Silicon-based modulator chip based on resonance spectrum compensation

Abstract

The invention provides a silicon-based modulator chip based on resonance spectrum compensation, and relates to the technical field of silicon-based modulator chips. The silicon-based modulator chip based on resonance spectrum compensation comprises a first unit, a second unit and a first support arm, and the first unit and the second unit are arranged on the first support arm; wherein the first unit is used for performing amplitude modulation and phase modulation processing on an input first light beam to output a second light beam, and the transmission directions of the second light beam and the first light beam on the first support arm are the same; the second unit is used for carrying out amplitude modulation and phase modulation processing on the modulated and phase-modulated second light beam to output a third light beam, and the transmission directions of the third light beam and the second light beam on the first support arm are opposite; the amplitude and the phase of the second light beam are controlled through the first unit, and the amplitude and the phase of the third light beam are controlled through the second unit, so that the second light beam and the third light beam interfere in the first support arm to form a resonance spectrum with adjustable linearity.

Description

Technical Field

[0001] The present disclosure relates to the technical field of silicon-based modulator chips, and more particularly, to a silicon-based modulator chip based on resonance spectrum compensation. Background Art

[0002] Microwave photonic links based on analog signal transmission have strict requirements on the linearity of electro-optic modulators. For silicon-based integrated microwave photonic chips and systems, the linearity of silicon-based electro-optic modulators directly determines the degree of distortion of the transmitted signal in the system. How to improve the linearity of silicon-based modulators has been one of the research hotspots in academia and industry in recent years. Summary of the invention

[0003] In view of this, the present disclosure provides a silicon-based modulator chip based on resonance spectrum compensation.

[0004] The present disclosure provides a silicon-based modulator chip based on resonance spectrum compensation, comprising: a first unit 1, a second unit 2 and a first arm 3, wherein the first unit 1 and the second unit 2 are arranged on the first arm 3; wherein the first unit 1 is used to perform amplitude modulation and phase modulation processing on the input first light beam i to output a second light beam ii-1, and the transmission direction of the second light beam ii-1 and the first light beam i on the first arm 3 is the same; the second unit 2 is used to perform amplitude modulation and phase modulation processing on the modulated and phase-modulated second light beam ii-1 to output a third light beam iii-1, and the transmission direction of the third light beam iii-1 and the second light beam ii-1 on the first arm 3 are opposite; the amplitude and phase of the second light beam ii-1 are controlled by the first unit 1, and the amplitude and phase of the third light beam iii-1 are controlled by the second unit 2, so that the second light beam ii-1 and the third light beam iii-1 interfere with each other in the first arm 3 to form a resonance spectrum with adjustable linearity.

[0005] According to an embodiment of the present disclosure, the first unit 1 includes a first interferometer 11 and a first annular optical waveguide 12; the first interferometer 11 is connected to the first arm 3, and is used to perform a first beam splitting on the input first light beam i to generate a fourth light beam i-1 and a fifth light beam i-2, and the fourth light beam i-1 and the fifth light beam i-2 are phase-adjusted and combined in sequence, and the splitting ratio of the second beam splitting is determined according to the phase difference between the fourth light beam i-1 and the fifth light beam i-2 after phase adjustment, so as to output a sixth light beam i-3 and a seventh light beam i-4; the first annular optical waveguide 12 is connected to the first interferometer 11, and is used to bidirectionally transmit the received sixth light beam i-3 and the seventh light beam i-4, so as to output an eighth light beam i-3' and a ninth light beam i-4'.

[0006] According to an embodiment of the present disclosure, the first interferometer 11 is also used to: perform a first beam combining and splitting process, a phase adjustment process and a second beam combining and splitting process on the received eighth beam i-3' and ninth beam i-4' in sequence to output a second beam ii-1 and a tenth beam ii-2.

[0007] According to an embodiment of the present disclosure, the first interferometer 11 includes: a first multimode interferometer 111, which is used to combine and / or split an input light beam; a second multimode interferometer 112, which is used to combine and split an input light beam; an upper arm 113 and a lower arm 114, which are used to perform phase modulation processing on the input light beam; the first multimode interferometer 111 includes a first input end, a second input end, a first output end, and a second output end; the first input end is used to input a first light beam i, the second input end is used to output a second light beam ii-1, the first output end is connected to one end of the upper arm 113, and the second output end is connected to one end of the lower arm 114; the second The multimode interferometer 112 includes a third input end, a fourth input end, a third output end and a fourth output end; the third input end is connected to the other end of the upper arm 113, the fourth input end is connected to the other end of the lower arm 114, the third output end is connected to one end of the first annular optical waveguide 12, and is used to output one of the sixth light beam i-3 and the seventh light beam i-4, and receive one of the eighth light beam i-3' and the ninth light beam i-4'; the fourth output end is connected to the other end of the first annular optical waveguide 12, and is used to output the other of the sixth light beam i-3 and the seventh light beam i-4, and receive the other of the eighth light beam i-3' and the ninth light beam i-4'.

[0008] According to an embodiment of the present disclosure, the upper arm 113 includes a first thermo-optical phase shifter 115, and the lower arm 114 includes a second thermo-optical phase shifter 116. The first thermo-optical phase shifter 115 and the second thermo-optical phase shifter 116 are used to adjust the phases of the two corresponding light beams on the upper arm 113 and the lower arm 114.

[0009] According to an embodiment of the present disclosure, when the first light beam i is input through the first input end, the phase difference between the corresponding two light beams on the upper arm 113 and the lower arm 114 is adjusted to control the splitting ratio of the second multimode interferometer 112; when the third output end and the fourth output end receive the eighth light beam i-3' and the ninth light beam i-4' correspondingly, the phase difference between the corresponding two light beams on the upper arm 113 and the lower arm 114 is adjusted to control the splitting ratio of the first multimode interferometer 111.

[0010] According to an embodiment of the present disclosure, the first multimode interferometer 111 is also configured as follows: when the third output end and the fourth output end correspondingly receive the eighth light beam i-3' and the ninth light beam i-4', according to the splitting ratio of the first multimode interferometer 111, the first input end is also used to output the tenth light beam ii-2; wherein the tenth light beam ii-2 is used to monitor the linearity of the resonance spectrum, and to regulate the phase and amplitude of the second light beam ii-1 and the third light beam iii-1 according to the monitoring results to achieve adjustable linearity of the resonance spectrum.

[0011] According to an embodiment of the present disclosure, the first arm 3 includes: a first PN junction 31 disposed between the first unit 1 and the second unit 2 , and configured to modulate a small signal to drive the first PN junction 31 to modulate the second light beam.

[0012] According to an embodiment of the present disclosure, the first arm 3 further includes a third thermo-optical phase shifter 32 disposed between the first PN junction 31 and the second unit 32 for adjusting the resonant wavelength of the resonant spectrum.

[0013] According to an embodiment of the present disclosure, it also includes: a second PN junction 41, a fourth thermo-optical phase shifter 42 and a second arm 4, wherein the second PN junction 41 and the fourth thermo-optical phase shifter 42 are arranged on the second arm 4; the second PN junction 41 is configured to modulate a small signal to drive the second PN junction 41 to modulate the input eleventh light beam IV, and to adjust the bias operating point of the first PN junction 31; the fourth thermo-optical phase shifter 42 is used to adjust the phase of the modulated eleventh light beam IV to control the phase difference between the twelfth light beam iii-2 and the modulated and phase-adjusted eleventh light beam IV, wherein the eleventh light beam IV is the input light beam of the second arm, the twelfth light beam iii-2 is the light beam output by the second unit, and the twelfth light beam has the same transmission direction as the first light beam on the first arm (3).

[0014] The silicon-based modulator chip based on resonance spectrum compensation provided in the embodiments of the present disclosure has at least the following beneficial effects:

[0015] By setting the first unit 1 and the second unit 2 to generate the second light beam ii-1 and the third light beam iii-1 with opposite transmission directions, and controlling the amplitude and phase of the second light beam ii-1 and the third light beam iii-1, the second light beam ii-1 and the third light beam iii-1 interfere with each other in the first arm 31 to form a resonance spectrum with adjustable linearity to compensate for the nonlinear distortion generated during the modulation process. The adjustable linearity of the resonance spectrum has high flexibility and can be freely adjusted according to application needs, and has a good linear modulation range. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0017] Figure 1 The structure diagram of the silicon-based modulator chip based on resonance spectrum compensation according to the embodiment of the present disclosure is schematically shown;

[0018] Figure 2 The cross-sectional view of a PN junction and a thermo-optical phase shifter according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known systems and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0020] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0021] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0022] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0023] The spurious-free dynamic range (SFDR) is a property used to describe the degree of linearity of the modulator, which means the range of the baseband signal output frequency and the nonlinear distortion signal output power when the power of the nonlinear distortion signal is equal to the noise floor.

[0024] There are two main methods for optimizing the linearity of silicon-based modulators: electrical domain linear optimization and optical domain linear optimization. Electrical domain linear optimization techniques include pre-distortion compensation, feedback compensation, and digital signal processing, which can improve the SFDR of silicon-based electro-optical modulators by designing complex circuits. However, the bandwidth of such solutions is limited by electronic components and cannot achieve high-speed modulation. At present, typical optical domain linear optimization techniques include micro-ring-assisted silicon-based Mach-Zehnder Modulator (MZM), the introduction of linear electro-optical effects such as lithium niobate materials or III-V materials, and the regulation of carrier distribution in the PN junction of the modulation arm. In addition, the silicon-based micro-ring modulator (Micro-Ring Modulator, MRM) based on the micro-ring resonator structure has great application prospects in microwave photonic links due to its compact structure and high modulation efficiency. However, compared with silicon-based MZM, the modulation curve of silicon-based MRM has stronger nonlinearity. The reported SFDR of silicon-based MRM at 1GHz is only 84dBHz 2 / 3 , its linearity is far from meeting the requirement of at least 100dBHz in microwave photonic links. 2 / 3 requirements.

[0025] Based on this, the embodiments of the present disclosure provide a resonant spectrum line with adjustable linearity to offset the second-order nonlinearity and third-order nonlinearity of the modulated optical signal, thereby obtaining a good linear modulation range.

[0026] Figure 1 The schematic diagram shows the structure of a silicon-based modulator chip based on resonance spectrum compensation according to an embodiment of the present disclosure.

[0027] like Figure 1 As shown, the embodiment of the present disclosure provides a silicon-based modulator chip based on resonance spectrum compensation, including: a first unit 1, a second unit 2 and a first arm 3, wherein the first unit 1 and the second unit 2 are arranged on the first arm 3. The first unit 1, the second unit 2 and the first arm 3 constitute an arm of a Mach-Zehnder interferometer.

[0028] The first unit 1 is used to perform amplitude modulation and phase modulation on the input first light beam i to output a second light beam ii-1, and the transmission direction of the second light beam ii-1 on the first arm 3 is the same as that of the first light beam i.

[0029] The second unit 2 is used for performing amplitude modulation and phase modulation processing on the received second light beam ii-1 to output a third light beam iii-1. The third light beam iii-1 is opposite to the transmission direction of the second light beam ii-1 on the first arm 3.

[0030] The amplitude and phase of the second light beam ii-1 are controlled by the first unit 1, and the amplitude and phase of the third light beam iii-1 are controlled by the second unit 2, so that the second light beam ii-1 and the third light beam iii-1 interfere with each other in the first arm 31 to form a resonant spectrum with adjustable linearity.

[0031] In the embodiments of the present disclosure, when an optical carrier is loaded with a radio frequency signal, nonlinear distortion often occurs during the modulation process due to limitations of material properties and device structure. Nonlinearity usually causes problems such as signal distortion, increased bit error rate, and reduced spurious free dynamic range (SFDR), thereby affecting the quality of signal transmission.

[0032] Based on this, this embodiment controls the first unit 1 to output a second light beam ii-1 in the same transmission direction as the input first light beam i, and controls the second unit 2 to output a third light beam iii-1 in the opposite transmission direction of the second light beam. And by controlling the phase difference between the second light beam ii-1 and the third light beam iii-1, a resonance effect occurs at a specific wavelength to generate a resonance spectrum, which can effectively offset the second-order nonlinearity and third-order nonlinearity generated during the modulation process, and has a good linear modulation range. At the same time, the preset phase difference can be adjusted as needed to change the shape of the resonance spectrum and optimize the linearity.

[0033] On the basis of the above embodiment, the first unit 1 includes a first interferometer 11 and a first ring optical waveguide 12 .

[0034] The first interferometer 11 is connected to the first arm 3, and is used for performing a first beam splitting on the input first light beam i to generate a fourth light beam i-1 and a fifth light beam i-2. The fourth light beam i-1 and the fifth light beam i-2 are phase-adjusted and combined in sequence. The splitting ratio of the second beam splitting is determined according to the phase difference between the fourth light beam i-1 and the fifth light beam i-2 after phase adjustment to output a sixth light beam i-3 and a seventh light beam i-4.

[0035] The first annular optical waveguide 12 is connected to the first interferometer 11, and is used for bidirectionally transmitting the received sixth light beam i-3 and seventh light beam i-4 to output an eighth light beam i-3' and a ninth light beam i-4'.

[0036] Furthermore, the first interferometer 11 is also used to sequentially perform a first beam combining and splitting process, a phase adjustment process and a second beam combining and splitting process on the received eighth light beam i-3' and ninth light beam i-4' to output a second light beam ii-1 and a tenth light beam ii-2.

[0037] In the embodiment of the present disclosure, the first interferometer 11 performs phase modulation after splitting the input first light beam i, and determines the splitting ratio of the second splitting according to the phase difference of the two light beams after phase modulation, thereby realizing the performance of adjustable splitting ratio. The splitting ratio can be flexibly set according to the actual application needs to optimize signal processing. The first annular optical waveguide 12 receives the two light beams i-3 and i-4 output by the first interferometer 11. The two light beams i-3 and i-4 are transmitted toward each other in the first annular optical waveguide 12, and return to the first interferometer 11 after interference occurs at the meeting point. And according to the splitting ratio determined above, it enters the upper and lower arms 113 and 114 of the first interferometer 11, and the phase difference of the two light beams in the upper and lower arms 113 and 114 can be adjusted as needed to determine the splitting ratio of the second splitting to output the second light beam ii-1 and the tenth light beam ii-2. In this embodiment, by accurately adjusting the phase difference of the light beams in the upper and lower branches of the first interferometer 11, the second light beam ii-1 with a preset phase and amplitude can be output as needed. The first interferometer 11 and the first annular optical waveguide 12 form a Sagnac ring 1, which can generate a second light beam ii-1 and a tenth light beam ii-2 with adjustable splitting ratio. The transmission directions of the second light beam and the tenth light beam ii-2 on the first arm 3 are opposite.

[0038] On the basis of the above embodiment, the first interferometer 11 includes: a first multimode interferometer 111, used for combining and / or splitting the input light beam; a second multimode interferometer 112, used for combining and splitting the input light beam; an upper arm 113 and a lower arm 114, used for phase modulation of the input light beam.

[0039] The first multimode interferometer 111 includes a first input end, a second input end, a first output end, and a second output end. The first input end is used to input the first light beam i, the second input end is used to output the second light beam ii-1, the first output end is connected to one end of the upper arm 113, and the second output end is connected to one end of the lower arm 114.

[0040] The second multimode interferometer 112 includes a third input end, a fourth input end, a third output end and a fourth output end. The third input end is connected to the other end of the upper arm 113, and the fourth input end is connected to the other end of the lower arm 114. The third output end is connected to one end of the first annular optical waveguide 12, and is used to output one of the sixth light beam i-3 and the seventh light beam i-4, and to receive one of the eighth light beam i-3' and the ninth light beam i-4'. The fourth output end is connected to the other end of the first annular optical waveguide 12, and is used to output the other of the sixth light beam i-3 and the seventh light beam i-4, and to receive the other of the eighth light beam i-3' and the ninth light beam i-4'.

[0041] In the embodiment of the present disclosure, the beam splitting and combining operations of the first multimode interferometer 111 ensure that the light beam can be accurately distributed to the upper arm 113 and the lower arm 114 of different paths, providing a basis for subsequent phase adjustment. And through the combination of the first multimode interferometer 111, the second multimode interferometer 112, the upper arm 113 and the lower arm 114, the second light beam ii-1 with a preset phase and amplitude can be accurately obtained.

[0042] When the first input end of the first multimode interferometer 111 is used to input the first light beam i, the first multimode interferometer 111 divides the first light beam i into two light beams i-1 and i-1 in equal proportion, and inputs the two light beams i-1 and i-1 in equal proportion into the upper and lower arms 113 and 114 for phase modulation processing. At this time, the first multimode interferometer 111 performs beam splitting processing.

[0043] When the second multimode interferometer 112 receives the two light beams i-3' and i-4' output from the first annular optical waveguide 12, the second multimode interferometer 112 first performs a beam combining process, and then performs a beam splitting process according to the splitting ratio output from the second multimode interferometer 112 to the first annular optical waveguide 12. At this time, the upper and lower arms 113 and 114 receive the two split light beams, and after phase adjustment, input the two light beams into the first multimode interferometer 111 for beam combining, and determine the splitting ratio according to the phase difference between the two light beams to split and output the second light beam ii-1 and the tenth light beam ii-2.

[0044] On the basis of the above embodiment, the upper arm 113 includes a first thermo-optic phase shifter 115, and the lower arm 114 includes a second thermo-optic phase shifter 116. The first thermo-optic phase shifter 115 and the second thermo-optic phase shifter 116 are used to adjust the phases of the two corresponding light beams on the upper arm 113 and the lower arm 114. Two light beams with corresponding phase differences can be output as needed.

[0045] In the embodiments of the present disclosure, the transmission coefficient can be changed by adjusting the voltage loaded on the thermo-optic phase shifters 115 and 116 in the Sagnac ring 1 with adjustable splitting ratio, thereby adjusting the shape of the generated resonance spectrum, and the linearity of the corresponding Lorentz curve can be freely adjusted.

[0046] On the basis of the above embodiment, when the first light beam i is input through the first input end, the phase difference between the two corresponding light beams on the upper arm 113 and the lower arm 114 is adjusted to control the splitting ratio of the second multimode interferometer 112 .

[0047] When the third output end and the fourth output end receive the eighth light beam i-3' and the ninth light beam i-4' respectively, the phase difference between the two corresponding light beams on the upper arm 113 and the lower arm 114 is adjusted to control the splitting ratio of the first multimode interferometer 111.

[0048] In the embodiment of the present disclosure, when the first light beam i is input through the first input end of the first multimode interferometer 111, it is divided into two light beams i-1 and i-2, which enter the upper arm 113 and the lower arm 114 respectively. The two light beams i-1 and i-2 are phase-adjusted by thermo-optical phase shifters in the upper arm 113 and the lower arm 114 respectively. By adjusting the phase difference between the two light beams on the upper arm 113 and the lower arm 114, the interference conditions of the two light beams in the second multimode interferometer 112 can be changed, thereby determining the splitting ratio of the second multimode interferometer 112. Therefore, by adjusting the phase difference, the precise control of the output beam ratio of the second multimode interferometer 112 can be achieved, ensuring that subsequent operations can be performed in accordance with design requirements.

[0049] Similarly, when the second multimode interferometer 112 receives the two light beams i-3' and i-4' output by the first annular optical waveguide 12, the phases of the corresponding light beams are adjusted in the upper and lower arms 113 and 114, and the splitting ratio of the first multimode interferometer 111 is determined according to the phase difference of the light beams at this time.

[0050] By adjusting the phase difference between the upper arm 113 and the lower arm 114 , the splitting ratio of the multi-mode interferometer can be precisely controlled at different stages.

[0051] According to an embodiment of the present disclosure, the first multimode interferometer 111 is further configured as follows: when the third output end and the fourth output end receive the eighth light beam i-3' and the ninth light beam i-4' correspondingly, the first input end outputs the tenth light beam ii-2 according to the splitting ratio of the first multimode interferometer 111. The tenth light beam ii-2 is used to monitor the linearity of the resonance spectrum, and to adjust the amplitude and phase of the second light beam ii-1 and the third light beam iii-1 according to the monitoring result to achieve adjustable linearity of the resonance spectrum.

[0052] In the embodiments of the present disclosure, the parameters of the resonance spectrum can be adjusted in real time through the real-time feedback intensity, extinction ratio, resonance wavelength, modulation depth, etc. of the tenth light beam ii-2, and the free adjustment of the spectrum parameters can be achieved.

[0053] According to an embodiment of the present disclosure, the second unit 2 includes:

[0054] The second interferometer 21 is connected to the first arm 3, and is used for performing a first beam splitting on the modulated and phase-adjusted second light beam ii-1 to generate two light beams, performing phase adjustment and beam combining on the two light beams in turn, and determining the splitting ratio of the second beam splitting according to the phase difference between the two light beams after phase adjustment to output two light beams with adjustable splitting ratio.

[0055] The second annular optical waveguide 22 is connected to the second interferometer 21 and is used for bidirectionally transmitting the two received light beams with adjustable splitting ratio and outputting two light beams.

[0056] The second interferometer 21 is also used for: performing a first beam combining and splitting process on the two light beams output by the received second annular optical waveguide 22 to generate two light beams, performing phase adjustment and beam combining on the two light beams, determining the splitting ratio of the second beam splitting according to the phase difference between the two light beams after phase adjustment, and outputting a third light beam iii-1 and a twelfth light beam iii-1, wherein the transmission directions of the third light beam iii-1 and the twelfth light beam iii-2 on the first arm 3 are opposite to each other.

[0057] In the embodiment of the present disclosure, the second unit 2 may have the same structure as the first unit 1. The second interferometer 21 and the second ring waveguide 22 form a Sagnac ring 2. The cascaded Sagnac ring is designed to generate a second light beam ii-1 and a third light beam iii-1 with opposite transmission directions on the first arm 3, so as to interfere on the first arm 3 and generate a resonance spectrum with adjustable linearity.

[0058] According to an embodiment of the present disclosure, the first arm 3 includes: a first PN junction 31 disposed between the first unit 1 and the second unit 2. The first PN junction 31 is configured to modulate a small signal to drive the first PN junction 31 to modulate a resonance spectrum with adjustable linearity.

[0059] According to an embodiment of the present disclosure, the first arm 3 further includes a third thermo-optical phase shifter 32 disposed between the first PN junction 31 and the second unit 2 for adjusting the resonant wavelength of the resonant spectrum.

[0060] In the embodiment of the present disclosure, the first unit 1, the second unit 2, the first PN junction 33 and the third thermo-optic phase shifter 35 constitute a Fabry-Perot resonant modulator. The resonant wavelength is changed by controlling the voltage on the thermo-optic phase shifter 32, that is, the bias operating point of the Fabry-Perot resonant modulator is adjusted. In this embodiment, the Fabry-Perot resonant modulator is regulated to generate the tenth light beam ii-2, which is used as a monitoring light beam, and the feedback intensity, extinction ratio, resonant wavelength, modulation depth, etc. of this light beam can be obtained. Based on this, the voltage loaded on the thermo-optic phase shifters 115 and 116, the thermo-optic phase shifter 32, and the PN junction modulation area 31 can be further feedback-regulated. That is, the Fabry-Perot resonant modulator can generate a resonant spectrum with adjustable linearity, and the spectral parameters can be freely adjustable by monitoring the tenth light beam ii-2.

[0061] According to an embodiment of the present disclosure, the device further includes: a second PN junction 41 , a fourth thermo-optical phase shifter 42 and a second arm 4 , wherein the second PN junction 41 and the fourth thermo-optical phase shifter 42 are disposed on the second arm 4 .

[0062] The second PN junction 41 is configured to modulate a small signal to drive the second PN junction 41 to modulate the input sixth light beam and adjust the bias operating point of the first PN junction 33 .

[0063] The fourth thermo-optical phase shifter 36 is used to adjust the phase of the modulated eleventh light beam IV to control the phase difference between the twelfth light beam iii-2 and the modulated and phase-adjusted eleventh light beam IV, wherein the eleventh light beam IV is the input light beam of the second arm, the twelfth light beam iii-2 is the light beam output by the second unit, and the twelfth light beam iii-2 has the same transmission direction as the first light beam i on the first arm 3.

[0064] According to an embodiment of the present disclosure, the first PN junction 31 and the second PN junction 41 may be carrier-depleted PN junctions, and the first interferometer 11 and the second interferometer 21 may be Mach-Zehnder interferometers.

[0065] According to an embodiment of the present disclosure, the silicon-based modulator chip based on resonant spectrum compensation also includes: a multimode interferometer 52 and a multimode interferometer 8. The two output ends of the multimode interferometer 52 are respectively connected to one end of the first arm 3 and one end of the second arm 4. The two input ends of the multimode interferometer 8 are respectively connected to the other end of the first arm 3 and the other end of the second arm 4. The two output ends of the multimode interferometer 8 are port 9 and port 10. The multimode interferometer 8 is used to combine the eleventh light beam IV and the twelfth light beam iii-2 that have been modulated and phase-adjusted, and determine the splitting ratio of the multimode interferometer 8 based on the phase difference between the two light beams for beam splitting.

[0066] The multimode interferometer 52, the multimode interferometer 8, the first branch 3 and the first branch 4 constitute a Mach-Zehnder interferometer.

[0067] Furthermore, it also includes a Mach-Zehnder interferometer 5. The Mach-Zehnder interferometer 5 includes a multimode interferometer 51, a multimode interferometer 52, and a thermo-optical phase shifter 53 arranged on the upper and lower arms. The first input end 6 of the multimode interferometer 51 is used to input an optical carrier, and the second input end 7 is used to output the processed tenth light beam ii-2. The resonance spectrum is monitored by the feedback light beam received through this port.

[0068] The optical carrier is input from the first input terminal 6 into the multimode interferometer 51 for equal splitting and outputting two light beams. The two light beams are respectively regulated in the Mach-Zehnder interferometer 5 by thermo-optical phase shifters arranged on the upper and lower arms to adjust the phases of the corresponding light beams of the upper and lower arms. The splitting ratio of the multimode interferometer 52 is determined according to the phase difference of the two light beams to generate the corresponding first light beam i and eleventh light beam IV.

[0069] The first light beam i enters the first multimode interferometer 111 in the first interferometer 11 along the first arm 31 and is equally split. The output fourth light beam i-1 and the fifth light beam i-2 are phase-adjusted in the two arms of the first interferometer 11 to adjust the phase difference between the two light beams. The splitting ratio of the second multimode interferometer 112 is determined based on this phase difference to split and output the sixth light beam i-3 and the seventh light beam i-4, which enter the first annular optical waveguide 12. The two light beams propagate bidirectionally in the first annular optical waveguide 12 and interfere at the meeting point to output the eighth light beam i-3' and the ninth light beam i-4'. Based on the splitting ratio of the above-mentioned second multimode interferometer 112, the two light beams are split and output after being combined in the second multimode interferometer 112. At this time, the two light beams are phase-adjusted in the two arms of the first interferometer 11 to adjust the phase difference between the two light beams. The splitting ratio of the first multimode interferometer 111 is determined based on this phase difference to output the second light beam ii-1 and the tenth light beam ii-2.

[0070] The second light beam ii-1 is modulated by a small signal at the first PN junction 31, and the phase of the modulated second light beam ii-1 is adjusted by the third thermo-optical phase shifter 32. The modulated and phase-adjusted second light beam ii-1 enters the second interferometer 21 in the second unit 2 and is equally split and input into the two correspondingly connected arms for phase adjustment to adjust the phase difference between the two light beams. The splitting ratio of the multimode interferometer connected to the second ring waveguide 22 is determined based on this phase difference, and the two light beams are split and output to the second ring waveguide 22. The two light beams are transmitted in opposite directions in the second ring waveguide 22 and interfere at the meeting point. Based on the splitting ratio of the above-mentioned multimode interferometer, the two light beams are output after the beams are combined in the multimode interferometer connected to the second ring optical waveguide 22. At this time, the two light beams are phase-adjusted in the two arms of the second interferometer 21 to adjust the phase difference between the two light beams. The splitting ratio of the multimode interferometer connected to the first arm 31 is determined based on this phase difference to output the third light beam iii-1 and the twelfth light beam iii-2.

[0071] The eleventh light beam IV is transmitted in the second arm 4, and a small signal is modulated in the second PN junction 41. The phase of the modulated eleventh light beam IV can be regulated by the fourth thermo-optical phase shifter 42 to control the phase difference between the modulated eleventh light beam IV and the twelfth light beam iii-2, and the splitting ratio of the multimode interferometer 8 is determined based on the phase difference to output two light beams from the corresponding ports 9 and 10.

[0072] The second light beam ii-1 and the third light beam iii-1 interfere with each other in the opposite directions of propagation in the first arm 3 to generate a resonance spectrum.

[0073] At this time, the tenth light beam ii-2 is split into two light beams according to the splitting ratio of the multimode interferometer 52, and enters the upper and lower arms of the Mach-Zehnder interferometer 5 respectively, and then is combined in the multimode interferometer 51 and then split into equal ratios to enter the first input end 6 and the second input end 7. The first input end 6 realizes the isolation of the feedback light through an external circulator.

[0074] The linearity of the resonance spectrum is adjusted according to the feedback light beam received by the second input terminal 7, and the phase and amplitude of the corresponding light beam are controlled by adjusting the voltage of the first thermo-optic phase shifter 115, the second thermo-optic phase shifter 116 and the third thermo-optic phase shifter 32 and adjusting the first PN junction 31, thereby achieving adjustable linearity of the resonance spectrum. At the same time, in addition to the linearity of the resonance spectrum, its extinction ratio, quality factor and resonance wavelength position can be freely adjusted according to application requirements.

[0075] Therefore, in this embodiment, the resonant spectrum generated by the Fabry-Perot resonant modulator composed of cascaded Sagnac rings is used to offset the second-order nonlinearity and third-order nonlinearity of the modulated optical signal, thereby obtaining a good linear modulation range. It can also suppress the generation of high-order harmonics and intermodulation distortion in microwave photonic links, and can effectively reduce the transmission bit error rate in digital optical communication systems.

[0076] Figure 2 The cross-sectional view of a PN junction and a thermo-optical phase shifter according to an embodiment of the present disclosure is schematically shown.

[0077] like Figure 2 As shown, 9 is the second metal layer in the optical chip, which is generally aluminum or copper; 10 is the first metal layer in the optical chip, which is generally aluminum or copper; 11 is a through-hole structure between the first and second metal layers; 12 is a connecting through-hole between the first metal layer and the carrier-depleted PN junction; 13 is a P++ doped region; 14 is a P+ doped region; 15 is a P-type doped region; 16 is an N-type doped region; 17 is an N+ doped region; 18 is an N++ doped region; 19 is a thermo-optical phase shifter; and 20 is a silicon-based waveguide.

[0078] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0079] 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 the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A silicon-based modulator chip based on resonance spectrum compensation, characterized in that: include: A first unit (1), a second unit (2) and a first support arm (3), wherein the first unit (1) and the second unit (2) are arranged on the first support arm (3); The first unit (1) is used to perform amplitude modulation and phase modulation processing on the input first light beam (i) to output a second light beam (ii-1), and the second light beam (ii-1) has the same transmission direction as the first light beam (i) on the first arm (3); The second unit (2) is used to perform amplitude modulation and phase modulation processing on the modulated and phase-adjusted second light beam (ii-1) to output a third light beam (iii-1), wherein the third light beam (iii-1) is directed in the opposite direction to the transmission direction of the second light beam (ii-1) on the first arm (3); The amplitude and phase of the second light beam (ii-1) are controlled by the first unit (1), and the amplitude and phase of the third light beam (iii-1) are controlled by the second unit (2), so that the second light beam (ii-1) and the third light beam (iii-1) interfere with each other in the first arm (3), so as to form a resonance spectrum with adjustable linearity.

2. The silicon-based modulator chip based on resonance spectrum compensation according to claim 1, characterized in that: The first unit (1) comprises a first interferometer (11) and a first annular optical waveguide (12); The first interferometer (11) is connected to the first arm (3) and is used to perform a first beam splitting on the input first light beam (i) to generate a fourth light beam (i-1) and a fifth light beam (i-2), the fourth light beam (i-1) and the fifth light beam (i-2) are sequentially phase-adjusted and beam-combined, and a splitting ratio of a second beam splitting is determined according to a phase difference between the fourth light beam (i-1) and the fifth light beam (i-2) after the phase adjustment, so as to output a sixth light beam (i-3) and a seventh light beam (i-4); The first annular optical waveguide (12) is connected to the first interferometer (11) and is used for bidirectionally transmitting the received sixth light beam (i-3) and the seventh light beam (i-4) to output an eighth light beam (i-3') and a ninth light beam (i-4').

3. The silicon-based modulator chip based on resonance spectrum compensation according to claim 2, characterized in that: The first interferometer (11) is also used for: The received eighth light beam (i-3') and ninth light beam (i-4') are sequentially subjected to a first beam combining and splitting process, a phase adjustment process and a second beam combining and splitting process to output the second light beam (ii-1) and the tenth light beam (ii-2).

4. The silicon-based modulator chip based on resonance spectrum compensation according to claim 3, characterized in that: The first interferometer (11) comprises: A first multi-mode interferometer (111), used for performing beam combining and / or beam splitting processing on an input light beam; A second multi-mode interferometer (112) is used to perform beam combining and beam splitting processing on the input light beams; The upper support arm (113) and the lower support arm (114) are used to perform phase modulation processing on the input light beam; The first multimode interferometer (111) comprises a first input end, a second input end, a first output end and a second output end; the first input end is used to input the first light beam (i), the second input end is used to output the second light beam (ii-1), the first output end is connected to one end of the upper arm (113), and the second output end is connected to one end of the lower arm (114); The second multi-mode interferometer (112) comprises a third input end, a fourth input end, a third output end and a fourth output end; the third input end is connected to the other end of the upper arm (113), and the fourth input end is connected to the other end of the lower arm (114); The third output end is connected to one end of the first annular optical waveguide (12), and is used for outputting one of the sixth light beam (i-3) and the seventh light beam (i-4), and receiving one of the eighth light beam (i-3') and the ninth light beam (i-4'); The fourth output end is connected to the other end of the first annular optical waveguide (12) and is used to output the other of the sixth light beam (i-3) and the seventh light beam (i-4), and to receive the other of the eighth light beam (i-3') and the ninth light beam (i-4').

5. The silicon-based modulator chip based on resonance spectrum compensation according to claim 3, characterized in that: The upper arm (113) comprises a first thermo-optic phase shifter (115), and the lower arm (114) comprises a second thermo-optic phase shifter (116), wherein the first thermo-optic phase shifter (115) and the second thermo-optic phase shifter (116) are used to adjust the phases of two corresponding light beams on the upper arm (113) and the lower arm (114).

6. The silicon-based modulator chip based on resonance spectrum compensation according to claim 5, characterized in that: When the first light beam (i) is input through the first input end, the splitting ratio of the second multi-mode interferometer (112) is controlled by adjusting the phase difference between the two corresponding light beams on the upper arm (113) and the lower arm (114); When the third output end and the fourth output end receive the eighth light beam (i-3') and the ninth light beam (i-4') respectively, the phase difference between the two corresponding light beams on the upper arm (113) and the lower arm (114) is adjusted to control the splitting ratio of the first multi-mode interferometer (111).

7. The silicon-based modulator chip based on resonance spectrum compensation according to claim 5, characterized in that: The first multimode interferometer (111) is further configured as: In the case where the third output end and the fourth output end receive the eighth light beam (i-3') and the ninth light beam (i-4') respectively, the first input end is further used to output the tenth light beam (ii-2) according to the splitting ratio of the first multi-mode interferometer (111); wherein the tenth light beam (ii-2) is used to monitor the linearity of the resonance spectrum, and to adjust the amplitude and phase of the second light beam (ii-1) and the third light beam (iii-1) according to the monitoring result to achieve adjustable linearity of the resonance spectrum.

8. The silicon-based modulator chip based on resonance spectrum compensation according to claim 1, characterized in that: The first arm (3) comprises: The first PN junction (31) is arranged between the first unit (1) and the second unit (2), and is configured to modulate a small signal to drive the first PN junction (31) to modulate the linearity-adjustable resonance spectrum.

9. The silicon-based modulator chip based on resonance spectrum compensation according to claim 8, characterized in that: The first arm (3) further comprises: A third thermo-optical phase shifter (32) is arranged between the first PN junction (31) and the second unit (2) and is used to adjust the resonant wavelength of the resonant spectrum.

10. The silicon-based modulator chip based on resonance spectrum compensation according to claim 1, characterized in that: Also includes: a second PN junction (41), a fourth thermo-optical phase shifter (42) and a second branch arm (4), wherein the second PN junction (41) and the fourth thermo-optical phase shifter (42) are arranged on the second branch arm (4); The second PN junction (41) is configured to modulate a small signal to drive the second PN junction (41) to modulate the input eleventh light beam (IV), and to adjust the bias operating point of the first PN junction (31); The fourth thermo-optical phase shifter (42) is used to adjust the phase of the modulated eleventh light beam (IV) to control the phase difference between the twelfth light beam (iii-2) and the modulated and phase-adjusted eleventh light beam (IV), wherein the eleventh light beam (IV) is an input light beam of the second arm, the twelfth light beam (iii-2) is an output light beam of the second unit, and the twelfth light beam (iii-2) has the same transmission direction as the first light beam (i) on the first arm (3).

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