Optoelectronic chip integration system and manufacturing method therefor

Abstract

An optoelectronic chip integration system (10) and a manufacturing method therefor. The optoelectronic chip integration system (10) comprises a laser (100), a free-form surface coupler (200) and a chip (300), wherein the laser (100) is used for emitting a light beam; the free-form surface coupler (200) is located on a light path of an emergent light beam of the laser (100), and is used for receiving the light beam and reflecting and shaping the light beam; and the chip (300) is connected to the laser (100), and comprises a waveguide structure (310), which is connected to the free-form surface coupler (200) so as to receive the reflected and shaped light beam.

Description

Optoelectronic chip integrated system and manufacturing method thereof Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to an optoelectronic chip integrated system and a manufacturing method thereof. Background Art

[0002] Surface-emitting lasers have important application value in the fields of interconnection, computing, and perception. Their on-chip integration can effectively improve the stability of the system, increase integration, and reduce power consumption. It is an important direction for the future development of optical systems.

[0003] However, the current methods of interconnecting on-chip lasers with silicon-based optoelectronic chips mainly include two hybrid integration methods based on grating diffraction and bevel reflection, which have low integration and coupling efficiency.

[0004] Summary of the Invention

[0005] The present application provides an optoelectronic chip integration system and a manufacturing method thereof, which can improve the integration and coupling efficiency of laser and chip interconnection.

[0006] One aspect of the present application provides an optoelectronic chip integration system, comprising: a laser for emitting a light beam; a free-form surface coupler located on the optical path of the light beam emitted by the laser, for receiving the light beam and reflecting and shaping the light beam; a chip connected to the laser, the chip including a waveguide structure, the waveguide structure connected to the free-form surface coupler, for receiving the reflected and shaped light beam.

[0007] The optoelectronic chip integration system provided in this application improves the integration and coupling efficiency of the interconnection between the laser and the chip by regulating the free-form surface coupler to connect the laser and the chip, thereby realizing a highly integrated, highly stable and highly efficient optoelectronic chip integration system to meet the chip's requirements for the input light beam.

[0008] Furthermore, the free-form surface coupler includes an input end, an output end and a free-form surface, the input end is connected to the laser, and at least part of the output end is connected to the waveguide structure. The free-form surface is used to convert the transmission direction of the light beam to be parallel to the extension direction of the waveguide structure, and convert the transmission mode of the light beam into a waveguide transmission mode. The waveguide structure is used to receive the light beam after the transmission direction and transmission mode are converted.

[0009] Furthermore, the chip also includes a cladding and a substrate layer, the waveguide structure is buried in the cladding, and the substrate layer is arranged on the side of the cladding away from the laser; the chip also includes an etched groove, the waveguide structure includes an input side, the etched groove is connected to the input side of the waveguide structure, and is recessed from the cladding toward the substrate layer, the free-form surface coupler is located in the etched groove, and the output end of the free-form surface coupler is connected to the input side of the waveguide structure.

[0010] Furthermore, the free-form surface coupler is formed by processing in the etched groove filled with photoresist.

[0011] Furthermore, the waveguide structure includes a tapered waveguide and a straight waveguide connected to the tapered waveguide. The tapered waveguide is connected to the output end of the free-form surface coupler for receiving the light beam and transmitting the light beam to the straight waveguide.

[0012] Furthermore, the tapered waveguide includes a first end and a second end, the first end is connected to the output end of the free-form surface coupler, and the second end is connected to the straight waveguide, wherein the width of the tapered waveguide tends to gradually increase from the first end to the second end.

[0013] Furthermore, the material of the waveguide structure includes at least one of silicon waveguide, silicon nitride and lithium niobate.

[0014] Furthermore, the laser is flip-chip welded to the surface of the chip.

[0015] Furthermore, the laser includes a substrate and a first bonding electrode, and the first bonding electrode is provided on the substrate; the chip also includes a second bonding electrode provided on the surface of the chip, and the second bonding electrode corresponds to the first bonding electrode and is used to electrically connect the chip and the laser.

[0016] Furthermore, the laser includes a vertical cavity surface emitting laser, which includes a light-emitting portion for emitting the light beam, the light-emitting portion is arranged on the substrate, the light-emitting portion and the first bonding electrode are arranged on opposite sides of the substrate, and the emission direction of the light beam is perpendicular to the substrate.

[0017] Furthermore, the laser includes a horizontal cavity surface emitting laser, which includes a light-emitting portion and a reflecting portion. The light-emitting portion is used to emit the light beam. The light-emitting portion is arranged on a side of the substrate perpendicular to the extension direction of the substrate. The emission direction of the light beam is parallel to the extension direction of the substrate. The reflecting portion is used to reflect the light beam so that the light beam is emitted in a direction perpendicular to the substrate.

[0018] Furthermore, a section of the free-form surface perpendicular to the extension direction of the waveguide structure is a curve.

[0019] Furthermore, the free-form surface includes a parabola, and the input side of the waveguide structure connected to the free-form surface coupler is close to the focus of the parabola.

[0020] Furthermore, a section of the free-form surface perpendicular to the extension direction of the waveguide structure is a straight line.

[0021] Another aspect of the present application provides a method for manufacturing an optoelectronic chip integrated system, comprising: providing a chip including a waveguide structure; forming a free-form surface coupler on the chip to connect the free-form surface coupler and the waveguide structure; connecting a laser and the chip so that the free-form surface coupler is located in the optical path of the light beam emitted by the laser.

[0022] Furthermore, forming a free-form surface coupler on the chip and connecting the free-form surface coupler and the waveguide structure includes: etching an etched groove at a location connected to the input side of the waveguide structure; filling the etched groove with photoresist; and processing the photoresist to form the free-form surface coupler.

[0023] Furthermore, the laser includes a substrate and a first bonding electrode, wherein the first bonding electrode is provided on the substrate;

[0024] The method of connecting the laser and the chip so that the free-form surface coupler is located below the laser includes: preparing a second bonding electrode on the surface of the chip, wherein the second bonding electrode corresponds to the first bonding electrode; positioning the laser on the chip according to the position of the second bonding electrode; and flip-chip welding the laser to the surface of the chip so that the free-form surface coupler is located in the optical path of the light beam emitted by the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0026] FIG1 is a schematic structural diagram of an embodiment of an optoelectronic chip integration system of the present application;

[0027] FIG2 is a schematic diagram showing the three-dimensional structure of the optoelectronic chip integrated system shown in FIG1 ;

[0028] FIG3 is a schematic diagram showing the principle of the optoelectronic chip integration system shown in FIG1 ;

[0029] FIG4 is a schematic structural diagram of another embodiment of the optoelectronic chip integration system shown in FIG1 ;

[0030] FIG5 is a schematic structural diagram of another embodiment of the optoelectronic chip integration system shown in FIG1 ;

[0031] FIG6 is a schematic structural diagram of another embodiment of the optoelectronic chip integration system shown in FIG1 ;

[0032] FIG7 is a schematic structural diagram of an embodiment of a waveguide structure of the optoelectronic chip integrated system shown in FIG1 ;

[0033] FIG8 is a schematic diagram showing a light field transmission simulation of the optoelectronic chip integrated system shown in FIG1 ;

[0034] FIG9 is a morphology diagram of a light beam emitted by a laser of the optoelectronic chip integrated system shown in FIG1 at the output end;

[0035] FIG10 is a morphology diagram of a light beam emitted by a laser of the optoelectronic chip integrated system shown in FIG1 at a receiving end;

[0036] FIG11 is a schematic diagram showing the relationship between the coupling loss of the optoelectronic chip integrated system shown in FIG1 and the wavelength of the light beam;

[0037] FIG12 is a schematic diagram showing the relationship between the coupling loss of the optoelectronic chip integrated system shown in FIG1 and the lateral position offset between the free-form surface coupler and the chip;

[0038] FIG13 is a schematic diagram showing the relationship between the coupling loss of the optoelectronic chip integrated system shown in FIG1 and the longitudinal position offset between the free-form surface coupler and the chip;

[0039] FIG14 is a schematic flow chart showing an embodiment of a method for manufacturing an optoelectronic chip integrated system of the present application;

[0040] FIG15 is a schematic flow chart showing an embodiment of step S200 in the manufacturing method shown in FIG14 ;

[0041] FIG16 is a schematic flow chart showing an embodiment of step S300 in the manufacturing method shown in FIG14 ;

[0042] FIG17 is a schematic diagram showing a manufacturing process of manufacturing an optoelectronic chip integrated system using the manufacturing method shown in FIG14 . DETAILED DESCRIPTION

[0043] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0044] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. Unless otherwise defined, technical or scientific terms used in this application should have the ordinary meaning understood by a person of ordinary skill in the art to which this application belongs. The terms "first," "second," and similar words used in this specification and claims do not denote any order, quantity, or importance, but are simply used to distinguish different components. Similarly, the terms "a" or "an" and similar words do not denote a limitation of quantity, but rather indicate the presence of at least one. The terms "plurality" or "several" mean at least two. Unless otherwise indicated, the terms "front," "rear," "lower," and / or "upper" and similar words are for convenience only and are not intended to limit to a single position or spatial orientation. The terms "include" or "comprising" and similar words mean that the elements or objects listed before "include" or "comprising" include the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. The terms "connected" or "connected" and similar words are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect.

[0045] As used in this specification and the appended claims, the singular forms "a," "an," "said," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0046] The optoelectronic chip integrated system provided herein includes a laser, a freeform surface coupler, and a chip. The laser is used to emit a light beam. The freeform surface coupler is located in the optical path of the laser's output beam and is used to receive, reflect, and shape the beam. The chip is connected to the laser, and the chip includes a waveguide structure. The waveguide structure is connected to the freeform surface coupler and is used to receive the reflected and shaped light beam.

[0047] The optoelectronic chip integration system provided in this application improves the integration and coupling efficiency of the interconnection between the laser and the chip by regulating the free-form surface coupler to connect the laser and the chip, thereby realizing a highly integrated, highly stable and highly efficient optoelectronic chip integration system to meet the chip's requirements for the input light beam.

[0048] The manufacturing method of the optoelectronic chip integrated system provided in the present application includes: providing a chip including a waveguide structure; forming a free-form surface coupler on the chip to connect the free-form surface coupler and the waveguide structure; connecting a laser and the chip so that the free-form surface coupler is located in the optical path of the light beam emitted by the laser.

[0049] The optoelectronic chip integrated system and its manufacturing method of the present application are described in detail below with reference to the accompanying drawings. In the absence of conflict, the features of the following embodiments and implementations can be combined with each other.

[0050] Figure 1 shows a schematic structural diagram of an embodiment of an optoelectronic chip integrated system 10 of the present application. The optoelectronic chip integrated system 10 of the embodiment of the present application includes a laser 100, a free-form surface coupler 200 and a chip 300. The laser 100 is used to emit a light beam. The free-form surface coupler 200 is located on the optical path of the outgoing light beam of the laser 100, and is used to receive the light beam and reflect and shape the light beam. The chip 300 is connected to the laser 100, and the chip 300 includes a waveguide structure 310. The waveguide structure 310 is connected to the free-form surface coupler 200 and is used to receive the reflected and shaped light beam. The optoelectronic chip integrated system 10 of the embodiment of the present application improves the integration and coupling efficiency of the interconnection between the laser 100 and the chip 300 by regulating the free-form surface coupler 200, thereby realizing a highly integrated, highly stable and highly efficient optoelectronic chip integrated system 10 to meet the requirements of the chip 300 for the input light beam.

[0051] FIG2 is a schematic diagram of the three-dimensional structure of the optoelectronic chip integrated system 10 shown in FIG1 . FIG3 is a schematic diagram of the principle of the optoelectronic chip integrated system 10 shown in FIG1 . In some embodiments, the free-form surface coupler 200 includes an input end 210, an output end 220, and a free-form surface 230. The input end 210 is connected to the laser 100, and at least part of the output end 220 is connected to the waveguide structure 310. The free-form surface 230 is used to convert the transmission direction of the light beam to be parallel to the extension direction of the waveguide structure 310, and to convert the transmission mode of the light beam to a waveguide transmission mode. The waveguide structure 310 is used to receive the light beam after the transmission direction and transmission mode are converted. As shown in FIG1 and FIG2 , the input end 210 of the free-form surface coupler 200 may include a flat surface. The input end 210 may be flush with the upper surface of the chip 300 or higher than the upper surface of the chip 300. The output end 220 of the free-form surface coupler 200 may include a flat surface to connect to the waveguide structure 310. After the laser 100 emits a light beam, the interface of the free-form surface 230 of the free-form surface coupler 200 converts the spot size of the laser 100 into the waveguide mode spot size of the chip 300 through total reflection and light beam convergence, and at the same time, the transmission direction of the light beam is converted to a direction parallel to the extension direction of the waveguide structure 310.

[0052] In some embodiments, the laser 100 includes a substrate 111 and a first bonding electrode 112, wherein the first bonding electrode 112 is disposed on the substrate 111. The chip 300 also includes a second bonding electrode 350 disposed on the surface of the chip 300. The second bonding electrode 350 corresponds one-to-one with the first bonding electrode 112 and is used to electrically connect the chip 300 and the laser 100. The number of first bonding electrodes 112 can be determined based on the number of bonding electrodes in the finished laser 100. As shown in FIG1 , the number of first bonding electrodes 112 is four, including a first bonding electrode 112a, a first bonding electrode 112b, a first bonding electrode 112c, and a first bonding electrode 112d. Accordingly, the number and position of the second bonding electrodes 350 provided on the surface of the chip 300 correspond to the number and position of the first bonding electrodes 112, including second bonding electrodes 350a, second bonding electrodes 350b, second bonding electrodes 350c, and second bonding electrodes 350d. This prevents the second bonding electrodes 350 from being misaligned, thereby ensuring the stability and accuracy of the interconnection between the laser 100 and the chip 300. The laser 100 can be attached to the input end 210 of the free-form surface coupler 200, and ensure that the first bonding electrode 112 of the laser 100 and the second bonding electrode 350 on the chip 300 are in good contact, thereby achieving an electrical connection between the laser 100 and the chip 300. After the laser 100 emits a light beam, the free-form surface 230 of the free-form surface coupler 200 converts the spot size of the laser 100 to the waveguide mode spot size of the optoelectronic chip 300 to be processed through total internal reflection and light beam convergence at the interface. Simultaneously, the propagation direction of the light beam is transformed to be parallel to the extension direction of the waveguide structure, thereby achieving an optical connection between the laser 100 and the chip 300. The first bonding electrode 112 and the second bonding electrode 350 are made of a conductive metal.

[0053] In some embodiments, the laser 100 is flip-chip soldered to the surface of the chip 300. The laser 100 is inverted and attached to the free-form surface coupler 200 by flip-chip soldering. Specifically, the laser 100 is soldered to the chip 300 prefabricated with the second bonding electrode 350 by heating and pressurizing, and ensures that the first bonding electrode 112 of the laser 100 and the second bonding electrode 350 on the chip 300 are in good contact. The laser 100 and the chip 300 of the embodiment of the present application adopt a flip-chip soldering process, which can have better self-alignment and connection reliability under certain pressure and temperature. Optionally, the flip-chip soldering process includes hot pressing, reflow soldering, epoxy resin light curing and anisotropic conductive adhesive bonding.

[0054] Laser 100 may include a surface-emitting laser or a laser packaged in other ways that emits light perpendicular to the surface or at a certain angle. A surface-emitting laser is a semiconductor laser whose light emission direction is perpendicular to the surface of chip 300. Compared to edge-emitting lasers, surface-emitting lasers are easier to arrange in a two-dimensional array, thereby enabling the construction of high-density arrays and controllable multiple optical channels.

[0055] Surface-emitting lasers can include vertical-cavity surface-emitting lasers (VCSELs) and horizontal-cavity surface-emitting lasers (HCSELs). The VCSEL's resonator is composed of multiple vertical epitaxial layers and has the characteristics of high beam quality, low lasing threshold, and high differential efficiency. The HCSEL's resonator is formed by lateral micro-nanostructures and has the characteristics of high output power, narrow spectral linewidth, and small temperature drift.

[0056] Currently, there are two main ways to interconnect surface-emitting lasers and silicon-based optoelectronic chips: hybrid integration based on grating diffraction and bevel reflection. Based on these two interconnection methods, the freedom of light beam mode field transformation is limited, making it difficult to achieve precise mode field matching and efficient integration, which restricts the development of system integration. The momentum compensation method based on grating diffraction has the inherent limitation of many diffraction orders, and the room for improving coupling efficiency is limited. It is also sensitive to the wavelength and polarization of the laser. The grating resonant wavelength drifts significantly due to temperature, and its stability needs to be improved. The momentum compensation method based on reflection is still mainly based on tilted planes. It can change the propagation direction, but lacks the ability to control its mode field distribution and cannot achieve precise mode field matching. Therefore, it is difficult to achieve high coupling efficiency for surface-emitting lasers and chips interconnected by the above two methods. The optoelectronic chip integrated system 10 of the embodiment of the present application improves the integration and coupling efficiency of the interconnection between the laser 100 and the chip 300 by regulating the free-form surface coupler 200, thereby realizing a highly integrated, highly stable and highly efficient optoelectronic chip integrated system 10 to meet the chip 300's requirements for the input light beam.

[0057] FIG4 is a schematic structural diagram of another embodiment of the optoelectronic chip integrated system 10 shown in FIG1 . In some embodiments, the laser 100 includes a vertical cavity surface emitting laser 120. The vertical cavity surface emitting laser 120 includes a light emitting portion 113 for emitting a light beam. The light emitting portion 113 is provided on a substrate 111, and the light emitting portion 113 and the first bonding electrode 112 are provided on opposite sides of the substrate 111. The emission direction of the light beam is perpendicular to the extension direction of the substrate 111. In this embodiment, the vertical cavity surface emitting laser 120 serves as the light source of the optoelectronic chip integrated system 10. After being powered on, the vertical cavity surface emitting laser 120 emits a Gaussian beam vertically, and the emitted Gaussian beam has good quality. Specifically, the beam waist radius of the Gaussian beam is several microns, and the divergence angle is several milliradians. It can be considered to be nearly parallel transmission in the free-form surface coupler 200. The freeform surface coupler 200 converts a perpendicularly incident Gaussian beam into a waveguide transmission beam parallel to the plane of the chip 300. This not only changes the transmission direction by 90 degrees, but also converts the micrometer-sized Gaussian beam into a submicrometer waveguide transmission mode. The beam emitted by the laser 100 can be perpendicular to the input end 210 of the freeform surface coupler 200 or at any other incident angle, which is not limited in this application.

[0058] The structural characteristics of the freeform surface 230 can be determined based on the characteristics of the incident light beam. When the incident light beam is perpendicular to the input end 210 of the freeform surface coupler 200, the freeform surface 230 changes the propagation direction of the light beam by 90 degrees, so that the propagation direction of the light beam is parallel to the extension direction of the chip 300. In this way, the waveguide structure 310 can receive the light beam after the propagation direction is changed. Of course, the optoelectronic chip integrated system 10 of the embodiment of the present application is also applicable to coupling light beams incident at other angles, simply by constructing the freeform surface 230 with a different structure.

[0059] FIG5 is a schematic structural diagram of another embodiment of the optoelectronic chip integrated system 10 shown in FIG1 . In some embodiments, the laser 100 includes a horizontal cavity surface emitting laser 130, and the horizontal cavity surface emitting laser 130 includes a light-emitting portion 113 and a reflective portion 114. The light-emitting portion 113 is used to emit a light beam. The light-emitting portion 113 is provided on a side of the substrate 111 perpendicular to the extension direction of the substrate 111. The emission direction of the light beam is parallel to the extension direction of the substrate 111. The reflective portion 114 is used to reflect the light beam so that the light beam is emitted in a direction perpendicular to the substrate 111. It should be noted that the direction indicated by the arrow in FIG5 is the transmission direction of the light beam. After the light beam is emitted from the light-emitting portion 113, its transmission direction is parallel to the extension direction of the waveguide structure 310. After the light beam is transmitted to the reflective portion 114, the transmission direction is changed, and the light beam is finally emitted in a direction perpendicular to the substrate 111.

[0060] 5 , in some embodiments, the input end 210 of the freeform surface coupler 200 may be in close contact with the HCSEL 130. In other embodiments, the input end 210 of the freeform surface coupler 200 may be at a certain distance from the HCSEL 130.

[0061] Optionally, the free-form surface 230 includes, but is not limited to, a parabola, an extended surface of a parabola, and other curved surfaces. As shown in FIG3 , in one embodiment, the free-form surface 230 includes a parabola. The light beam emitted by the laser 100 is reflected and converged by the parabola, converting its transmission direction and mode before entering the waveguide structure 310. The free-form surface coupler 200 includes a quadratic surface, including, but not limited to, a parabola, an extended structure of a parabola, and other curved surface structures.

[0062] 4 and 5 , based on the above-mentioned embodiment, the section of the free-form surface 230 in the extension direction perpendicular to the waveguide structure 310 is a curve. Optionally, the free-form surface 230 includes a parabola. One side of the waveguide structure 310 connected to the free-form surface coupler 200 is close to the focus of the parabola. In this way, the light beam distributed at different positions of the laser 100 is successively totally reflected through the interface of the free-form surface 230 and turned to focus near the focus of the free-form surface 230. One side of the waveguide structure 310 is located near the focus of the free-form surface 230, and the focus is the focusing position of the light beam, thereby realizing efficient collection of the Gaussian light beam emitted by the laser 100 onto the chip.

[0063] Figure 6 is a schematic structural diagram of another embodiment of the optoelectronic chip integrated system 10 shown in Figure 1. In some other embodiments, the section of the free-form surface 230 perpendicular to the extension direction of the waveguide structure 310 is a straight line. Specifically, the free-form surface 230 can be a hyperbolic paraboloid.

[0064] The chip 300 of the embodiment of the present application may include an all-optical chip 300 or an optoelectronic hybrid chip 300. The chip 300 may be made of any material. The waveguide structure 310 may include a straight waveguide 312, a tapered waveguide 311, and a multimode interference coupler. The specific structure of the waveguide structure 310 may be flexibly selected based on actual conditions. Alternatively, the material of the waveguide structure 310 includes, but is not limited to, silicon waveguide, silicon nitride, lithium niobate waveguide, and other materials.

[0065] In some embodiments, the chip 300 further includes a cladding 320 and a substrate layer 330. The waveguide structure 310 is buried in the cladding 320, and the substrate layer 330 is disposed on a side of the cladding 320 away from the laser 100. The chip 300 further includes an etched groove 340. The waveguide structure 310 includes an input side. The etched groove 340 is connected to the input side of the waveguide structure and is recessed from the cladding 320 toward the substrate layer 330. The freeform surface coupler 200 is located within the etched groove 340, and the output end 220 of the freeform surface coupler 200 is connected to the input side of the waveguide structure 310. Optionally, the material of the cladding 320 may include silicon dioxide, and the material of the substrate layer 330 may include silicon.

[0066] FIG7 is a schematic diagram illustrating an embodiment of a waveguide structure 310 of the optoelectronic chip integrated system 10 shown in FIG1 . In some embodiments, the waveguide structure 310 includes a tapered waveguide 311 and a straight waveguide 312 connected to the tapered waveguide 311. The tapered waveguide 311 is connected to the output end 220 of the freeform surface coupler 200 to receive a light beam and transmit the light beam to the straight waveguide 312. The tapered waveguide 311 is used to losslessly convert the mode field converted by the freeform surface 230 into a waveguide transmission mode in the chip 300.

[0067] In some embodiments, the tapered waveguide 311 includes a first end 311a and a second end 311b. The first end 311a is connected to the output end 220 of the freeform surface coupler 200, and the second end 311b is connected to the straight waveguide 312. The width of the tapered waveguide 311 gradually increases from the first end 311a to the second end 311b. The first end 311a of the tapered waveguide 311, i.e., the side with the smallest width, is in close proximity to the output end 220 of the freeform surface coupler 200 and is located near the focal point of the freeform surface coupler 200. The length and minimum width of the tapered waveguide 311 can be determined based on the specific material and the beam waist radius of the output light spot of the surface emitter.

[0068] In some embodiments, the free-form surface coupler 200 is formed by processing within an etched groove 340 filled with photoresist. The fabrication process for the free-form surface coupler 200 includes, but is not limited to, two-photon lithography, grayscale lithography, nanoimprinting, and other micro-nanofabrication techniques. Alternatively, the interface of the free-form surface 230 can be placed in an air environment through an etching process to increase the refractive index difference between the free-form surface 230 and the environment. The photoresist material can include a polymer. The side length of the etched groove 340 is on the order of hundreds of microns.

[0069] The laser 100 of the optoelectronic chip integrated system 10 of the embodiment of the present application is invertedly attached to the free-form surface coupler 200 by flip-chip bonding and ensures good contact between the surface-emitting laser electrode and the bonding electrode on the chip 300. It can radiate a Gaussian beam with a diameter of several microns under voltage drive; the radiated Gaussian beam is vertically incident on the free-form surface coupler 200 from the input end of the free-form surface coupler 200. Since the divergence angle of the Gaussian beam is small, the beam is transmitted in the free-form surface coupler 200 in an almost parallel manner; according to the characteristics of the beam propagation in the parabola, the parallel incident beam will be focused at the focus of the parabola after being reflected on the parabola; the input side of the waveguide structure 310 in the chip 300 is placed at the focal position of the parabola of the free-form surface coupler 200, so that most of the light reflected by the free-form surface coupler 200 will be collected by the waveguide structure 310; from the perspective of the transmission mode, the vertically incident micron-level Gaussian beam is transformed into a waveguide mode of parallel waveguide transmission after coupling through the free-form surface 230, thereby realizing efficient interconnection between the laser 100 and the chip 300.

[0070] In one specific embodiment, the waveguide structure 310 utilizes a silicon nitride waveguide, which is buried in a silicon oxide environment. The first end 311a of the tapered waveguide 311, i.e., the minimum waveguide width, is 0.15 μm. The laser 100 utilizes a vertical cavity surface emitting laser 120 with a beam waist radius of 4 μm. The freeform coupler 200 utilizes a parabola, and the focal length of the parabola is p / 2 = 26 μm (parabola equation). The etched groove 340 is formed by etching, with a side length of 100 μm and an etch depth of 140 μm.

[0071] Based on the above embodiment, the Finite Difference Time Domain method (FDTD) is used to simulate the light field transmission between the laser 100 and the chip 300. In the simulation parameter design, a Gaussian beam is used as the light source, the wavelength of the Gaussian beam is set to 1550nm, and it enters the free-form surface coupler 200 vertically; the width of the first end 311a of the waveguide structure 310 of the chip 300 is 150nm, the height is 220nm, and the refractive index of the free-form surface coupler 200 region is 1.4714.

[0072] FIG8 is a schematic diagram of a light field transmission simulation of the optoelectronic chip integrated system 10 shown in FIG1 . As shown in FIG8 , the Gaussian beam emitted by the vertical cavity surface emitting laser 120 is reflected at the interface of the freeform surface coupler 200, effectively converting the propagation direction to be parallel to the extension direction of the waveguide structure 310.

[0073] Figure 9 shows the topography of the light beam emitted by the laser 100 of the optoelectronic chip integrated system 10 shown in Figure 1 at the output end. Figure 10 shows the topography of the light beam emitted by the laser 100 of the optoelectronic chip integrated system 10 shown in Figure 1 at the receiving end. As shown in Figures 9 and 10, after the reflection and convergence of the freeform surface coupler 200, the spot size of the light beam is well converted into a mode that supports low-loss transmission in the waveguide structure 310, demonstrating the excellent performance of the freeform surface coupler 200 in mode spot conversion.

[0074] FIG11 is a schematic diagram illustrating the relationship between coupling loss and beam wavelength for the optoelectronic chip integrated system 10 shown in FIG1 . As shown in FIG11 , for the TE mode, the waveguide loss is less than 1.5 dB across the entire 1300 nm to 1700 nm wavelength range (spanning the O, E, S, C, L, and U bands), and the 1 dB bandwidth exceeds 300 nm. This demonstrates that the reflective free-form surface coupler 200 is wavelength- and polarization-independent, offering distinct advantages over diffraction grating couplers.

[0075] FIG12 is a schematic diagram showing the relationship between the coupling loss of the optoelectronic chip integrated system 10 shown in FIG1 and the lateral position offset between the free-form surface coupler 200 and the chip 300. FIG13 is a schematic diagram showing the relationship between the coupling loss of the optoelectronic chip integrated system 10 shown in FIG1 and the longitudinal position offset between the free-form surface coupler 200 and the chip 300. As shown in FIG12 and FIG13, the alignment tolerance of the free-form surface coupler 200 is simulated by transforming the relationship between the coupling loss and the position. According to FIG12, the in-plane alignment tolerance of the free-form surface 230 coupling is ±2μm. In addition, since the laser 100 is flip-chip mounted on the upper end of the free-form surface coupler 200, the out-of-plane alignment tolerance is negligible, indicating that the structure of the free-form surface coupler 200 can have a good alignment tolerance for the processing process. As can be seen from FIG13 , the bonding process of the laser 100 and the chip 300 is insensitive to the vertical distance between the laser 100 and the chip 300 , that is, the alignment tolerance in the vertical direction is large, which is also a major advantage of the optoelectronic chip integrated system 10 of the embodiment of the present application.

[0076] 14 is a flow chart of a method for manufacturing an optoelectronic chip integrated system according to an embodiment of the present application. The optoelectronic chip integrated system according to an embodiment of the present application includes steps S100 to S300.

[0077] In step S100 , a chip including a waveguide structure is provided.

[0078] In step S200 , a free-form surface coupler is formed on a chip, and the free-form surface coupler and a waveguide structure are connected.

[0079] In step S300 , the laser and the chip are connected so that the free-form surface coupler is located on the optical path of the light beam emitted by the laser.

[0080] It should be noted that the chip of the embodiment of the present application may include an all-optical chip or an optoelectronic hybrid chip. The chip may be made of any material.

[0081] In some embodiments, the chip further includes a cladding layer and a substrate layer, the waveguide structure is buried in the cladding layer, and the substrate layer is located on the side of the cladding away from the laser. Based on the above embodiment, the freeform surface coupler can be fabricated on the same silicon-based substrate layer as the chips to be connected.

[0082] Figure 15 is a flow chart of an embodiment of step S200 in the manufacturing method shown in Figure 14. In some embodiments, as shown in Figure 15, step S200 in the manufacturing method of the optoelectronic chip integrated system of the present application may include steps S210 to S230.

[0083] In step S210, an etched groove is etched at a location adjacent to the input side of the waveguide structure.

[0084] In step S220 , the etched grooves are filled with photoresist.

[0085] In step S230 , the photoresist is processed to form a free-form surface coupler.

[0086] In some embodiments, in step S210, a deep etching process may be used to etch an etched groove at the chip where the input side of the waveguide structure meets the input side, with the input side of the waveguide structure located at the edge of the etched groove, wherein the side length of the etched groove is on the order of hundreds of microns.

[0087] In some embodiments, in step S220, a photoresist can be spin-coated into the deep etched grooves. Overprinting and two-photon lithography are then used to form a parabolic freeform surface coupler layer by layer in the polymer photoresist filling the etched grooves. After the freeform surface coupler region is exposed, the non-exposed region can be etched away through an etching process, exposing the outer side of the freeform surface of the freeform surface coupler to the air environment to increase the refractive index difference between the freeform surface and the environment. The photoresist material includes a polymer.

[0088] Figure 16 is a flow chart of an embodiment of step S300 in the manufacturing method shown in Figure 14. In some embodiments, as shown in Figure 16, step S300 in the manufacturing method of the optoelectronic chip integrated system of the present application may include steps S310 to S330.

[0089] In step S310 , a second bonding electrode is prepared on the surface of the chip, wherein the second bonding electrode corresponds to the first bonding electrode.

[0090] In step S320 , the laser is positioned on the chip according to the position of the second bonding electrode.

[0091] In step S330, the laser is flip-chip bonded to the surface of the chip so that the free-form surface coupler is located on the optical path of the light beam emitted by the laser.

[0092] In this embodiment, the first bonding electrode and the second bonding electrode cooperate with each other to achieve precise positioning of the laser and the chip.

[0093] FIG17 is a schematic diagram of the manufacturing process for manufacturing the optoelectronic chip integrated system 10 using the manufacturing method shown in FIG14 . As shown in FIG17( a ), the manufacturing process for the optoelectronic chip integrated system 10 includes providing a chip 300, wherein the chip 300 includes a waveguide structure 310, a cladding layer 320, and a substrate layer 330, with the waveguide structure 310 being buried in a silicon oxide environment. As shown in FIG17( b ), the manufacturing process for the optoelectronic chip integrated system 10 also includes etching a groove 340 at a location adjacent to the input side of the waveguide structure 310. The depth of the groove 340 can be greater than or equal to the depth of the waveguide structure 310 to connect the freeform surface coupler 200 to the waveguide structure 310. One side of the groove 340 is connected to the input side of the waveguide structure 310. As shown in FIG17( c ), the manufacturing process for the optoelectronic chip integrated system 10 also includes spin coating photoresist within the groove 340. As shown in Figure 17(d), the manufacturing process of the optoelectronic chip integrated system 10 includes forming a parabolic free-form surface coupler 200 layer by layer in a polymer photoresist filled in an etched groove 340. After exposing the free-form surface coupler 200 area, the non-exposed area is etched away through an etching process, exposing the outer side of the free-form surface 230 of the free-form surface coupler 200 to the air environment. As shown in Figure 17(e), the manufacturing process of the optoelectronic chip integrated system 10 includes flip-chip bonding the laser 100 to the surface of the chip 300, so that the free-form surface coupler 200 is located in the optical path of the light beam emitted by the laser 100.

[0094] As for the method embodiment, since it basically corresponds to the apparatus embodiment, the relevant parts can be referred to the partial description of the apparatus embodiment. The method embodiment and the apparatus embodiment complement each other.

[0095] The above descriptions are only some embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An optoelectronic chip integrated system, comprising: A laser for emitting a light beam; A free-form surface coupler is located on the optical path of the laser output light beam, and is used to receive the light beam and reflect and shape the light beam; A chip is connected to the laser, wherein the chip comprises a waveguide structure, and the waveguide structure is connected to the free-form surface coupler and is used for receiving the reflected and shaped light beam.

2. The optoelectronic chip integrated system according to claim 1, wherein: The free-form surface coupler includes an input end, an output end and a free-form surface, the input end is connected to the laser, at least part of the output end is connected to the waveguide structure, the free-form surface is used to convert the transmission direction of the light beam to be parallel to the extension direction of the waveguide structure, and convert the transmission mode of the light beam to a waveguide transmission mode, and the waveguide structure is used to receive the light beam after the transmission direction and transmission mode are converted.

3. The optoelectronic chip integrated system according to claim 2, wherein: The chip further comprises a cladding layer and a substrate layer, the waveguide structure is buried in the cladding layer, and the substrate layer is arranged on a side of the cladding layer away from the laser; The chip also includes an etched groove, the waveguide structure includes an input side, the etched groove is connected to the input side of the waveguide structure, and is recessed from the cladding toward the substrate layer, the free-form surface coupler is located in the etched groove, and the output end of the free-form surface coupler is connected to the input side of the waveguide structure.

4. The optoelectronic chip integrated system according to claim 3, wherein: The free-form surface coupler is formed by machining in the etched groove filled with photoresist.

5. The optoelectronic chip integrated system according to claim 3, wherein: The waveguide structure includes a tapered waveguide and a straight waveguide connected to the tapered waveguide. The tapered waveguide is connected to the output end of the free-form surface coupler to receive the light beam and transmit the light beam to the straight waveguide.

6. The optoelectronic chip integrated system according to claim 5, wherein: The tapered waveguide includes a first end and a second end, the first end is connected to the output end of the free-form surface coupler, and the second end is connected to the straight waveguide, wherein the width of the tapered waveguide tends to gradually increase from the first end to the second end.

7. The optoelectronic chip integrated system according to claim 1, wherein: The material of the waveguide structure includes at least one of silicon waveguide, silicon nitride and lithium niobate.

8. The optoelectronic chip integrated system according to claim 1, wherein: The laser is flip-chip welded on the surface of the chip.

9. The optoelectronic chip integrated system according to claim 1, wherein: The laser includes a substrate and a first bonding electrode, wherein the first bonding electrode is arranged on the substrate; the chip also includes a second bonding electrode arranged on the surface of the chip, wherein the second bonding electrode corresponds to the first bonding electrode and is used to electrically connect the chip and the laser.

10. The optoelectronic chip integrated system according to claim 9, wherein: The laser comprises a vertical cavity surface emitting laser, which comprises a light emitting portion for emitting the light beam, wherein the light emitting portion is arranged on the substrate, the light emitting portion and the first bonding electrode are arranged on opposite sides of the substrate, and the emission direction of the light beam is perpendicular to the substrate.

11. The optoelectronic chip integrated system according to claim 9, wherein: The laser comprises a horizontal cavity surface emitting laser, which comprises a light emitting portion and a reflecting portion. The light emitting portion is used to emit the light beam. The light emitting portion is arranged on a side of the substrate that is perpendicular to the extension direction of the substrate. The emission direction of the light beam is parallel to the extension direction of the substrate. The reflecting portion is used to reflect the light beam so that the light beam is emitted in a direction perpendicular to the substrate.

12. The optoelectronic chip integrated system according to claim 10 or 11, wherein: A section line of the free-form surface perpendicular to the extension direction of the waveguide structure is a curve.

13. The optoelectronic chip integrated system according to claim 12, wherein: The free-form surface includes a parabola, and a side where the waveguide structure and the free-form surface coupler are connected is close to a focus of the parabola.

14. The optoelectronic chip integrated system according to claim 10 or 11, wherein: A section line of the free-form surface perpendicular to the extension direction of the waveguide structure is a straight line.

15. A method for manufacturing an optoelectronic chip integrated system, wherein: include: Providing a chip including a waveguide structure; forming a free-form surface coupler on the chip, and connecting the free-form surface coupler and the waveguide structure; The laser is connected to the chip so that the free-form surface coupler is located on the optical path of the light beam emitted by the laser.

16. The manufacturing method according to claim 15, wherein: A free-form surface coupler is formed on the chip, and the free-form surface coupler and the waveguide structure are connected, comprising: Etching an etched groove at a position connected to the input side of the waveguide structure; Filling the etching groove with photoresist; The photoresist is processed to form the free-form surface coupler.

17. The manufacturing method according to claim 15, wherein: The laser comprises a substrate and a first bonding electrode, wherein the first bonding electrode is arranged on the substrate; Connecting the laser and the chip so that the free-form surface coupler is located below the laser comprises: Preparing a second bonding electrode on the surface of the chip, wherein the second bonding electrode corresponds to the first bonding electrode; Positioning the laser on the chip according to the position of the second bonding electrode; The second bonding electrode and the first bonding electrode are electrically connected to enable the laser to be flip-chip soldered to the surface of the chip, so that the free-form surface coupler is located on the optical path of the light beam emitted by the laser.

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