Silicon-based modulator chip based on resonance spectrum compensation

Abstract

This disclosure provides a silicon-based modulator chip based on resonance spectrum compensation, relating to the field of silicon-based modulator chip technology. The silicon-based modulator chip based on resonance spectrum compensation includes: a first unit, a second unit, and a first arm, wherein the first unit and the second unit are disposed on the first arm; wherein the first unit is used to perform amplitude and phase modulation processing on an input first beam to output a second beam, the second beam having the same transmission direction as the first beam on the first arm; the second unit is used to perform amplitude and phase modulation processing on the modulated and phase-modulated second beam to output a third beam, the third beam having the opposite transmission direction to the second beam on the first arm; the amplitude and phase of the second beam are controlled by the first unit, and the amplitude and phase of the third beam are controlled by the second unit, so that the second beam and the third beam interfere in the first arm to form a resonance spectrum with adjustable linearity.

Description

Technical Field

[0001] This disclosure relates to the technical field of silicon-based modulator chips, and more specifically, to silicon-based modulator chips based on resonance spectrum compensation. Background Technology

[0002] Microwave photonic links based on analog signal transmission place stringent 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 become one of the research hotspots in academia and industry in recent years. Summary of the Invention

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

[0004] This 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 disposed on the first arm 3; wherein, the first unit 1 is used to perform amplitude and phase modulation processing on the input first beam i to output a second beam ii-1, the second beam ii-1 having the same transmission direction as the first beam i on the first arm 3; the second unit 2 is used to perform amplitude and phase modulation processing on the modulated and phase-modulated second beam ii-1 to output a third beam iii-1, the third beam iii-1 having the opposite transmission direction to the second beam ii-1 on the first arm 3; the amplitude and phase of the second beam ii-1 are controlled by the first unit 1, and the amplitude and phase of the third beam iii-1 are controlled by the second unit 2, so that the second beam ii-1 and the third beam iii-1 interfere in the first arm 3 to form a resonance spectrum with adjustable linearity.

[0005] According to an embodiment of this disclosure, the first unit 1 includes a first interferometer 11 and a first ring optical waveguide 12; the first interferometer 11, connected to the first arm 3, is used to split the input first beam i into a fourth beam i-1 and a fifth beam i-2 for the first time, and the fourth beam i-1 and the fifth beam i-2 are sequentially subjected to phase modulation and beam combining processes. The splitting ratio of the second beam split is determined according to the phase difference between the phase-modulated fourth beam i-1 and the fifth beam i-2, so as to output a sixth beam i-3 and a seventh beam i-4; the first ring optical waveguide 12, connected to the first interferometer 11, is used to transmit the received sixth beam i-3 and seventh beam i-4 bidirectionally, so as to output an eighth beam i-3' and a ninth beam i-4'.

[0006] According to an embodiment of this disclosure, the first interferometer 11 is further configured to: sequentially perform a first beam combining and splitting process, a phase modulation process, and a second beam combining and splitting process on the received eighth beam i-3' and ninth beam i-4' to output a second beam ii-1 and a tenth beam ii-2.

[0007] According to embodiments of this disclosure, the first interferometer 11 includes: a first multimode interferometer 111 for performing beam combining and / or beam splitting on an input beam; a second multimode interferometer 112 for performing beam combining and beam splitting on an input beam; an upper arm 113 and a lower arm 114 for performing phase modulation on the input beam; the first multimode interferometer 111 includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal; the first input terminal is used to input a first beam i, the second input terminal is used to output a second beam ii-1, the first output terminal is connected to one end of the upper arm 113, and the second output terminal is connected to one end of the lower arm 114; the second... The multimode interferometer 112 includes a third input terminal, a fourth input terminal, a third output terminal, and a fourth output terminal. The third input terminal is connected to the other end of the upper support arm 113, the fourth input terminal is connected to the other end of the lower support arm 114, and the third output terminal is connected to one end of the first annular optical waveguide 12 for outputting one of the sixth beam i-3 and the seventh beam i-4, and receiving one of the eighth beam i-3' and the ninth beam i-4'. The fourth output terminal is connected to the other end of the first annular optical waveguide 12 for outputting the other of the sixth beam i-3 and the seventh beam i-4, and receiving the other of the eighth beam i-3' and the ninth 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 phase of the corresponding two beams on the upper arm 113 and the lower arm 114.

[0009] According to embodiments of this disclosure, when the first beam i is input through the first input terminal, the splitting ratio of the second multimode interferometer 112 is controlled by adjusting the phase difference between the two corresponding beams on the upper arm 113 and the lower arm 114; when the eighth beam i-3' and the ninth beam i-4' are received at the third and fourth output terminals respectively, the splitting ratio of the first multimode interferometer 111 is controlled by adjusting the phase difference between the two corresponding beams on the upper arm 113 and the lower arm 114.

[0010] According to an embodiment of the present disclosure, the first multimode interferometer 111 is further configured such that, when the eighth beam i-3' and the ninth beam i-4' are received at the third output end and the fourth output end respectively, the first input end is also used to output a tenth beam ii-2 according to the splitting ratio of the first multimode interferometer 111; wherein the tenth beam ii-2 is used to monitor the linearity of the resonance spectrum, and to adjust the phase and amplitude of the second beam ii-1 and the third beam iii-1 according to the monitoring result 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, configured to modulate a small signal to drive the first PN junction 31 to modulate the second beam.

[0012] According to an embodiment of this 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 controlling the resonant wavelength of the resonant spectrum.

[0013] According to an embodiment of this disclosure, it 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; the second PN junction 41 is configured to modulate the input eleventh beam IV by modulating the small signal driving the second PN junction 41, and to regulate the bias operating point of the first PN junction 31; the fourth thermo-optical phase shifter 42 is used to regulate the phase of the modulated eleventh beam IV to control the phase difference between the twelfth beam iii-2 and the modulated phase-modulated eleventh beam IV, wherein the eleventh beam IV is the input beam of the second arm, the twelfth beam iii-2 is the beam output by the second unit, and the twelfth beam and the first beam have the same transmission direction on the first arm (3).

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

[0015] By setting up the first unit 1 and the second unit 2 to generate a second beam ii-1 and a third beam iii-1 with opposite transmission directions, and controlling the amplitude and phase of the second beam ii-1 and the third beam iii-1, interference between the second beam ii-1 and the third beam iii-1 in the first arm 31 can form a linearly adjustable resonance spectrum to compensate for the nonlinear distortion generated during modulation. Furthermore, the linearity of the resonance spectrum is adjustable, offering high flexibility and allowing for free adjustment according to application needs, while also providing a good linear modulation range. Attached Figure Description

[0016] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0017] Figure 1 The schematic diagram illustrates the structure of a silicon-based modulator chip based on resonance spectrum compensation according to an embodiment of the present disclosure;

[0018] Figure 2 A schematic cross-sectional view of a PN junction and a thermo-optical phase shifter according to an embodiment of the present disclosure is shown. Detailed Implementation

[0019] The embodiments of the present disclosure will now 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 disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known systems and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

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

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

[0023] Spurious-Free Dynamic Range (SFDR) is a property used to describe the linearity of a modulator. It means the range between the output frequency of the fundamental signal and the output power of the nonlinear distortion signal when the power of the nonlinear distortion signal is equal to the noise floor.

[0024] Methods for optimizing the linearity of silicon-based modulators can be broadly categorized into two types: electrical domain linearity optimization and optical domain linearity optimization. Electrical domain linearity optimization techniques, including predistortion compensation, feedback compensation, and digital signal processing, can improve the SFDR (Signal-to-Flat Rate) of silicon-based electro-optic modulators by designing complex circuits. However, the bandwidth of these schemes is limited by electronic components, preventing high-speed modulation. Currently, typical optical domain linearity optimization techniques include micro-ring-assisted silicon-based Mach-Zehnder modulators (MZMs), introducing linear electro-optic effects using materials such as lithium niobate or III-V group materials, and controlling the carrier distribution in the PN junction of the modulation arm. Furthermore, silicon-based micro-ring modulators (MRMs) based on micro-ring resonator structures have great potential for application in microwave photonic links due to their compact structure and high modulation efficiency. However, compared to silicon-based MZMs, silicon-based MRMs exhibit stronger nonlinearity in their modulation curves. The reported SFDR of silicon-based MRMs at 1 GHz is only 84 dBHz. 2 / 3 Its linearity is still far from meeting the requirements of at least 100 dBHz in microwave photonic links. 2 / 3 Requirements.

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

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

[0027] like Figure 1 As shown, this 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 disposed on the first arm 3. The first unit 1, the second unit 2, and the first arm 3 constitute one arm of a Mach-Zehnder interferometer.

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

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

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

[0031] In the embodiments of this disclosure, when loading radio frequency signals onto an optical carrier, nonlinear distortion often occurs during modulation due to limitations in material properties and device structure. This nonlinearity typically leads to signal distortion, increased bit error rate, and reduced spurious-free dynamic range (SFDR), thus affecting the quality of signal transmission.

[0032] Based on this, this embodiment controls the first unit 1 to output a second beam ii-1 with the same transmission direction as the input first beam i, and controls the second unit 2 to output a third beam iii-1 with the opposite transmission direction to the second beam. By controlling the phase difference between the second beam ii-1 and the third beam iii-1, a resonance effect is achieved at a specific wavelength to generate a resonance spectrum. This effectively cancels out the second-order and third-order nonlinearities generated during modulation, resulting in a good linear modulation range. Furthermore, the preset phase difference can be adjusted as needed to change the shape of the resonance spectrum and optimize linearity.

[0033] Based on the above embodiments, the first unit 1 includes a first interferometer 11 and a first ring optical waveguide 12.

[0034] The first interferometer 11, connected to the first arm 3, is used to split the input first beam i into a fourth beam i-1 and a fifth beam i-2. The fourth beam i-1 and the fifth beam i-2 are sequentially phase-modulated and combined. The splitting ratio of the second beam split is determined based on the phase difference between the phase-modulated fourth beam i-1 and the fifth beam i-2, so as to output the sixth beam i-3 and the seventh beam i-4.

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

[0036] Furthermore, the first interferometer 11 is also used to perform a first beam combining and splitting process, a phase modulation 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 the second beam ii-1 and the tenth beam ii-2.

[0037] In the embodiments of this disclosure, the first interferometer 11 splits the input first beam i and performs phase modulation processing, and determines the splitting ratio of the beams to be split again based on the phase difference between the two beams after phase modulation, thus achieving adjustable splitting ratio performance. The splitting ratio can be flexibly set according to actual application needs to optimize signal processing. The first ring optical waveguide 12 receives the two beams i-3 and i-4 output by the first interferometer 11. These two beams i-3 and i-4 are transmitted towards each other in the first ring optical waveguide 12 and return to the first interferometer 11 after interference at the meeting point. They then enter the upper and lower arms 113 and 114 of the first interferometer 11 according to the determined splitting ratio. The splitting ratio of the two beams in the upper and lower arms 113 and 114 can be adjusted as needed to determine the splitting ratio of the beams to be split again to output the second beam ii-1 and the tenth beam ii-2. In this embodiment, by precisely adjusting the phase difference of the beams in the upper and lower branches of the first interferometer 11, the second 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 beam ii-1 and a tenth beam ii-2 with adjustable splitting ratios. The second beam and the tenth beam ii-2 are transmitted in opposite directions on the first arm 3.

[0038] Based on the above embodiments, the first interferometer 11 includes: a first multimode interferometer 111 for performing beam combining and / or beam splitting on the input beam; a second multimode interferometer 112 for performing beam combining and beam splitting on the input beam; and an upper arm 113 and a lower arm 114 for performing phase modulation on the input beam.

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

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

[0041] In the embodiments of this disclosure, the beam splitting and combining operations of the first multimode interferometer 111 ensure that the 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. Furthermore, by combining the first multimode interferometer 111, the second multimode interferometer 112, the upper arm 113, and the lower arm 114, a second beam ii-1 with a preset phase and amplitude can be accurately obtained.

[0042] When the first input terminal of the first multimode interferometer 111 is used to input the first beam i, the first multimode interferometer 111 divides the first beam i into two beams i-1 and i-1 in equal proportion, and inputs the two 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 beams i-3' and i-4' output from the first ring optical waveguide 12, the second multimode interferometer 112 first performs beam combining, and then performs beam splitting according to the splitting ratio of the output from the second multimode interferometer 112 to the first ring optical waveguide 12. At this time, the upper and lower arms 113 and 114 receive the two split beams, perform phase modulation on the two beams, and input them into the first multimode interferometer 111 for beam combining. Based on the phase difference between the two beams at this time, the splitting ratio is determined to output the second beam ii-1 and the tenth beam ii-2.

[0044] Based on the above embodiment, 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 phase of the two corresponding beams on the upper arm 113 and the lower arm 114. Two beams with corresponding phase differences can be output as needed.

[0045] In the embodiments of this disclosure, the transmission coefficient can be changed by adjusting the voltage applied to the thermo-optical phase shifters 115 and 116 within the Sagnac ring 1 with adjustable splitting ratio, thereby controlling the shape of the generated resonance spectrum, and the linearity of the corresponding Lorentz curve can be freely adjusted.

[0046] Based on the above embodiments, when the first beam i is input through the first input terminal, the splitting ratio of the second multimode interferometer 112 is controlled by adjusting the phase difference between the two corresponding beams on the upper arm 113 and the lower arm 114.

[0047] When the eighth beam i-3' and the ninth beam i-4' are received at the third and fourth output ends respectively, the splitting ratio of the first multimode interferometer 111 is controlled by adjusting the phase difference between the two corresponding beams on the upper arm 113 and the lower arm 114.

[0048] In the embodiments of this disclosure, when the first beam i is input through the first input terminal of the first multimode interferometer 111, it is split into two beams i-1 and i-2, which enter the upper arm 113 and the lower arm 114, respectively. These two beams i-1 and i-2 undergo phase adjustment via thermo-optical phase shifters in the upper arm 113 and the lower arm 114, respectively. By adjusting the phase difference between the two beams in the upper arm 113 and the lower arm 114, the interference conditions of these two beams in the second multimode interferometer 112 can be changed, thereby determining the splitting ratio of the second multimode interferometer 112. Therefore, by controlling the phase difference, precise control of the output beam ratio of the second multimode interferometer 112 can be achieved, ensuring that subsequent operations can be performed according to design requirements.

[0049] Similarly, when the second multimode interferometer 112 receives the two beams i-3' and i-4' output from the first annular optical waveguide 12, the phase of the corresponding beam is 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 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 multimode interferometer can be precisely controlled at different stages.

[0051] According to embodiments of this disclosure, the first multimode interferometer 111 is further configured to: when the eighth beam i-3' and the ninth beam i-4' are received at the third and fourth output terminals respectively, the first input terminal outputs a tenth beam ii-2 according to the splitting ratio of the first multimode interferometer 111. The tenth beam ii-2 is used to monitor the linearity of the resonance spectrum, and to adjust the amplitude and phase of the second beam ii-1 and the third beam iii-1 according to the monitoring results to achieve adjustable linearity of the resonance spectrum.

[0052] In the embodiments of this disclosure, the parameters of the resonant spectrum can be adjusted in real time by using the feedback intensity, extinction ratio, resonant wavelength, modulation depth, etc. of the tenth beam ii-2, thus achieving free adjustment of the spectral parameters.

[0053] According to embodiments of this disclosure, the second unit 2 includes:

[0054] The second interferometer 21, connected to the first arm 3, is used to split the second beam ii-1, which has been modulated and phase-modulated, into two beams in the first split, and to perform phase modulation and beam combining on the two beams in sequence. The splitting ratio of the second split is determined according to the phase difference of the two beams after phase modulation so as to output two beams with adjustable splitting ratio.

[0055] The second ring optical waveguide 22 is connected to the second interferometer 21 and is used to perform bidirectional transmission processing on the two received beams with adjustable splitting ratios and output two beams.

[0056] The second interferometer 21 is also used to: perform a first beam combining and beam splitting process on the two beams output from the received second annular optical waveguide 22 to generate two beams, perform phase modulation and beam combining on the two beams, determine the splitting ratio of the second beam splitting based on the phase difference of the two beams after phase modulation, and output a third beam iii-1 and a twelfth beam iii-2, with the third beam iii-1 and the twelfth beam iii-2 having opposite transmission directions on the first arm 3.

[0057] In embodiments of this 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. By designing the cascaded Sagnac rings to generate a second beam ii-1 and a third beam iii-1 with opposite transmission directions on the first arm 3, interference occurs on the first arm 3, producing a resonant spectrum with adjustable linearity.

[0058] According to an embodiment of this 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 linearly tunable resonance spectrum by modulating a small signal driving the first PN junction 31.

[0059] According to an embodiment of this 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 controlling the resonant wavelength of the resonant spectrum.

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

[0061] According to embodiments of this disclosure, it 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 the input sixth beam by driving the second PN junction 41 with a small signal, and to 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 beam IV to control the phase difference between the twelfth beam iii-2 and the modulated eleventh beam IV. The eleventh beam IV is the input beam of the second arm, and the twelfth beam iii-2 is the output beam of the second unit. The twelfth beam iii-2 has the same transmission direction as the first beam i on the first arm 3.

[0064] According to embodiments of this disclosure, the first PN junction 31 and the second PN junction 41 can be carrier depletion PN junctions, and the first interferometer 11 and the second interferometer 21 can be Mach-Zehnder interferometers.

[0065] According to embodiments of this disclosure, the silicon-based modulator chip based on resonance spectrum compensation further includes a multimode interferometer 52 and a multimode interferometer 8. The two output terminals 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 terminals 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 terminals of the multimode interferometer 8 are port 9 and port 10, respectively. The multimode interferometer 8 is used to combine the eleventh beam IV and the twelfth beam iii-2, which have undergone modulation and phase-modulation processing, and to perform beam splitting processing based on the phase difference between the two beams, determining the splitting ratio of the multimode interferometer 8.

[0066] The multimode interferometer 52, multimode interferometer 8, first branch 3 and 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 disposed on the upper and lower arms. The first input terminal 6 of the multimode interferometer 51 is used to input the optical carrier, and the second input terminal 7 is used to output the processed tenth beam ii-2. The feedback beam received through this port is used to monitor the resonance spectrum.

[0068] An optical carrier wave is input from the first input terminal 6 into a multimode interferometer 51, where it is divided into two beams for equal splitting. These two beams are then processed in a Mach-Zehnder interferometer 5, where the phases of the corresponding beams on the upper and lower arms are adjusted by thermo-optical phase shifters mounted on the upper and lower arms. The splitting ratio of the multimode interferometer 52 is determined based on the phase difference between the two beams, resulting in the generation of the corresponding first beam i and eleventh beam IV.

[0069] The first beam i enters the first multimode interferometer 111 along the first arm 31 and is equally divided. The output beams i-1 and i-2 are then phase-modulated in the two arms of the first interferometer 11 to adjust their phase difference. Based on this phase difference, the splitting ratio of the second multimode interferometer 112 is determined to split the beams into a sixth beam i-3 and a seventh beam i-4, which enter the first annular waveguide 12. These two beams propagate bidirectionally in the first annular waveguide 12 and interfere at their meeting point, outputting an eighth beam i-3' and a ninth beam i-4'. Based on the splitting ratio of the second multimode interferometer 112, the beams are combined in the second multimode interferometer 112 and then split into two beams. These two beams are then phase-modulated in the two arms of the first interferometer 11 to adjust their phase difference. Based on this phase difference, the splitting ratio of the first multimode interferometer 111 is determined to output a second beam ii-1 and a tenth beam ii-2.

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

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

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

[0073] At this point, the tenth beam ii-2 is split into two beams according to the splitting ratio of the multimode interferometer 52, which enter the upper and lower arms of the Mach-Zehnder interferometer 5 respectively. After being combined in the multimode interferometer 51, the beams are split equally and enter the first input terminal 6 and the second input terminal 7. The first input terminal 6 isolates the feedback light through an external circulator.

[0074] The linearity of the resonant spectrum is adjusted based on the feedback beam received at the second input terminal 7. Furthermore, the phase and amplitude of the corresponding beam are controlled by adjusting the voltages of the first thermo-optical phase shifter 115, the second thermo-optical phase shifter 116, and the third thermo-optical phase shifter 32, as well as by adjusting the first PN junction 31, thereby achieving adjustable linearity of the resonant spectrum. In addition to linearity, the extinction ratio, quality factor, and resonant wavelength position of the resonant spectrum can also be freely adjusted according to application requirements.

[0075] Therefore, in this embodiment, the resonant spectral lines generated by the Fabry-Perot resonator modulator composed of cascaded Sagnac rings are used to cancel the second-order and third-order nonlinearities of the modulated optical signal, thereby obtaining a good linear modulation range. This also suppresses the generation of higher-order harmonics and intermodulation distortion in microwave photonic links and effectively reduces the transmission bit error rate in digital optical communication systems.

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

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

[0078] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0079] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A silicon-based modulator chip based on resonance spectrum compensation, characterized in that, include: The first unit (1), the second unit (2), and the first arm (3) are disposed on the first arm (3); The first unit (1) is used to perform amplitude and phase modulation processing on the input first beam (i) to output a second beam (ii-1), and the second beam (ii-1) has the same transmission direction as the first beam (i) on the first arm (3). The second unit (2) is used to perform amplitude and phase modulation processing on the modulated and phase-modulated second beam (ii-1) to output a third beam (iii-1), the third beam (iii-1) being opposite to the transmission direction of the second beam (ii-1) on the first arm (3); The amplitude and phase of the second beam (ii-1) are controlled by the first unit (1), and the amplitude and phase of the third beam (iii-1) are controlled by the second unit (2), so that the second beam (ii-1) and the third beam (iii-1) interfere in the first arm (3) to form a linearly adjustable resonant spectrum; The first unit (1) includes a first interferometer (11) and a first ring optical waveguide (12). The first interferometer (11) is connected to the first arm (3) and is used to split the input first beam (i) into a fourth beam (i-1) and a fifth beam (i-2) for the first time. The fourth beam (i-1) and the fifth beam (i-2) are sequentially subjected to phase modulation and beam combining. The splitting ratio of the second beam split is determined according to the phase difference between the fourth beam (i-1) and the fifth beam (i-2) after phase modulation, so as to output a sixth beam (i-3) and a seventh beam (i-4). The first annular optical waveguide (12) is connected to the first interferometer (11) for bidirectional transmission of the received sixth beam (i-3) and seventh beam (i-4) to output the eighth beam (i-3') and ninth beam (i-4'). The structure of the second unit (2) is the same as that of the first unit (1).

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

3. The silicon-based modulator chip based on resonance spectrum compensation according to claim 2, characterized in that, The first interferometer (11) includes: The first multimode interferometer (111) is used to combine and / or split the input beam; The second multimode interferometer (112) is used to combine and split the input beam; The upper arm (113) and the lower arm (114) are used for phase modulation of the input beam; The first multimode interferometer (111) includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal; the first input terminal is used to input the first beam (i), the second input terminal is used to output the second beam (ii-1), the first output terminal is connected to one end of the upper arm (113), and the second output terminal is connected to one end of the lower arm (114); The second multimode interferometer (112) includes a third input terminal, a fourth input terminal, a third output terminal, and a fourth output terminal; the third input terminal is connected to the other end of the upper arm (113), and the fourth input terminal is connected to the other end of the lower arm (114); The third output terminal is connected to one end of the first annular optical waveguide (12) and is used to output one of the sixth beam (i-3) and the seventh beam (i-4), and to receive one of the eighth beam (i-3') and the ninth beam (i-4'). The fourth output terminal is connected to the other end of the first annular optical waveguide (12) and is used to output the other beam of the sixth beam (i-3) and the seventh beam (i-4), and to receive the other beam of the eighth beam (i-3') and the ninth beam (i-4').

4. The silicon-based modulator chip based on resonance spectrum compensation according to claim 3, characterized in that, 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 phase of the two corresponding beams on the upper arm (113) and the lower arm (114).

5. The silicon-based modulator chip based on resonance spectrum compensation according to claim 4, characterized in that, When the first beam (i) is input through the first input terminal, the splitting ratio of the second multimode interferometer (112) is controlled by adjusting the phase difference between the two corresponding beams on the upper arm (113) and the lower arm (114); When the third output end and the fourth output end receive the eighth beam (i-3') and the ninth beam (i-4') respectively, the splitting ratio of the first multimode interferometer (111) is controlled by adjusting the phase difference between the two corresponding 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 4, characterized in that, The first multimode interferometer (111) is also configured to: When the eighth beam (i-3') and the ninth beam (i-4') are received at the third output terminal and the fourth output terminal respectively, the first input terminal is also used to output the tenth beam (ii-2) according to the splitting ratio of the first multimode interferometer (111); wherein the tenth beam (ii-2) is used to monitor the linearity of the resonance spectrum, and to adjust the amplitude and phase of the second beam (ii-1) and the third beam (iii-1) according to the monitoring result to achieve adjustable linearity of the resonance spectrum.

7. The silicon-based modulator chip based on resonance spectrum compensation according to claim 1, characterized in that, The first arm (3) includes: The first PN junction (31), disposed between the first unit (1) and the second unit (2), is configured to modulate the first PN junction (31) to modulate the linearly adjustable resonance spectrum by modulating a small signal.

8. The silicon-based modulator chip based on resonance spectrum compensation according to claim 7, characterized in that, The first arm (3) also includes: The third thermo-optical phase shifter (32) is disposed between the first PN junction (31) and the second unit (2) and is used to adjust the resonant wavelength of the resonant spectrum.

9. The silicon-based modulator chip based on resonance spectrum compensation according to claim 7, characterized in that, Also includes: The second PN junction (41), the fourth thermo-optical phase shifter (42), and the second arm (4) are disposed on the second arm (4); The second PN junction (41) is configured to modulate the small signal driving the second PN junction (41) to modulate the input eleventh 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 beam (Ⅳ) to control the phase difference between the twelfth beam (iii-2) and the modulated eleventh beam (Ⅳ), wherein the eleventh beam (Ⅳ) is the input beam of the second arm, the twelfth beam (iii-2) is the output beam of the second unit, and the twelfth beam (iii-2) has the same transmission direction as the first beam (i) on the first arm (3).

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