Integrated mode-locked laser chip structure, measurement system and method of manufacture

Abstract

The application provides an integrated mode-locked laser chip structure, a measuring system and a manufacturing method, which comprises a doped film, a gain microcavity and a modulation module, the gain microcavity is formed on the surface of the doped film, the modulation module is used for locking the phase of multiple longitudinal modes in the gain microcavity, and the doped film contains doped ions. The mode-locked laser is integrated on a chip to reduce the volume and power consumption of the mode-locked laser, so as to solve the problems of large volume, large power consumption and complex assembly of the mode-locked laser in the prior art.

Description

Technical Field

[0001] This invention relates to the field of mode-locked laser technology, and in particular to an integrated mode-locked laser chip structure, measurement system, and manufacturing method. Background Technology

[0002] Mode-locked lasers are characterized by short pulse width, high peak power, wide spectrum, high time resolution, and high pulse repetition rate, making them significant for semiconductor manufacturing, fiber optic communication, laser surgery, and medical imaging. However, traditional mode-locked lasers are large in size, consume a lot of power, and require complex experimental setups.

[0003] On-chip mode-locked lasers can be reduced in size to the size of an adult's fingernail, while also lowering power consumption and making them portable, thus expanding their applications from the laboratory to industry. Therefore, designing the structure and manufacturing method of integrated mode-locked laser chips to achieve on-chip integrated mode-locked lasers, thereby reducing their size and power consumption, is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This invention provides an integrated mode-locked laser chip structure, measurement system, and manufacturing method to solve the problems of large size, high power consumption, and complex assembly of existing mode-locked lasers, thereby realizing an on-chip integrated mode-locked laser and reducing the size and power consumption of mode-locked lasers.

[0005] This invention provides an integrated mode-locked laser chip structure, comprising: a doped thin film, a gain microcavity, and a modulation module. The gain microcavity is formed on the surface of the doped thin film, and the modulation module is used to lock the phase of multiple longitudinal modes within the gain microcavity. The doped thin film contains dopant ions.

[0006] According to an integrated mode-locked laser chip structure provided by the present invention, the modulation module is a phase modulator, including a ground electrode and a signal electrode. The ground electrode is formed on at least one side of the gain microcavity, and the signal electrode is formed in the middle of the gain microcavity. The ground electrode and the signal electrode are used to connect to a microwave signal source.

[0007] According to the integrated mode-locked laser chip structure provided by the present invention, the distance between the ground electrode and the signal electrode is 4 μm or more.

[0008] According to the integrated mode-locked laser chip structure provided by the present invention, the doped thin film is: lithium niobate thin film, silicon nitride, silicon dioxide or silicon-based.

[0009] According to the integrated mode-locked laser chip structure provided by the present invention, the doping ions are: erbium-doped ions, ytterbium-doped ions, thulium-doped ions, or erbium-ytterbium dual-doped ions; the doping method of the doped thin film is: crystal growth method, thermal diffusion doping method, or ion implantation doping method.

[0010] According to an integrated mode-locked laser chip structure provided by the present invention, the modulation module is an amplitude modulator, which locks the phase of multiple longitudinal modes in the gain microcavity by controlling the bias voltage, modulation frequency and modulation depth.

[0011] According to an integrated mode-locked laser chip structure provided by the present invention, the modulation module is a saturable absorber, the transmittance of the saturable absorber is proportional to the intensity of the passing optical pulse, and the saturable absorber is passively mode-locked by the nonlinear saturable absorption characteristics of the optical pulse.

[0012] According to an integrated mode-locked laser chip structure provided by the present invention, the gain microcavity is a micro-ring cavity, a racetrack cavity, or a Fabry-Perot cavity.

[0013] The present invention also provides an integrated mode-locked laser chip measurement system, comprising the integrated mode-locked laser chip structure described in any of the above claims, and further comprising: a semiconductor pump laser, an attenuator, a polarization controller, a prism fiber, a displacement stage, a low-frequency photodetector, an oscilloscope, a spectrometer, a microscope, a display, an integrated mode-locked laser chip, and a beam splitter. The semiconductor pump laser, attenuator, polarization controller, prism fiber, and integrated mode-locked laser chip are connected sequentially. The integrated mode-locked laser chip is disposed on the displacement stage. One side of the beam splitter is connected to the integrated mode-locked laser chip, and the other side is connected to the low-frequency photodetector and the spectrometer. The low-frequency photodetector is connected to the oscilloscope. The microscope is disposed above the integrated mode-locked laser chip and connected to the display. The integrated mode-locked laser chip is coupled to the end face of the prism fiber.

[0014] The present invention also provides a method for manufacturing an integrated mode-locked laser chip, comprising:

[0015] Gain microcavity patterns are formed on the surface of the doped thin film using the first photolithography process, and then etched to form the gain microcavities.

[0016] A modulation module pattern region is formed on the surface of the doped thin film and located inside and outside the gain microcavity using a second photolithography process.

[0017] A metal coating is formed, and the second photoresist is removed by a stripping solution while the metal coating is stripped to form a modulation module in contact with the surface of the doped thin film in the modulation module pattern area, so as to obtain an integrated mode-locked laser chip.

[0018] The doped thin film contains doped ions; the modulation module includes a ground electrode and a signal electrode, the ground electrode being formed on at least one side of the gain microcavity, and the signal electrode being formed in the middle of the gain microcavity.

[0019] This invention provides an integrated mode-locked laser chip structure, measurement system, and manufacturing method. By forming a gain microcavity on the surface of a doped thin film, and using a modulation module to lock the phases of multiple longitudinal modes within the gain microcavity, an on-chip integrated mode-locked laser is achieved. By locking the different longitudinal mode phases of a freely operating laser using the modulation module, a frequency comb with high conversion efficiency, low microwave power, low pump power, and excellent coherence is obtained, realizing a miniaturized mode-locked laser. Furthermore, the high uniformity of the doped thin film allows its gain bandwidth, gain center, and repetition frequency to cover the corresponding operating range, resulting in a mode-locked laser based on this invention with advantages such as low operating threshold, large gain bandwidth, high gain, and low noise. This invention solves the problems of large size, high power consumption, and complex assembly in existing mode-locked lasers, realizing an on-chip integrated mode-locked laser to reduce its size and power consumption. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the integrated mode-locked laser chip structure provided by the present invention;

[0022] Figure 2 This is a schematic diagram illustrating the principle of stimulated emission in the integrated mode-locked laser chip structure provided by the present invention.

[0023] Figure 3 This is a finite element model diagram of the integrated mode-locked laser chip structure provided by the present invention;

[0024] Figure 4 This is a microwave field distribution diagram from the finite element simulation of the integrated mode-locked laser chip structure provided by this invention;

[0025] Figure 5 This is a finite element simulation diagram of the optical field distribution of the integrated mode-locked laser chip structure provided by the present invention.

[0026] Figure 6 This is a diagram showing the finite element analysis results of the integrated mode-locked laser chip structure provided by this invention;

[0027] Figure 7 This is a schematic diagram of the integrated mode-locked laser chip measurement system provided by the present invention;

[0028] Figure 8This is a schematic flowchart of the integrated mode-locked laser chip manufacturing method provided by the present invention;

[0029] Figure 9 This is a schematic diagram of the process for manufacturing an integrated mode-locked laser chip provided by the present invention.

[0030] Figure reference numerals: 1. First photoresist; 2. Second photoresist; 3. Doped thin film; 4. Metal coating; 5. Silicon dioxide; 6. Silicon; 7. Gain microcavity; 8. Modulation module; 81. Ground electrode; 82. Signal electrode; A1. Semiconductor pumped laser; A2. Attenuator; A3. Polarization controller; A4. Prism fiber; A5. Displacement stage; A6. Low-frequency photodetector; A7. Oscilloscope; A8. Spectrometer; A9. Microscope; A10. Display; A11. Microwave signal source; A12. Integrated mode-locked laser chip; A13. Beam splitter. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] The following is combined with Figures 1-6 The integrated mode-locked laser chip structure of the present invention is described.

[0033] The first embodiment of the present invention provides an integrated mode-locked laser chip structure, including: a doped thin film 3, a gain microcavity 7, and a modulation module 8. The gain microcavity 7 is formed on the surface of the doped thin film 3, and the modulation module 8 is used to lock the phase of multiple longitudinal modes in the gain microcavity 7. The thin film 3 contains dopant ions.

[0034] The first embodiment of this invention provides an integrated mode-locked laser chip structure. By forming a gain microcavity 7 on the surface of a doped thin film 3, and using a modulation module 8 to lock the phases of multiple longitudinal modes within the gain microcavity 7, an on-chip integrated mode-locked laser is achieved. By locking the different longitudinal mode phases of a freely operating laser using the modulation module 8, a frequency comb with high conversion efficiency, low microwave power, low pump light power, and excellent coherence is obtained, realizing a miniaturized mode-locked laser. Furthermore, the doped thin film 3 has high uniformity, and its gain bandwidth, gain center, and repetition frequency can cover the corresponding operating range. This results in a mode-locked laser based on the integrated mode-locked laser chip of this invention having advantages such as low operating threshold, large gain bandwidth, high gain, and low noise. This invention solves the problems of large size, high power consumption, and complex assembly in existing mode-locked lasers, realizing an on-chip integrated mode-locked laser to reduce its size and power consumption.

[0035] In this embodiment, the modulation module 8 is a phase modulator, including a ground electrode 81 and a signal electrode 82. The ground electrode 81 is formed on at least one side of the gain microcavity 7, and the signal electrode 82 is formed in the middle of the gain microcavity 7. The ground electrode 81 and the signal electrode 82 are used to connect to the microwave signal source A11.

[0036] like Figure 1 As shown, the integrated mode-locked laser chip structure of this embodiment includes: a doped thin film 3, a gain microcavity 7, and a modulation module 8. The gain microcavity 7 is formed on the surface of the doped thin film 3, and the modulation module 8 is formed on the surface of the gain microcavity 7. The modulation module 8 includes a ground electrode 81 and a signal electrode 82. The ground electrode 81 is formed on at least one side of the gain microcavity 7 (it can be formed on both sides of the gain microcavity 7), and the signal electrode 82 is formed in the middle of the gain microcavity 7. By adding electrodes to the gain microcavity 7 to form a modulator, and applying a microwave signal to the signal electrode 82 through a microwave signal source A11, the different longitudinal mode phases of the freely operating laser are locked, resulting in an optical frequency comb with high conversion efficiency, low microwave power, low pump light power, and excellent coherence, thus realizing a miniaturized mode-locked laser.

[0037] like Figure 2 As shown, in the microcavity serving as the gain medium, under the action of a strong pump light at 980 / 1480nm, erbium ions undergo stimulated transitions from the lower laser level E1 to the pump high level E3. The lifetime of the E3 level is short, and the erbium ions quickly transfer to the upper laser level E2 in the form of nonradiative transitions. The lifetime of the E2 level is very long, and the erbium ions can remain at the E2 level for a relatively long time. When the pump light energy is strong enough, a population inversion distribution can be formed between E2 and E1, thereby generating laser light through stimulated emission.

[0038] In this embodiment, a modulator is formed by adding electrodes to the gain microcavity 7. A microwave signal is applied to the signal electrode 82 via a microwave signal source A11, locking the different longitudinal modes of the freely rotating laser. This results in an optical frequency comb with high conversion efficiency, low microwave power, low pump light power, and excellent coherence, achieving a miniaturized mode-locked laser. Its electro-optic modulation exists throughout the entire resonant cavity, thus affecting both the pump light and the signal light. Under phase modulation, the pump light forms a resonant electro-optic comb, exhibiting a pulse sequence in the time domain. The pulse shape is affected by the dispersion and loss of the gain microcavity 7. Simultaneously, under strong pump light, the gain microcavity 7 absorbs pump photon energy, achieving erbium ion transitions, resulting in population inversion and generating signal light. After phase modulation, this also forms a time-domain pulse sequence, with its shape affected by the loss, dispersion, and nonlinearity of the gain microcavity 7.

[0039] In this embodiment, the distance between the ground electrode 81 and the signal electrode 82 is more than 4 μm.

[0040] Coupling and modulation efficiency are crucial factors affecting on-chip mode-locked lasers. Before assembling the measurement system for the mode-locked laser, the coupling at the microcavity pump light and signal light needs to be designed. Over-coupling at the pump light and proximity coupling at the signal light optimizes the laser lasing effect. Simultaneously, the influence of metal electrodes on waveguide absorption loss needs to be modeled and analyzed using the finite element method, such as... Figure 3 The finite element model diagram of the integrated mode-locked laser chip is shown below. Figure 4 The microwave field distribution diagram of the integrated mode-locked laser chip, as shown in the finite element simulation, is as follows: Figure 5 The image shows the optical field distribution of an integrated mode-locked laser chip, simulated using finite element analysis. When the electrode spacing is close, the modulation efficiency is high, but the optical waveguide loss is high; conversely, when the electrode spacing is far, the modulation efficiency is low, but the optical waveguide loss is low. Therefore, it is necessary to optimize the waveguide spacing to achieve both low-loss waveguide and high modulation efficiency. Figure 6 According to the finite element analysis results of the integrated mode-locked laser chip shown, when the electrode spacing between the ground electrode 81 and the signal electrode 82 is greater than 4 μm, the metal electrode hardly causes any absorption loss to the waveguide.

[0041] In this embodiment, the doped thin film 3 is: lithium niobate thin film, silicon nitride, silicon dioxide or silicon-based.

[0042] The doped thin film 3 in this embodiment is not limited to lithium niobate thin films; it is applicable to platforms such as silicon nitride, silicon dioxide, and silicon-based materials, thereby expanding the range of process materials while ensuring process quality.

[0043] In this embodiment, the doped ions are: erbium-doped ions, ytterbium-doped ions, thulium-doped ions, or erbium-ytterbium dual-doped ions; the production method of the doped thin film 3 is: crystal growth method, thermal diffusion doping method, or ion implantation doping method.

[0044] Doping ions are not limited to erbium-doped ions; ytterbium-doped ions, thulium-doped ions, and erbium-ytterbium dual-doped ions are also applicable. Doping methods are not limited to crystal growth; thermal diffusion doping and ion implantation doping are also applicable, expanding the range of materials selected for the process while ensuring process quality. In this embodiment, erbium-doped lithium niobate thin film material is used as the doped film 3. Lithium niobate crystals possess multiple properties, including piezoelectricity, ferroelectricity, electro-optics, nonlinear optics, and thermoelectricity. Based on this characteristic of the material, an active mode-locking method is used to lock the phase of multiple longitudinal modes of the gain microcavity 7, realizing an on-chip mode-locked laser that emits periodic ultrashort pulses.

[0045] In this embodiment, the modulation module 8 is an amplitude modulator, which locks the phase of multiple longitudinal modes in the gain microcavity 7 by controlling the bias voltage, modulation frequency and modulation depth.

[0046] The mode-locking method in this embodiment is not limited to the phase modulator mode-locking in the above-mentioned active mode-locking. The longitudinal mode locking of the laser can also be achieved by adding an amplitude modulator and appropriately controlling the bias voltage, modulation frequency and modulation depth.

[0047] In this embodiment, the modulation module 8 is a saturable absorber. The transmittance of the saturable absorber is proportional to the intensity of the light pulse passing through it. The saturable absorber is passively mode-locked by the nonlinear saturable absorption characteristics of the light pulse.

[0048] The mode-locking method in this embodiment can also passively mode-lock the nonlinear saturable absorption characteristics of the optical pulse using a saturable absorber. When the optical pulse passes through the saturable absorber, the higher the pulse intensity, the higher the transmittance, and the lower the intensity, the lower the transmittance. The transmittance of the saturable absorber is proportional to the intensity of the passing optical pulse, thus obtaining a narrower pulse compared to the input pulse. This causes low-peak-power noise and small pulses to suffer significant losses each time they pass through the saturable absorber, while high-intensity pulses pass almost completely and are amplified by the gain medium, resulting in only one giant pulse oscillating within the cavity.

[0049] In this embodiment, the gain microcavity 7 is a micro-ring cavity, a racetrack cavity, or a Fabry-Perot cavity.

[0050] Gain Microcavity 7 is not limited to micro-ring cavities; it is also applicable to raceway cavities and Fabry-Perot cavities, expanding the range of process materials while ensuring process quality.

[0051] A second embodiment of the present invention also provides an integrated mode-locked laser chip measurement system, including the aforementioned integrated mode-locked laser chip structure, and further comprising: a semiconductor pump laser A1, an attenuator A2, a polarization controller A3, a prism fiber A4, a displacement stage A5, a low-frequency photodetector A6, an oscilloscope A7, a spectrometer A8, a microscope A9, a display A10, an integrated mode-locked laser chip A12, and a beam splitter A13. The semiconductor pump laser A1, attenuator A2, polarization controller A3, prism fiber A4, displacement stage A5, low-frequency photodetector A6, oscilloscope A7, spectrometer A8, microscope A9, display A10, integrated mode-locked laser chip A12, and beam splitter A13 are described above. Fiber A4 and integrated mode-locked laser chip A12 are connected sequentially. The integrated mode-locked laser chip A12 is mounted on the displacement stage A5. One side of the beam splitter A13 is connected to the integrated mode-locked laser chip A12, and the other side is connected to the low-frequency photodetector A6 and the spectrometer A8, respectively. The low-frequency photodetector A6 is connected to the oscilloscope A7. The microscope A9 is positioned above the integrated mode-locked laser chip A12 and is connected to the display A10. The integrated mode-locked laser chip A12 is coupled to the end face of the prism fiber A4.

[0052] like Figure 7As shown, a semiconductor pump laser A1, attenuator A2, polarization controller A3, prism fiber A4, and integrated mode-locked laser chip A12 are connected sequentially to emit pump light to the integrated mode-locked laser chip A12. The integrated mode-locked laser chip A12 is mounted on a displacement stage A5, which is operated to adjust the integrated mode-locked laser chip A12. One side of the beam splitter A13 is connected to the integrated mode-locked laser chip A12, and the other side is connected to a low-frequency photodetector A6 and a spectrometer A8. The low-frequency photodetector A6 is connected to an oscilloscope A7 to receive the emitted light. A microscope A9 is positioned above the integrated mode-locked laser chip A12 and connected to a display A10 to observe and adjust the coupling position between the integrated mode-locked laser chip A12 and the prism fiber A4. The integrated mode-locked laser chip A12 is coupled to the end face of the prism fiber A4. The ground electrode 81 on one side and the signal electrode 82 in the middle of the integrated mode-locked laser chip A12 are connected to the microwave signal source A11.

[0053] The 980 / 1480nm pump light emitted by the semiconductor pump laser A1 first passes through attenuator A2 and polarization controller A3, and then is coupled into the integrated mode-locked laser chip A12 via the end face of prism fiber A4, generating a strong broadband gain and forming different longitudinal mode laser lasing. The coupling of the two end faces is optimized to achieve the best laser lasing effect. A microwave signal is applied to the electrodes by microwave signal source A11 to achieve mode-locking, resulting in a phase-locked optical frequency comb.

[0054] like Figure 8 As shown, the third embodiment of the present invention also provides a method for manufacturing an integrated mode-locked laser chip, specifically including the following steps:

[0055] Step S1: A gain microcavity 7 pattern is formed on the surface of the doped thin film 3 by the first photolithography process, and the gain microcavity 7 is formed after etching.

[0056] Step S2: Through a second photolithography process, a patterned area of ​​the modulation module 8 is formed on the surface of the doped thin film 3, and inside and outside the gain microcavity 7.

[0057] Step S3: Form a metal coating 4, remove the second photoresist 2 by stripping the photoresist solution, and simultaneously peel off the metal coating 4 to form a modulation module 8 in contact with the surface of the doped thin film 3 in the pattern area of ​​the modulation module 8, so as to obtain an integrated mode-locked laser chip.

[0058] The thin film 3 contains doped ions; the modulation module 8 includes a ground electrode 81 and a signal electrode 82, the ground electrode 81 is formed on at least one side of the gain microcavity 7, and the signal electrode 82 is formed in the middle of the gain microcavity 7.

[0059] like Figure 9The diagram shows a process flow chart for manufacturing an integrated mode-locked laser chip. Figure 9 As shown in (a), the structure of the integrated mode-locked laser chip to be processed, from bottom to top, includes: silicon 6, silicon dioxide 5, and a doped thin film 3. The doped thin film 3 can be selected from: lithium niobate thin film, silicon nitride, silicon dioxide, or silicon-based. In this embodiment, lithium niobate thin film is selected as the doped thin film 3. Lithium niobate thin films with doped ions have high uniformity, a gain bandwidth of tens of nm, and gain centers at 1064 nm, 1550 nm, and 2 μm. The repetition frequency ranges from hundreds of MHz to tens of GHz, covering the operating range of the microwave signal source A11. First, the doped thin film 3 is pretreated, i.e., its surface is cleaned by solution cleaning or short-time oxygen ion bombardment.

[0060] like Figure 9 As shown in (b), electron beam exposure is performed according to the pattern of the gain microcavity 7 using the first photoresist 1 as a mask, and then the photoresist is baked after development with the first developer. The first photoresist 1 can be either ma-N 2410 or HSQ, and the first developer is 2.38% tetramethylammonium hydroxide (TMAH).

[0061] like Figure 9 As shown in (c), the lithium niobate film masked by the first photoresist 1 is etched using inductively coupled plasma (ICP) to form a gain microcavity 7. The doped film 3 is then bombarded with argon plasma, preserving the photoresist-masked doped film 3 (lithium niobate film layer) to transfer the mask pattern to the lithium niobate film layer.

[0062] like Figure 9 As shown in (d), the residual photoresist 1 is treated and rinsed. The residual photoresist 1 is treated with Remover-PG stripper or O2 plasma (oxygen plasma cleaning). Then, the redeposition residue from inductively coupled plasma etching is removed with an ammonia solution (hydrogen peroxide: ammonia volume ratio = 1:1). Finally, it is rinsed with deionized water and dried with nitrogen gas.

[0063] like Figure 9 As shown in (e), a second photoresist 2 is formed. The second photoresist 2 is then subjected to electron beam exposure based on the electrode pattern to remove the second photoresist 2 corresponding to the electrode pattern regions located inside and outside the gain microcavity 7. Finally, it is developed using a second developer. The second photoresist 2 can be selected from AR-P 6200, PMMA, LOR 3A, or S1813, and the second developer can be selected from AR600-546 or MF319.

[0064] like Figure 9As shown in (f), a Ti / Au metal coating 4 is formed by electron beam evaporation.

[0065] like Figure 9 (g) The second photoresist 2 is removed by N,N-dimethylformamide stripper while the metal coating 4 is stripped to form an electrode in the electrode pattern area that contacts the surface of the doped thin film 3, so as to obtain an integrated mode-locked laser chip.

[0066] The doped thin film 3 contains dopant ions, which can be selected from erbium-doped ions, ytterbium-doped ions, thulium-doped ions, or a combination of erbium and ytterbium ions. The production method of the doped thin film 3 can be selected from crystal growth, thermal diffusion doping, or ion implantation doping. The gain microcavity 7 can be selected from micro-ring cavity, racetrack cavity, or Fabry-Perot cavity structures.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated mode-locked laser chip structure, characterized in that, include: The invention comprises a doped thin film, a gain microcavity, and a modulation module. The gain microcavity is formed on the surface of the doped thin film, and the modulation module is used to lock the phase of multiple longitudinal modes within the gain microcavity. The doped thin film contains dopant ions.

2. The integrated mode-locked laser chip structure according to claim 1, characterized in that, The modulation module is a phase modulator, including a ground electrode and a signal electrode. The ground electrode is formed on at least one side of the gain microcavity, and the signal electrode is formed in the middle of the gain microcavity. The ground electrode and the signal electrode are used to connect to a microwave signal source.

3. The integrated mode-locked laser chip structure according to claim 2, characterized in that, The distance between the grounding electrode and the signal electrode is 4 μm or more.

4. The integrated mode-locked laser chip structure according to claim 1, characterized in that, The doped thin film is: lithium niobate thin film, silicon nitride, silicon dioxide or silicon-based.

5. The integrated mode-locked laser chip structure according to claim 4, characterized in that, The doping ions are: erbium-doped ions, ytterbium-doped ions, thulium-doped ions, or erbium-ytterbium dual-doped ions; the doping method of the doped thin film is: crystal growth method, thermal diffusion doping method, or ion implantation doping method.

6. The integrated mode-locked laser chip structure according to claim 1, characterized in that, The modulation module is an amplitude modulator, which locks the phase of multiple longitudinal modes in the gain microcavity by controlling the bias voltage, modulation frequency and modulation depth.

7. The integrated mode-locked laser chip structure according to claim 1, characterized in that, The modulation module is a saturable absorber. The transmittance of the saturable absorber is proportional to the intensity of the light pulse passing through it. The saturable absorber passively modes-locks the light pulse through its nonlinear saturable absorption characteristics.

8. The integrated mode-locked laser chip structure according to any one of claims 1 to 7, characterized in that, The gain microcavity is a micro-ring cavity, a racetrack cavity, or a Fabry-Perot cavity.

9. An integrated mode-locked laser chip measurement system, characterized in that, The integrated mode-locked laser chip structure according to any one of claims 1 to 8 further includes: a semiconductor pump laser, an attenuator, a polarization controller, a prism fiber, a displacement stage, a low-frequency photodetector, an oscilloscope, a spectrometer, a microscope, a display, an integrated mode-locked laser chip, and a beam splitter. The semiconductor pump laser, attenuator, polarization controller, prism fiber, and integrated mode-locked laser chip are connected sequentially. The integrated mode-locked laser chip is disposed on the displacement stage. One side of the beam splitter is connected to the integrated mode-locked laser chip, and the other side is connected to the low-frequency photodetector and the spectrometer. The low-frequency photodetector is connected to the oscilloscope. The microscope is disposed above the integrated mode-locked laser chip and connected to the display. The integrated mode-locked laser chip is coupled to the end face of the prism fiber.

10. A method for manufacturing an integrated mode-locked laser chip, characterized in that, include: Gain microcavity patterns are formed on the surface of the doped thin film using the first photolithography process, and then etched to form the gain microcavities. A modulation module pattern region is formed on the surface of the doped thin film and located inside and outside the gain microcavity using a second photolithography process. A metal coating is formed, and the second photoresist is removed by a stripping solution while the metal coating is stripped to form a modulation module in contact with the surface of the doped thin film in the modulation module pattern area, so as to obtain an integrated mode-locked laser chip. The doped thin film contains doped ions; the modulation module includes a ground electrode and a signal electrode, the ground electrode being formed on at least one side of the gain microcavity, and the signal electrode being formed in the middle of the gain microcavity.

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