Apparatus and method for generating a soliton microcomb

Abstract

The application provides a soliton microcomb generation device and a soliton microcomb generation method, and relates to the technical field of lasers.The soliton microcomb generation device comprises a laser, a current controller, a first temperature controller, a phase shifter and an optical microcavity module, the laser is used for emitting a pump beam, the pump beam is incident on the optical microcavity module through the phase shifter; after the pump beam is incident on the optical microcavity module, optical sidebands are generated based on a four-wave mixing effect, the optical microcavity module reflects part of the pump beam into a cavity of the laser, the phase shifter is used for adjusting an optical path between the laser and the optical microcavity module, and a soliton microcomb is generated and output in the optical microcavity module based on a self-injection locking mechanism. The soliton microcomb generation device and the soliton microcomb generation method provided in the application can reduce the packaging difficulty of the generation device and the requirement for the precision of the device, can conveniently deploy a soliton microcomb light source outside a laboratory, and can improve the stability of the soliton microcomb output by the generation device.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a soliton microcomb generation device and method. Background Technology

[0002] In recent years, the method of generating optical frequency combs based on optical microcavities has attracted great attention, and the resulting optical frequency combs are called soliton microcombs.

[0003] The current mainstream approach to obtaining soliton microcombs using the self-injection locking method involves a packaging process that directly couples the semiconductor laser chip to the end face of the integrated photonic chip. This ensures that the optical phase between the semiconductor laser chip and the integrated photonic chip is within a suitable range. By setting appropriate current and temperature for the semiconductor laser chip, a soliton microcomb signal can be generated. However, this method has extremely strict requirements for feedback optical phase conditions, is very difficult to package, and even after packaging, the coupling conditions and phase between the semiconductor laser chip and the integrated photonic chip can still change due to thermal effects or mechanical stress. This can lead to unstable soliton microcomb signal output or even failure to generate a soliton microcomb. Furthermore, the center wavelength, repetition frequency, and other parameters of the soliton optical comb signal generated using this method cannot be continuously tuned, limiting the further application of soliton microcombs. Summary of the Invention

[0004] This invention provides a soliton microcomb generation device and method, which can reduce the packaging difficulty of the generation device and the requirements for device precision, and improve the stability of the soliton microcomb output by the generation device.

[0005] In a first aspect, embodiments of the present invention provide a soliton microcomb generating device, including a laser, a current controller, a first temperature controller, and an optical microcavity module. The optical microcavity module includes an optical microcavity and a phase shifter, and the output end of the laser is coupled to the input end of the optical microcavity module.

[0006] The laser is used to emit a pump beam, which is then incident on the optical microcavity module via a phase shifter;

[0007] The current controller is electrically connected to the laser and is used to modulate the magnitude and waveform of the drive current output to the laser.

[0008] The laser is connected to a first temperature controller, which is used to adjust the temperature of the laser.

[0009] The pump beam is incident on the optical microcavity module to generate a four-wave mixing effect. The optical microcavity module reflects part of the pump beam into the laser to generate a self-injection locking effect. The phase shifter is used to adjust the optical path between the laser and the optical microcavity so that soliton microcombs are generated and output in the optical microcavity.

[0010] Optionally, the soliton microcomb generation device also includes a mode converter, which is disposed in the optical path between the laser and the optical microcavity module. The mode converter is used to improve the coupling efficiency of the pump beam into the optical microcavity module.

[0011] Optionally, the soliton microcomb generation device also includes a beam splitter and a photodetector, wherein the input end of the beam splitter is coupled to the output end of the optical microcavity module, and the beam splitter includes a first output end and a second output end;

[0012] The beam splitter is used to split the soliton microcomb into a first signal and a second signal. The first signal is output from the first output terminal, and the second signal is output from the second output terminal.

[0013] The input terminal of the photodetector is connected to the first output terminal. The photodetector is used to detect the strength and frequency of the first signal.

[0014] Optionally, the soliton microcomb generation device also includes an isolator and a filter;

[0015] The input end of the isolator is coupled to the output end of the optical microcavity module. The isolator is used to enable unidirectional propagation of the soliton microcomb.

[0016] The input of the filter is coupled to the output of the isolator, and the filter is used to filter out the pump beam in the soliton microcomb.

[0017] Secondly, embodiments of the present invention provide a method for generating soliton microcombs, applicable to the soliton microcomb generating apparatus provided in any embodiment of the present invention, the method comprising:

[0018] The laser is activated, and it outputs a pump beam.

[0019] The pump beam is coupled into the optical microcavity module after passing through the phase shifter. The first temperature controller and current controller are adjusted to cause the optical microcavity module to produce nonlinear phenomena.

[0020] Record the driving current {I0, I1, I2, ...} when the optical microcavity module generates nonlinear phenomena;

[0021] Adjust the drive current from Increment to Adjust the first temperature controller and phase shifter so that the output of the optical microcavity module exhibits soliton step characteristic signals;

[0022] Determine the current value corresponding to the target soliton state;

[0023] Set the driving current to the current value corresponding to the target soliton state.

[0024] Optionally, after the optical microcavity module outputs a soliton step characteristic signal, it also includes:

[0025] If the step feature signal corresponding to the target soliton state is missing, adjust the first temperature controller until the step feature signal corresponding to the target soliton state appears.

[0026] Optionally, until the step feature signal corresponding to the target soliton state appears, the process also includes:

[0027] Adjust the first temperature controller until the linewidth of the step characteristic signal corresponding to the target soliton state is the longest, and record the temperature T0 of the first temperature controller at this time;

[0028] Adjust the temperature of the first temperature controller to T0.

[0029] Optionally, after setting the driving current to the current value corresponding to the target soliton state, the method further includes:

[0030] When the power fluctuation of the soliton signal acquired by the photodetector exceeds a preset threshold, the current controller is adjusted to stabilize the output power of the target soliton signal.

[0031] Optionally, after setting the driving current to the current value corresponding to the target soliton state, the method further includes:

[0032] When the step signal acquired by the photodetector changes in its order, the phase shifter is adjusted to cause the generating device to re-output the target soliton state signal.

[0033] Optionally, the drive current is adjusted from Increment to After adjusting the first temperature controller and phase shifter to make the optical microcavity module output a soliton step characteristic signal, the following steps are also included:

[0034] If the optical microcavity module cannot output the soliton step characteristic signal, then adjust the drive current from Increment to And adjust the first temperature controller and phase shifter until the output of the optical microcavity module exhibits a soliton step characteristic signal, where I n Let {I0, I1, I2, ...} be any term other than I0.

[0035] This invention provides a soliton microcomb generation device. By introducing an independently tunable phase shifter, the optical path between the laser and the optical microcavity becomes adjustable. By adjusting the optical path between the laser and the optical microcavity, the phase of the self-injected pump beam can be changed, which can accurately lock the soliton state of the soliton microcomb, improve the stability of the output soliton state, and stabilize the output of the soliton state of the soliton microcomb when the generation device is affected by the external environment. This reduces the packaging difficulty of the generation device and the requirements for device precision, and improves the stability of the soliton microcomb output by the generation device.

[0036] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0038] Figure 1 This is a schematic diagram of the structure of a soliton microcomb generating device provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of another soliton microcomb generating device provided in an embodiment of the present invention;

[0040] Figure 3 This is a graph showing the relationship between the power and frequency offset of a soliton microcomb provided in an embodiment of the present invention;

[0041] Figure 4 This is a graph showing the relationship between power and frequency offset of another soliton microcomb provided in an embodiment of the present invention;

[0042] Figure 5 This is a graph showing the relationship between the power and frequency offset of another soliton microcomb provided in this embodiment of the invention;

[0043] Figure 6 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention;

[0046] Figure 9 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention;

[0047] Figure 10 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention;

[0048] Figure 11 This is a flowchart of a method for generating soliton microcombs provided in an embodiment of the present invention;

[0049] Figure 12 This is a flowchart of another method for generating soliton microcombs provided in an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] Currently, devices that use the self-injection locking method to obtain soliton microcombs have very strict requirements for feedback phase conditions and are extremely difficult to package. Even after packaging, the coupling conditions and phase between the laser chip and the integrated photonic chip end face may change due to thermal effects or mechanical stress, resulting in unstable soliton microcomb signal output or even failure to generate soliton microcombs.

[0053] To address the aforementioned problems, embodiments of the present invention provide a soliton microcomb generation device. Figure 1 This is a schematic diagram of a soliton microcomb generation device provided in an embodiment of the present invention, with reference to... Figure 1The soliton microcomb generation device includes a laser 101, a current controller 102, a first temperature controller 103, and an optical microcavity module 105. The optical microcavity module 105 includes an optical microcavity 1051 and a phase shifter 104. The output terminal of the laser 101 is coupled to the input terminal of the phase shifter 104, and the output terminal of the phase shifter 104 is coupled to the input terminal of the optical microcavity module 105. The laser 101 is used to emit a pump beam, which passes through the phase shifter 104 and is incident on the optical microcavity module 105. The current controller 102 is electrically connected to the laser 101. The current controller 102 is used to modulate the magnitude and waveform of the drive current output to the laser 101; the laser 101 is connected to the first temperature controller 102, which is used to adjust the temperature of the laser 101; the pump beam is incident on the optical microcavity module to generate a four-wave mixing effect; the optical microcavity module 105 reflects part of the pump beam into the laser 101 to generate a self-injection locking effect; the phase shifter 104 is used to adjust the optical path between the laser 101 and the optical microcavity 1051 so that soliton microcomb is generated and output in the optical microcavity 1051.

[0054] Optionally, the laser 101 includes, but is not limited to, a distributed feedback laser (DFB) or a distributed Bragg reflector (DBR), wherein the wavelength of the pump beam output by the laser 101 is 1550 nm, 1064 nm, 980 nm, 785 nm, or 532 nm. The current controller 102 uses a programmable constant current source to provide the drive current. The current controller 102 is capable of providing sinusoidal current signals, triangular current signals, and pulsed current signals, while also providing low-noise DC signals. The phase shifter 104 includes, but is not limited to, a temperature controller, piezoelectric ceramics, resistive wire integrated waveguides, or optical fibers. The optical microcavity module 105 includes an optical microcavity and coupling devices. The optical microcavity includes all optical microcavities with whispering-gallery structures, such as discrete device optical microcavities made of alkali metal fluoride crystals or fused silica, and integrated photonic chip optical microcavities made of silicon nitride, lithium niobate, aluminum nitride, or silicon.

[0055] refer to Figure 1After the pump beam emitted by laser 101 passes through phase shifter 104 and enters optical microcavity 1051, the frequency and phase of the pump beam must satisfy the phase matching condition of four-wave mixing for soliton microcomb to be generated in optical microcavity 1051. The frequency and power of the pump beam are affected by temperature and driving current. Increasing the driving current of laser 101 increases the power of the pump beam, while decreasing the driving current decreases the power. Conversely, increasing the temperature of laser 101 decreases the frequency of the pump beam, while decreasing the temperature increases the frequency. Therefore, to generate soliton microcomb, the driving current output by current controller 102 and the first temperature controller 103 need to be adjusted to match the frequency of the pump beam with that of the optical microcavity and satisfy the phase matching condition. When the driving current and the temperature of laser 101 are adjusted to appropriate levels, optical microcavity 1051 will output soliton microcomb. Simultaneously, the optical microcavity 1051 reflects a portion of the pump beam to the output surface of the laser 101. This reflected pump beam triggers a self-injection locking mechanism, locking the soliton state of the soliton microcomb. By adjusting the optical path between the laser 101 and the optical microcavity 1051 using the phase shifter 104, the phase of the pump beam reflected to the output surface of the laser 101 can be changed, thereby achieving tuning of the soliton state output by the generating device. Furthermore, the drive current output by the current controller 102 may contain slight noise. Adjusting the phase shifter 104 can cancel the influence of the drive current noise on the soliton state output by the generating device, thus making the soliton state output by the generating device more stable.

[0056] Figure 2 This is a schematic diagram of another soliton microcomb generation device provided in an embodiment of the present invention, combined with... Figure 1 and Figure 2 As shown, the phase shifter 104 can be placed in the optical path between the laser 101 and the optical microcavity 1051, or the phase shifter 104 can be connected to the optical microcavity 1051. Both of these arrangements can adjust the optical path between the laser 101 and the optical microcavity 1051.

[0057] This invention provides a soliton microcomb generation device. By introducing an independently tunable phase shifter, the optical path between the laser and the optical microcavity becomes adjustable. By adjusting the optical path between the laser and the optical microcavity, the phase of the self-injected pump beam can be changed, which can accurately lock the soliton state of the soliton microcomb, improve the stability of the output soliton state, and stabilize the output of the soliton state of the soliton microcomb when the generation device is affected by the external environment. This reduces the packaging difficulty of the generation device and the requirements for device precision, and improves the stability of the soliton microcomb output by the generation device.

[0058] Figure 3This is a graph showing the relationship between the power and frequency offset of a soliton microcomb provided in an embodiment of the present invention.

[0059] Figure 4 This is a graph showing the relationship between power and frequency offset of another soliton microcomb provided in an embodiment of the present invention. Figure 5 This is a graph showing the relationship between the power and frequency offset of another soliton microcomb provided in this embodiment of the invention, combined with... Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the frequency offset is used to represent the relative magnitude of the frequency of the soliton microcomb. Figure 3 The soliton microcomb in the middle has a complete step structure. Figure 4 The first-level step structure of the soliton microcomb is missing. Figure 5 The third-level step structure of the soliton microcomb is missing, where each step structure corresponds to a soliton state. The frequency offset of the soliton microcomb corresponds to the amplitude of the driving current of the laser 101. By fixing the driving current value at the position corresponding to a certain soliton state, the generating device can output the corresponding soliton state signal. If the step structure of the target soliton state is missing or too short, the optical path between the laser 101 and the optical microcavity module 105 can be adjusted by the phase shifter 104 to change the phase of the pump beam reflected to the output end face of the laser 101, thereby adjusting the length of the step structure corresponding to the target soliton state, that is, tuning the center wavelength and repetition frequency of the soliton microcomb.

[0060] Figure 6 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention, with reference to... Figure 6 The soliton microcomb generation device also includes a pattern converter 106, which is disposed in the optical path between the laser 101 and the optical microcavity module 105. The pattern converter is used to improve the coupling efficiency of the pump beam into the optical microcavity module 105.

[0061] refer to Figure 6 The mode converter 106 can match the laser mode size of the pump beam with the mode size of the incident end of the optical microcavity module 105, thereby improving the coupling efficiency of the pump beam into the optical microcavity module 105 and reducing the loss of the pump beam. Optionally, the mode converter 106 includes a microlens, a silicon waveguide with a special structural design (such as an inverted cone shape), or a special end-face fiber (such as a wedge fiber or a coated lens fiber).

[0062] Figure 7 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention, with reference to... Figure 7The soliton microcomb generation device also includes a beam splitter 107 and a photodetector 108. The input end of the beam splitter 107 is coupled to the output end of the optical microcavity module 105. The beam splitter 107 includes a first output end and a second output end. The beam splitter 107 is used to split the soliton microcomb into a first signal S1 and a second signal S2. The first signal S1 is output from the first output end, and the second signal S2 is output from the second output end. The input end of the photodetector 108 is connected to the first output end, and the photodetector 108 is used to detect the intensity and frequency of the first signal S1. Optionally, the photodetector 108 is connected to a data acquisition card, which is used to store the data detected by the photodetector 108.

[0063] refer to Figure 7 The photodetector 108 converts the first signal S1 into an electrical signal. For example, the photodetector 108 is a photodiode, and changes in the frequency and intensity of the first signal S1 can be converted into changes in the photodiode current. The electrical signal output by the photodetector 108 is proportional to the light intensity of the first signal S1. During the generation and locking phase of the soliton microcomb, different states of the soliton microcomb can be determined by observing the photodetector 108. The first signal S1 is a detection signal used as input to the photodetector 108. The second signal S2 is the final output signal.

[0064] Optionally, the soliton microcomb generation device further includes an optical amplifier, the input of which is coupled to a second output, and the optical amplifier is used to amplify the second signal S2. Exemplarily, the optical amplifier includes a semiconductor optical amplifier (SOA) or an erbium-doped fiber application amplifier (EDFA).

[0065] Figure 8 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention, with reference to... Figure 8 The phase shifter 104 includes a piezoelectric module 109, which is connected to the optical microcavity module 105. The piezoelectric module 109 is used to move the optical microcavity module 105 to adjust the optical path between the laser 101 and the optical microcavity module 105.

[0066] refer to Figure 8 For example, the piezoelectric module 109 includes a piezoelectric ceramic sheet and a piezoelectric controller. The piezoelectric ceramic sheet is connected to the optical microcavity module 105. The piezoelectric controller controls the piezoelectric ceramic sheet to deform by applying voltage signals of different magnitudes to the piezoelectric ceramic sheet, thereby driving the optical microcavity module 105 to move, causing the distance between the optical microcavity module 105 and the laser 101 to change, thereby changing the optical path between the laser 101 and the optical microcavity module 105.

[0067] Figure 9 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention, with reference to... Figure 9 The phase shifter 104 includes a second temperature controller 110 and a thermistor waveguide 111. The first end of the thermistor waveguide 111 is coupled to the output end of the laser 101, and the second end of the thermistor waveguide 111 is coupled to the input end of the optical microcavity module 105. The second temperature controller 110 is connected to the thermistor waveguide 111 and is used to adjust the temperature of the thermistor waveguide 111 to adjust the optical path between the laser 101 and the optical microcavity module 105.

[0068] refer to Figure 9 The pump beam passes sequentially through the mode converter 106 and the thermistor waveguide 111 before being coupled into the optical microcavity module 105. The second temperature controller 110 heats the thermistor waveguide 111, causing it to expand and refractively. Thermal expansion changes the size of the thermistor waveguide 111, while thermal refractive change alters its refractive index for the same wavelength of laser light. This changes the size and refractive index of the thermistor waveguide 111, thereby altering the optical path length of the pump beam within it, and consequently, the optical path length between the laser 101 and the optical microcavity module 105. Exemplarily, the thermistor waveguide 111 comprises an integrated waveguide coated with a resistance wire. The second temperature controller 110 includes a voltage source that applies a voltage to the resistance wire, allowing the heat generated by the resistance wire to be transferred to the integrated waveguide, thus heating it.

[0069] Optionally, the thermal waveguide includes an optical fiber. Exemplarily, the optical fiber includes fused biconical taper fiber, and the optical fiber is made of silicon dioxide.

[0070] Figure 10 This is a schematic diagram of the structure of another soliton microcomb generating device provided in an embodiment of the present invention, with reference to... Figure 10 The soliton microcomb generation device also includes an isolator 113 and a filter 112. The input end of the isolator 113 is coupled to the output end of the optical microcavity module 105, and the isolator 113 is used to ensure unidirectional propagation of the soliton microcomb. The input end of the filter 112 is coupled to the output end of the optical microcavity module 105, and the filter 112 is used to filter out the pump beam in the soliton microcomb. The filter 112 is used to prevent the photodetector 108 from receiving the pump beam, thereby improving the detection accuracy of the photodetector 108. Exemplarily, the filter 112 includes, but is not limited to, a fiber Bragg grating, a thin-film filter, or an add-drop structure whispering-gallery optical microcavity. The isolator 113 can prevent the soliton microcomb from being reflected or scattered by subsequent optical devices and returning to the optical microcavity module 105, ensuring unidirectional propagation of the soliton microcomb.

[0071] Optionally, the generating device also includes a polarization-maintaining fiber connected to the optical components in the generating device for transmitting optical signals. The polarization-maintaining fiber can keep the polarization of the optical signal unchanged and improve the coherent signal-to-noise ratio.

[0072] Based on the same inventive concept, embodiments of the present invention provide a method for generating soliton microcombs, applicable to any of the soliton microcomb generating apparatuses provided in any embodiment of the present invention. Figure 11 This is a flowchart of a method for generating soliton microcombs according to an embodiment of the present invention, see reference. Figure 11 The methods of generation include:

[0073] S101. Start the laser, and the laser outputs a pump beam.

[0074] Specifically, in combination Figure 10 and Figure 11 As shown, first, the output direction of the laser 101 is aligned with the incident end face of the optical microcavity module 105. Then, the laser is turned on. When the output light intensity of the optical microcavity module 105 reaches its maximum value, it means that the coupling efficiency of the pump beam into the optical microcavity module 105 is the maximum, and the laser 101 and the optical microcavity module 105 are collimated.

[0075] S102. After passing through the phase shifter, the pump beam is coupled into the optical microcavity module. The first temperature controller and current controller are adjusted to cause the optical microcavity module to produce a nonlinear phenomenon.

[0076] Specifically, in combination Figure 10 and Figure 11 As shown, the temperature of the laser 101 is adjusted to T0 by regulating the first temperature controller 103, and then the driving current is controlled by the current controller 102 to monotonically increase from 0 at a certain step speed. By observing whether the photodetector 108 detects a new frequency, if the photodetector 108 detects a beam with a frequency different from that of the pump beam, it indicates that the optical microcavity module 105 has generated a nonlinear phenomenon. Further understanding is that the soliton microcomb generation device includes a filter 112, which can filter out the pump light. Therefore, when the optical power received by the photodetector 108 is greater than 0, it can be directly determined that the optical microcavity module 105 has generated a nonlinear phenomenon.

[0077] S103. Record the driving current {I0, I1, I2, ...} when the optical microcavity module generates nonlinear phenomena.

[0078] Specifically, the driving current I of all optical microcavity modules 105 when nonlinear phenomena are generated is recorded and denoted as the set {I0, I1, I2, ...}.

[0079] S104, Adjust the drive current from Increment to The first temperature controller and phase shifter are adjusted to make the output of the optical microcavity module exhibit soliton step characteristic signals.

[0080] Specifically, in combination Figure 10 and Figure 11 As shown, since the soliton microcomb is a series of electromagnetic waves within a certain frequency range, the driving current needs to scan within a certain amplitude to ensure that the generating device outputs a complete soliton microcomb. The driving current is set to a triangular wave frequency sweep current signal with frequency F0, center current I0, and amplitude ΔI0 by adjusting the current controller 102. For example, frequency F0 = 10Hz, amplitude ΔI0 = 10mA, and the driving current value is within... to The scanning process continues. Simultaneously, the first temperature controller 103 and the phase shifter 104 are adjusted until the optical microcavity module 105 outputs a soliton step characteristic signal. At this point, the soliton step characteristic signal may exhibit missing or excessively short step structures corresponding to the target soliton state. For example, for a soliton state... Figure 4 The stepped structure shown has a missing first-stage step. By gradually lowering the temperature of the laser 101 using the first temperature controller 103, the first-stage step can be made to appear. For example... Figure 5 The step structure shown has a short first-stage step. In this case, by controlling the first temperature controller 103 to gradually increase the temperature of the laser 101, the first-stage step structure can be lengthened.

[0081] S105. Determine the current value corresponding to the target soliton state.

[0082] Specifically, in combination Figure 10 and Figure 11 As shown, exemplarily, Figure 3 The frequency offset of the soliton microcomb in to The current values ​​between the two values ​​correspond, and thus the current value corresponding to the target soliton state can be determined.

[0083] S106. Set the driving current to the current value corresponding to the target soliton state.

[0084] Specifically, in combination Figure 10 and Figure 11 As shown, by setting the driving current to the current value corresponding to the target soliton state, the generating device can output the target soliton state. It can be understood that the longer the stepped structure is in the direction of frequency offset, the larger the corresponding driving current range. As long as the driving current is within this range, the corresponding soliton state can be obtained. If the frequency of the soliton state shifts during the output of the target soliton state, the output soliton state frequency can be adjusted to the center frequency of the target soliton state by adjusting the phase shifter 104, so that even if the frequency of the soliton state shifts to a certain extent, the output soliton state can still be maintained at the target soliton state.

[0085] Figure 12 This is a flowchart of another method for generating soliton microcombs provided in an embodiment of the present invention, see reference. Figure 12 The methods of generation include:

[0086] S201. Start the laser, and the laser outputs a pump beam.

[0087] S202. After passing through the phase shifter, the pump beam is coupled into the optical microcavity module. The first temperature controller and current controller are adjusted to cause the optical microcavity module to produce nonlinear phenomena.

[0088] S203. Record the driving current {I0, I1, I2, ...} when the optical microcavity module generates nonlinear phenomena.

[0089] S204, Adjust the drive current from Increment to Adjust the first temperature controller and phase shifter to make the output of the optical microcavity module exhibit soliton step characteristic signals.

[0090] S205. If the optical microcavity module cannot output the soliton step characteristic signal, adjust the drive current from... Increment to And adjust the first temperature controller and phase shifter until the output of the optical microcavity module exhibits a soliton step characteristic signal, where I n Let {I0, I1, I2, ...} be any term other than I0.

[0091] If the driving current is to If the optical microcavity module cannot output soliton step characteristic signals within the specified range, other driving currents that can induce nonlinear phenomena in the optical microcavity module can be selected, i.e., the driving current can be adjusted from... Increment to I n The driving current value is any value other than I0 in {I0, I1, I2, ...}, and the first temperature controller and phase shifter are adjusted again so that the output of the optical microcavity module presents a soliton step characteristic signal.

[0092] If the optical microcavity module still cannot output the soliton step characteristic signal, then other drive current values ​​need to be selected from {I0, I1, I2, ...} again, and the first temperature controller and phase shifter should be adjusted accordingly. Repeat this process until the optical microcavity module outputs the soliton step characteristic signal.

[0093] S206. If the step feature signal corresponding to the target soliton state is missing, adjust the first temperature controller until the step feature signal corresponding to the target soliton state appears.

[0094] After the optical microcavity module outputs a soliton step characteristic signal, the step characteristic signal corresponding to the target soliton state may be missing. When the step characteristic signal corresponding to the target soliton state is missing, the step characteristic signal corresponding to the target soliton state can be made to appear by adjusting the first temperature controller.

[0095] S207. Adjust the first temperature controller until the linewidth of the step characteristic signal corresponding to the target soliton state is the longest, and record the temperature T0 of the first temperature controller at this time.

[0096] There is a correlation between the frequency of the step feature signal and the driving current value. The longer the linewidth of the step feature signal corresponding to the target soliton state, the larger the range of the driving current value of the target soliton state that can be output. Therefore, when the linewidth of the step feature signal corresponding to the target soliton state is the longest, the accuracy requirement of the driving current value is the lowest.

[0097] S208. Adjust the temperature of the first temperature controller to T0.

[0098] Adjusting the temperature of the first temperature controller to T0 maximizes the range of the drive current value for the output target soliton state, making the output target soliton state more stable.

[0099] S209. Determine the current value corresponding to the target soliton state.

[0100] S210. Set the driving current to the current value corresponding to the target soliton state.

[0101] S211. When the power fluctuation of the soliton state signal acquired by the photodetector exceeds a preset threshold, the current controller is adjusted to stabilize the output power of the target soliton state signal.

[0102] Specifically, the preset threshold is used to determine whether the power of the soliton signal is stable. When the power fluctuation of the soliton signal exceeds the preset threshold, it indicates that the power of the soliton signal is unstable and the drive current may fluctuate or become noisy. It is necessary to adjust the current controller to stabilize the drive current so that the power of the output soliton signal remains stable.

[0103] S212. When the step signal acquired by the photodetector changes in level, the phase shifter is adjusted to make the generating device re-output the target soliton state signal.

[0104] Specifically, each step signal in the soliton step characteristic signal corresponds to a soliton state. When the step number in the soliton step characteristic signal corresponding to the soliton state signal acquired by the photodetector changes, it indicates that the soliton state of the soliton state signal output by the generating device has changed. This may be due to a jump in the drive current output by the current controller or a change in the external temperature. At this time, the generating device can be re-output as the target soliton state by adjusting the phase shifter.

[0105] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for generating soliton microcombs, characterized in that, The soliton microcomb generation method is applicable to a soliton microcomb generation device, which includes: a laser, a current controller, a first temperature controller, and an optical microcavity module. The optical microcavity module includes an optical microcavity and a phase shifter. The output end of the laser is coupled to the input end of the optical microcavity module. The laser is used to emit a pump beam, which is incident on the optical microcavity module through the phase shifter. The current controller is electrically connected to the laser and is used to modulate the magnitude and waveform of the driving current output to the laser. The laser is connected to the first temperature controller, which is used to adjust the temperature of the laser. The pump beam incident on the optical microcavity module generates a four-wave mixing effect. The optical microcavity module reflects part of the pump beam back into the laser, generating a self-injection locking effect. The phase shifter is used to adjust the optical path between the laser and the optical microcavity, so that a soliton microcomb is generated and output within the optical microcavity. The method for generating the soliton microcomb includes: The laser is activated, and the laser outputs a pump beam; The pump beam is coupled into the optical microcavity module after passing through the phase shifter. The first temperature controller and current controller are adjusted to cause the optical microcavity module to produce a nonlinear phenomenon. Record the driving current when the optical microcavity module generates nonlinear phenomena. ;in, It is the driving current when the optical microcavity module produces nonlinear phenomena under different conditions; Adjust the drive current from Increment to Adjusting the first temperature controller and phase shifter causes the optical microcavity module to output a soliton step characteristic signal; among which, It is the amplitude of the drive current of the current controller; Determine the current value corresponding to the target soliton state; The driving current is set to the current value corresponding to the target soliton state.

2. The method for generating soliton microcombs according to claim 1, characterized in that, The soliton microcomb generation device also includes a speckle converter, which is disposed in the optical path between the laser and the optical microcavity module. The speckle converter is used to improve the coupling efficiency of the pump beam into the optical microcavity module.

3. The method for generating soliton microcombs according to claim 1, characterized in that, The soliton microcomb generating device further includes a beam splitter and a photodetector. The input end of the beam splitter is coupled to the output end of the optical microcavity module. The beam splitter includes a first output end and a second output end. The beam splitter is used to split the soliton microcomb into a first signal and a second signal, the first signal being output from the first output terminal and the second signal being output from the second output terminal; The input terminal of the photodetector is connected to the first output terminal, and the photodetector is used to detect the intensity and frequency of the first signal.

4. The method for generating soliton microcombs according to claim 1, characterized in that, The soliton microcomb generating device also includes an isolator and a filter; The input end of the isolator is coupled to the output end of the optical microcavity module, and the isolator is used to enable the soliton microcomb to propagate in one direction. The input of the filter is coupled to the output of the isolator, and the filter is used to filter out the pump beam in the soliton microcomb.

5. The method for generating soliton microcombs according to claim 4, characterized in that, After enabling the optical microcavity module to output a soliton step characteristic signal, the following is also included: If the step feature signal corresponding to the target soliton state is missing, adjust the first temperature controller until the step feature signal corresponding to the target soliton state appears.

6. The method for generating soliton microcombs according to claim 5, characterized in that, Until the step feature signal corresponding to the target soliton state appears, the process also includes: Adjust the first temperature controller until the laser pump current range corresponding to the target soliton state is at its maximum, and record the temperature of the first temperature controller at this time. ; Adjust the temperature of the first temperature controller to .

7. The method for generating soliton microcombs according to claim 3, characterized in that, After setting the driving current to the current value corresponding to the target soliton state, the method further includes: When the power fluctuation of the soliton state signal acquired by the photodetector exceeds a preset threshold, the current controller is adjusted to stabilize the output power of the target soliton state signal.

8. The method for generating soliton microcombs according to claim 3, characterized in that, After setting the driving current to the current value corresponding to the target soliton state, the method further includes: When the step signal acquired by the photodetector changes in level, the phase shifter is adjusted to cause the generating device to re-output the target soliton state signal.

9. The method for generating soliton microcombs according to claim 1, characterized in that, Adjust the drive current from Increment to After adjusting the first temperature controller and phase shifter to make the optical microcavity module output a soliton step characteristic signal, the following steps are also included: If the optical microcavity module cannot output the soliton step characteristic signal, then adjust the driving current from Increment to The first temperature controller and the phase shifter are adjusted until the optical microcavity module outputs the soliton step characteristic signal, wherein... for Except Any one of the following.

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