and since:

[0073]

[0074] When the output port light signal is the strongest in the high level case, the output port light signal is the weakest in the low level case:

[0075] Pp2_out1 ≈0<P p2 (6)

[0076] Since the error of actual manufacturing process is considered, it is not equal to zero, and the optical signal extinction ratio at this time is:

[0077] ER=10log10(P p1_out1 / P p2_out1 ) (7)

[0078] The optical signal extinction ratio after the Mach-Zehnder type modulation unit 100 is:

[0079] ER=10log10(P p1 / P p2 ) (8)

[0080] It can be found through the calculation of formula (7) and formula (8) and the comparison of results that the extinction ratio of the optical signal modulated by the nonlinear switch unit 200 is significantly improved. Therefore, the modulated optical signal transmitted by the Mach-Zehnder type modulation unit 100 and the nonlinear switch unit 200 has a large electro-optic modulation bandwidth and a large extinction ratio.

[0081] It should be further noted that the directional terms mentioned in the embodiments, such as “up”, “down”, “front”, “back”, “left”, “right”, etc., are only the directions of the drawings and are not intended to limit the protection scope of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion to the understanding of the present disclosure, the conventional structures or configurations will be omitted.

[0082] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A silicon-on-chip based electro-optic modulator, characterized by, Comprising: an input waveguide for inputting an optical signal; a Mach-Zehnder type modulation unit, an input end of which is connected with the input waveguide, the Mach-Zehnder type modulation unit comprising modulation arms, an arm length of the modulation arms being less than 2 mm to increase a bandwidth of an output optical signal; and a nonlinear switching unit comprising: a first 1x2 beam splitter, an output end of which is connected with an output end of the Mach-Zehnder type modulation unit; a first power arm, one output end of the first 1x2 beam splitter being connected with the first power arm, the first power arm being adapted to suppress a Kerr effect of a modulated optical signal; a second power arm, the other output end of the first 1x2 beam splitter being connected with the second power arm, a power of the second power arm being higher than a power of the first power arm, so that a Kerr effect of the second power arm is greater than a Kerr effect of the first power arm, thereby generating a Kerr effect phase difference; a 2x2 coupler, the 2x2 coupler comprising a first output port and a second output port, two input ends of the 2x2 coupler being connected with the first power arm and the second power arm respectively, the 2x2 coupler being configured to increase an extinction ratio of a modulation signal output by the first output port in response to an increase of the Kerr effect phase difference.

2. The silicon-based electro-optic modulator on-chip based according to claim 1, characterized in that, The Mach-Zehnder modulation unit further comprises: a second 1x2 beam splitter, an input end of which is connected with the input waveguide, the second 1x2 beam splitter being adapted to split the optical signal into two beams; a first modulation arm, an input end of which is connected with a first output end of the second 1x2 beam splitter, the first modulation arm comprising: a thermal tuning region, adapted to modulate one of the two beams of the optical signal by using a thermo-optic effect; and a first modulation region, adapted to electro-optically modulate the one of the two beams of the optical signal modulated by the thermal tuning region by using a plasma dispersion effect; and a second modulation arm, an input end of which is connected with a second output end of the second 1x2 beam splitter, the second modulation arm comprising a second modulation region, the second modulation region being adapted to electro-optically modulate the other of the two beams of the optical signal by using the plasma dispersion effect; wherein the first modulation region and the second modulation region have the same doping region cross section and length; the first modulation region and the second modulation region respectively use a traveling wave electrode, and are differentially driven by using a differential electrical signal.

3. The silicon-on-chip based electro-optic modulator of claim 2, wherein, The first modulation arm and the second modulation arm have the same waveguide cross section and arm length to balance a phase difference of the first modulation arm and the second modulation arm except for the thermal tuning region, the first modulation region and the second modulation region.

4. The silicon-on-chip based electro-optic modulator of claim 2, wherein, The Mach-Zehnder modulation unit further comprises: a 2x1 beam combiner, a first input end of the 2x1 beam combiner being connected with an output end of the first modulation arm, a second input end of the 2x1 beam combiner being connected with an output end of the second modulation arm, the 2x1 beam combiner being used to combine the optical signals of the first modulation arm and the second modulation arm.

5. The silicon-based electro-optical modulator on chip according to claim 1, wherein the first power arm comprises: a cascaded beam splitting and combining group, used to reduce an optical power of one of the beams of the optical signal output by the first 1x2 beam splitter, thereby reducing a phase shift of the Kerr effect of the first power arm; The first thermal tuning region is adapted to modulate the optical signal outputted from the cascaded beam splitting and combining group to compensate for the phase shift caused by manufacturing error. 6.The silicon-on-insulator based electro-optical modulator according to claim 5, wherein, the second power arm comprises: The second thermal tuning region is adapted to modulate the other optical signal outputted from the first 1×2 beam splitter to compensate for the phase shift caused by manufacturing error. The voltage of the first thermal tuning region and the second thermal tuning region is adjusted to increase the extinction ratio of the modulated signal outputted from the first output port.

7. The on-silicon, silicon-based electro-optic modulator of claim 1, wherein, The first power arm and the second power arm have the same length to make the transmission loss the same and the amplitude balanced.

8. The silicon-on-chip based electro-optic modulator of claim 5, wherein, The cascaded beam splitting and combining group comprises a plurality of cascaded beam splitting and combining units, each of which comprises: a beam splitter and a beam combiner; and at least two waveguides arranged in parallel between the beam splitter and the beam combiner.

9. The on-silicon, silicon-based electro-optic modulator of claim 1, wherein, The 2×2 coupler is a 3dB coupler, which is a beam splitter based on multimode interference or a 3dB directional coupler based on evanescent wave coupling.

10. The on-silicon, silicon-based electro-optical modulator of claim 1, wherein, The electro-optical modulator is configured to be obtained by photolithography and etching of the top layer of silicon on insulator.

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