Optical Modulator and Its Control Method

Abstract

The present application provides an optical modulator and a control method thereof. The optical modulator includes: an input waveguide for receiving an initial optical signal; a tunable ring resonator, which is coupled to the input waveguide and is used for resonating and modulating the initial optical signal and outputting a first optical signal; a feedback loop waveguide, which is coupled to the tunable ring resonator and is used for receiving and transmitting the first optical signal; a first mode converter, which is coupled to the feedback loop waveguide and is used for performing mode conversion on the first optical signal and outputting a second optical signal; the tunable ring resonator is further used for resonating and modulating the second optical signal and outputting a third optical signal; an output waveguide, which is coupled to the tunable ring resonator and is used for receiving and outputting the third optical signal. The optical signal can be subjected to secondary resonance processing through the tunable ring resonator to improve the extinction ratio of the optical signal.

Description

Technical Field

[0001] The embodiments of the present application relate to, but are not limited to, the field of optoelectronic devices, and particularly to an optical modulator and its control method. Background Art

[0002] With the development of optoelectronic technology, silicon-based integrated optoelectronic technology has the advantages of high integration, CMOS process compatibility, and large-scale mass production, and has become the mainstream research direction of integration in the field of optical communication.

[0003] In modern society, the demand for data communication capacity continues to climb, and the requirements for the indicators (such as extinction ratio) of optical communication modules (such as optical modulators) are getting higher and higher. However, the optical modulators in related technologies have the problem of relatively low extinction ratio. Summary of the Invention

[0004] The embodiments of the present application provide an optical modulator and its control method, which can perform secondary superposition resonance adjustment on an optical signal through an adjustable ring resonator to improve the extinction ratio of the optical signal.

[0005] In a first aspect, the embodiments of the present application provide an optical modulator, which includes:

[0006] An input waveguide for receiving an initial optical signal;

[0007] An adjustable ring resonator, coupled to the input waveguide, for performing resonance processing on the initial optical signal and outputting a first optical signal;

[0008] A feedback loop waveguide, coupled to the adjustable ring resonator, for receiving and transmitting the first optical signal;

[0009] A first mode converter, coupled to the feedback loop waveguide, for performing mode conversion on the first optical signal and outputting a second optical signal;

[0010] The adjustable ring resonator is further configured to perform resonance processing on the second optical signal and output a third optical signal;

[0011] An output waveguide, coupled to the adjustable ring resonator, for receiving and outputting the third optical signal.

[0012] In a second aspect, the embodiments of the present application provide an optical modulator control method, including:

[0013] Receiving an initial optical signal through an input waveguide;

[0014] Performing resonance processing on the initial optical signal through an adjustable ring resonator and outputting a first optical signal;

[0015] Receiving the first optical signal through a feedback loop waveguide and transmitting it to a first mode converter;

[0016] Using the first mode converter to perform mode conversion on the first optical signal and output a second optical signal;

[0017] Performing resonance processing on the second optical signal through the tunable ring resonator and outputting a third optical signal;

[0018] Receiving and outputting the third optical signal through an output waveguide.

[0019] Embodiments of the present application include: performing resonance processing on an initial optical signal through a tunable ring resonator and outputting a first optical signal, performing mode conversion on the first optical signal by a first mode converter and outputting a second optical signal, and performing resonance processing on the second optical signal through the tunable ring resonator and outputting a third optical signal, performing secondary superposition resonance and modulation processing on the optical signal through the tunable ring resonator to improve the extinction ratio of the optical signal. That is, by performing mode multiplexing on the tunable ring resonator to modulate optical signals of multiple modes simultaneously to improve the extinction ratio of the optical signal.

[0020] Other features and advantages of the present application will be described in the subsequent specification, and part of them will be obvious from the specification or understood by implementing the present application. The objectives and other advantages of the present application can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solutions of the present application and do not constitute a limitation to the technical solutions of the present application.

[0022] Figure 1 It is a schematic structural diagram of an optical modulator provided by an embodiment of the present application;

[0023] Figure 2A It is a schematic cross-sectional structural diagram of a silicon-based optoelectronic modulation module in an embodiment of the present application;

[0024] Figure 2B It is a schematic cross-sectional structural diagram of a silicon-based optoelectronic modulation module in another embodiment of the present application;

[0025] Figure 3A It is a schematic structural diagram of a first / second mode converter in an embodiment of the present application;

[0026] Figure 3B It is a schematic structural diagram of a first / second mode converter in another embodiment of the present application;

[0027] Figure 4A It is a simulation schematic diagram for modulating the first optical signal of the TE0 mode provided by another embodiment of the present application;

[0028] Figure 4B It is a simulation schematic diagram for modulating the second optical signal of the TM0 mode provided by another embodiment of the present application;

[0029] Figure 5A It is a simulation schematic diagram of resonant spectroscopy provided by another embodiment of the present application;

[0030] Figure 5B It is a simulation schematic diagram of resonant spectroscopy drift provided by another embodiment of the present application;

[0031] Figure 6A It is a simulation schematic diagram for modulating the first optical signal of the TE0 mode provided by another embodiment of the present application;

[0032] Figure 6B It is a simulation schematic diagram for modulating the second optical signal of the TE1 mode provided by another embodiment of the present application;

[0033] Figure 7A It is a simulation schematic diagram of resonant spectroscopy provided by another embodiment of the present application;

[0034] Figure 7B It is a simulation schematic diagram of resonant spectroscopy drift provided by another embodiment of the present application.

[0035] Reference numerals: 100, input waveguide; 101, single-mode input waveguide; 102, first tapered waveguide; 103, multimode input waveguide; 200, feedback loop waveguide; 201, feedback multimode waveguide; 202, arc waveguide; 203, second tapered waveguide; 300, ring resonator; 301, first half-ring waveguide; 302, second half-ring waveguide; 303, first straight waveguide; 304, second straight waveguide; 400, first mode converter; 401, first input single-mode waveguide; 402, first single-mode coupling waveguide; 403, first multimode coupling waveguide; 404, first conversion tapered waveguide; 405, first output multimode waveguide; 500, second mode converter; 501, output waveguide; 601, first electrode; 602, second electrode; 6011, first metal via; 6021, second metal via; 603, upper cladding; 604, lower surface; 605, silicon substrate layer; 606, silicon waveguide layer; 6061, first P-type heavily doped region; 6062, first P-type lightly doped region; 6063, first N-type lightly doped region; 6064, first N-type heavily doped region. Detailed implementation manners

[0036] In order to make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Without conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other.

[0037] It should be noted that although functional module division is performed in the device schematic diagram and the logical sequence is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from the module division in the device or the sequence in the flowchart. The terms "first", "second", etc. in the description, claims, and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0038] With the development of optoelectronic technology, silicon-based integrated optoelectronic technology has the advantages of high integration, CMOS process compatibility, and large-scale mass production, and has become the mainstream research direction of integration in the field of optical communication. In an optical communication system, mode multiplexing is a technology that can effectively increase the transmission capacity of a single channel. By transmitting multiple modes in the same optical fiber / optical waveguide channel, the density of optical signals in the same channel is greatly increased, doubling the total transmission capacity. In an on-chip integrated optical interconnection system, the research on mode multiplexing devices has also become increasingly mature, which can effectively increase the transmission density of on-chip interconnections.

[0039] In modern society, the demand for data communication capacity continues to rise, and the requirements for the indicators (such as extinction ratio) of optical communication modules (such as optical modulators) are getting higher and higher. However, the optical modulators in related technologies have the problem of relatively low extinction ratio.

[0040] For example, due to the sensitivity of silicon materials to temperature changes, the wavelength drift caused by temperature in a microring modulator will make the operation of the optical modulator unstable. For a carrier-depletion-type microring modulator, the modulation efficiency can be improved by increasing the silicon doping concentration, but this will increase the optical absorption loss in the waveguide and the extinction ratio is relatively low.

[0041] Based on this, the embodiments of the present application provide an optical modulator and its control method, which can perform secondary superimposed resonance adjustment on an optical signal through an adjustable ring resonator to improve the extinction ratio of the optical signal.

[0042] Please refer to Figure 1, An optical modulator, comprising: an input waveguide 100 for receiving an initial optical signal; an adjustable ring resonator, coupled to the input waveguide 100, for resonating and modulating the initial optical signal and outputting a first optical signal; a feedback loop waveguide 200, coupled to the adjustable ring resonator, for receiving and transmitting the first optical signal; a first mode converter 400, coupled to the feedback loop waveguide 200, for mode conversion of the first optical signal and outputting a second optical signal; the adjustable ring resonator is further configured to resonate and modulate the second optical signal and output a third optical signal; an output waveguide 501, coupled to the adjustable ring resonator 300, for receiving and outputting the third optical signal.

[0043] The initial optical signal is received by the input waveguide 100 and transmitted into the ring resonator 300, where the initial optical signal resonates. Since the initial optical signal is a continuous optical signal, after the ring resonator 300 resonates the initial optical signal, the amplitude of the optical signal with a specific frequency is amplified to generate a first optical signal. The first optical signal is transmitted through the ring feedback loop waveguide 200 to the first mode converter 400, which performs mode conversion on the first optical signal and outputs a second optical signal. By coupling the second optical signal back into the adjustable ring resonator 300 again and performing resonance processing to amplify the amplitude of the optical signal with a specific frequency in the second optical signal to generate a third optical signal, the third optical signal is output through the output waveguide 501 coupled to the adjustable ring resonator 300. That is, by multiplexing the ring resonator 300, the initial optical signal and the second optical signal are resonated and the amplitude of the optical signal with a specific frequency is amplified, thereby obtaining a third optical signal with a higher extinction ratio. That is, by mode multiplexing the adjustable ring resonator, optical signals of multiple modes are modulated simultaneously to improve the extinction ratio of the optical signal.

[0044] Among them, the first mode converter 400 can convert the first optical signal into optical signals of different orthogonal modes or optical signals of different orders. Since the second optical signal and the initial optical signal are optical signals of different modes, and the ring resonator 300 can support the transmission of multi-mode optical signals, when the second optical signal and the initial optical signal are transmitted in the ring resonator 300, they are transmitted separately without interference or crosstalk. The ring resonator 300 can be a circular micro-ring resonator or a racetrack-shaped micro-ring resonator, and the bent waveguide of the micro-ring resonator supports the transmission of two or more modes in the micro-ring resonator.

[0045] In addition, the effective refractive index in the cavity of the ring resonator 300 is adjusted by the first optoelectronic modulation module and the second optoelectronic modulation module, so that the optical signal accumulates a phase change during transmission in the cavity and the phase change is converted into an intensity change through an interference effect to modulate the resonant wavelength of the optical signal in the cavity.

[0046] In some embodiments, the optical modulator further includes: a second mode converter 500. The input end of the second mode converter 500 is coupled to the output waveguide 501, and is configured to perform mode conversion on the third optical signal and output a fourth optical signal, so that the output signal of the optical modulator is an optical signal in a target mode.

[0047] Among them, the initial optical signal, the first optical signal, and the fourth optical signal are optical signals in the first mode, and the second optical signal and the third optical signal are optical signals in the second mode.

[0048] The initial optical signal in the first mode is resonated and modulated through the tunable ring resonator to generate the first optical signal in the first mode; the first optical signal in the first mode is subjected to mode conversion through the first mode converter 400 to generate the second optical signal in the second mode; the second optical signal in the second mode is resonated and modulated through the tunable ring resonator to generate the third optical signal in the second mode; the second mode converter 500 performs mode conversion on the third optical signal in the second mode to generate the fourth optical signal in the first mode.

[0049] It should be noted that the first mode and the second mode can be any optical modes. Hereinafter, an example will be given in which the first mode is the TE0 mode, and the second mode is the TE1 mode or the TM0 mode.

[0050] In some specific embodiments, the first mode converter 400 and the second mode converter 500 are identical and oppositely arranged mode converters. The initial optical signal and the first optical signal are optical signals in the TE0 mode. The first optical signal is subjected to mode conversion through the first mode converter 400 and the second optical signal in the TE1 mode or the TM0 mode is output, and the second optical signal is resonated through the tunable ring resonator 300 to generate the third optical signal. The input end of the second mode converter 500 is coupled to the output waveguide 501 to perform mode conversion on the third optical signal and output the fourth optical signal. Among them, the third optical signal is an optical signal in the TE1 mode or the TM0 mode, and the fourth optical signal is an optical signal in the TE0 mode. By setting the first mode converter 400 and the second mode converter 500, the initial optical signal and the fourth optical signal have the same mode, that is, the output signal of the optical modulator and the input signal have the same mode.

[0051] In addition, when the third optical signal in the TE1 mode or TM0 mode is transmitted to the first mode converter 400 via the feedback loop waveguide 200, the third optical signal will experience losses to ensure that the input signal of the first mode converter 400 is the first optical signal; when the first optical signal in the TE0 mode is transmitted to the second mode converter 500 via the output waveguide 501, the first optical signal will experience optical losses to ensure that the output signal of the second mode converter 500 is the fourth optical signal. By providing a single-mode waveguide that only supports the transmission of the TE0 mode in the feedback loop waveguide 200, the third optical signal in the TE1 mode or TM0 mode is gradually lost during transmission.

[0052] In some embodiments, the tunable ring resonator includes a first coupling region and a second coupling region; the tunable ring resonator is coupled to the input waveguide 100 through the first coupling region, and the tunable ring resonator is coupled to the feedback loop waveguide 200 through the first coupling region; the first mode converter 400 is coupled to the tunable ring resonator through the second coupling region, and the tunable ring resonator is coupled to the output waveguide 501 through the second coupling region.

[0053] By coupling with the input waveguide 100 and connecting to the feedback loop waveguide 200 through the first coupling region, the initial optical signal can be input from the input waveguide 100 into the ring resonator 300, and the first optical signal can be input from the ring resonator 300 into the feedback loop waveguide 200; by coupling with the output waveguide 501 through the second coupling region, the second optical signal can be input from the output waveguide 501 into the ring resonator 300, and the fourth optical signal can be output from the ring resonator 300 to the output waveguide 501.

[0054] Among them, the first mode converter 400 and the second mode converter 500 respectively include: a silicon substrate layer; a silica lower cladding layer provided on one side of the silicon substrate layer; a silicon waveguide layer provided on the side of the silica lower cladding layer away from the silicon substrate layer; a silica upper cladding layer provided on the side of the silicon waveguide layer away from the silica lower cladding layer.

[0055] The tunable ring resonator further includes: a first electro-optical modulation module, a second electro-optical modulation module, and a ring resonator 300; the first electro-optical modulation module is used to adjust the refractive index of the first region of the ring resonator 300; the second electro-optical modulation module is used to adjust the refractive index of the second region of the ring resonator 300. The ring resonator 300 includes: a first straight waveguide 303, a second straight waveguide 304, a first half-ring waveguide 301, and a second half-ring waveguide 302. The first half-ring waveguide 301 is respectively connected to one ends of the first straight waveguide 303 and the second straight waveguide 304, and the second half-ring waveguide 302 is respectively connected to the other ends of the first straight waveguide 303 and the second straight waveguide 304 to form a ring waveguide.

[0056] Among them, the first optoelectronic modulation module and the second optoelectronic modulation module respectively adjust the refractive indices of different regions of the ring resonator 300. By adjusting the refractive indices of the first region and the second region, the initial optical signal and the second optical signal accumulate phase changes during transmission in the first region and the second region, and interfere in the first straight waveguide 303 and the second straight waveguide 304 in the ring resonator 300 respectively, so as to convert the phase change into an intensity change.

[0057] In some embodiments, the first straight waveguide 303 and the second straight waveguide 304 are respectively the first coupling region and the second coupling region; the first half-ring waveguide 301 and the second half-ring waveguide 302 are the first region and the second region of the ring resonator 300.

[0058] In some embodiments, by increasing the number of optoelectronic modulation modules, the effective refractive indices of multiple regions in the ring resonator 300 are synchronously modulated to modulate the phase change of the optical signal in the ring resonator 300. Further, by setting a ring optoelectronic modulation module, the effective refractive indices of all regions of the resonator are synchronously modulated.

[0059] In some embodiments, the first region may be the first half-ring waveguide 301, and the second region may be the second half-ring waveguide 302.

[0060] Please refer to Figure 2A , both the first optoelectronic modulation module and the second optoelectronic modulation module are silicon-based optoelectronic modulation modules; the silicon-based optoelectronic modulation module includes, arranged in sequence: a first P-type heavily doped region 6061, a first N-type heavily doped region 6064, a first P-type lightly doped region 6062, a first N-type lightly doped region 6063; the first P-type lightly doped region 6062 is arranged on one side of the first P-type heavily doped region 6061; the first N-type lightly doped region 6063 is arranged on one side of the first P-type lightly doped region 6062 away from the first P-type heavily doped region 6061; the first N-type heavily doped region 6064 is arranged on one side of the first N-type lightly doped region 6063 away from the first P-type lightly doped region 6062.

[0061] Among them, the ring resonator 300 is a ridge waveguide. The first region of the ring resonator 300 is composed of a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063, and a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063 can form a ridge waveguide. The first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 are respectively planar waveguides, and the first P-type heavily doped region 6061 is electrically connected to the first P-type lightly doped region 6062, and the first N-type heavily doped region 6064 is electrically connected to the first N-type lightly doped region 6063 so that the planar waveguide is electrically connected to the ridge waveguide to form a first photoelectric modulation module, and a depletion region is formed around the combination interface of the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063. Among them, the ridge waveguide and the first half-ring waveguide 301 can be of the same structure, and the resonance and modulation processing of the optical signal in the tunable ring resonator cavity are realized through multiplexing.

[0062] In addition, the second region of the tunable ring resonator 300 is composed of a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063, and a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063 can form a ridge waveguide. The first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 are respectively planar waveguides, and the first P-type heavily doped region 6061 is electrically connected to the first P-type lightly doped region 6062, and the first N-type heavily doped region 6064 is electrically connected to the first N-type lightly doped region 6063 so that the planar waveguide is electrically connected to the ridge waveguide to form a second photoelectric modulation module, and a depletion region is formed around the combination interface of the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063. Among them, the ridge waveguide and the second half-ring waveguide 302 can be of the same structure, and the resonance and modulation processing of the optical signal in the tunable ring resonator 300 cavity are realized through multiplexing.

[0063] In this embodiment, the first P-type heavily doped region 6061, the first N-type heavily doped region 6064, the first P-type lightly doped region 6062, and the first N-type lightly doped region 6063 are arranged in the same layer to form a silicon waveguide layer 606. The first photoelectric modulation module and the second photoelectric modulation module further include: an upper cladding 603 provided on the upper surface of the silicon waveguide layer 606; a lower cladding provided on the lower surface 604 of the silicon waveguide layer 606; a substrate layer provided on the side of the lower cladding away from the silicon waveguide layer 606. Among them, the substrate layer is a silicon substrate layer 605, and the upper cladding 603 and the lower cladding are silicon dioxide claddings.

[0064] In addition, several first electrodes 601 and several second electrodes 602 are provided on the side of the upper cladding 603 away from the silicon waveguide layer 606, and the several first electrodes 601 and several second electrodes 602 are distributed in a semi-ring shape. First metal vias 6011 and second metal vias 6021 are provided in the upper cladding 603. Through the first metal vias 6011 and the second metal vias 6021, the first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 are respectively connected to the first electrode 601 and the second electrode 602 in correspondence. The first electrode 601 and the second electrode 602 are electrically connected to an external electrical signal source to apply an electrical modulation signal to the first P-type heavily doped region 6061 and the first N-type heavily doped region 6064, thereby adjusting the carrier concentration in the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063, and further changing the effective refractive index of the optical mode transmitted in the waveguide. The ridge waveguide of the microring resonator supports multiple mode transmissions. Among them, the main material of the waveguide layer is silicon, the total thickness is 340 nm, the ridge height of the ridge waveguide is 290 nm, the width of the ridge waveguide is 500 nm, and the height of the planar waveguide is 50 nm.

[0065] In some embodiments, according to specific modulation requirements, specific parameters in the waveguide layer (such as waveguide thickness, ridge height, width) can be adaptively adjusted.

[0066] Please refer to Figure 2B , as Figure 2B shown, in some embodiments, the first P-type lightly doped region 6062 includes at least two surfaces, and the first N-type lightly doped region 6063 covers at least two surfaces of the first P-type lightly doped region 6062; or, the first N-type lightly doped region 6063 includes at least two surfaces, and the first P-type lightly doped region 6062 covers at least two surfaces of the first N-type lightly doped region 6063.

[0067] Among them, the first N-type lightly doped region 6063 covers at least two surfaces of the first P-type lightly doped region 6062 to form an L-shaped PN junction doping structure. By making the first N-type lightly doped region 6063 cover at least two surfaces of the first P-type lightly doped region 6062, the overlapping area of the optical signal mode field and the depletion region can be increased, so as to effectively improve the modulation efficiency of the first optoelectronic modulation module, and the use of the L-shaped PN junction doping structure can increase the refractive index change range of the modulated region of the ring resonator 300.

[0068] In some embodiments, the first P-type lightly doped region 6062 covers at least two surfaces of the first N-type lightly doped region 6063 to form an L-shaped PN junction doping structure. By making the first P-type lightly doped region 6062 cover at least two surfaces of the first N-type lightly doped region 6063, the overlapping area between the optical signal mode field and the depletion region can be increased, so as to effectively improve the modulation efficiency of the first optoelectronic modulation module, and the use of the L-shaped PN junction doping structure can increase the refractive index change range of the region of the ring resonator 300 to be modulated.

[0069] Please refer again to Figure 1 , the input waveguide 100 includes: a single-mode input waveguide 101, a first tapered waveguide 102, and a multimode input waveguide 103;

[0070] One end of the first tapered waveguide 102 is connected to the multimode input waveguide 103, and the other end of the first tapered waveguide 102 is connected to the single-mode input waveguide 101. The initial optical signal is received by the single-mode input waveguide 101 and transmitted to the multimode input waveguide 103 via the first tapered waveguide 102. The initial optical signal is transmitted to the tunable ring resonator 300 through the coupling of the multimode input waveguide 103 and the tunable ring resonator 300 to perform resonance processing on the initial optical signal and generate a first optical signal.

[0071] The feedback loop waveguide 200 includes: a feedback multimode waveguide 201, an arc waveguide 202, and a second tapered waveguide 203; one end of the feedback multimode waveguide 201 is connected to the multimode input waveguide 103, and the other end of the feedback multimode waveguide 201 is connected to one end of the second tapered waveguide 203; the other end of the second tapered waveguide 203 is connected to one end of the arc waveguide 202; the other end of the arc waveguide 202 is connected to the first mode converter 400. Among them, the feedback multimode waveguide 201 is coupled to the tunable ring resonator to receive the first optical signal and is incident into the arc waveguide 202 via the second tapered waveguide 203; the first optical signal is incident into the first mode converter 400 via the arc waveguide 202.

[0072] Among them, the arc waveguide 202 includes: a silicon substrate layer 605; a silica lower cladding layer provided on one side of the silicon substrate layer 605; a silicon waveguide layer 606 provided on the side of the silica lower cladding layer away from the silicon substrate layer 605; a silica upper cladding layer 603 provided on the side of the silicon waveguide layer 606 away from the silica lower cladding layer.

[0073] Among them, the feedback multimode waveguide 201 and the multimode input waveguide 103 can be an integral structure, and by multiplexing the same multimode waveguide, the output function of the initial optical signal and the output function of the first optical signal are realized.

[0074] The arc waveguide 202 includes: a silicon substrate layer; a lower silica cladding layer disposed on one side of the silicon substrate layer; a silicon waveguide layer disposed on the side of the lower silica cladding layer away from the silicon substrate layer; and an upper silica cladding layer disposed on the side of the silicon waveguide layer away from the lower silica cladding layer. Among them, the arc waveguide 202 is a single-mode waveguide that only supports the transmission of optical signals in the TE0 mode. Therefore, optical signals in other modes will experience optical loss during the transmission in the arc waveguide 202, such that the input signal of the first mode converter 400 is only the optical signal in the TE0 mode.

[0075] The silicon waveguide layer 606 is provided with a ridge waveguide or a strip waveguide. When the waveguide provided in the silicon waveguide layer 606 is a strip waveguide, a transition waveguide is provided between the arc waveguide 202 and the first mode converter 400 for optical signal matching. Among them, the transition waveguide can be a tapered waveguide with a ridge waveguide linearly transitioning to a strip waveguide.

[0076] Please refer to Figure 1 、 Figure 3A , in some embodiments, the first mode converter 400 includes: a first input single-mode waveguide 401, one end of the first input single-mode waveguide 401 is connected to the feedback loop waveguide 200; a first single-mode coupling waveguide 402, one end of the first single-mode coupling waveguide 402 is connected to the other end of the first input single-mode waveguide 401; a first multimode coupling waveguide 403, coupled to the first single-mode coupling waveguide 402; a first conversion tapered waveguide 404, one end of the first conversion tapered waveguide 404 is connected to the first multimode coupling waveguide 403; a first output multimode waveguide 405, one end of the first output multimode waveguide 405 is connected to the other end of the first conversion tapered waveguide 404, and the other end of the first output multimode waveguide 405 is connected to the output waveguide 501.

[0077] Among them, the first output multimode waveguide 405 and the output waveguide 501 can be an integral structure, and by multiplexing the same multimode waveguide, the output functions of the second optical signal and the third optical signal are realized.

[0078] In some specific embodiments, the first single-mode coupling waveguide 402 is coupled to the first multimode coupling waveguide 403 and satisfies the phase matching condition. The first optical signal is transmitted from the first input single-mode waveguide 401 to the first single-mode coupling waveguide 402, and after being transmitted through a certain coupling length, the first optical signal is coupled into the first multimode coupling waveguide 403 and converted into an optical signal in other modes for transmission to the first conversion tapered waveguide 404. The first conversion tapered waveguide 404 performs a mode conversion process on the first optical signal in other modes and outputs a second optical signal, which is coupled into the tunable ring resonator through the first output multimode waveguide 405, and the tunable ring resonator 300 performs a resonance process on the second optical signal to generate a third optical signal.

[0079] For example, the first optical signal is in the TE0 mode. After being coupled and transmitted through the first multimode coupling waveguide 403 and the first single-mode coupling waveguide 402, an optical signal in the TE1 mode is generated. The optical signal in the TE1 mode is transmitted in the first conversion tapered waveguide 404 and gradually converted into a second optical signal in the TM0 mode, and the second optical signal in the TM0 mode is coupled into the tunable ring resonator 300 through the first output multimode waveguide 405.

[0080] Referring to Figure 3B , in some embodiments, the first mode converter 400 includes: a first input single-mode waveguide 401, one end of the first input single-mode waveguide 401 is connected to the feedback loop waveguide 200; a first single-mode coupling waveguide 402, one end of the first single-mode coupling waveguide 402 is connected to the other end of the first input single-mode waveguide 401; a first multimode coupling waveguide 403, which is coupled and connected to the first single-mode coupling waveguide 402; a first output multimode waveguide 405, one end of the first output multimode waveguide 405 is connected to one end of the first multimode coupling waveguide 403, and the other end of the first output multimode waveguide 405 is connected to the output waveguide 501.

[0081] In some specific embodiments, the first single-mode coupling waveguide 402 is coupled and connected to the first multimode coupling waveguide 403 and satisfies the phase matching condition. The first optical signal is transmitted from the first input single-mode waveguide 401 into the first single-mode coupling waveguide 402, and after being transmitted through a certain coupling length, the first optical signal is coupled into the first multimode coupling waveguide 403 and converted into a second optical signal in another mode and transmitted to the first output multimode waveguide 405. The second optical signal is coupled into the tunable ring resonator 300 through the first output multimode waveguide 405, and the tunable ring resonator 300 performs resonance processing on the second optical signal to generate a third optical signal.

[0082] For example, the first optical signal is in the TE0 mode. After being coupled and transmitted through the first multimode coupling waveguide 403 and the first single-mode coupling waveguide 402, a second optical signal in the TE1 mode is generated, and the second optical signal in the TE1 mode is coupled into the tunable ring resonator 300 through the first output multimode waveguide 405.

[0083] In some embodiments, the second mode converter 500 includes: a second input multimode waveguide, one end of the second input multimode waveguide is connected to the output waveguide; a second conversion tapered waveguide, one end of the second conversion tapered waveguide is connected to the other end of the second input multimode waveguide; a second multimode coupling waveguide, one end of the second multimode coupling waveguide is connected to the other end of the second conversion tapered waveguide; a second single-mode coupling waveguide, the second single-mode coupling waveguide is coupled and connected to the second multimode coupling waveguide; a second output single-mode waveguide, one end of the second output single-mode waveguide is connected to one end of the second single-mode coupling waveguide.

[0084] In some specific embodiments, the second single-mode coupling waveguide is coupled to the second multimode coupling waveguide and satisfies the phase matching condition. The third optical signal is transmitted through the second input multimode waveguide to the second conversion tapered waveguide, and after being transmitted through the second conversion tapered waveguide for a certain distance, it is converted into an optical signal of other modes and transmitted to the second multimode coupling waveguide. After being transmitted through a certain coupling length, the optical signal of other modes is coupled into the second single-mode coupling waveguide and converted into the fourth optical signal.

[0085] For example, the third optical signal is a TM0 mode and is transmitted in the second conversion tapered waveguide and gradually converted into an optical signal of TE1 mode; after the optical signal of TE1 mode is coupled and transmitted through the second multimode coupling waveguide and the second single-mode coupling waveguide, an optical signal of TE0 mode is generated in the second single-mode coupling waveguide.

[0086] In some embodiments, the second mode converter 500 includes: a second input multimode waveguide, one end of the second input multimode waveguide is connected to the output waveguide; a second multimode coupling waveguide, one end of the second multimode coupling waveguide is connected to the other end of the second input multimode waveguide; a second single-mode coupling waveguide, the second single-mode coupling waveguide is connected to the second multimode coupling waveguide; a second output single-mode waveguide, one end of the second output single-mode waveguide is connected to one end of the second single-mode coupling waveguide.

[0087] In some specific embodiments, the second single-mode coupling waveguide is coupled to the second multimode coupling waveguide and satisfies the phase matching condition. The third optical signal is transmitted through the second input multimode waveguide to the second multimode coupling waveguide, and after being transmitted through a certain coupling length, the third optical signal is coupled into the second single-mode coupling waveguide and converted into the fourth optical signal of other modes.

[0088] For example, the third optical signal is an optical signal of TE1 mode. After the optical signal of TE1 mode is coupled and transmitted through the second multimode coupling waveguide and the second single-mode coupling waveguide, an optical signal of TE0 mode is generated in the second single-mode coupling waveguide.

[0089] Please refer to Figure 1 、 Figure 2A 、 Figure 3A, in a specific embodiment, an optical modulator includes: an input waveguide 100 for receiving an initial optical signal; an adjustable ring resonator, which is coupled to the input waveguide 100 and is used for resonating the initial optical signal and outputting a first optical signal; a feedback loop waveguide 200, which is coupled to the adjustable ring resonator and is used for receiving and transmitting the first optical signal; a first mode converter 400, which is coupled to the feedback loop waveguide 200 and is used for performing mode conversion on the first optical signal and outputting a second optical signal; the adjustable ring resonator is further used for resonating the second optical signal and outputting a third optical signal; an output waveguide 501, which is coupled to the adjustable ring resonator and is used for receiving and outputting the third optical signal; a second mode converter 500, the input end of the second mode converter 500 is coupled to the output waveguide 501 and is used for performing mode conversion on the third optical signal and outputting a fourth optical signal, so that the output signal is an optical signal in a target mode. By performing mode multiplexing on the adjustable ring resonator, optical signals in multiple modes are modulated simultaneously to improve the extinction ratio of the optical signal.

[0090] Among them, the first mode converter 400 and the second mode converter 500 are identical and oppositely arranged mode converters.

[0091] The adjustable ring resonator includes: a first optoelectronic modulation module, a second optoelectronic modulation module, and a ring resonator 300; the first optoelectronic modulation module is used for adjusting the refractive index of the first region of the ring resonator 300; the second optoelectronic modulation module is used for adjusting the refractive index of the second region of the ring resonator 300.

[0092] Both the first optoelectronic modulation module and the second optoelectronic modulation module are silicon-based optoelectronic modulation modules; the silicon-based optoelectronic modulation module includes: a first P-type heavily doped region 6061, a first N-type heavily doped region 6064, a first P-type lightly doped region 6062, and a first N-type lightly doped region 6063; the first P-type lightly doped region 6062 is disposed on one side of the first P-type heavily doped region 6061; the first N-type lightly doped region 6063 is disposed on the side of the first P-type lightly doped region 6062 away from the first P-type heavily doped region 6061; the first N-type heavily doped region 6064 is disposed on the side of the first N-type lightly doped region 6063 away from the first P-type lightly doped region 6062.

[0093] Among them, the tunable ring resonator 300 is a ridge waveguide. Both the first region and the second region of the tunable ring resonator 300 are composed of a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063, and a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063 can form a ridge waveguide. The first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 are respectively planar waveguides, and the first P-type heavily doped region 6061 is electrically connected to the first P-type lightly doped region 6062, and the first N-type heavily doped region 6064 is electrically connected to the first N-type lightly doped region 6063 so that the planar waveguide is electrically connected to the ridge waveguide to form a PN junction type optical modulator, and a depletion region is formed around the bonding interface of the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063.

[0094] The first mode converter 400 includes: a first input single-mode waveguide 401, a first single-mode coupling waveguide 402, a first multimode coupling waveguide 403, a first conversion tapered waveguide 404, and a first output multimode waveguide 405; one end of the first input single-mode waveguide 401 is connected to the feedback loop waveguide 200, and the other end of the first input single-mode waveguide 401 is connected to the first single-mode coupling waveguide 402; one end of the first conversion tapered waveguide 404 is connected to the first multimode coupling waveguide 403, the other end of the first conversion tapered waveguide 404 is connected to one end of the first output multimode waveguide 405, and the other end of the first output multimode waveguide 405 is connected to the output waveguide 501; wherein, the first single-mode coupling waveguide 402 is coupled to the first multimode coupling waveguide 403. The second mode converter 500 includes: a second input multimode waveguide, a second single-mode coupling waveguide, a second multimode coupling waveguide, a second conversion tapered waveguide, and a second output single-mode waveguide; one end of the second input multimode waveguide is connected to the output waveguide 501, and the other end of the second input multimode waveguide is connected to one end of the second conversion tapered waveguide; the other end of the second conversion tapered waveguide is connected to the second multimode coupling waveguide; one end of the second single-mode coupling waveguide is connected to the second output single-mode waveguide; wherein, the second single-mode coupling waveguide is coupled to the second multimode coupling waveguide.

[0095] The initial optical signal is a continuous optical signal in the TE0 mode, which is received by the single-mode input waveguide 101 and transmitted to the multimode input waveguide 103 via the first tapered waveguide 102. The initial optical signal is transmitted to the ring resonator 300 through the coupling of the multimode input waveguide 103 and the ring resonator 300 to perform resonance processing on the initial optical signal and generate a first optical signal. Among them, the first optical signal is in the TE0 mode.

[0096] Specifically, an electro-modulation signal is applied to the first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 through a plurality of electrodes to adjust the carrier concentration in the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063, thereby changing the effective refractive index of the optical mode transmitted in the waveguide. During the transmission of the first optical signal in the ring resonator 300, a phase change is accumulated, and interference occurs in the first straight waveguide 303 and the second straight waveguide 304 of the ring resonator 300 respectively to convert the phase change into an intensity change, thereby modulating the resonant wavelength in the tunable ring resonator 300.

[0097] The first optical signal in the TE0 mode is converted into the second optical signal in the TM0 mode through the first mode converter 400, and the second optical signal in the TM0 mode is coupled into the ring resonator 300 via the first output multimode waveguide 405; the ring resonator 300 performs resonance processing on the second optical signal and generates a third optical signal to obtain a third optical signal with a high extinction ratio. Among them, the third optical signal is in the TM0 mode. By multiplexing the modes of the tunable ring resonator, optical signals of multiple modes are modulated simultaneously to improve the extinction ratio of the optical signal.

[0098] The third optical signal in the TM0 mode is converted into the fourth optical signal in the TE0 mode through the second mode converter 500 to obtain an optical signal in the TE0 mode with a high extinction ratio.

[0099] Please refer to Figure 4A 、 4B , the abscissa is the applied voltage value (absolute value of the voltage, unit: V) of the first photoelectric modulation module and the second photoelectric modulation module respectively, the left ordinate is the effective refractive index, and the right ordinate is the unit power loss (unit: dB / cm). L41 is the relationship curve between the applied voltage value and the effective refractive index of the TE0 mode, L43 is the relationship curve between the applied voltage value and the effective refractive index of the TM0 mode, L42 is the relationship curve between the applied voltage value and the unit power loss of the TE0 mode (unit: dB / cm), and L43 is the relationship curve between the applied voltage value and the unit power loss of the TM0 mode.

[0100] As Figure 4A shown, as the applied voltage value of the first photoelectric modulation module gradually increases, in the tunable ring resonator 300, the effective refractive index of the TE0 mode gradually increases, and the unit power loss becomes smaller; as the applied voltage value of the second photoelectric modulation module gradually increases, in the tunable ring resonator 300, the effective refractive index of the TM0 mode gradually increases, and the unit power loss becomes smaller.

[0101] By changing the voltage values applied to the first optoelectronic modulation module and the second optoelectronic modulation module, the effective refractive indices of the first region and the second region in the ring resonator 300 are changed, so that the optical signals of the TE0 mode and the TM0 mode accumulate phase changes in the ring resonator 300. The optical signals of the TE0 mode and the TM0 mode interfere in the first straight waveguide 303 and the second straight waveguide 304 respectively, so as to convert the phase change into an intensity change, thereby changing the resonant wavelength in the tunable ring resonator 300.

[0102] Please refer to Figure 5A 、 5B together. The abscissa is the wavelength (unit: nm), and the ordinate is the signal power (unit: dB). L TE0 、L TM0 are the curves of the resonant wavelengths of different modes, and L TE0+TM0 is the total resonant spectrum. L1 to LN are the curves of the relationship between different applied voltages and resonant wavelengths.

[0103] As Figure 5A shown, the resonant wavelengths of the TE0 mode and the TM0 mode completely coincide. Therefore, the resonant processing can be performed on the initial wavelength of the TE0 mode to obtain the first optical signal of the TE0 mode. The first optical signal of the TE0 mode is converted into the second optical signal of the TM0 mode through the first mode converter 400, and the second optical signal of the TM0 mode is coupled into the tunable ring resonator 300 through the first output multimode waveguide 405; the tunable ring resonator 300 performs resonant processing on the second optical signal and generates a third optical signal to obtain a third optical signal with a high extinction ratio. That is, by performing secondary resonant processing on the optical signal, an optical signal with a high extinction ratio is obtained, and the resonant processing is performed on the optical signals of two different modes through the same tunable ring resonator 300.

[0104] As Figure 5B shown, by performing resonance on the TE0 mode and the TM0 mode respectively to obtain an optical signal with a high extinction ratio, in the spectrum of this optical signal, as the reverse voltage increases, the resonant peak gradually drifts. Among them, the reverse voltage applied to the curve corresponding to L1 is 0V, and the reverse voltage applied to the curve corresponding to LN is 10V. Specifically, as the reverse voltage increases, the resonant wavelength gradually increases.

[0105] Please refer to Figure 1 、 Figure 2B 、 Figure 3B, in a specific embodiment, an optical modulator includes: an input waveguide 100 for receiving an initial optical signal; an adjustable ring resonator 300, which is coupled to the input waveguide 100 and is used to perform resonance processing on the initial optical signal and output a first optical signal; a feedback loop waveguide 200, which is coupled to the adjustable ring resonator 300 and is used to receive and transmit the first optical signal; a first mode converter 400, which is coupled to the feedback loop waveguide 200, and the first mode converter 400 is used to perform mode conversion processing on the first optical signal and output a second optical signal; the adjustable ring resonator 300 is further used to perform resonance processing on the second optical signal and output a third optical signal; an output waveguide 501, which is coupled to the adjustable ring resonator 300 and is used to receive and output the third optical signal; a second mode converter 500, the input end of the second mode converter 500 is coupled to the output waveguide 501, and is used to perform mode conversion processing on the third optical signal and output a fourth optical signal, so that the output signal is an optical signal of a target mode.

[0106] Among them, the first mode converter 400 and the second mode converter 500 are identical and oppositely arranged mode converters.

[0107] Among them, the adjustable ring resonator 300 is a ridge waveguide. The first region and the second region of the adjustable ring resonator 300 are both composed of a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063, and a first P-type lightly doped region 6062 and a first N-type lightly doped region 6063 can form a ridge waveguide. The first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 are respectively planar waveguides, and the first P-type heavily doped region 6061 is electrically connected to the first P-type lightly doped region 6062, and the first N-type heavily doped region 6064 is electrically connected to the first N-type lightly doped region 6063 so that the planar waveguide is electrically connected to the ridge waveguide to form a PN junction type optical modulator, and a depletion region is formed around the bonding interface of the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063.

[0108] The first mode converter 400 includes: a first input single-mode waveguide 401, a first single-mode coupling waveguide 402, a first multimode coupling waveguide 403, and a first output multimode waveguide 405; one end of the first input single-mode waveguide 401 is connected to the feedback loop waveguide 200, and the other end of the first input single-mode waveguide 401 is connected to the first single-mode coupling waveguide 402; one end of the first output multimode waveguide 405 is connected to the first multimode coupling waveguide 403, and the other end of the first output multimode waveguide 405 is connected to the output waveguide 501; among them, the first single-mode coupling waveguide 402 is coupled to the first multimode coupling waveguide 403.

[0109] The second mode converter 500 includes: a second input multimode waveguide, a second single-mode coupling waveguide, a second multimode coupling waveguide, a second conversion tapered waveguide, and a second output single-mode waveguide; one end of the second input multimode waveguide is connected to the output waveguide 501, and the other end of the second input multimode waveguide is connected to one end of the second conversion tapered waveguide; the other end of the second conversion tapered waveguide is connected to the second multimode coupling waveguide; one end of the second single-mode coupling waveguide is connected to the second output single-mode waveguide; wherein, the second single-mode coupling waveguide is coupled to the second multimode coupling waveguide.

[0110] The initial optical signal is a continuous optical signal in the TE0 mode, which is received by the single-mode input waveguide 101 and transmitted to the multimode input waveguide 103 through the first tapered waveguide 102. The initial optical signal is coupled to the tunable ring resonator 300 through the multimode input waveguide 103 to perform resonance processing on the initial optical signal and generate a first optical signal. Wherein, the first optical signal is in the TE0 mode.

[0111] Specifically, an electro-modulation signal is applied to the first P-type heavily doped region 6061 and the first N-type heavily doped region 6064 through a plurality of electrodes to adjust the carrier concentration in the first P-type lightly doped region 6062 and the first N-type lightly doped region 6063, thereby changing the effective refractive index of the optical mode transmitted in the waveguide. The first optical signal accumulates a phase change during the transmission in the tunable ring resonator 300 and interferes respectively in the first straight waveguide 303 and the second straight waveguide 304 of the tunable ring resonator 300 to convert the phase change into an intensity change, thereby modulating the resonant wavelength in the tunable ring resonator 300.

[0112] The first optical signal in the TE0 mode is converted into a second optical signal in the TE1 mode by the first mode converter 400, and the second optical signal in the TE1 mode is coupled into the tunable ring resonator 300 through the first output multimode waveguide 405; the tunable ring resonator 300 performs resonance processing on the second optical signal and generates a third optical signal to obtain a third optical signal with a high extinction ratio. Wherein, the third optical signal is in the TE1 mode.

[0113] The third optical signal in the TE1 mode is converted into a fourth optical signal in the TE0 mode by the second mode converter 500 to obtain an optical signal in the TE0 mode with a high extinction ratio.

[0114] Please refer to Figure 6A 、 6B, the abscissa is the applied voltage values (absolute value of voltage, unit: V) of the first and second photoelectric modulation modules respectively, the left ordinate is the effective refractive index, and the right ordinate is the unit power loss (unit: dB / cm). L61 is the relationship curve between the applied voltage value and the effective refractive index of the TE0 mode, L63 is the relationship curve between the applied voltage value and the effective refractive index of the TE1 mode, L62 is the relationship curve between the applied voltage value and the unit power loss of the TE0 mode, and L43 is the relationship curve between the applied voltage value and the unit power loss of the TE1 mode.

[0115] As Figure 6A shown, as the applied voltage value of the first photoelectric modulation module gradually increases, in the tunable ring resonator 300, the effective refractive index of the TE0 mode gradually increases, and the unit power loss becomes smaller; as the applied voltage value of the second photoelectric modulation module gradually increases, in the tunable ring resonator 300, the effective refractive index of the TE1 mode gradually increases, and the unit power loss becomes smaller.

[0116] By changing the applied voltage values of the first and second photoelectric modulation modules, the effective refractive indices of the first and second regions in the tunable ring resonator 300 are changed, so that the optical signals of the TE0 mode and the TE1 mode accumulate phase changes in the tunable ring resonator 300. The optical signals of the TE0 mode and the TE1 mode interfere in the first straight waveguide 303 and the second straight waveguide 304 respectively, so as to convert the phase change into an intensity change, thereby changing the resonant wavelength in the tunable ring resonator 300.

[0117] Please refer to Figure 7A and 7B together. The abscissa is the wavelength (unit: nm), and the ordinate is the signal power (unit: dB). L TE0 and L TE1 are the curves of the resonant wavelengths of different modes, L TE0+TE1 is the total resonant spectrum, and L1 to LN are the relationship curves between different applied voltages and the resonant wavelength.

[0118] As Figure 7AAs shown, the resonant wavelengths of the TE0 mode and the TE1 mode completely coincide. Therefore, the initial wavelength of the TE0 mode can be resonated to obtain the first optical signal of the TE0 mode. The first optical signal of the TE0 mode is converted into the second optical signal of the TM0 mode by the first mode converter 400, and the second optical signal of the TE1 mode is coupled into the tunable ring resonator 300 via the first output multimode waveguide 405. The tunable ring resonator 300 resonates the second optical signal to generate a third optical signal to obtain a third optical signal with a high extinction ratio. That is, by performing secondary resonance processing on the optical signal, an optical signal with a high extinction ratio is obtained, and the optical signals of two different modes are resonated by the same tunable ring resonator 300.

[0119] As Figure 7B shown, by resonating the TE0 mode and the TE1 mode respectively to obtain an optical signal with a high extinction ratio. In the spectrum of this optical signal, as the reverse voltage increases, the resonant peak gradually drifts. L1 to LN are the relationship curves between different applied voltages and resonant wavelengths. Among them, the reverse voltage applied to the curve corresponding to L1 is 0V, and the reverse voltage applied to the curve corresponding to LN is 10V.

[0120] Specifically, as the reverse voltage increases, the resonant wavelength gradually increases.

[0121] Please refer again to Figure 1 A method for controlling an optical modulator includes: receiving an initial optical signal through an input waveguide 100; resonating the initial optical signal through a tunable ring resonator 300 and outputting a first optical signal; receiving the first optical signal through a feedback loop waveguide 200 and transmitting it to a first mode converter 400; using the first mode converter 400 to perform mode conversion on the first optical signal and output a second optical signal, and resonating the second optical signal through the tunable ring resonator 300 and outputting a third optical signal; receiving and outputting the third optical signal through an output waveguide 501.

[0122] The initial optical signal is received by the input waveguide 100 and transmitted into the tunable ring resonator 300, where the initial optical signal resonates. Since the initial optical signal is a continuous optical signal, after the tunable ring resonator 300 performs resonance processing on the initial optical signal, the amplitude of the optical signal with a specific frequency is amplified to generate a first optical signal. The first optical signal is transmitted to the first mode converter 400 through the loop feedback loop waveguide 200, and the first mode converter 400 performs mode conversion on the first optical signal and outputs a second optical signal. By coupling the second optical signal into the tunable ring resonator 300 again and performing resonance processing to amplify the amplitude of the optical signal with a specific frequency in the second optical signal to generate a third optical signal, the third optical signal is output through the output waveguide 501 coupled to the tunable ring resonator 300. That is, by multiplexing the tunable ring resonator 300 to simultaneously perform resonance processing on the initial optical signal and the second optical signal to amplify the amplitude of the optical signal with a specific frequency, a third optical signal with a better extinction ratio is obtained.

[0123] Among them, the first mode converter 400 can convert the first optical signal into optical signals of different orthogonal modes or optical signals of different orders of modes. Since the second optical signal and the initial optical signal are optical signals of different modes, and the tunable ring resonator 300 can support the transmission of multi-mode optical signals, when the second optical signal and the initial optical signal are transmitted in the tunable ring resonator 300, they are transmitted separately without interference or crosstalk. The micro-ring resonator can be a circular tunable ring resonator 300 or a racetrack-shaped micro-ring resonator, and the curved waveguide of the micro-ring resonator supports the transmission of more than two modes in the micro-ring resonator. By performing mode multiplexing on the tunable ring resonator to simultaneously modulate optical signals of multiple modes, the extinction ratio of the optical signal is improved.

[0124] The optical modulator control method further includes: performing mode conversion on the third optical signal through the second mode converter 500 and outputting a fourth optical signal; the input end of the second mode converter 500 is coupled to the output waveguide 501.

[0125] In some specific embodiments, the first mode converter 400 and the second mode converter 500 are identical and oppositely arranged mode converters. The initial optical signal and the first optical signal are optical signals in the TE0 mode. The first mode converter 400 performs mode conversion on the first optical signal and outputs a second optical signal in the TE1 mode or the TM0 mode, and the tunable ring resonator 300 performs resonance processing on the second optical signal to generate a third optical signal. The input end of the second mode converter 500 is coupled to the output waveguide 501 to perform mode conversion on the third optical signal and output a fourth optical signal. Among them, the third optical signal is an optical signal in the TE1 mode or the TM0 mode, and the fourth optical signal is an optical signal in the TE0 mode. By setting the first mode converter 400 and the second mode converter 500, the initial optical signal and the fourth optical signal have the same mode, that is, the output signal of the optical modulator and the input signal have the same mode.

[0126] In addition, when the third optical signal in the TE1 mode or the TM0 mode is transmitted to the first mode converter 400 via the feedback loop waveguide 200, the third optical signal will experience loss to ensure that the output signal of the first mode converter 400 is the first optical signal; when the first optical signal in the TE0 mode is transmitted to the second mode converter 500 via the output waveguide 501, the first optical signal will experience optical loss to ensure that the output signal of the second mode converter 500 is the fourth optical signal.

[0127] The optical modulator control method further includes: adjusting the refractive index of the first region of the tunable ring resonator 300 by setting the first photoelectric modulation module; adjusting the refractive index of the second region of the tunable ring resonator 300 by setting the second photoelectric modulation module.

[0128] Among them, the first photoelectric modulation module and the second photoelectric modulation module respectively adjust the refractive indices of different regions of the tunable ring resonator 300. By adjusting the refractive indices of the first region and the second region, the initial optical signal and the second optical signal accumulate phase changes during transmission in the first region and the second region, and interference occurs in the first straight waveguide 303 and the second straight waveguide 304 in the tunable ring resonator 300 respectively, so as to convert the phase change into an intensity change.

[0129] The optical modulator control method further includes: the initial optical signal, the first optical signal and the fourth optical signal are in the TE0 mode; the second optical signal and the third optical signal are in any one of the TM0 mode or the TE1 mode. The first mode converter 400 and the second mode converter 500 perform conversion on the optical signal so that optical signals in different modes resonate in the tunable ring resonator 300 without interfering with each other.

[0130] In some specific embodiments, the first mode converter 400 and the second mode converter 500 are identical and oppositely arranged mode converters. The initial optical signal and the first optical signal are optical signals in the TE0 mode. The first mode converter 400 performs mode conversion on the first optical signal and outputs a second optical signal in the TE1 mode or the TM0 mode, and the tunable ring resonator 300 performs resonance processing on the second optical signal to generate a third optical signal. The input end of the second mode converter 500 is coupled to the output waveguide 501 to perform mode conversion on the third optical signal and output a fourth optical signal. Among them, the third optical signal is an optical signal in the TE1 mode or the TM0 mode, and the fourth optical signal is an optical signal in the TE0 mode. By setting the first mode converter 400 and the second mode converter 500, the initial optical signal and the fourth optical signal have the same mode, that is, the output signal of the optical modulator and the input signal have the same mode.

[0131] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0132] Those of ordinary skill in the art can understand that all or some of the steps and systems disclosed above can be implemented as software, firmware, hardware, and their appropriate combinations. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cassette, tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those of ordinary skill in the art, communication media typically includes computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any information delivery medium.

[0133] The above is a specific description of the preferred embodiment of the present application. However, the present application is not limited to the above-mentioned embodiments. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present application, and these equivalent deformations or substitutions are all included within the scope defined by the claims of the present application.

Claims

1. An optical modulator, characterized in that include: an input waveguide for receiving an initial optical signal; an adjustable ring resonator, coupled to the input waveguide, for resonating and modulating the initial optical signal and outputting a first optical signal; a feedback loop waveguide coupled to the tunable ring resonator and configured to receive and transmit the first optical signal; a first mode converter, coupled to the feedback loop waveguide, for performing mode conversion processing on the first optical signal and outputting a second optical signal to the tunable ring resonator; The tunable ring resonator is further configured to resonate and modulate the second optical signal and output a third optical signal; an output waveguide coupled to the tunable ring resonator and configured to receive and output the third optical signal; A second mode converter, wherein an input end of the second mode converter is coupled to the output waveguide and is configured to perform mode conversion processing on the third optical signal and output a fourth optical signal.

2. The optical modulator according to claim 1, wherein The first mode converter and the second mode converter are identical mode converters that are arranged in opposite directions.

3. The optical modulator according to any one of claims 1 to 2, characterized in that The tunable ring resonator comprises a first coupling region and a second coupling region; The adjustable ring resonator is coupled to the input waveguide via the first coupling region; the adjustable ring resonator is coupled to the feedback loop waveguide via the first coupling region; The first mode converter is coupled to the tunable ring resonator through the second coupling region, and the tunable ring resonator is coupled to the output waveguide through the second coupling region.

4. The optical modulator according to claim 3, wherein The adjustable ring resonator further comprises: a first photoelectric modulation module, a second photoelectric modulation module, and a ring resonator; The first optoelectronic modulation module is used to adjust the refractive index of the first region of the ring resonator; The second optoelectronic modulation module is used to adjust the refractive index of the second region of the ring resonator; The first region is connected to the first coupling region and the second coupling region respectively, and the second region is connected to the first coupling region and the second coupling region respectively.

5. The optical modulator according to claim 4, wherein The first photoelectric modulation module and the second photoelectric modulation module are both silicon-based photoelectric modulation modules; The silicon-based photoelectric modulation module includes: a first P-type heavily doped region, a first P-type lightly doped region, a first N-type lightly doped region and a first N-type heavily doped region arranged in sequence.

6. The optical modulator according to claim 5, wherein The first P-type lightly doped region includes at least two surfaces, and the first N-type lightly doped region covers at least two surfaces of the first P-type lightly doped region; or, The first N-type lightly doped region includes at least two surfaces, and the first P-type lightly doped region covers at least the two surfaces of the first N-type lightly doped region.

7. The optical modulator according to claim 1, 2, 4, 5 or 6, characterized in that: The input waveguide comprises: a single-mode input waveguide for receiving an initial optical signal; a first tapered waveguide, one end of which is connected to the single-mode input waveguide; A multimode input waveguide is connected to the other end of the first tapered waveguide.

8. The optical modulator according to claim 7, wherein The feedback loop waveguide comprises: a feedback multimode waveguide, one end of which is connected to the multimode input waveguide; a second tapered waveguide, one end of the second tapered waveguide being connected to the other end of the feedback multimode waveguide; an arc-shaped waveguide, one end of which is connected to the other end of the second tapered waveguide; The other end of the arc waveguide is connected to the first mode converter.

9. The optical modulator according to claim 1, wherein The first mode converter comprises: a first input single-mode waveguide, one end of which is connected to the feedback loop waveguide; a first single-mode coupling waveguide, one end of the first single-mode coupling waveguide being connected to the other end of the first input single-mode waveguide; A first multimode coupling waveguide, coupled to the first single-mode coupling waveguide; a first conversion tapered waveguide, one end of which is connected to the first multimode coupling waveguide; A first output multimode waveguide, wherein one end of the first output multimode waveguide is connected to the other end of the first conversion tapered waveguide, and the other end of the first output multimode waveguide is connected to the output waveguide.

10. The optical modulator according to claim 1, wherein The first mode converter comprises: a first input single-mode waveguide, one end of which is connected to the feedback loop waveguide; a first single-mode coupling waveguide, one end of the first single-mode coupling waveguide being connected to the other end of the first input single-mode waveguide; A first multimode coupling waveguide, coupled to the first single-mode coupling waveguide; A first output multimode waveguide, wherein one end of the first output multimode waveguide is connected to one end of the first multimode coupling waveguide, and the other end of the first output multimode waveguide is connected to the output waveguide.

11. The optical modulator according to claim 1, wherein The second mode converter comprises: a second input multimode waveguide, one end of which is connected to the output waveguide; a second conversion tapered waveguide, one end of the second conversion tapered waveguide being connected to the other end of the second input multimode waveguide; a second multimode coupling waveguide, one end of the second multimode coupling waveguide being connected to the other end of the second conversion tapered waveguide; a second single-mode coupled waveguide, wherein the second single-mode coupled waveguide is coupled to the second multi-mode coupled waveguide; A second output single-mode waveguide, one end of which is connected to one end of the second single-mode coupling waveguide.

12. The optical modulator according to claim 1, wherein The second mode converter comprises: a second input multimode waveguide, one end of which is connected to the output waveguide; a second multimode coupling waveguide, one end of the second multimode coupling waveguide being connected to the other end of the second input multimode waveguide; a second single-mode coupled waveguide, the second single-mode coupled waveguide being connected to the second multimode coupled waveguide; A second output single-mode waveguide, one end of which is connected to one end of the second single-mode coupling waveguide.

13. A method for controlling an optical modulator, characterized in that: include: receiving an initial optical signal through an input waveguide; Resonate and modulate the initial optical signal through the adjustable ring resonator and output a first optical signal; receiving the first optical signal through a feedback loop waveguide and transmitting the signal to a first mode converter; Performing mode conversion processing on the first optical signal through the first mode converter and outputting a second optical signal; Resonate and modulate the second optical signal through the tunable ring resonator and output a third optical signal; receiving and outputting the third optical signal through an output waveguide; The third optical signal is subjected to mode conversion processing by the second mode converter and a fourth optical signal is output.

14. The optical modulator control method according to claim 13, wherein: The first mode converter and the second mode converter are identical mode converters that are arranged in opposite directions.

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