Silicon optical chip, external cavity laser and method for inhibiting micro-ring nonlinear effect

Abstract

The invention relates to the technical field of optical communication, in particular to a silicon optical chip, an external cavity laser and a method for restraining a micro-ring nonlinear effect. The P-doped region and the N-doped region at the two sides of the micro-ring resonant waveguide are respectively connected with the ground and an input voltage through an electrical connection module, so that a transverse electric field is formed in the micro-ring resonant waveguide, and free carriers generated after light passes through the micro-ring resonant waveguide are removed through the transverse electric field; and on the other hand, the P-doped region and the N-doped region are respectively connected with an external input voltage and the ground through the electrical connection module, so that bias voltage control on the two sides of the micro-ring resonant waveguide can be realized on the basis of not increasing redundant pins, free carriers generated in the micro-ring resonant cavity are eliminated, and the reliability of the micro-ring resonant cavity is improved. Therefore, the nonlinear effect of the micro-ring resonant cavity is effectively suppressed, and the micro-ring resonant cavity has the advantages of being simple in structure and meeting the miniaturization requirement.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to a silicon photonic chip, an external cavity laser, and a method for suppressing micro-ring nonlinear effects. Background Technology

[0002] Digital coherent optical communication, with its potential for high-capacity and long-distance transmission, is considered the future direction of optical communication systems. Driven by fiber optic capacities reaching 100 Gbps or higher, the deployment of coherent optical systems is continuously increasing. Coherent tunable lasers are a crucial and advantageous element in such networks. To meet the emerging demands and requirements of future coherent systems, coherent tunable lasers are required to possess the largest possible wavelength tuning range, the narrowest possible linewidth, low size, and low power consumption.

[0003] To achieve these goals, silicon-based external cavity tunable lasers (ECLs) based on microring resonators have emerged. However, the power enhancement effect of the microring resonator and the strong two-photon absorption effect of the silicon waveguide significantly affect the output power and linewidth of the ECL. In most cases, when a high-power laser is injected into the microring resonator, the two-photon absorption effect of silicon generates free carriers and holes. If the free carriers cannot be removed from the waveguide in time, the carrier dispersion effect, carrier absorption effect, and random recombination of free carriers and holes in silicon will generate thermal effects that affect the resonant wavelength of the microring, and under certain conditions, may cause oscillations in the resonant wavelength of the microring.

[0004] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to eliminate the free carriers generated in the micro-ring resonator, thereby effectively suppressing the nonlinear effects of the micro-ring resonator.

[0006] The present invention adopts the following technical solution: In a first aspect, a silicon photonics chip is provided, comprising: an electrical connection module, a microring resonant waveguide, and an optical reflection module; wherein the microring resonant waveguide is coupled to the optical reflection module; The micro-ring resonant waveguide is used to receive a first optical signal from the outside and to perform wavelength selection on the first optical signal to obtain a second optical signal; the optical reflection module is used to reflect the second optical signal back to the outside along the original optical path; The electrical connection module is used to connect to the external input voltage and ground, respectively; The micro-ring resonant waveguide has P-doped and N-doped regions on both sides, and the N-doped and P-doped regions are respectively connected to the electrical connection module. The N-doped region is connected to an external input voltage via the electrical connection module, and the P-doped region is grounded via the electrical connection module, so as to construct a transverse electric field in the micro-ring resonant waveguide and remove the free carriers generated by the micro-ring resonant waveguide after light transmission through the transverse electric field.

[0007] Preferably, it further includes a heating module, which is connected to the electrical connection module; the heating module is disposed adjacent to the microring resonant waveguide, and the heating module is used to adjust the phase of the optical signal in the microring resonant waveguide by heating.

[0008] Preferably, the device further includes a detection module, which is connected to the electrical connection module and coupled to the microring resonant waveguide for monitoring the intensity of the optical signal in the microring resonant waveguide.

[0009] Preferably, the detection module includes a photodiode, a transimpedance amplifier, and a feedback resistor; the photodiode is coupled to the microring resonant waveguide. The non-inverting input terminal of the transimpedance amplifier is connected to the electrical connection module for connection to the input voltage via the electrical connection module; the anode of the photodiode is connected to the inverting input terminal of the transimpedance amplifier for connection to the input voltage via the electrical connection module. The cathode of the photodiode is connected to the electrical connection module for connection to the input voltage via the electrical connection module; One end of the feedback resistor is connected to the output terminal of the transimpedance amplifier, and the other end of the feedback resistor is connected to the inverting input terminal of the transimpedance amplifier. The output terminal of the transimpedance amplifier is connected to the electrical connection module so as to connect to an external electrical control module through the electrical connection module.

[0010] Preferably, it further includes a mode converter, which is coupled to the input end of the microring resonant waveguide, and the mode converter is used to reduce the loss of the first optical signal entering the microring resonant waveguide.

[0011] Preferably, the microring resonant waveguide includes at least two cascaded microring resonant cavities, and the radii of the two microring resonant cavities differ by a predetermined size.

[0012] In a second aspect, an external cavity laser is provided, including a gain chip, an electrical control module, and a silicon photonics chip as described in the first aspect; The electrical control module is connected to the electrical connection module in the silicon photonics chip and the control terminal of the gain chip, respectively; the gain chip is coupled to the input terminal of the micro-ring resonant waveguide; The gain chip is used to emit the first optical signal under the drive of the electrical control module and transmit the first optical signal to the micro-ring resonant waveguide; The gain chip is also used to receive a second optical signal from the micro-ring resonant waveguide as the output optical signal of the external cavity laser.

[0013] Preferably, an antireflection film is deposited on the coupling surface between the gain chip and the silicon photonic chip, and a reflective film is deposited on the other side of the gain chip.

[0014] Thirdly, a method for suppressing micro-ring nonlinear effects is provided, applied to silicon photonic chips as described in the first aspect, including: The N-doped region is connected to an external input voltage through the electrical connection module, and the P-doped region is grounded through the electrical connection module, so as to construct a transverse electric field in the micro-ring resonant waveguide. The transverse electric field removes the free carriers generated in the microring resonant waveguide after light transmission.

[0015] Preferably, the method further includes: changing the intensity of the transverse electric field in the microring resonant waveguide by changing the input voltage applied to the N-doped region, thereby controlling the removal rate of free carriers in the microring resonant waveguide.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention connects to an external input voltage and ground via an electrical connection module. The P-doped and N-doped regions on both sides of the microring resonant waveguide are respectively connected to ground and the input voltage via the electrical connection module to form a transverse electric field in the microring resonant waveguide. The transverse electric field is used to remove the free carriers generated in the microring resonant waveguide after light is transmitted.

[0017] On the other hand, the P-doped region and the N-doped region are connected to the external input voltage and ground respectively through an electrical connection module, which can achieve bias control on both sides of the micro-ring resonant waveguide without adding extra pins, eliminate free carriers generated in the micro-ring resonant cavity, and thus effectively suppress the nonlinear effect of the micro-ring resonant cavity. It has the advantages of simple structure and meeting the miniaturization requirements. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a silicon photonics chip provided in an embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of a microring resonant waveguide provided in an embodiment of the present invention; Figure 3 This is a schematic cross-sectional view of another micro-ring resonant waveguide provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of another silicon photonic chip provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of a heating module provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of another silicon photonic chip provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of a detection module provided in an embodiment of the present invention; Figure 8 This is a more specific structural schematic diagram of a silicon photonics chip provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of an external cavity laser provided in an embodiment of the present invention; Figure 10 This is a flowchart illustrating a method for suppressing micro-ring nonlinear effects provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention 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 merely illustrative and not intended to limit the invention.

[0021] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as openly inclusive, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples" are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples; that is, although they may be incorporated into embodiments or examples using the above terms for reasons such as order and position, it does not limit them to be incorporated in combination by a single embodiment or example.

[0022] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more. Furthermore, for example, the description may use the prefix "A" or "B" to describe the same type of nouns as two independent entities. In this case, the corresponding features defined with "A" and "B" are used only to distinguish between similar entities and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0023] In describing some embodiments, the terms "coupled," "coupled," and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "connected" or "coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other, such as "optical coupling," "wireless connection," etc. The embodiments disclosed herein are not necessarily limited to the scope of this invention.

[0024] Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Example 1: When a high-power laser is injected into a microring resonator, the silicon material absorbs the energy of two photons, generating an electron-hole pair (i.e., a free carrier). These newly generated free carriers significantly increase optical power loss. Furthermore, they convert light energy into heat, leading to a local temperature increase. Both the increased free carrier concentration and the temperature rise alter the refractive index of silicon. The combined effects of these factors cause the microring resonator wavelength to drift and become detuned, the resonant peak to broaden, the Q value to decrease, and may even cause the microring resonator to completely fail, severely damaging the device's function and stability.

[0026] To address the aforementioned problems, this embodiment proposes a silicon photonics chip. In one embodiment, such as... Figure 1 As shown, it includes: an electrical connection module, a micro-ring resonant waveguide, and an optical reflection module; the micro-ring resonant waveguide is coupled to the optical reflection module (e.g., through directional coupler coupling, waveguide cross coupling, or direct end-face coupling); the micro-ring resonant waveguide is used to receive an external first optical signal and perform wavelength selection on the first optical signal to obtain a second optical signal; the optical reflection module is used to reflect the second optical signal back to the outside along the original optical path.

[0027] The micro-ring resonant waveguide receives an externally input first optical signal (typically containing multiple wavelengths) and utilizes its resonant characteristics for wavelength selection, allowing only a second optical signal of a specific resonant wavelength to resonate within its ring and establish a high optical power density. In one embodiment, the optical reflection module can be a Sagnac interferometer, used to reflect the second optical signal along the original optical path. The original optical path refers to the input optical path of the first optical signal, only the direction of optical signal transmission is reversed.

[0028] The electrical connection module is used to connect to an external input voltage and ground, respectively; in one embodiment, such as Figure 2 As shown, the microring resonant waveguide has P-doped regions (P) and N-doped regions (N) on both sides, respectively. The N-doped and P-doped regions are connected to the electrical connection module. The N-doped region is connected to an external input voltage via the electrical connection module, while the P-doped region is grounded via the same module. This creates a transverse electric field within the microring resonant waveguide and removes the free carriers generated after light passes through it.

[0029] For ease of display, Figure 2 The figure shows a cross-sectional view of the micro-ring resonant waveguide.

[0030] In one embodiment, the electrical connection module provides multiple input / output pins integrated on the external pins of the silicon photonics chip, serving as the physical interface between the silicon photonics chip and external circuitry (such as the electrical control module described below, which has power supply and control capabilities). The input voltage provided by the external circuitry is connected to the N-doped region on the microring resonant waveguide. Ground (0V) is connected to the P-doped region of the microring resonant waveguide. Through this connection, a reverse bias voltage is applied between the P-doped and N-doped regions of the microring resonant waveguide, resulting in the transverse electric field.

[0031] In one embodiment, the microring resonant waveguide is located in the middle, with P-doping (introducing holes as majority carriers) on one side (e.g., the left side) and N-doping (introducing electrons as majority carriers) on the other side (e.g., the right side). In one embodiment, as... Figure 3 As shown, higher concentrations of doping (such as P++ and N++ doping) can be applied to the corresponding regions of P-doping and N-doping to reduce electrical connection resistance and lower power consumption. Impedance is inversely proportional to doping concentration. Typically, the P-doping concentration can be 10-1. 16 Concentration, P++ doping concentration is 10 20 Concentration. Further, refer to... Figure 3 P++ doping can be performed in the outer region of the P-doped region, or P++ doping can be performed alone. However, performing P++ doping alone will increase some optical loss. The optimal solution is to continue P++ doping in the outer region of the P-doped region. The specific doping process will not be described in detail in this embodiment.

[0032] An external circuit applies an input voltage to the transverse electric field through the input / output pins of the electrical connection module; that is, a positive voltage (input voltage) is applied to the N-doped region, and the P-doped region is grounded (0V). Under the action of the reverse bias voltage, when a high-power optical signal propagates in the micro-ring resonant waveguide and generates free carriers, these free carriers are immediately subjected to the force of the transverse electric field. Free electrons (i.e., negative charges) are pushed towards the N-doped region by the electric field force, and free holes (i.e., positive charges) are pushed towards the P-doped region by the electric field force, so that the free carriers are quickly swept to their respective doped regions and then flow away through the external circuit, thus leaving the micro-ring resonant waveguide.

[0033] In one embodiment, the P-doped and N-doped regions are connected to an external circuit via the electrical connection module, eliminating the need for separate wiring, thus simplifying the structure of the silicon photonic chip and meeting the requirements for miniaturization.

[0034] In one embodiment, such as Figure 4As shown, the silicon photonic chip also includes a heating module, which is connected to the electrical connection module; the heating module is disposed adjacent to the microring resonant waveguide, and the heating module is used to adjust the phase of the optical signal in the microring resonant waveguide by heating.

[0035] The heating module is typically a miniature resistance heater (e.g., a meandering resistance wire made of doped or polycrystalline silicon) integrated onto a silicon photonic chip. It is designed to be located adjacent to, typically above or to the side of, the microring resonant waveguide, and isolated from it by an insulating layer (such as silicon dioxide) to minimize optical loss while ensuring efficient heat conduction. Furthermore, the heating module is connected to an electrical connection module, receiving drive current or voltage from external circuitry via input / output pins to generate heat.

[0036] When an external circuit applies a drive current or voltage to the heating module via the electrical connection module, the current flows through the resistor, generating Joule heat. This heat is transferred to the silicon material of the adjacent microring resonant waveguide via thermal conduction. The heat causes the silicon temperature in the microring waveguide region to rise. By precisely controlling the electrical power (drive current or voltage) applied to the heating module, the heat transferred to the microring resonant waveguide can be finely adjusted, thereby achieving active, dynamic, and programmable tuning of its resonant wavelength position.

[0037] In one embodiment, such as Figure 5 As shown, the heating module is a heating resistor, and its specific model and resistance value are not limited in this embodiment. One end of the heating resistor is connected to the electrical connection module to receive the drive current from the external circuit, and the other end of the heating resistor is grounded. When the drive current output by the external circuit arrives, the heating resistor heats up. The amount of heat generated is controlled by controlling the magnitude of the drive current, so as to accurately realize the active, dynamic, and programmable tuning of the resonant wavelength position in the micro-ring resonant waveguide. In one embodiment, such as Figure 6 As shown, the microring resonant waveguide includes at least two cascaded microring resonant cavities, and the radii of the two microring resonant cavities differ by a predetermined size. The size of the predetermined size is not elaborated upon in this embodiment. In one embodiment, controlling the difference in radii between the two microring resonant cavities by a predetermined size is to achieve wavelength selectivity over a wide range through the vernier effect. The corresponding joint free spectral range (FSR) is:

[0038] in, and These represent the free spectral ranges of the two microring resonators, respectively.

[0039] To monitor the intensity of the optical signal in the microring resonant waveguide, in one embodiment, such as Figure 6 As shown, the silicon photonics chip also includes a detection module, which is connected to the electrical connection module and coupled to the micro-ring resonant waveguide for monitoring the intensity of the optical signal in the micro-ring resonant waveguide.

[0040] When the microring resonant waveguide includes two microring resonant cavities, the silicon photonic chip includes two monitoring modules. The detection module is coupled to the drop port of the microring resonant cavity in the microring resonant waveguide to monitor the intensity of the optical signal therein.

[0041] In one embodiment, such as Figure 7 As shown, the detection module includes a photodiode (i.e., R1-MPD), a transimpedance amplifier (i.e., U1), and a feedback resistor (i.e., R1); the photodiode is coupled to the microring resonant waveguide; wherein, the photodiode is coupled to the drop end of the microring resonant cavity in the microring resonant waveguide.

[0042] The non-inverting input terminal of the transimpedance amplifier is connected to the electrical connection module for connection to the input voltage via the electrical connection module; the anode of the photodiode is connected to the inverting input terminal of the transimpedance amplifier for connection to the input voltage via the electrical connection module; the cathode of the photodiode is connected to the electrical connection module for connection to the input voltage via the electrical connection module; one end of the feedback resistor is connected to the output terminal of the transimpedance amplifier, and the other end of the feedback resistor is connected to the inverting input terminal of the transimpedance amplifier; the output terminal of the transimpedance amplifier is connected to the electrical connection module for connection to an external electrical control module via the electrical connection module.

[0043] In one embodiment, the input voltage received by the cathode of the photodiode is greater than the input voltage received by the anode of the photodiode. The input voltage received by the cathode and the anode of the photodiode are also different from the input voltage received by the non-inverting input terminal of the transimpedance amplifier. The above structure is mainly used to convert the weak current signal generated by the photodiode into a voltage signal output.

[0044] In one embodiment, the input voltage received at the non-inverting input terminal of the transimpedance amplifier is 2.5V. The anode of the photodiode is forcibly pulled to +2.5V through the virtual short of the transimpedance amplifier. That is, the voltage at the anode of the photodiode is 2.5V, and the input voltage received at the cathode of the photodiode is 3.3V. This generates a reverse voltage difference of 0.8V between the cathode and anode of the photodiode, enabling the photodiode to efficiently convert incident light into current and output TIA_OUT to the electrical connection module, significantly accelerating the photodiode's response speed to rapidly changing light signals. The current is then fed to external circuits for processing and analysis via the input / output pins on the electrical connection module. More specific details are not elaborated in this embodiment.

[0045] Specifically, when an optical signal from the drop end of the micro-ring resonant waveguide illuminates the photodiode, photons excite electron-hole pairs, generating a photocurrent. The photocurrent flows from the cathode to the anode (in reverse bias mode, the photocurrent is in the same direction as the reverse leakage current). The transimpedance amplifier forces the voltage at the inverting input terminal to be equal to the voltage at the non-inverting input terminal through negative feedback.

[0046] The photocurrent flows from the cathode (3.3V) to the anode (2.5V). Due to the infinite input impedance of the ideal operational amplifier, the photocurrent cannot flow into the input terminal of the transimpedance amplifier. Therefore, the photocurrent must flow to the output terminal of the transimpedance amplifier through the feedback resistor R1. After the photocurrent passes through the feedback resistor R1 (resistance value R1), a voltage drop is generated. Finally, the voltage TIA_OUT at the output terminal of the transimpedance amplifier is TIA_OUT = 2.5V - photocurrent × R1. The final output TIA_OUT is inversely proportional to the incident light intensity; that is, the greater the light intensity, the smaller the output TIA_OUT. Finally, the output TIA_OUT is sent to the external circuit for processing and analysis through the input / output pins on the electrical connection module to obtain the intensity of the optical signal in the microring resonant waveguide. In one embodiment, when the microring resonant waveguide includes two microring resonant cavities, the above two detection modules need to be set up. For the sake of wiring simplicity, in actual connection, it is only necessary to connect the cathode of a photodiode to the N-doped region on the microring resonant waveguide.

[0047] To achieve miniaturization and integration, on the one hand, all grounded ports in the silicon photonics chip are connected to a unified grounding line via an electrical connection module. On the other hand, the N-doped region on the microring resonant waveguide is connected to the cathode of the photodiode to create a 3.3V transverse electric field in the microring resonant waveguide. Free carriers in the microring resonant waveguide are rapidly removed from the waveguide under the influence of this 3.3V transverse electric field.

[0048] In order to reduce the optical loss of the first optical signal entering the micro-ring resonant waveguide, in one embodiment, such as Figure 8As shown, the silicon photonics chip also includes a mode converter, which is coupled to the input end of the micro-ring resonant waveguide. The mode converter is used to reduce the loss of the first optical signal entering the micro-ring resonant waveguide.

[0049] The mode converter provides an optical mode size that matches the rear end face of the external gain chip, so as to couple as much of the first optical signal emitted by the semiconductor-based gain chip into the silicon photonic chip to reduce optical loss. The specific structure will not be described in detail in this embodiment.

[0050] In this embodiment, the P-doped and N-doped regions on both sides of the micro-ring resonant waveguide are connected to the external input voltage and ground via electrical connection modules. These electrical connection modules are then connected to ground and the input voltage, respectively, to form a transverse electric field within the micro-ring resonant waveguide. This transverse electric field removes the free carriers generated after light passes through the micro-ring resonant waveguide. Furthermore, the P-doped and N-doped regions are connected to the external input voltage and ground via electrical connection modules, enabling bias control of both sides of the micro-ring resonant waveguide without adding extra pins. This eliminates the free carriers generated in the micro-ring resonant cavity, effectively suppressing the nonlinear effects of the micro-ring resonant cavity. This design offers advantages such as simple structure and miniaturization requirements.

[0051] Example 2: This embodiment proposes an external cavity laser, in one embodiment, such as Figure 9 As shown, the external cavity laser includes a gain chip, an electrical control module, and a silicon photonic chip as described in Embodiment 1; the electrical control module is connected to the electrical connection module in the silicon photonic chip and the control terminal of the gain chip respectively; the gain chip is coupled to the input terminal of the micro-ring resonant waveguide; the gain chip is used to emit the first optical signal under the drive of the electrical control module and transmit the first optical signal to the micro-ring resonant waveguide; the gain chip is also used to receive a second optical signal from the micro-ring resonant waveguide as the output optical signal of the external cavity laser.

[0052] The gain chip, based on semiconductor technology, is supplied with current by an electrical control module. Carrier recombination in the gain chip generates broadband spontaneous emission light (i.e., a first optical signal), which is then transmitted to the silicon photonic chip. In one embodiment, referencing... Figure 9 An antireflection film is deposited on the coupling surface (i.e., surface a) of the gain chip and the silicon photonic chip to reduce reflection, and a reflective film is deposited on the other side (i.e., surface b) of the gain chip to establish standing wave conditions, thereby increasing the light coupled into the silicon photonic chip.

[0053] The first optical signal input to the silicon photonics chip is output by the gain chip after wavelength selection by the silicon photonics chip and reflection by the optical reflection module, and serves as the output optical signal of the external cavity laser.

[0054] In this embodiment, the P-doped and N-doped regions on both sides of the micro-ring resonant waveguide are connected to the external input voltage and ground via electrical connection modules. These electrical connection modules are then connected to ground and the input voltage, respectively, to form a transverse electric field within the micro-ring resonant waveguide. This transverse electric field removes the free carriers generated after light passes through the micro-ring resonant waveguide. Furthermore, the P-doped and N-doped regions are connected to the external input voltage and ground via electrical connection modules, enabling bias control of both sides of the micro-ring resonant waveguide without adding extra pins. This eliminates the free carriers generated in the micro-ring resonant cavity, effectively suppressing the nonlinear effects of the micro-ring resonant cavity. This design offers advantages such as simple structure and miniaturization requirements.

[0055] Example 3: This embodiment proposes a method for suppressing the nonlinear effect of microrings. In one embodiment, such as... Figure 10 As shown, the method includes: Step 101: The N-doped region is connected to an external input voltage through the electrical connection module, and the P-doped region is grounded through the electrical connection module, so as to construct a transverse electric field in the micro-ring resonant waveguide.

[0056] In one embodiment, the microring resonant waveguide is located in the middle, with P-doping (introducing holes as majority carriers) on one side (e.g., the left side) and N-doping (introducing electrons as majority carriers) on the other side (e.g., the right side). In one embodiment, reference... Figure 3 Higher concentrations of doping (such as P++ doping and N++ doping) can be applied to the corresponding regions where P and N doping are performed to reduce electrical connection resistance and power consumption. The specific doping process will not be described in detail in this embodiment.

[0057] Step 102: Remove the free carriers generated by the micro-ring resonant waveguide after light transmission using the transverse electric field.

[0058] The external circuit applies an input voltage to the transverse electric field through the input / output pins of the electrical connection module; that is, a positive voltage (input voltage) is applied to the N-doped region, and the P-doped region is grounded (0V). Under the action of the reverse bias voltage, when a high-power optical signal propagates in the micro-ring resonant waveguide and generates free carriers, these free carriers are immediately subjected to the force of the transverse electric field. Free electrons (i.e., negative charges) are pushed towards the N-doped region by the electric field force, and free holes (i.e., positive charges) are pushed towards the P-doped region by the electric field force, so that the free carriers are quickly swept to their respective doped regions and then flow away through the external circuit, thus leaving the micro-ring resonant waveguide.

[0059] In one embodiment, in order to control the removal rate of free carriers, the method for suppressing the nonlinear effect of the microring further includes: changing the intensity of the transverse electric field in the microring resonant waveguide by changing the input voltage applied to the N-doped region, thereby controlling the removal rate of free carriers in the microring resonant waveguide.

[0060] In this embodiment, the P-doped and N-doped regions on both sides of the micro-ring resonant waveguide are connected to the external input voltage and ground via electrical connection modules. These electrical connection modules are then connected to ground and the input voltage, respectively, to form a transverse electric field within the micro-ring resonant waveguide. This transverse electric field removes the free carriers generated after light passes through the micro-ring resonant waveguide. Furthermore, the P-doped and N-doped regions are connected to the external input voltage and ground via electrical connection modules, enabling bias control of both sides of the micro-ring resonant waveguide without adding extra pins. This eliminates the free carriers generated in the micro-ring resonant cavity, effectively suppressing the nonlinear effects of the micro-ring resonant cavity. This design offers advantages such as simple structure and miniaturization requirements.

[0061] The specific structure of the silicon photonics chip is described in Example 1 and will not be repeated in this example.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A silicon photonics chip, characterized in that, include: An electrical connection module, a micro-ring resonant waveguide, and an optical reflection module; the micro-ring resonant waveguide is coupled to the optical reflection module. The micro-ring resonant waveguide is used to receive a first optical signal from the outside and to perform wavelength selection on the first optical signal to obtain a second optical signal; the optical reflection module is used to reflect the second optical signal back to the outside along the original optical path; The electrical connection module is used to connect to the external input voltage and ground, respectively; The micro-ring resonant waveguide has P-doped and N-doped regions on both sides, and the N-doped and P-doped regions are respectively connected to the electrical connection module. The N-doped region is connected to an external input voltage via the electrical connection module, and the P-doped region is grounded via the electrical connection module, so as to construct a transverse electric field in the micro-ring resonant waveguide and remove the free carriers generated by the micro-ring resonant waveguide after light transmission through the transverse electric field.

2. The silicon photonics chip according to claim 1, characterized in that, It also includes a heating module, which is connected to the electrical connection module; the heating module is disposed adjacent to the microring resonant waveguide, and the heating module is used to adjust the phase of the optical signal in the microring resonant waveguide by heating.

3. The silicon photonics chip according to claim 1, characterized in that, It also includes a detection module, which is connected to the electrical connection module and coupled to the microring resonant waveguide for monitoring the intensity of the optical signal in the microring resonant waveguide.

4. The silicon photonics chip according to claim 3, characterized in that, The detection module includes a photodiode, a transimpedance amplifier, and a feedback resistor; the photodiode is coupled to the micro-ring resonant waveguide. The non-inverting input terminal of the transimpedance amplifier is connected to the electrical connection module for connection to the input voltage via the electrical connection module; the anode of the photodiode is connected to the inverting input terminal of the transimpedance amplifier for connection to the input voltage via the electrical connection module. The cathode of the photodiode is connected to the electrical connection module for connection to the input voltage via the electrical connection module; One end of the feedback resistor is connected to the output terminal of the transimpedance amplifier, and the other end of the feedback resistor is connected to the inverting input terminal of the transimpedance amplifier. The output terminal of the transimpedance amplifier is connected to the electrical connection module so as to connect to an external electrical control module through the electrical connection module.

5. The silicon photonics chip according to claim 1, characterized in that, It also includes a mode converter, which is coupled to the input end of the microring resonant waveguide and is used to reduce the loss of the first optical signal entering the microring resonant waveguide.

6. The silicon photonic chip according to claim 1, characterized in that, The microring resonant waveguide includes at least two cascaded microring resonant cavities, and the radii of the two microring resonant cavities differ by a predetermined size.

7. An external cavity laser, characterized in that, Includes a gain chip, an electrical control module, and a silicon photonics chip as described in any one of claims 1-6; The electrical control module is connected to the electrical connection module in the silicon photonics chip and the control terminal of the gain chip, respectively; the gain chip is coupled to the input terminal of the micro-ring resonant waveguide; The gain chip is used to emit the first optical signal under the drive of the electrical control module and transmit the first optical signal to the micro-ring resonant waveguide; The gain chip is also used to receive a second optical signal from the micro-ring resonant waveguide as the output optical signal of the external cavity laser.

8. The external cavity laser according to claim 7, characterized in that, An antireflection coating is deposited on the coupling surface between the gain chip and the silicon photonic chip, and a reflective coating is deposited on the other side of the gain chip.

9. A method for suppressing the nonlinear effect of microrings, characterized in that, Applied to the silicon photonics chip as described in any one of claims 1-6, comprising: The N-doped region is connected to an external input voltage through the electrical connection module, and the P-doped region is grounded through the electrical connection module, so as to construct a transverse electric field in the micro-ring resonant waveguide. The transverse electric field removes the free carriers generated in the microring resonant waveguide after light transmission.

10. The method for suppressing micro-ring nonlinear effects according to claim 9, characterized in that, The method further includes: changing the intensity of the transverse electric field in the microring resonant waveguide by changing the input voltage applied to the N-doped region, thereby controlling the removal rate of free carriers in the microring resonant waveguide.

Images