Preparation method and structure of tunable laser

Abstract

The invention discloses a preparation method and structure of a tunable laser, and the method comprises the steps: carrying out the surface layout of a substrate, and sequentially dividing the substrate into a front gain region, a front phase region, a common grating region, a rear phase region and a rear gain region; growing an active layer, manufacturing a butt-joint mask pattern in the gain region, etching to remove the active layer in the common grating region and the phase region, performing butt-joint growth of a passive layer, removing a mask, manufacturing a grating in the common grating region, and growing a cladding and an electric contact layer; manufacturing an inverted table shallow ridge waveguide structure, and etching an electrical isolation trench; and a cantilever arm structure is manufactured and formed in the common grating area, a titanium-platinum heating resistor, a grating electrode and a grounding electrode are manufactured, and the tunable laser is obtained after preparation of a P-surface electrode and an N-surface electrode is completed. The back-to-back double lasers share the thermal tuning grating, double-end light emitting and wavelength synchronous control are achieved, the cantilever arm structure of the grating ridge waveguide is manufactured, energy consumption of wavelength tuning is reduced, and a solution is provided for large-scale use of tunable light emitting chips in the future.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor optoelectronic tunable lasers, and in particular to a preparation method and structure of a tunable laser. Background Art

[0002] With the rapid development of 5G networks, data centers, and artificial intelligence, on the one hand, higher requirements are placed on the bandwidth of data transmission. In order to increase the bandwidth of a single optical transmitter chip, monolithic integration of multifunctional devices is adopted to fully utilize the advantages of each functional device. On the other hand, with the large-scale use of optical transmitter chips, modules, and equipment, reducing the power consumption of each link of optical transmission is becoming increasingly important. As the core chip of optical transmission, the optical transmitter chip has become increasingly integrated, and solving the power consumption problem of the optical transmitter chip has become particularly important.

[0003] Most existing tunable lasers utilize independent gain and grating regions, making dual-end synchronous output and high-precision wavelength control impossible. Furthermore, the high power consumption of traditional thermal tuning structures limits their application in large-scale integration and long-duration operation scenarios. Furthermore, existing fabrication processes suffer from insufficient precision and poor repeatability in selective growth and material etching, resulting in unstable device performance and hindering large-scale mass production.

[0004] This invention proposes a method and structure for fabricating a tunable laser. By integrating two wavelength-tunable lasers back-to-back, sharing a grating region and emitting light from both ends, this method achieves dual-end synchronous output and precise wavelength control, significantly improving performance. By fabricating a cantilever arm structure for the grating ridge waveguide and forming an air slot thermal insulation structure, the wavelength tuning is shifted from electrical tuning to thermal tuning. This reduces wavelength tuning energy consumption to one-third of the original level. Combined with dual-end light emission, this significantly reduces chip power consumption. This invention proposes a new solution for the future large-scale deployment of tunable light-emitting chips. Summary of the Invention

[0005] In view of this, the present invention provides a method and structure for preparing a tunable laser, which can solve the technical problems of difficult wavelength synchronization control, high power consumption and poor heat dissipation of tunable lasers in the prior art.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for preparing a tunable laser, comprising: Performing surface layout on the substrate, dividing the substrate surface into a front gain region, a front phase region, a common grating region, a rear phase region, and a rear gain region in sequence along the length direction; and growing an active layer on the substrate surface using a metal organic chemical vapor deposition device; A silicon dioxide layer is grown on the substrate surface using plasma chemical vapor deposition equipment, and a butt-jointed mask pattern is produced in the front and rear gain regions using photolithography and wet etching techniques. Reactive ion etching equipment is used to etch away the active layers of the common grating region, the front phase region, and the back phase region, and the substrate is cleaned and the active layer material remaining on the surface is removed by etching; A passive layer is grown on the common grating region, the front phase region and the rear phase region by using a metal organic chemical vapor deposition device; the fluorescence wavelength of the passive layer is smaller than the fluorescence wavelength of the front and rear gain regions; Removing the docking mask pattern, making a grating in the common grating area, and sequentially growing a cladding layer and an electrical contact layer on the entire surface of the laser; Fabricating an inverted shallow ridge waveguide structure on the cladding layer and the electrical contact layer; Etching electrical isolation grooves on the electrical contact layer to achieve electrical isolation between functional areas; Reactive ion etching equipment and hydrobromic acid etching are used on both sides of the ridge waveguide structure in the shared grating area to form a cantilever arm structure in the ridge waveguide structure in the shared grating area; A silicon nitride film is grown on the surface of the laser to make a titanium-platinum heating resistor for the shared grating region ridge waveguide, as well as a grating electrode and a ground electrode; P-side electrodes are made on the electrode contact layers of the front / rear phase region and the front / rear gain region. After the substrate is thinned, N-side electrodes are made on the bottom to complete the tunable laser fabrication.

[0007] Furthermore, the fluorescence wavelength of the passive layer is 90-200 nm shorter than the fluorescence wavelength of the gain region.

[0008] Furthermore, the cantilever arm structure is formed by etching with a reactive ion etching device and hydrobromic acid on both sides of the ridge waveguide structure in the shared grating region, including: In the preset rectangular strip areas on both sides of the ridge waveguide structure in the shared grating area, a reactive ion etching device is used to etch away the electrical contact layer, the cladding layer and the passive layer; The ridge waveguide in the shared grating region is etched with hydrobromic acid to form a cantilever arm structure.

[0009] Furthermore, the cantilever arm structure includes: hexagonal air slots on both sides of the cantilever arm, and a cantilever arm below the ridge waveguide.

[0010] Furthermore, the preset rectangular strip area is two rectangular grooves with a width of 5 microns and a length of 350 microns, and the groove spacing is 25 microns.

[0011] Furthermore, the active layer includes a lower waveguide layer, a multi-quantum well layer, and an upper waveguide layer from bottom to top. The thickness of the lower waveguide layer and the upper waveguide layer are both 100 nm. The multi-quantum well layer is formed by alternating growth of multiple quantum well layers and barrier layers.

[0012] Furthermore, the materials of the active layer and the passive layer are both InGaAsP.

[0013] Furthermore, the cleaning of the substrate and etching to remove the active layer material remaining from the etching process include: thoroughly cleaning the substrate with acetone and ethanol, and etching to remove the active layer material remaining from the etching process with H2SiO4 solution.

[0014] Furthermore, the lengths of the front gain region and the rear gain region are both 300 microns, the lengths of the front phase region and the rear phase region are 100 microns, and the length of the common grating region is 350 microns.

[0015] On the other hand, the present invention also provides a structure of a tunable laser, wherein the laser is manufactured using the manufacturing method described in the above technical solution, wherein the laser is divided into a front gain region, a front phase region, a common grating region, a rear phase region, and a rear gain region in sequence along the length direction starting from one side; Among them, the fluorescence wavelength of the light in the shared grating area, front phase area and rear phase area is 90-200nm smaller than the fluorescence wavelength of the light in the front and rear gain areas; the ridge waveguide structure of the shared grating area is a cantilever arm structure, with hexagonal air slots on both sides of the cantilever arm to form an air slot insulation structure, which changes the wavelength tuning from electrical tuning to thermal tuning.

[0016] Compared with the prior art, the advantages of the tunable laser preparation method and structure provided by the present invention are: (1) This method integrates two wavelength-tunable lasers back-to-back by sharing a grating structure, sharing the grating area, and achieving dual-end-face light output, which can meet the needs of different transmission directions and links, and improve the flexibility and reliability of the system. In applications such as optical multiplexing and optical sensing that require precise wavelength matching, this synchronous control can effectively reduce the interference caused by wavelength drift and improve the performance and accuracy of the system. In addition, from a production perspective, reducing the number of grating preparations and the technical complexity can improve production efficiency and reduce the cost of a single device in large-scale production.

[0017] (2) By creating a cantilever arm structure for the grating ridge waveguide and forming an air slot thermal insulation structure, the wavelength tuning is changed from electrical tuning to thermal tuning. The energy consumption of wavelength tuning is reduced to one-third of the original. Combined with the double-ended light output, the chip's power consumption is greatly reduced, proposing a new solution for the large-scale use of tunable light emitting chips in the future. Lower power consumption can also slow the aging of the internal materials of the device, extend the service life of the laser, and reduce the replacement frequency and maintenance costs of the device.

[0018] In summary, the present invention solves the problems of difficult wavelength synchronization, high power consumption, and poor heat dissipation in existing tunable lasers through an innovative shared grating structure and cantilever arm thermal insulation design, achieving dual-end light output and low-energy thermal tuning, significantly improving the performance and reliability of optical communication and optical sensing systems, reducing production costs, extending device service life, and providing an efficient solution for large-scale applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic flow chart of a method for preparing a tunable laser provided by the present invention; Figure 2 This is a schematic diagram of the structure of the substrate and area division and active layer after fabrication provided by the present invention; Figure 3 This is a schematic diagram of the structure after etching away the active layer materials of the phase region and grating region provided by the present invention; Figure 4 This is a schematic diagram of the structure after the grating region and the phase region passive material are butt-grown according to the present invention; Figure 5 A schematic diagram of the structure after the grating is manufactured and the cladding layer and the electrical contact layer are grown according to the present invention; Figure 6 A cross-sectional schematic diagram of the inverted shallow ridge waveguide structure fabricated on the cladding layer and the electrical contact layer provided by the present invention; Figure 7 This is a schematic diagram of the structure after the isolation grooves between the functional areas are formed according to the present invention; Figure 8 A schematic diagram of the structure of the air insulation grooves on both sides of the ridge waveguide in the grating area provided by the present invention; Figure 9 A schematic cross-sectional view of the cantilever beam for making a grating area provided by the present invention; Figure 10 A schematic diagram of the distribution of electrodes in various regions on the surface of the device provided by the present invention; In the figure, 1-front gain region, 2-front phase region, 3-common grating region, 4-back gain region, 5-back phase region, 10-substrate, 11-lower confinement layer, 12-multi-quantum well layer, 13-upper confinement layer, 14-docking mask pattern, 15-passive layer, 16-grating, 17-cladding, 18-electric contact layer, 19-rectangular groove, 20-air groove, 21-suspended arm, 22-grating electrode, 23-ground electrode, 24-first P-surface electrode, 25-second P-surface electrode, 26-third P-surface electrode, 27-fourth P-surface electrode. DETAILED DESCRIPTION

[0020] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, and are not used to limit the scope of the present invention.

[0021] Example 1 See Figure 1 , Figure 1 A schematic flow chart of a method for preparing a tunable laser provided in this embodiment is shown, the method comprising: Step S101: performing surface layout on the substrate, dividing the substrate surface into a front gain region, a front phase region, a common grating region, a rear phase region, and a rear gain region in sequence along the length direction; and growing an active layer on the substrate surface using a metal organic chemical vapor deposition device; Step S102: growing a silicon dioxide layer on the substrate surface using a plasma chemical vapor deposition device, and forming a butt-jointed mask pattern in the front / rear gain region using photolithography and wet etching techniques; Step S103: using a reactive ion etching device to etch away the active layers of the common grating region, the front phase region, and the back phase region, cleaning the substrate, and etching away the active layer material remaining on the surface; Step S104: using metal organic chemical vapor deposition equipment to grow a passive layer on the common grating region, the front phase region and the back phase region; the fluorescence wavelength of the passive layer is smaller than the fluorescence wavelength of the gain region; Step S105: removing the docking mask pattern, forming a grating in the common grating area, and sequentially growing a cladding layer and an electrical contact layer on the entire surface of the device; Step S106: fabricating an inverted shallow ridge waveguide structure on the cladding layer and the electrical contact layer; Step S107: etching electrical isolation grooves on the electrical contact layer to achieve electrical isolation between functional areas; Step S108: using a reactive ion etching device and hydrobromic acid to etch both sides of the ridge waveguide structure in the shared grating area, so that the ridge waveguide structure in the shared grating area forms a cantilever arm structure; Step S109: growing a layer of silicon nitride film on the surface of the laser to form a titanium-platinum heating resistor shared with the ridge waveguide in the grating region, as well as a grating electrode and a ground electrode; Step S110: fabricating P-side electrodes on the electrode contact layers of the front phase region, the back phase region and the gain region, and fabricating N-side electrodes on the bottom after thinning the substrate to complete the fabrication of the tunable laser.

[0022] The tunable laser fabrication method provided in this embodiment integrates two wavelength tunable lasers back-to-back, and forms an air slot thermal insulation structure by fabricating a cantilever arm structure of a grating ridge waveguide. This allows the wavelength tuning to be changed from electrical tuning to thermal tuning, reducing the energy consumption of wavelength tuning to one-third of the original level. Combined with dual-end light output, this significantly reduces the power consumption of the chip, providing a new solution for the future large-scale use of tunable optical emission chips.

[0023] The following combination Figure 2-Figure 10 The above steps are shown and explained in detail.

[0024] As a specific embodiment, the steps of the production method include: (1) An N-type indium phosphide substrate 10 is selected, and the substrate surface is divided into a front gain region 1, a front phase region 2, a common grating region 3, a rear phase region 4, and a rear gain region 5 in sequence along the length direction; wherein the length of the front gain region is 300 μm, the length of the front phase region 2 is 100 μm, the length of the common grating region 3 is 350 μm, the length of the rear phase region 4 is 100 μm, and the length of the rear gain region 5 is 300 μm.

[0025] (2) Using metal organic chemical vapor deposition equipment to grow an active layer on the substrate, the active layer is made of InGaAsP and includes a lower confinement layer 11, a multi-quantum well layer 12 and an upper confinement layer 13; wherein the thickness of the lower confinement layer 11 and the upper confinement layer 13 are both 100nm, and the multi-quantum well layer 12 is formed by alternating growth of six 5nm thick quantum well layers and seven 9nm thick barrier layers, as shown in FIG. Figure 2 shown.

[0026] (3) A SiO2 layer with a thickness of 200 nm is grown on the substrate surface using a plasma chemical vapor deposition device, and a docking mask pattern 14 is made in the gain region 4 using photolithography and wet etching techniques.

[0027] (4) Reactive ion etching equipment is used to etch away the InGaAsP active layer materials of the common grating region 3, the front phase region 2 and the back phase region 4. The substrate is cleaned with acetone and ethanol, and the InGaAsP material remaining during etching is etched away with H2SiO4 solution. At this time, the structure of the laser is as follows: Figure 3 shown.

[0028] (5) Metal organic chemical vapor deposition equipment is used to grow the passive layer of the common grating region 3, the front phase region 2 and the back phase region 4. The passive layer is an InGaAsP bulk material 15, and its light fluorescence wavelength is smaller than the light fluorescence wavelength of the gain region by 90-200nm. Figure 4It should be noted that the fluorescence wavelengths of the grating and phase regions are designed to be shorter than those of the front and rear gain regions. This allows for a blue shift of the grating and phase regions relative to the gain region. During laser operation, the gain region provides efficient light amplification, while the phase region precisely controls the phase of the light wave, thereby ensuring the laser's output spectrum quality and tuning accuracy.

[0029] (6) Remove the mating mask pattern 14, make a grating 16 in the common grating area 3, and then grow a cladding layer 17 and an electrical contact layer 18 on the surface using a metal organic chemical vapor deposition device. The cladding layer 17 is a 1.5 micron thick InP layer; the electrical contact layer 18 is a 300 nanometer thick InGaAs layer. The specific structure is as follows: Figure 5 shown.

[0030] (7) Fabricate an inverted shallow ridge waveguide structure on the cladding layer 17 and the electrical contact layer 18 of the entire material, such as Figure 6 As shown, Figure 6 A cross-sectional view of a shallow ridge waveguide is shown; (8) An electrical isolation groove is etched on the ridge wave conductive contact layer 18. The width of the electrical isolation groove is 50 microns, thereby achieving electrical isolation between the common grating region 3, the front phase region 2 and the rear phase region 4, and the front gain region 1 and the rear gain region 5. The structure at this time is as follows: Figure 7 shown.

[0031] (9) In the rectangular strip area 19 on both sides of the ridge waveguide of the shared grating area 3, 400 nm of semiconductor material is removed by etching with a reactive ion etching device, and then etched with hydrobromic acid for 20 minutes to form a cantilever arm structure of the ridge waveguide of the shared grating area 3. In the rectangular groove area, two rectangular grooves with a width of 5 microns and a length of 350 microns are set, and the spacing between the rectangular grooves is 25 microns. Figure 8 As shown, Figure 8 FIG. 1 is a top view of the layout of the rectangular strip area 19. Figure 9 As shown, the cantilever arms of the ridge waveguide in the shared grating region 3 are provided with hexagonal air slots 20 on both sides, and a cantilever arm 21 is provided below the ridge waveguide.

[0032] Specifically, the working principle and effect of the above-mentioned setting are introduced here. By hollowing out the two sides and small faces of the ridge waveguide in the grating area, it is physically isolated from the semiconductor material. There is air between the structures. The thermal conductivity of air is very poor, which prevents the heat in the grating area from dissipating. This makes it easy to change the temperature of the ridge waveguide in the grating area, thereby changing the refractive index of the grating material, and thus achieving the purpose of changing the grating period. The change in grating period will change the laser lasing wavelength, thereby achieving wavelength tuning, and changing the wavelength tuning from electrical tuning to thermal tuning. Thermal tuning significantly reduces power consumption compared to traditional electrical tuning. This is because electrical tuning requires high current to change the refractive index, while thermal tuning only requires low-power heating resistors. Therefore, it can reduce energy loss, extend the service life of the device, and reduce operating costs. It is particularly suitable for large-scale photonic integration applications. In addition, this structure optimizes the heat dissipation characteristics of the grating area. The hollowing design allows heat to be easily dissipated to the surrounding environment, preventing excessive heating from causing performance degradation or damage, and improving the stability and reliability of laser operation.

[0033] (10) A layer of silicon nitride film with a thickness of 250 nm is grown on the surface of the laser using plasma vapor deposition equipment to produce a titanium-platinum heating resistor for the three-ridge waveguide in the shared grating area. The titanium-platinum heating resistor has a strong bonding force with the silicon nitride substrate and a high resistance temperature coefficient, and has high heating efficiency after power is turned on.

[0034] At the same time, the grating electrode 22 and the ground electrode 23 are made; the first P-surface electrode 24 and the second P-surface electrode 25 are made in the front phase region 2 and the rear phase region 4 respectively; the third P-surface electrode 26 and the fourth P-surface electrode 27 are made in the front gain region 1 and the rear gain region 5 respectively; after the substrate is thinned, the N-surface electrode is made at the bottom of the entire device to complete the production of the laser. Figure 10 As shown, Figure 10 A top view of the completed laser.

[0035] The tunable laser fabrication method provided in this embodiment integrates two wavelength tunable lasers back-to-back, and forms an air slot thermal insulation structure by fabricating a cantilever arm structure of a grating ridge waveguide. This allows the wavelength tuning to be changed from electrical tuning to thermal tuning, reducing the energy consumption of wavelength tuning to one-third of the original level. Combined with dual-end light output, this significantly reduces the power consumption of the chip, providing a new solution for the future large-scale use of tunable optical emission chips.

[0036] Example 2 The embodiment of the present invention further provides a structure of a laser, which is manufactured using the method for manufacturing a tunable laser as described in Example 1. The laser is manufactured using the method described in the above technical solution. The laser starts from one side, such as Figure 7 As shown, it is divided into a front gain region 1, a front phase region 2, a common grating region 3, a rear phase region 4 and a rear gain region 5 in sequence along the length direction; Among them, the light fluorescence wavelength of the shared grating area 3, the front phase area 2 and the back phase area 4 is 90-200nm smaller than the light fluorescence wavelength of the gain area; the ridge waveguide structure of the shared grating area 3 is a cantilever arm structure, and there are hexagonal air grooves on both sides of the cantilever arm to form an air groove insulation structure, which changes the wavelength tuning from electrical tuning to thermal tuning.

[0037] In the laser structure provided in this embodiment, dual-end light emission is achieved through the layout of the front gain region, front phase region, shared grating region, rear phase region and rear gain region, meeting the requirements of different transmission directions and links, and improving the flexibility and reliability of the system. In applications such as optical multiplexing and optical sensing, wavelength drift interference is effectively reduced, and system performance and accuracy are improved; the cantilever arm structure of the shared grating region and the air slot insulation structure formed by the hexagonal air slot change the wavelength tuning from electrical tuning to thermal tuning, reducing power consumption by two-thirds, significantly reducing chip power consumption, and providing a new solution for the large-scale use of tunable light emitting chips. At the same time, low power consumption slows down the aging of internal materials of the device, extends the service life of the laser, and reduces replacement frequency and maintenance costs; the light fluorescence wavelength of the shared grating region, front phase region and rear phase region is 90-200nm smaller than that of the gain region, which helps to optimize the optical performance of the laser and improve tuning efficiency and stability.

[0038] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a tunable laser, characterized in that: include: Performing surface layout on the substrate, dividing the substrate surface into a front gain region, a front phase region, a common grating region, a rear phase region and a rear gain region in sequence along the length direction; Growing an active layer on the substrate surface using metal organic chemical vapor deposition equipment; A silicon dioxide layer is grown on the substrate surface using plasma chemical vapor deposition equipment, and a butt-jointed mask pattern is produced in the front and rear gain regions using photolithography and wet etching techniques. Using reactive ion etching equipment to etch away the active layers of the common grating region, the front phase region, and the back phase region, cleaning the substrate, and etching away the active layer material remaining on the surface; A passive layer is grown on the common grating region, the front phase region and the rear phase region by using a metal organic chemical vapor deposition device; the fluorescence wavelength of the passive layer is smaller than the fluorescence wavelength of the front and rear gain regions; Removing the docking mask pattern, making a grating in the common grating area, and sequentially growing a cladding layer and an electrical contact layer on the entire surface of the laser; Fabricating an inverted shallow ridge waveguide structure on the cladding layer and the electrical contact layer; Etching electrical isolation grooves on the electrical contact layer to achieve electrical isolation between functional areas; Reactive ion etching equipment and hydrobromic acid etching are used on both sides of the ridge waveguide structure in the shared grating area to form a cantilever arm structure in the ridge waveguide structure in the shared grating area; A silicon nitride film is grown on the surface of the laser to make a titanium-platinum heating resistor for the shared grating region ridge waveguide, as well as a grating electrode and a ground electrode; P-side electrodes are made on the electrode contact layers of the front / rear phase region and the front / rear gain region. After the substrate is thinned, N-side electrodes are made on the bottom to complete the tunable laser fabrication.

2. The method for preparing a tunable laser according to claim 1, wherein: The fluorescence wavelength of the passive layer is 90-200 nm shorter than the fluorescence wavelength of the gain region.

3. The method for preparing a tunable laser according to claim 1, wherein: The method of forming a cantilever arm structure by using a reactive ion etching device and hydrobromic acid etching on both sides of the ridge waveguide structure in the shared grating region comprises: In the preset rectangular strip areas on both sides of the ridge waveguide structure in the shared grating area, a reactive ion etching device is used to etch away the electrical contact layer, the cladding layer and the passive layer; The ridge waveguide in the shared grating region is etched with hydrobromic acid to form a cantilever arm structure.

4. The method for preparing a tunable laser according to claim 3, wherein: The cantilever arm structure includes: hexagonal air slots on both sides of the cantilever arm, and a cantilever arm below the ridge waveguide.

5. The method for preparing a tunable laser according to claim 3, wherein: The preset rectangular strip area is two rectangular grooves with a width of 5 microns and a length of 350 microns, and the groove spacing is 25 microns.

6. The method for preparing a tunable laser according to claim 1, wherein: The active layer includes a lower waveguide layer, a multi-quantum well layer, and an upper waveguide layer from bottom to top. The thickness of the lower waveguide layer and the upper waveguide layer are both 100 nm. The multi-quantum well layer is formed by alternating growth of multiple quantum well layers and barrier layers.

7. The method for preparing a tunable laser according to claim 1, wherein: The materials of the active layer and the passive layer are both InGaAsP.

8. The method for preparing a tunable laser according to claim 1, wherein: The cleaning of the substrate and the etching to remove the active layer material remaining therefrom include: using acetone and ethanol to clean the substrate thoroughly, and using H2SiO4 solution to remove the active layer material and defects remaining therefrom during the etching process.

9. The method for preparing a tunable laser according to claim 1, wherein: The lengths of the front gain region and the rear gain region are both 300 microns, the lengths of the front phase region and the rear phase region are 100 microns, and the length of the common grating region is 350 microns.

10. A structure of a tunable laser, characterized in that: The device is manufactured by the manufacturing method according to any one of claims 1 to 9, wherein the laser is divided into a front gain region, a front phase region, a common grating region, a rear phase region and a rear gain region in sequence along the length direction starting from one side; Among them, the fluorescence wavelength of the light in the shared grating area, front phase area and rear phase area is 90-200nm smaller than the fluorescence wavelength of the light in the front and rear gain areas; the ridge waveguide structure of the shared grating area is a cantilever arm structure, with hexagonal air slots on both sides of the cantilever arm to form an air slot insulation structure, which changes the wavelength tuning from electrical tuning to thermal tuning.

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