Large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precise light source and preparation method thereof

Abstract

The invention discloses a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precise light source and a preparation method thereof. The light source comprises an REC multi-wavelength laser array, an MMI multimode optical fiber coupler of an N * N structure and N SOA amplifiers. N output ends of the REC multi-wavelength laser array are correspondingly connected with N input ends of the MMI multimode optical fiber coupler, and N output ends of the MMI multimode optical fiber coupler are correspondingly connected with the N SOA amplifiers. Light source input is carried out based on an REC laser array chip structure, wave combination and light splitting of light beams are carried out through an N * N coupler, a multi-wavelength output mode of N channels and multiplexing of N wavelengths in each channel is achieved, namely N * N wave multi-wavelength output is achieved, optical power balance and amplification are achieved by adding an SOA array, and the optical power output is achieved. Therefore, the power of the emergent light of the MMI can be accurately adjusted and enhanced, so that the light with different wavelengths can obtain proper power improvement, the overall performance of the laser is improved, and the application range of the laser is widened.

Description

Technical Field

[0001] The present invention belongs to the fields of semiconductor laser array chip technology and wavelength division multiplexing optical data transmission technology, and in particular relates to a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source and a preparation method thereof. Background Art

[0002] With the current rapidly increasing demand for AI computing, computing power has become a critical factor. Hardware architectures for improving computing power primarily rely on two approaches: enhancing the performance of individual chips and improving the efficiency of data transmission between chips. Enhancing the performance of individual chips is closely related to semiconductor manufacturing processes and requires continuous advancement of advanced process technology. Improving the efficiency of inter-chip data transmission, on the other hand, involves multiple technical areas and offers significant development potential and opportunities. One key development direction is integrating optical transmission technology into inter-chip data transmission architectures, employing optical I / O technology. This technology can significantly increase data transmission capacity while reducing latency and energy consumption.

[0003] For example, large-scale laser light sources, constrained by traditional technologies, can suffer from issues like low wavelength precision, insufficient number of optical carriers, and insufficient power balance. Furthermore, achieving large-scale multi-channel output often requires complex structural designs, increasing production costs and complexity, hindering large-scale production and application.

[0004] Therefore, a new large-scale REC multi-wavelength laser light source is urgently needed. This new light source can effectively solve the problems existing in existing technologies and meet the growing technological needs.

[0005] Compared to REC lasers, traditional EBL lasers, due to their less precise control over the laser generation mechanism, can only output a small amount of photon carriers, failing to provide sufficient bandwidth and energy support. Furthermore, they also have shortcomings in wavelength accuracy and power balance, further limiting their applicability in AI computing applications. Summary of the Invention

[0006] Technical Problem Solved: For large-scale light sources, achieving precise output while maintaining high optical power is crucial. This directly impacts the transmission quality of optical signals and is a key factor in ensuring effective coupling of optical signals at interfaces. To achieve large-scale, balanced, high-power output, this invention provides a large-scale, monolithic, heterogeneously integrated, high-power, balanced REC multi-wavelength precision light source and its fabrication method. This light source is input using an REC laser array chip structure, followed by beam splitting by an N×N coupler to increase the number of overall optical carriers. An SOA array is then added to achieve optical power balancing and amplification.

[0007] Technical solution:

[0008] In a first aspect, the present invention discloses a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source, which includes a REC multi-wavelength laser array, an MMI multimode fiber coupler in an N×N structure, and N SOA amplifiers;

[0009] The N output ends of the REC multi-wavelength laser array are correspondingly connected to the N input ends of the MMI multi-mode fiber coupler, and the N output ends of the MMI multi-mode fiber coupler are correspondingly connected to the N SOA amplifiers;

[0010] Each output end of the REC multi-wavelength laser array outputs a composite light composed of N laser beams of different wavelengths. All composite lights simultaneously enter the MMI multimode fiber coupler, where they are beam-splitted. The N×N beams obtained by separation enter corresponding SOA amplifiers for amplification and output.

[0011] The inference formula of the MMI multimode fiber coupler satisfies the following conditions:

[0012]

[0013] The difference in propagation constants between the fundamental mode and the v-order mode of the waveguide is expressed as:

[0014]

[0015] The beat length L of the fundamental mode and the same order mode π :

[0016]

[0017] There is also an imaging rule at the midpoint of the positive image and the mirror image, and the distance L from the input light field satisfies:

[0018]

[0019] Where W M is the multimode waveguide width; the refractive indices of the core and cladding are n r and n C ; m is the number of modes when the multimode waveguide operates at a wavelength of λ0, and the order of each mode is expressed by v, where v = 0, 1, 2, ..., m-1; the longitudinal propagation constant of each mode along the z-axis is set to β v , W ev is the effective width obtained after calculating the cladding penetration energy in the v-order mode. The equivalent width of the fundamental mode is W e0 , σ is the polarization factor of the mode, L π It represents the beat length of the same-order mode of the fundamental mode.

[0020] Furthermore, the laser array, MMI multimode fiber coupler and SOA amplifier are heterogeneously integrated by photon wire bonding, and the transmission and conversion of optical signals are achieved through the photon wires.

[0021] Furthermore, the structural parameters of the laser array meet the following conditions:

[0022]

[0023]

[0024] Where P is the sampling period, Λ0 is the seed grating period, Δn(z) is the refractive index modulation of the grating part, Δn0 is the refractive index modulation amplitude of the seed grating, and F m is the Fourier coefficient of the mth order sub-grating, z is the position along the laser cavity, ΔP is the change in sampling period, Λ +1 is the period of the +1-order sub-grating; cc represents the complex conjugate.

[0025] In a second aspect, the present invention discloses a method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source, the preparation method comprising the following steps:

[0026] S1, fabricating a uniform grating on the chip and removing part of the grating using a sampling structure to prepare a REC multi-wavelength laser array;

[0027] S2, based on a given wavelength λ0 and effective W ev , the simulation length of the MMI multimode fiber coupler is calculated, and the MMI multimode fiber coupler with self-image effect is prepared by silicon photonics process;

[0028] The inference formula of the MMI multimode fiber coupler satisfies the following conditions:

[0029]

[0030] The difference in propagation constants between the fundamental mode and the v-order mode of the waveguide is expressed as:

[0031]

[0032] The beat length L of the fundamental mode and the same order mode π :

[0033]

[0034] There is also an imaging rule at the midpoint of the positive image and the mirror image, and the distance L from the input light field satisfies:

[0035]

[0036] Where W M is the multimode waveguide width; the refractive indices of the core and cladding are n r and n C ; m is the number of modes when the multimode waveguide operates at a wavelength of λ0, and the order of each mode is expressed by v, where v = 0, 1, 2, ..., m-1; the longitudinal propagation constant of each mode along the z-axis is set to β v , W ev is the effective width obtained after calculating the cladding penetration energy in the v-order mode. The equivalent width of the fundamental mode is W e0 , σ is the polarization factor of the mode, L π represents the beat length of the same-order mode of the fundamental mode;

[0037] S3, designing the array spacing of the SOA amplifier to match the output port spacing of the MMI multimode fiber coupler; preparing the SOA amplifier;

[0038] S4, heterogeneously integrating the REC laser array, the MMI multimode interference coupler, and the SOA array by photonic wire bonding; wherein the N output ends of the REC multi-wavelength laser array are correspondingly connected to the N input ends of the MMI multimode fiber coupler, and the N output ends of the MMI multimode fiber coupler are correspondingly connected to the N SOA amplifiers;

[0039] Each output end of the REC multi-wavelength laser array outputs a composite light composed of N laser beams of different wavelengths. All the composite lights simultaneously enter the MMI multimode fiber coupler, where the beams are separated. The N×N separated beams respectively enter the corresponding SOA amplifiers for amplification and output.

[0040] Step S1 further comprises:

[0041] The epitaxial material growth is achieved by sequentially depositing a multilayer structure on an n-InP substrate using a two-stage MOCVD technique;

[0042] The grating is made by etching, the contact layer is grown, the ridge waveguide is formed by wet etching, and electrical isolation is achieved by shallow etching of the trench; metallization treatment and secondary electrode process are performed to obtain a suitable electrode pad arrangement;

[0043] The wafer is cut and an anti-reflection film is formed to prepare a REC multi-wavelength laser array.

[0044] Furthermore, in step S1, the parameters of the REC multi-wavelength laser array are calculated using the following formula:

[0045]

[0046] Where P is the sampling period, Λ0 is the seed grating period, Δn(z) is the refractive index modulation of the grating part, Δn0 is the refractive index modulation amplitude of the seed grating, and F m is the Fourier coefficient of the mth order sub-grating, z is the position along the laser cavity, ΔP is the change in sampling period, Λ +1 is the period of the +1-order sub-grating; cc represents the complex conjugate.

[0047] Step S2 further comprises:

[0048] Design the width of the MMI multimode fiber coupler, substitute it into the MMI self-imaging formula, and calculate the length of the MMI multimode fiber coupler. Use the finite-difference time-domain method to calculate the output power of each port during simulation.

[0049] The input and output port spacing of the MMI multimode fiber coupler is expanded to match the port spacing of the laser array by using a curved waveguide.

[0050] An MMI multimode fiber coupler is prepared using silicon photonics. Specifically, a silicon substrate is prepared, and the MMI structural pattern is defined on the silicon substrate using photolithography technology. A photoresist is coated on the substrate, exposed using a mask, and then developed to transfer the designed MMI structural pattern to the photoresist. An etching process is used to etch the pattern on the photoresist onto the silicon substrate to form the MMI waveguide structure. An oxidation process is then performed to form a silicon dioxide insulating layer on the waveguide surface.

[0051] Furthermore, a substrate material the same as that of the laser is selected, and a multi-layer semiconductor structure is sequentially grown on the substrate using metal organic chemical vapor deposition or molecular beam epitaxy technology to prepare an SOA amplifier.

[0052] Step S4 further comprises:

[0053] Mount the pre-processed laser array, MMI multimode fiber coupler, and SOA amplifier on the processed carrier, and make the light output ends at the same height;

[0054] Photoresist is evenly dripped onto the carrier, and two-photon exposure technology is used to prepare photonic leads with nanometer-level precision; photonic leads are used to realize optical signal transmission and conversion between laser arrays, MMI multimode fiber couplers and SOA amplifiers.

[0055] Beneficial effects:

[0056] First, the large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source and its preparation method of the present invention can accurately adjust and enhance the power of the MMI output light through the amplification structure of the SOA array, especially avoiding the problem of SOA power saturation, so that light of different wavelengths can obtain appropriate power boost, thereby improving the overall performance and application range of the laser.

[0057] Second, the large-scale monolithic heterogeneously integrated high-power balanced REC multi-wavelength precision light source and its preparation method of the present invention use a multi-wavelength REC laser light source that can achieve large-scale integration and has a very high degree of integration, which is conducive to large-scale production and application. At the same time, due to the REC processing technology, the production cost can be effectively reduced.

[0058] Third, the present invention's large-scale, monolithic, heterogeneously integrated, high-power, balanced REC multi-wavelength precision light source and its fabrication method leverage the high wavelength accuracy and multi-channel output of REC array laser chips to meet the needs of multi-channel data transmission. With relatively low cost, it is expected to play a key role in scenarios such as optical interconnection within data centers, providing strong support for improving data transmission efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 Schematic diagram of the structure of a large-scale REC multi-wavelength laser light source according to an embodiment of the present invention;

[0060] Figure 2 Schematic diagram of an eight-channel REC array laser according to an embodiment of the present invention;

[0061] Figure 3 This is the mode field distribution diagram output by FDTD calculation of the MMI coupler according to an embodiment of the present invention;

[0062] Figure 4 The transmittance diagram of the output port of the MMI coupler according to the embodiment of the present invention is calculated using FDTD;

[0063] Figure 5 This is the output spectrum diagram of the eight-channel REC array laser according to an embodiment of the present invention. DETAILED DESCRIPTION

[0064] The following examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0065] The present invention discloses a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source, which includes a REC multi-wavelength laser array, an MMI multimode fiber coupler in an N×N structure, and N SOA amplifiers.

[0066] The N output ends of the REC multi-wavelength laser array are correspondingly connected to the N input ends of the MMI multi-mode optical fiber coupler, and the N output ends of the MMI multi-mode optical fiber coupler are correspondingly connected to the N SOA amplifiers.

[0067] Each of the N output ports of the REC multi-wavelength laser array outputs a composite light beam consisting of N laser beams of different wavelengths. These composite lights simultaneously enter the MMI multimode fiber coupler. In the MMI multimode fiber coupler, each input port receives a composite light beam and decomposes it into N beams of light of different wavelengths. The MMI coupler has N input ports and N output ports. The composite light received at each input port is decomposed into N beams, which are then output through the coupler at N output ports as N x N beams. These beams then enter N SOA amplifiers for amplification. Each SOA amplifier amplifies the N input beams of different wavelengths and outputs N amplified beams of different wavelengths.

[0068] The reasoning formula of MMI multimode fiber coupler meets the following conditions:

[0069]

[0070] The difference in propagation constants between the fundamental mode and the v-order mode of the waveguide is expressed as:

[0071]

[0072] The beat length L of the fundamental mode and the same order mode π :

[0073]

[0074] There is also an imaging rule at the midpoint of the positive image and the mirror image, and the distance L from the input light field satisfies:

[0075]

[0076] Where W M is the multimode waveguide width; the refractive indices of the core and cladding are n r and n C ; m is the number of modes when the multimode waveguide operates at a wavelength of λ0, and the order of each mode is expressed by v, where v = 0, 1, 2, ..., m-1; the longitudinal propagation constant of each mode along the z-axis is set to β v , W ev is the effective width obtained after calculating the cladding penetration energy in the v-order mode. The equivalent width of the fundamental mode is W e0 , σ is the polarization factor of the mode, L π It represents the beat length of the same-order mode of the fundamental mode.

[0077] The structure, preparation process and working principle of the high-power balanced REC multi-wavelength precision light source of the present invention are further described below with reference to the accompanying drawings.

[0078] (1) Design and preparation of REC laser

[0079] The basic principle of REC technology can be summarized as a uniform grating plus an equivalent sampling structure. First, a uniform grating is made on the chip, and then a portion of the grating is removed using a sampling structure. Special structures such as phase shift, chirp, and toe-cut required for high-performance semiconductor lasers can all be achieved through similar sampling gratings.

[0080] The preparation process of the laser is as follows: first, a multi-layer structure is deposited on the n-InP substrate in sequence using a two-stage MOCVD technique to achieve epitaxial material growth, then a grating is made by etching, and then a contact layer is grown, and then a ridge waveguide is formed by wet etching, and then electrical isolation is achieved by shallow etching of the groove, followed by metallization and secondary electrode processing to obtain a suitable electrode pad arrangement, and finally the wafer is cut and an anti-reflection film is made. The design principle is the following formula. The first formula involves the refractive index modulation amplitude of the seed grating, the Fourier coefficient of the sub-grating, and the position in the laser cavity, which is used to calculate the equivalent phase shift. The second formula calculates the period of the +1-order sub-grating based on the change in the sampling period, which is crucial for achieving laser oscillation in the required wavelength range. The third formula shows the relationship between the change in the period of the +1-order sub-grating and the change in the sampling period.

[0081]

[0082] Where P is the sampling period, Λ0 is the seed grating period, Δn(z) is the refractive index modulation of the grating part, Δn0 is the refractive index modulation amplitude of the seed grating, and F m is the Fourier coefficient of the mth order sub-grating, z is the position along the laser cavity, ΔP is the change in sampling period, Λ +1 is the period of the +1-order sub-grating; cc represents the complex conjugate.

[0083] (2) Design and preparation of MMI coupler

[0084] The design principle of the coupler is the self-imaging effect of MMI. The self-imaging effect is an optical transmission characteristic of multimode waveguides. Multiple guided modes will be generated in the multimode waveguide. These guided modes interfere with each other in the waveguide transmission direction. At periodic intervals in the direction of light wave transmission, they continuously self-replicate single or multiple images of the input field, resulting in a self-imaging phenomenon.

[0085] According to the formula of the self-image effect of the MMI coupler, the equivalent width of the fundamental mode is W e0 , and the relationship can be expressed as:

[0086]

[0087] With the help of the above formula, the difference in propagation constants between the fundamental mode and the v-order mode of the waveguide can be expressed as:

[0088]

[0089] The beat length L of the fundamental mode and the same order mode π :

[0090]

[0091] There is also an imaging rule at the midpoint of the positive image and the mirror image, and the distance L from the input light field satisfies:

[0092]

[0093] Where W M is the multimode waveguide width, and the refractive indices of the core and cladding are n r and n C , m is the number of modes when the multimode waveguide operates at a wavelength of λ0, the order of each mode is expressed by v (v = 0, 1, 2, ..., m-1), and the longitudinal propagation constant of each mode along the z-axis is set to β v , W ev is the effective width obtained after calculating the cladding penetration energy in the v-order mode. The equivalent width of the fundamental mode is W e0 , σ is the polarization factor of the mode, L π It represents the beat length of the same-order mode of the fundamental mode.

[0094] According to the above, when the distance L from the input field satisfies At the same position, a replica image of the input light field symmetrical about the x=0 axis will be generated. The above formula can be used to calculate the N×N coupler at a given wavelength λ0 and effective W ev The required simulation length is then calculated. The MMI multimode interference coupler can then be fabricated using silicon photonics processing according to the relevant parameters.

[0095] (III) Heterogeneous integration of lasers, couplers, and SOA arrays based on PWB

[0096] The heterogeneous integration in this implementation patent adopts PWB (printed wiring board) technology to connect the REC laser array, MMI multimode interference coupler and SOA array.

[0097] In this patent implementation, the REC laser array is the basis for light source generation, and its material properties determine the light emission performance. The MMI multimode interference coupler is manufactured using silicon photonics technology based on the above principles, thereby achieving light splitting operations. The SOA array is used for optical power amplification. They are tightly connected through the PWB, and a stable electrical connection is established for the three components. This ensures that the optical signal emitted from the laser array can smoothly pass through the coupler, achieve precise light splitting, and then be fully transmitted to the SOA array for amplification. This ensures the integrity and accuracy of the optical signal throughout the process, avoiding signal loss or interference. In terms of physical support, the PWB provides a reliable foundation for the three, determining their reasonable spatial layout and relative positions. This enables the laser array, coupler, and SOA array to work together stably, maintain the normal operation of the entire system, and fully utilize the performance of each component, thereby ensuring the efficient operation of the large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source system.

[0098] Examples

[0099] In order to better demonstrate the functional characteristics of the REC multi-wavelength laser light source system, this patent embodiment takes a light source with 64 light waves as an example. The REC multi-wavelength laser light source system includes a laser array based on REC technology, an 8×8MMI multimode fiber coupler, and 8 SOA amplifiers. This structure can realize the simultaneous input of multiple wavelengths of light from 8 ports, realize beam separation in the MMI, output 64 lights, and the output light realizes optical power balancing and amplification in the SOA array. The structural diagram is as follows Figure 1 shown.

[0100] Step 1: Based on the laser wavelengths of 1547.6nm, 1548.4nm, 1549.2nm, 1550nm, 1550.8nm, 1551.6nm, 1552.4nm, and 1553.2nm, the sampling periods are approximately 3.8μm, 3.9μm, 4μm, 4.1μm, 4.2μm, 4.3μm, 4.4μm, and 4.5μm. The zero-order Bragg wavelength of the grating is designed to be 1630nm, corresponding to a seed grating period of 256nm. The epitaxial structure's photon emission spectrum is designed to be centered at 1550.4nm to ensure optimal luminescence performance. Once the design is complete, fabrication begins. First, a suitable substrate material, such as gallium arsenide, is selected. The substrate's crystal structure and electrical properties have a significant impact on subsequent epitaxial growth and laser performance. Next, using epitaxial techniques such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), a multilayer semiconductor structure is sequentially grown on the substrate. The schematic diagram of the eight-way REC array laser according to the embodiment of the present invention is as follows: Figure 2 shown.

[0101] Step 2. Due to the requirement of small size of silicon photonic process, the width of the MMI multimode interference coupler designed in this experimental patent is 8.3μm. Substituting it into the above MMI self-imaging formula, the calculated MMI length is 168μm. The finite difference time domain method (FDTD) is used to calculate the output power of each port during simulation. Since the MMI is symmetrical in the upper and lower directions, the optical characteristics at the same position remain consistent, so only the overall coupling characteristics of the upper four ports are calculated. Its electric field distribution is as follows Figure 3 As shown in the figure, the four figures represent the electric field distribution when the input is incident from input ports 1, 2, 3, and 4. The horizontal and vertical coordinates in the figure represent the position, which is represented by Figure 3 It can be seen that when the MMI is incident on each port, a uniform high-energy eight-array output can be obtained. When the incident light is incident on the input port, the transmission efficiency of different output ports is as follows: Figure 4 As shown, the eight graphs sequentially represent the transmittance of the eight output ports. The horizontal axis represents wavelength, and the vertical axis represents transmittance. The graphs show that the transmittance of each port varies with wavelength, with the overall transmission efficiency exceeding 80%. Prior to fabricating the MMI, the eight ports required by the design were relatively close together, mismatching the port spacing of the REC laser. Therefore, this patent application utilizes a curved waveguide to extend the spacing between the MMI input and output ports to 20μm, matching the laser port spacing. The MMI is then fabricated using silicon photonics. First, a silicon substrate is prepared, and then the MMI structure pattern is defined on the substrate using photolithography. The substrate is coated with photoresist, exposed using a mask, and then developed to transfer the designed MMI pattern to the photoresist. Next, an etching process is used to precisely etch the pattern from the photoresist into the silicon substrate, forming the MMI waveguide structure. An oxidation process is then performed to form a silicon dioxide insulating layer on the waveguide surface to improve its optical performance and stability.

[0102] The SOA array pitch is designed to be 20μm to match the spacing of the MMI output ports. Once the design is complete, fabrication begins. Using epitaxial techniques such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE), a substrate material identical to the laser is used to sequentially grow multiple layers of the semiconductor structure. This ensures that the laser's output wavelength can be well amplified by the fabricated SOA, and that the photon emission spectra of the SOA array and laser are consistent.

[0103] Step 4: Use photon wire bonding to heterogeneously integrate different materials such as lasers, couplers, and SOA arrays. Specifically: First, the pre-processed lasers, couplers, SOA arrays and other different materials are precisely mounted on the processed carrier to ensure that the light output ends are at the same height for better integration. Then, photoresist is evenly dripped onto the carrier on which these materials are mounted. The photoresist is specially formulated and has specific photosensitivity and chemical properties. It can react under subsequent light irradiation to achieve pattern transfer and structure preparation. Subsequently, two-photon exposure technology is used to prepare photon wires with nanometer-level precision. These photon wires can effectively realize the transmission and conversion of optical signals between different materials such as lasers, couplers and SOAs, integrate the above materials into one, and provide a basis for constructing optoelectronic devices and integrated optical systems.

[0104] Step 5: Test the prepared large-scale REC multi-wavelength laser light source. By collecting a large amount of data, the REC laser output spectrum is finally obtained, as shown in the following figure: Figure 5 As shown, all eight ports can output eight wavelengths with a spacing of 100 GHz and 0.8 nm.

[0105] Through the above specific implementation methods, the large-scale REC multi-wavelength laser of the present invention can achieve highly precise wavelength output and sufficiently large and balanced optical power output, thereby meeting the demand of high-computing power AI chip optical interconnection technology for precise multi-wavelength light sources, and providing a more reliable solution for improving the efficiency of data transmission between chips.

[0106] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source, characterized in that: The high-power balanced REC multi-wavelength precision light source includes a REC multi-wavelength laser array, an MMI multi-mode fiber coupler in an N×N structure, and N SOA amplifiers; The N output ends of the REC multi-wavelength laser array are connected to the N input ends of the MMI multi-mode optical fiber coupler, and the N output ends of the MMI multi-mode optical fiber coupler are connected to the N SOA amplifiers. Each output end of the REC multi-wavelength laser array outputs a composite light composed of N laser beams of different wavelengths, and all the composite lights enter the MMI multi-mode optical fiber coupler at the same time, where the beams are separated, and the separated N×N beams enter the corresponding SOA amplifiers for amplification and output respectively; The inference formula of the MMI multimode fiber coupler satisfies the following conditions: The difference in propagation constants between the fundamental mode and the v-order mode of the waveguide is expressed as: The beat length L of the fundamental mode of the same order π : There are also imaging rules at the midpoint of the positive image and the mirror image, and the distance L from the input light field satisfies: Where W M is the multimode waveguide width; the refractive indices of the core and cladding are n r and n C ; m is the number of modes when the multimode waveguide operates at a wavelength of λ0, and the order of each mode is expressed by v, v = 0, 1, 2, ..., m-1; the longitudinal propagation constant of each mode along the z-axis is set to β v , W ev is the effective width obtained after calculating the cladding penetration energy in the v-order mode. The equivalent width of the fundamental mode is W e0 , σ is the polarization factor of the mode, L π It represents the beat length of the same order mode of the fundamental mode.

2. The large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 1, characterized in that: The laser array, the MMI multimode optical fiber coupler and the SOA amplifier are heterogeneously integrated by photon wire bonding, and the transmission and conversion of optical signals are realized by the photon wires.

3. The large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 1, characterized in that: The structural parameters of the laser array meet the following conditions: Where P is the sampling period, Λ0 is the seed grating period, Δn(z) is the refractive index modulation of the grating part, Δn0 is the refractive index modulation amplitude of the seed grating, and F m is the Fourier coefficient of the m-th order sub-grating, z is the position along the laser cavity, ΔP is the change in sampling period, Λ +1 is the period of the +1-order sub-grating; cc represents the complex conjugate.

4. A method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source, characterized in that: The preparation method comprises the following steps: S1, making a uniform grating on the chip, removing part of the grating using a sampling structure, and preparing a REC multi-wavelength laser array; S2, based on a given wavelength λ0 and effective W ev , the simulated length of the MMI multimode fiber coupler is calculated, and the MMI multimode fiber coupler with self-imaging effect is prepared by silicon photonics process; The inference formula of the MMI multimode fiber coupler satisfies the following conditions: The difference in propagation constants between the fundamental mode and the v-order mode of the waveguide is expressed as: The beat length L of the fundamental mode of the same order π : There are also imaging rules at the midpoint of the positive image and the mirror image, and the distance L from the input light field satisfies: Where W M is the multimode waveguide width; the refractive indices of the core and cladding are n r and n C ; m is the number of modes when the multimode waveguide operates at a wavelength of λ0, and the order of each mode is expressed by v, v = 0, 1, 2, ..., m-1; the longitudinal propagation constant of each mode along the z-axis is set to β v , W ev is the effective width obtained after calculating the cladding penetration energy in the v-order mode. The equivalent width of the fundamental mode is W e0 , σ is the polarization factor of the mode, L π It represents the beat length of the same order mode of the fundamental mode; S3, designing the array spacing of the SOA amplifier to match the output port spacing of the MMI multimode fiber coupler; preparing the SOA amplifier; S4, heterogeneously integrating the REC laser array, the MMI multimode interference coupler and the SOA array by photon wire bonding; wherein the N output ends of the REC multi-wavelength laser array are correspondingly connected to the N input ends of the MMI multimode fiber coupler, and the N output ends of the MMI multimode fiber coupler are correspondingly connected to the N SOA amplifiers; Each output end of the REC multi-wavelength laser array outputs composite light composed of N laser beams of different wavelengths. All composite lights enter the MMI multi-mode optical fiber coupler at the same time, and the beams are separated in the MMI multi-mode optical fiber coupler. The separated N×N beams enter the corresponding SOA amplifiers for amplification and output.

5. The method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 5, characterized in that: Step S1 further comprises: The epitaxial material growth is achieved by sequentially depositing a multilayer structure on an n-InP substrate using a two-stage MOCVD technique; The grating is made by etching, the contact layer is grown, the ridge waveguide is formed by wet etching, and the electrical isolation is achieved by shallow etching of the groove; the metallization treatment and the secondary electrode process are performed to obtain the appropriate electrode pad arrangement; The wafer is cut and an anti-reflection film is made to prepare a REC multi-wavelength laser array.

6. The method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 5, characterized in that: In step S1, the parameters of the REC multi-wavelength laser array are calculated using the following formula: Where P is the sampling period, Λ0 is the seed grating period, Δn(z) is the refractive index modulation of the grating part, Δn0 is the refractive index modulation amplitude of the seed grating, and F m is the Fourier coefficient of the m-th order sub-grating, z is the position along the laser cavity, ΔP is the change in sampling period, Λ +1 is the period of the +1-order sub-grating; cc represents the complex conjugate.

7. The method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 5, characterized in that: Step S2 further comprises: Design the width of the MMI multimode fiber coupler, substitute it into the MMI self-imaging formula, calculate the length of the MMI multimode fiber coupler, and use the finite difference time domain method to calculate the output power of each port during simulation; The input and output port spacing of the MMI multimode fiber coupler is expanded to match the port spacing of the laser array by using a curved waveguide; The MMI multimode fiber coupler is prepared by using silicon photonics technology; specifically, a silicon-based substrate is prepared, and the structural pattern of the MMI is defined on the silicon-based substrate using photolithography technology; photoresist is coated on the substrate, and a mask is used for exposure, and then the designed MMI structural pattern is transferred to the photoresist after development; an etching process is used to etch the pattern on the photoresist onto the silicon-based substrate to form a waveguide structure of the MMI; an oxidation process is performed to form a layer of silicon dioxide insulation layer on the surface of the waveguide.

8. The method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 5, characterized in that: The same substrate material as the laser is selected, and a multi-layer semiconductor structure is sequentially grown on the substrate using metal organic chemical vapor deposition or molecular beam epitaxy technology to prepare an SOA amplifier.

9. The method for preparing a large-scale monolithic heterogeneous integrated high-power balanced REC multi-wavelength precision light source according to claim 5, characterized in that: Step S4 further comprises: Mount the pre-processed laser array, MMI multimode fiber coupler and SOA amplifier on the processed carrier, and make the light output ends at the same height; Photoresist is evenly dripped onto the carrier, and two-photon exposure technology is used to prepare photonic leads with nanometer-level precision; the photonic leads are used to realize the transmission and conversion of optical signals between the laser array, MMI multimode fiber coupler and SOA amplifier.

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