Optical amplifier and method of coupling the same to an optical assembly

Abstract

The application discloses an optical amplifier and a coupling method thereof. The coupling method comprises the following steps: providing an optical amplifier, wherein the optical amplifier comprises a substrate, an epitaxial structure formed on the substrate, a first waveguide and a second waveguide formed on the epitaxial structure; coupling a first optical component to a first coupling end surface of the second waveguide, and determining a first alignment coordinate of the first optical component; determining a second alignment coordinate of a first target optical component based on a preset distance and the first alignment coordinate, and then actively coupling and adjusting the first target optical component to be coupled to a first end surface of the first waveguide; determining a third alignment coordinate of a second target optical component based on a preset distance and a preset alignment coordinate, and then actively coupling and adjusting the second target optical component to be coupled to a second end surface of the first waveguide. The application solves the problems of great difficulty in coupling and low coupling efficiency of the first waveguide of the optical amplifier and the optical component.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an optical amplifier and a method for coupling the amplifier with an optical component. Background Technology

[0002] As a core optoelectronic device in fields such as optical communication, optical sensing, and optical signal processing, the optical coupling efficiency between the optical amplifier and optical fiber or other optical components directly determines the gain performance and signal transmission quality of the device.

[0003] During the end-face coupling process of an optical amplifier, some incident light is reflected at the end face of the amplifier, forming backlight. When this backlight is injected into the active region of the optical amplifier, it strongly interferes with the forward-transmitted optical signal in the active region. This not only directly causes abnormal output light phenomena such as output power fluctuations, spectral distortion, and increased signal noise, affecting the transmission quality of the optical signal, but also causes long-term continuous backlight interference, which can damage the active region material of the optical amplifier, abnormally increase the threshold current, and reduce the photoelectric conversion efficiency. Ultimately, this can lead to irreversible failure of the optical amplifier, severely limiting the application scenarios and practical value of optical amplifiers in mid-to-high-end optoelectronic systems.

[0004] To suppress the interference of reflected light on the active region of the optical amplifier during end-face coupling, existing technologies employ special waveguide structures with a certain degree of tilt or curvature in the optical amplifier design. For example, slanted waveguides are designed by tilting the waveguide at a certain angle to the normal of the optical amplifier end-face, while curved waveguides are designed by introducing specific radii of curvature and bending directions to change the optical path. Both can effectively reduce end-face reflectivity and suppress reflected light.

[0005] However, while suppressing backlight, this special waveguide structure also brings great difficulties to the coupling and alignment between the optical amplifier and the optical fiber or other optical components. The difficulty of coupling and alignment is much higher than that of traditional straight waveguide structures, which has become the core pain point restricting the mass production yield, performance consistency and large-scale application of optical amplifiers.

[0006] Specifically, the coupling alignment of slanted waveguides and curved waveguide structures is quite difficult, mainly due to the combined effect of multiple factors:

[0007] First, the structural geometry is significantly asymmetrical. Inclined waveguides have a fixed tilt angle, while curved waveguides have specific requirements for the radius of curvature and the direction of curvature. Compared with the symmetrical and regular traditional straight waveguides, the spatial geometry of the two is more complex, which greatly increases the difficulty of matching the spatial attitude of the optical fiber and the waveguide during coupling, making it difficult to achieve precise alignment.

[0008] Secondly, mode field distortion is a prominent issue. The tilted structure of the slanted waveguide causes the optical signal propagation direction to shift, while the curvature change of the curved waveguide will induce mode dispersion of the optical signal. Both of these will cause mode field broadening, shift, or distortion when the optical signal propagates in the waveguide, which will significantly reduce the overlap between the waveguide mode field and the fiber mode field, and thus directly affect the coupling efficiency.

[0009] Third, the strong coupling characteristics of multiple degrees of freedom are obvious. During the coupling alignment process, it is necessary to simultaneously and precisely control the positional accuracy of the optical fiber and waveguide in multiple degrees of freedom such as horizontal, vertical, axial, and rotation. Moreover, the degrees of freedom influence each other and have strong coupling effects. Even a tiny positional deviation at the micrometer level can lead to a sharp deterioration in the coupling effect, further increasing the difficulty of alignment.

[0010] Therefore, there is an urgent need in this field for a technical solution that can quickly and efficiently achieve the coupling and alignment of slanted waveguide or curved waveguide optical amplifiers with optical components without changing the orientation of the optical amplifier. Summary of the Invention

[0011] The purpose of this invention is to overcome the shortcomings of the prior art and provide an optical amplifier and a coupling method therewith with an optical component.

[0012] This invention provides a coupling method between an optical amplifier and an optical component, comprising the following steps: providing an optical amplifier, the optical amplifier including a substrate, an epitaxial structure formed on the substrate, and a first waveguide and a second waveguide formed on the epitaxial structure; the end face of the first waveguide forms an acute angle with the coupling end face of the optical amplifier, any part of the second waveguide forms a right angle with the coupling end face of the optical amplifier, the second waveguide and the first waveguide are spaced apart by a preset distance, the coupling end face includes a first coupling end face and a second coupling end face correspondingly disposed, the end face including a first end face and a second end face respectively corresponding to the first coupling end face and the second coupling end face; coupling and aligning a first optical component with the first coupling end face of the second waveguide, determining a first alignment coordinate of the first optical component; and determining a second alignment coordinate of a first target optical component and a third alignment coordinate of the second target optical component based on the preset distance and the first alignment coordinate; Active coupling is adjusted to adjust at least one of the target optical component and the optical amplifier until the target optical component is coupled and aligned with the first waveguide; The target optical component includes a first target optical component and a second target optical component; the alignment of the target optical component with the first waveguide includes coupling the first target optical component to a first end face of the first waveguide and coupling the second target optical component to a second end face of the first waveguide.

[0013] According to one embodiment of the present invention, actively coupling and adjusting at least one of the target optical component and the optical amplifier until the target optical component is coupled and aligned with the first waveguide includes: determining a second alignment coordinate of the first target optical component based on the preset distance and the first alignment coordinate, and then actively coupling and adjusting the first target optical component to couple and align the first target optical component with a first end face of the first waveguide; determining a third alignment coordinate of the second target optical component based on the preset distance and the preset alignment coordinate, and then actively coupling and adjusting the second target optical component to couple and align the second target optical component with a second end face of the first waveguide.

[0014] According to one embodiment of the present invention, coupling and aligning a first optical component with a first coupling end face of a second waveguide, and determining a first alignment coordinate of the first optical component, includes: actively coupling and aligning the first optical component with the first coupling end face of the second waveguide; and determining the position coordinates at which the maximum output optical power of the second waveguide is reached as the first alignment coordinates.

[0015] According to one embodiment of the present invention, the step of actively coupling and adjusting the first target optical component to couple and align the first target optical component with the first end face of the first waveguide includes: using the position corresponding to the second alignment coordinate as a reference, adjusting the deflection angle of the first target optical component relative to the first end face of the first waveguide, performing active coupling adjustment on the first waveguide until the optical power received by the first target optical component reaches the maximum value, and determining the position of the first target optical component. The step of actively coupling and adjusting the second target optical component to align the second target optical component with the second end face of the first waveguide includes: using the third alignment coordinate as a reference, adjusting the deflection angle of the second target optical component relative to the second end face of the first waveguide, performing active coupling adjustment on the first waveguide until the optical power received by the first target optical component reaches its maximum value, and determining the position of the second target optical component.

[0016] According to one embodiment of the present invention, the distance between the first waveguide and the second waveguide at the first coupling end face of the optical amplifier is a first distance; the first distance is determined based on the distance from the first target optical component to the first coupling end face of the optical amplifier, the horizontal divergence angle of the emitted light spot of the first waveguide, and the radial dimension of the first target optical component.

[0017] According to one embodiment of the present invention, the preset alignment coordinates are either the first alignment coordinates or the second alignment coordinates, and the third alignment coordinates are determined based on the second distance between the first waveguide and the second waveguide at the second coupling end face of the optical amplifier, the preset alignment coordinates, and the cavity length of the optical amplifier. Alternatively, the second optical component is actively coupled and aligned with the second coupling end face of the second waveguide, and the position coordinates at which the maximum output optical power of the second waveguide is determined are the fourth alignment coordinates, and the preset alignment coordinates are the fourth alignment coordinates; the third alignment coordinates are determined based on the second distance between the first waveguide and the second waveguide at the second coupling end face of the optical amplifier and the fourth alignment coordinates.

[0018] According to one embodiment of the present invention, the step of actively coupling and adjusting the second target optical component to couple and align the second target optical component with the second end face of the first waveguide includes: acquiring the second optical power of the second waveguide and the first optical power of the first waveguide; adjusting the third alignment coordinates based on the first optical power until the difference between the first optical power and the second optical power is less than a preset value.

[0019] The present invention also provides an optical amplifier, comprising: a substrate; an epitaxial structure formed on the substrate; a first waveguide and a second waveguide, both formed on the epitaxial structure; the end face of the first waveguide forms an acute angle with the coupling end face of the optical amplifier, and any portion of the second waveguide forms a right angle with the coupling end face, wherein the second waveguide and the first waveguide are spaced apart by a predetermined distance; the coupling end face includes a first coupling end face and a second coupling end face correspondingly disposed thereon, and both the second waveguide and the first waveguide extend from the first coupling end face of the optical amplifier to the opposite second coupling end face.

[0020] According to one embodiment of the present invention, an electrical isolation region is provided between the second waveguide and the first waveguide.

[0021] According to one embodiment of the present invention, the epitaxial structure includes at least an active layer, and the electrically isolated region includes an electrically isolated trench extending at least to the active layer and an insulating region formed in the electrically isolated trench; or, the optical amplifier further includes a metal electrode disposed on the epitaxial structure, and the electrically isolated region is a region in which the metal electrode is at least partially stripped between the first waveguide and the second waveguide to expose the epitaxial structure.

[0022] According to one embodiment of the present invention, the distance between the electrically isolated region and the second waveguide is 20-30 μm; and / or the distance between the second waveguide and the first waveguide is greater than twice the ridge width of the first waveguide.

[0023] According to one embodiment of the present invention, the distance between the first waveguide and the second waveguide at the first coupling end face is greater than or equal to a threshold C; wherein, the threshold C is determined based on the lateral diffusion width A of the first waveguide at the first coupling end face and the radial dimension of the optical component, the lateral diffusion width A is determined based on the distance between the optical component and the first coupling end face and a first angle of horizontal divergence of the emitted light spot of the first waveguide, the first angle being the angle between the line connecting the two ends of the first waveguide and the cavity length direction of the optical amplifier.

[0024] According to one embodiment of the present invention, the distance between the first waveguide and the second waveguide at the second coupling end face is greater than or equal to a threshold E; wherein the threshold E is determined based on the threshold C, the cavity length of the optical amplifier, and the first included angle.

[0025] The beneficial effects of this invention are as follows: By simultaneously setting a first waveguide as the main waveguide and a second waveguide as an auxiliary alignment reference on the optical amplifier, the nanometer-level precision of semiconductor photolithography ensures that the spacing between the two is precisely controllable. A coupling reference is first established using the easily aligned first waveguide, and then the coupling position of the second waveguide is calculated based on a preset distance. This solves the complex alignment problem of special waveguide structures by combining simple second waveguide alignment with fixed offset calculations, significantly reducing the difficulty of coupling alignment. This second waveguide, used for auxiliary alignment, can also be used to quickly evaluate epitaxial quality and process performance because its shorter optical path and lower transmission loss allow for a more convenient reflection of the intrinsic optical and electrical properties of the epitaxial structure in the growth direction. Attached Figure Description

[0026] Figure 1 This is a cross-sectional structural diagram of an optical amplifier according to an embodiment of the present invention; Figure 2 This is a cross-sectional structural schematic diagram of an optical amplifier according to another embodiment of the present invention; Figure 3 This is a top view of the structure of an optical amplifier according to an embodiment of the present invention; Figure 4 This is a top view of the optical amplifier according to another embodiment of the present invention; Figures 5(a) to 5(c) are schematic diagrams of the structure corresponding to each step of the optical amplifier and optical component coupling method in one embodiment of the present invention.

[0027] Among them, 100 is an optical amplifier; 10 is a substrate; 20 is an epitaxial structure; 21 is an N-type cladding; 22 is an N-type waveguide layer; 23 is an active layer; 24 is a P-type waveguide layer; 25 is a P-type cladding; 26 is a capping layer; 30 is a first waveguide; 301 is a first end face; 302 is a second end face; 40 is a second waveguide; 31 is a first trench; 41 is a second trench; 50 is an electrically isolated region; 101 is a first coupling end face; 102 is a second coupling end face; 201 is a first optical component; 202 is a second optical component; 203 is a first target optical component; and 204 is a second target optical component. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] For ease of explanation, this document uses terms indicating relative spatial position, such as "above," "below," "behind," and "front," to describe the relationship of one unit or feature shown in the accompanying drawings relative to another unit or feature. Terms indicating relative spatial position can include different orientations of the device during use or operation besides those shown in the figures. For example, if the device in the figures is flipped, a unit described as being "below" or "above" other units or features will be located "below" or "above" other units or features. Therefore, the exemplary term "below" can encompass both "below" and "above" spatial orientations.

[0031] Please refer to Figure 1 As shown in Figure 5, the present invention provides an optical amplifier 100 and a coupling method therewith with an optical component. The optical amplifier 100 includes a substrate 10, an epitaxial structure 20 formed on the substrate 10, and a first waveguide 30 and a second waveguide 40 formed on the epitaxial structure 20.

[0032] The substrate 10 may be made of conventional semiconductor substrate materials in the art, such as III-V compound semiconductor substrates 10 such as InP and GaAs, and the present invention does not limit it.

[0033] The epitaxial structure 20 is formed on the substrate 10 and can be prepared using conventional epitaxial growth processes in the art, such as metal-organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

[0034] Both the first waveguide 30 and the second waveguide 40 are formed on the epitaxial structure 20. Both the second waveguide 40 and the first waveguide 30 extend from the first coupling end face 101 of the epitaxial structure 20 to the opposite second coupling end face 102. The first coupling end face 101 is, for example, the output end face of the optical amplifier 100, and the second coupling end face 102 is, for example, the incident end face of the optical amplifier 100. Both the first coupling end face 101 and the second coupling end face 102 can serve as coupling end faces of the optical amplifier 100 for optical coupling with optical components.

[0035] The end face of the first waveguide 30 forms an acute angle with the coupling end face of the optical amplifier. This end face includes a first end face 301 and a second end face 302, respectively corresponding to the first coupling end face 101 and the second coupling end face 102. Specifically, the first waveguide 30 is, for example, an inclined waveguide or a bent waveguide, and is the main operating waveguide of the optical amplifier 100, undertaking the main transmission and amplification functions of the optical signal.

[0036] like Figure 3 As shown, in one embodiment, the first waveguide 30 is an angled waveguide, and the extension direction of the first waveguide 30 forms a certain angle with the normal of the coupling end face of the optical amplifier 100, such as 5°-10°. By making a certain angle between the extension direction of the first waveguide 30 and the normal of the coupling end face of the optical amplifier 100, the reflected light at the end face of the optical amplifier 100 can be deviated from the original propagation optical path, preventing the reflected light from being injected back into the active operating area of ​​the optical amplifier 100, and effectively reducing reflected light interference.

[0037] like Figure 4 As shown, in one embodiment, the first waveguide 30 is a curved waveguide with a specific radius of curvature and bending direction, which can achieve isolation of backlight by changing the optical path. For a curved waveguide, some bands can be perpendicular to the coupling end face; as long as the end face forms an acute angle with the coupling end face, backlight can also be suppressed.

[0038] Any portion of the second waveguide 40 is perpendicular to the coupling end face. In this embodiment, the second waveguide 40 is a straight waveguide, and its extension direction is parallel to the normal of the coupling end face of the optical amplifier 100, that is, the extension direction of the second waveguide 40 is perpendicular to the coupling end face of the optical amplifier 100. The second waveguide 40 and the first waveguide 30 are spaced apart by a preset distance d.

[0039] Compared to the first waveguide 30, the second waveguide 40 has a regular and symmetrical geometry, making coupling alignment easier. It can be used as an auxiliary reference for coupling alignment and does not undertake the transmission and amplification function of the main working optical signal. Even if the second waveguide 40 is a straight waveguide with end-face backlight, it will not interfere with the active working area of ​​the first waveguide 30 and will not affect the normal operation of the first waveguide 30.

[0040] The spacing between the first waveguide 30 and the second waveguide 40 can be preset during the layout design stage of the optical amplifier 100, such as by setting a preset distance d. Since the first waveguide 30 and the second waveguide 40 share the same epitaxial structure 20, and the layout design and fabrication process of the optical amplifier 100 is usually at the nanometer level, the relative height of each pattern structure inside the optical amplifier 100 is fixed and the positional accuracy is reliable. Therefore, the preset distance d between the first waveguide 30 and the second waveguide 40 can be directly obtained from the design layout of the optical amplifier 100 without additional measurement.

[0041] This invention, by setting a first waveguide 30 and a second waveguide 40 with a spacing distribution, allows the coupling reference coordinates to be determined first through the second waveguide 40 during the coupling alignment process (i.e., determining the coupling reference coordinates when the coupling accuracy between the optical component and the second waveguide 40 is the highest). Combined with the preset distance d between the first waveguide 30 and the second waveguide 40, the coupling position of the first waveguide 30 can be derived. Only a small range of fine adjustments is needed to complete the coupling alignment, eliminating the need for a full-degree-of-freedom large-range search alignment of the first waveguide 30 from the initial position. This significantly reduces the time cost and technical difficulty of coupling alignment for optical amplifiers 100 with oblique or curved waveguides, achieving fast and efficient alignment.

[0042] In one specific embodiment, the epitaxial structure 20, from the substrate 10 upwards, sequentially includes an N-type cladding layer 21, an N-type waveguide layer 22, an active layer 23, a P-type waveguide layer 24, a P-type cladding layer 25, and a capping layer 26. The active layer 23 can be an InGaAsP multiple quantum well structure. When an injection current is applied, electrons and holes recombine in the active layer 23 to generate stimulated emission, amplifying the gain of the transmitted optical signal.

[0043] The N-type cladding 21 and P-type cladding 25 are layers of materials with low refractive index. They confine the light field to the active layer 23 and its adjacent region, forming a vertical optical waveguide structure. For example, the N-type cladding 21 and N-type waveguide layer 22 can be made of N-type doped InP material, and the P-type waveguide layer 24 and P-type cladding 25 can be made of P-type doped InP material.

[0044] The top cover layer 26 is a heavily doped contact layer, for example, using heavily doped InGaAs material, to reduce the contact resistance between the metal electrode and the contact layer.

[0045] In one embodiment, both the first waveguide 30 and the second waveguide 40 are ridge waveguides formed on the capping layer 26. The capping layer 26 includes first trenches 31 etched on both sides of the first waveguide 30 and second trenches 41 etched on both sides of the second waveguide 40. Specifically, the first waveguide 30 and the second waveguide 40 are ridge structures formed by photolithography and etching processes on the capping layer 26, wherein the capping layer 26 is retained in the ridge structure portion, while the capping layer 26 on both sides is at least partially etched away to form the first trenches 31 and the second trenches 41, thereby defining the ridge contours of the first waveguide 30 and the second waveguide 40. The ridge waveguides can be fabricated using dry etching or wet etching processes commonly used in the art.

[0046] The second waveguide 40 can be designed as a single-mode waveguide or a multimode waveguide, depending on cost and device size limitations. When designed as a single-mode waveguide, it offers higher mode field matching with optical components such as optical fibers, resulting in better coupling efficiency; when designed as a multimode waveguide, it provides greater alignment tolerance and simplifies alignment operations. Those skilled in the art can choose according to specific application requirements.

[0047] To avoid crosstalk and interference between the light emitted from the first waveguide 30 and the second waveguide 40, the spacing between the second waveguide 40 and the first waveguide 30 is preferably set to be more than twice the ridge width of the first waveguide 30. Setting a reasonable spacing can ensure that the mode fields of the first waveguide 30 and the second waveguide 40 are fully separated in the lateral direction, avoiding crosstalk problems caused by overlapping optical fields.

[0048] like Figure 2 As shown, in one embodiment, an electrical isolation region 50 is provided between the second waveguide 40 and the first waveguide 30. The function of the electrical isolation region 50 is to achieve electrical isolation between the first waveguide 30 and the second waveguide 40, and to prevent electrical crosstalk and light interference between the first waveguide 30 and the second waveguide 40 during operation.

[0049] The electrically isolated region 50 can be implemented, for example, by means of quantum well etching. In the epitaxial structure 20, the electrically isolated region 50 includes an electrically isolated trench extending at least to the active layer 23 and an insulating region formed within the electrically isolated trench. Specifically, in one embodiment, the electrically isolated trench is etched downwards from the upper surface of the epitaxial structure 20 by an etching process, with the etching depth extending at least to the active layer 23, preferably to the N-type cladding 21 or the substrate 10. The width of the electrically isolated trench can be determined according to the process conditions. An insulating material, such as SiO2, SiN, or a combination thereof, is filled into the electrically isolated trench to form an insulating region. By providing an electrically isolated trench and forming an insulating region between the two waveguides, the current path on both sides is completely cut off from the physical structure, achieving a good electrically isolated effect.

[0050] Another implementation includes a metal stripping method. The optical amplifier 100 also includes metal electrodes disposed on the epitaxial structure 20. The electrical isolation region 50 is formed by stripping the metal electrodes in at least a portion of the region between the first waveguide 30 and the second waveguide 40, exposing the epitaxial structure 20 in that region. This method does not rely on physical trenching, but achieves electrical isolation by stripping the metal electrodes and utilizing the high resistance characteristics of the epitaxial structure 20 itself. This method has a simple process, does not damage the active region, and is suitable for scenarios with relatively low requirements for electrical isolation.

[0051] In the actual fabrication process, the region between the first waveguide 30 and the second waveguide 40 can be left without metal electrodes by photolithography and lift-off processes, while the top of the ridge waveguides of the first waveguide 30 and the second waveguide 40 retain metal electrodes to form electrode contacts.

[0052] In one embodiment of the present invention, the electrically isolated region 50 is disposed biased towards the second waveguide 40, that is, the electrically isolated region 50 is closer to the second waveguide 40 than the first waveguide 30. The distance between the electrically isolated region 50 and the second waveguide 40 is 20μm to 30μm. Distributing the electrically isolated region 50 close to the second waveguide 40 ensures that the region containing the first waveguide 30 has sufficient current injection area to guarantee gain performance. Simultaneously, it avoids the electrical isolation structure from adversely affecting the optical field distribution of the first waveguide 30, and effectively isolates the second waveguide 40, preventing interference from the second waveguide 40 with the operating state of the first waveguide 30.

[0053] At the coupling end face of the optical amplifier 100, the preset distance d between the first waveguide 30 and the second waveguide 40 can be designed according to the actual process conditions of optical fiber coupling.

[0054] A preset distance d is spaced between the first waveguide 30 and the second waveguide 40. The distance between the first waveguide 30 and the second waveguide 40 at the first coupling end face 101 is a first distance d1, and the distance between the first waveguide 30 and the second waveguide 40 at the second coupling end face 102 where coupling is required is a second distance d2. To avoid physical interference between the optical components and the coupling end face of the optical amplifier 100, and to ensure sufficient adjustment margin in the coupled optical path, a minimum threshold is set for the values ​​of the first distance d1 and / or the second distance d2. This minimum threshold can be determined based on factors such as the set distance from the optical fiber to the end face of the optical amplifier 100, the horizontal divergence angle of the emitted light spot from the second waveguide 40, and the radial dimension of the optical fiber.

[0055] Specifically, taking the first coupling end face 101 as an example, the distance between the first waveguide 30 and the second waveguide 40 on the first coupling end face 101 is a first distance d1, which is greater than or equal to a threshold C. The threshold C is determined based on the lateral diffusion width A of the first waveguide 30 on the first coupling end face 101 and the radial dimension of the optical component. The lateral diffusion width A is determined based on the distance between the optical component and the first coupling end face 101, the horizontal divergence angle of the emitted light spot from the first waveguide 30, and a first included angle, which is the angle between the line connecting the two ends of the first waveguide 30 and the cavity length direction of the optical amplifier.

[0056] Let B be the distance from the optical component to the first coupling end face 101, and θ be the horizontal divergence angle of the emitted light spot from the first waveguide 30. Then, the lateral diffusion width A of the first waveguide 30 at the first coupling end face 101 satisfies: A = B × tan(θ / 2 + Δ), where Δ is the first included angle, i.e., the angle between the line connecting the two ends of the first waveguide 30 and the cavity length direction of the optical amplifier 100. The value of Δ ranges from 5° to 10°. B is the distance from the optical component to the first coupling end face 101, and its maximum value does not exceed 10 μm. It can be calculated based on 10 μm during design.

[0057] When optical components use optical fibers, the radial dimension of the optical component mainly considers the cladding thickness of the fiber. For example, the cladding thickness of a standard single-mode fiber is 125 μm. Then, the threshold C (μm) of the first distance d1 at the first coupling end face 101 satisfies: C = A + 125. Based on the above calculations, the threshold C of the first distance d1 at the first coupling end face 101 generally ranges from 130 μm to 140 μm.

[0058] In addition, when the optical amplifier 100 is coupled to the optical fiber at the second coupling end face 102, i.e. the incident end face of the optical amplifier 100, the optical amplifier 100 must also meet the condition of avoiding optical fiber interference. The distance between the first waveguide 30 and the second waveguide 40 at the second coupling end face 102 where coupling is required is the second distance d2. The second distance d2 at the second coupling end face 102 is greater than or equal to the threshold E. The threshold E can be simply determined based on the threshold C of the first distance d1 at the first coupling end face 101, the cavity length of the optical amplifier 100, and the angle between the first waveguide 30 and the first coupling end face 101.

[0059] In practical applications, because the optical component cannot be closely attached to the coupling end face of the optical amplifier, the output light of the optical amplifier has a divergence angle. Therefore, when the optical component is fully coupled and aligned with the first waveguide 30, the maximum coupling power point is not located at the geometric coaxial position of the second waveguide. Therefore, it is necessary to limit the spacing between the two waveguides to reserve space for full coupling in this non-coaxial state.

[0060] like Figure 3As shown, the specific calculation formula for the threshold E is: E = C ± L × tan Δ; where Δ is the first included angle, that is, the angle between the line connecting the two ends of the first waveguide 30 and the cavity length direction of the optical amplifier 100, and the value range of Δ is 5° to 10°, and L is the cavity length of the optical amplifier; the positive and negative relationship is determined according to the deflection direction of the first waveguide 30 relative to the cavity length direction. From the second coupling end face 102 to the first coupling end face 101, if the first waveguide 30 extends towards the second waveguide 40, a positive sign is taken, and if the first waveguide 30 extends away from the second waveguide 40, a negative sign is taken. In this way, the threshold requirement of the second distance d2 at the second coupling end face 102 can be quickly obtained, and the parameter design is completed.

[0061] It should be noted that the above numerical ranges are calculated based on standard single-mode fiber (cladding diameter of 125 μm) and typical SOA optical amplifier 100 parameters. When the fiber type, optical amplifier cavity length, waveguide tilt angle, or bending curvature changes, the above spacing ranges can be adjusted accordingly, but the design principle remains unchanged.

[0062] The distance between the first waveguide 30 and the second waveguide 40 at the coupling end face, determined by the above method, is the basis for the specific value of the preset distance d. This preset distance d is fixed during the layout design stage of the optical amplifier 100, guaranteed by the photolithography layout accuracy, and serves as a reference parameter for calculating the coupling position of the first waveguide 30 in the subsequent coupling process.

[0063] An embodiment of the present invention also provides a coupling method between an optical amplifier 100 and an optical component, wherein the optical component can be an optical fiber or an optical fiber array.

[0064] The coupling method proposed in this embodiment includes at least the following: An optical amplifier is provided, the optical amplifier including a substrate 10, an epitaxial structure 20 formed on the substrate 10, a first waveguide 30 and a second waveguide 40 formed on the epitaxial structure 20; The end face of the first waveguide 30 forms an acute angle with the coupling end face of the optical amplifier, and any part of the second waveguide 40 forms a right angle with the coupling end face of the optical amplifier. The second waveguide 40 and the first waveguide 30 are spaced apart by a preset distance. The coupling end face includes a first coupling end face 101 and a second coupling end face 102, respectively. The end face includes a first end face 301 and a second end face 302, respectively, which are correspondingly provided with the first coupling end face 101 and the second coupling end face 102. The first optical component 201 is coupled and aligned with the first coupling end face 101 of the second waveguide 40 to determine the first alignment coordinates of the first optical component 201. Based on the preset distance and the first alignment coordinates, the second alignment coordinates of the first target optical component 203 and the third alignment coordinates of the second target optical component 204 are determined; Active coupling is adjusted to adjust at least one of the target optical component and the optical amplifier until the target optical component is coupled and aligned with the first waveguide 30; The target optical component includes the first target optical component 203 and the second target optical component 204; the alignment of the target optical component with the first waveguide 30 includes coupling the first target optical component 203 to the first end face 301 of the first waveguide 30 and coupling the second target optical component 204 to the second end face 302 of the first waveguide 30.

[0065] In one embodiment, the angle between the first waveguide 30 at the first end face 301 and the angle at the second end face 302 can be equal or unequal. Since the device packaging structure is a fixed structure, its spatial dimensions and other structural conditions cannot meet the requirement of achieving coupling alignment between the optical component and the first waveguide 30 by adjusting the optical component. Furthermore, when the angle between the first waveguide 30 at the first end face 301 and the angle at the second end face 302 are unequal, achieving coupling alignment between the target optical component and the first waveguide 30 by adjusting the optical amplifier would be difficult and the coupling steps would not be simpler. Therefore, it is preferable to achieve coupling alignment between the target optical component and the first waveguide 30 by adjusting the target optical component.

[0066] In another embodiment, when the angle between the first waveguide 30 at the first end face 301 and the angle at the second end face 302 are equal, or when the application scenario is optical design (i.e., the coupling alignment efficiency between the first waveguide 30 and the target optical component does not need to reach the peak value), it is preferable to achieve the coupling alignment between the target optical component and the first waveguide 30 by adjusting the optical amplifier.

[0067] In one implementation, refer to Figures 5(a) to 5(c) The method includes the following steps: Step S1: Provide an optical amplifier 100 as described in the above embodiment.

[0068] Step S2: Align the first optical component 201 with the first coupling end face 101 of the second waveguide 40 to determine the first alignment coordinates of the first optical component 201.

[0069] Step S3: After determining the second alignment coordinates of the first target optical component 203 according to the preset distance and the first alignment coordinates, the first target optical component 203 is actively coupled and adjusted to couple the first target optical component 203 to the first end face 301 of the first waveguide 30. Step S4: Based on the preset distance and preset alignment coordinates, after determining the third alignment coordinates of the second target optical component 204, the second target optical component 204 is actively coupled and adjusted to couple and align the second target optical component 204 with the second end face 302 of the first waveguide 30.

[0070] Specifically, step S1 first provides an optical amplifier 100 as described above. The optical amplifier 100 includes a first waveguide 30 and a second waveguide 40, with a preset distance d between them. The end face of the first waveguide 30 forms an acute angle with the coupling end face of the optical amplifier 100; any part of the second waveguide 40 forms a right angle with the coupling end face of the optical amplifier 100.

[0071] The coupling end face includes a first coupling end face 101 and a second coupling end face 102 respectively. The end face of the first waveguide 30 includes a first end face 301 and a second end face 302 respectively corresponding to the first coupling end face 101 and the second coupling end face 102.

[0072] Then, in step S2, the first optical component 201 and the second waveguide 40 are coupled and aligned at the first coupling end face 101 of the optical amplifier 100 to obtain the first alignment coordinates of the first optical component 201.

[0073] Specifically, as shown in Figure 5(a), the optical component coupling can adopt a structure of two independent optical links, including a first optical component 201 and a second optical component 202 disposed at the first coupling end face 101 and the second coupling end face 102 of the second waveguide 40, and a first target optical component 203 and a second target optical component 204 disposed at the first end face 301 and the second end face 302 of the first waveguide 30.

[0074] The coupling alignment of the first optical component 201 and the second optical component 202 with the second waveguide 40 adopts an active coupling method. In specific operation, the optical component, such as the optical fiber, is brought close to the position corresponding to the second waveguide 40 on the coupling end face of the optical amplifier 100 through a multi-dimensional adjustment frame. An optical signal is injected into the second waveguide 40, and the optical power at the output end is detected simultaneously. By finely adjusting the position of the first optical component 201 or the second optical component 202 in the cavity length direction (X-axis) and along the horizontal axis (Y-axis) of the optical amplifier, the position corresponding to the maximum output optical power is found. The coordinates of this position are the first alignment coordinates.

[0075] Since the second waveguide 40 is a straight waveguide, its mode field is regular and symmetric, the coupling alignment process is simple, the alignment tolerance is large, and the optimal coupling position can be determined quickly.

[0076] If the first coupling end face 101 is selected, the first optical component 201 and the second waveguide 40 are first coupled and aligned at the first coupling end face 101. The first alignment coordinate of the first optical component 201 to the second waveguide 40 is determined by detecting the position coordinate of the second waveguide 40 when the optical power at the output end reaches the maximum value.

[0077] If the second coupling end face 102 is selected, the second optical component 202 and the second waveguide 40 are coupled and aligned at the second coupling end face 102. Similarly, by detecting the position coordinates of the second waveguide 40 at the maximum optical power at the output end, the fourth alignment coordinates of the second optical component 202 with the second waveguide 40 are determined. For optical amplifier structures that require simultaneous coupling of optical fibers at both ends of the optical amplifier, the alignment operation is performed sequentially on the first coupling end face 101 and the second coupling end face 102 according to the above procedure.

[0078] In the embodiment shown in Figure 5(a), two sets of optical fibers can be used to actively couple and debug the second waveguide 40 at the first coupling end face 101 and the second coupling end face 102, respectively. Since the second waveguide 40 only serves as an auxiliary alignment reference and does not undertake the main signal amplification function, during the active coupling and debugging process, it is only necessary to ensure that the injected optical power is greater than or equal to the minimum optical power threshold of the optical amplifier 100 to achieve effective alignment. A lower injected optical power can quickly establish an optical path reference and avoid end face backlight interference caused by excessively high injected optical power, thereby preventing abnormal performance or even failure of the optical amplifier 100 and achieving indirect protection of the optical amplifier 100.

[0079] Step S3 determines the second alignment coordinates of the coupling between the first target optical component 203 and the first waveguide 30 based on the preset distance and the first alignment coordinates. Since the layout design and fabrication process of the optical amplifier 100 is at the nanometer level, the relative position between the first waveguide 30 and the second waveguide 40 is fixed and the positional accuracy is reliable. Therefore, after obtaining the first alignment coordinates corresponding to the second waveguide 40, the second alignment coordinates of the first target optical component 203 corresponding to the first waveguide 30 can be calculated by combining the preset distance d between the first waveguide 30 and the second waveguide 40 in the design of the optical amplifier 100. That is, the coupling target position of the first target optical component 203.

[0080] Specifically, if the first alignment coordinates are (X0, Y0), the distance between the first waveguide 30 and the second waveguide 40 at the first coupling end face 101 of the optical amplifier 100 is a first distance d1, and the two waveguides are arranged horizontally, then the second alignment coordinates are (X0, Y0 ± d1), with the sign depending on the relative position of the two waveguides. This calculation process can be programmed in the equipment according to different product categories to achieve automated control.

[0081] As shown in Figure 5(b), step S3 sets the first target optical component 203 at the position corresponding to the second alignment coordinates, completing the passive coupling alignment with the first waveguide 30. This method allows for rapid completion of the coarse alignment process of the first waveguide 30. Since the second alignment coordinates have been calculated based on precise design parameters, the initial position of the first target optical component 203 is very close to the optimal coupling position, significantly reducing the range and time of blind searching.

[0082] As shown in Figure 5(c), step S3 further includes active coupling adjustment of the first target optical component 203, and coupling the first target optical component 203 to the first end face 301 of the first waveguide 30.

[0083] The first waveguide 30 is, for example, an oblique waveguide or a curved waveguide, whose optical axis direction differs from that of a straight waveguide. Therefore, after completing the coarse alignment of the planar position (X, Y coordinates), it is necessary to perform small-range angle fine-tuning and optimization for the oblique waveguide or the curved waveguide.

[0084] Specifically, the first target optical component 203 is actively coupled and adjusted based on the position corresponding to the second alignment coordinates. The deflection angle of the first target optical component 203 relative to the first end face 301 of the first waveguide 30 is adjusted to perform active coupling adjustment on the first waveguide 30 until the optical power received by the first target optical component 203 reaches the maximum value, and the position of the first target optical component 203 is determined.

[0085] In a preferred embodiment, after the coupling alignment of the first waveguide 30 is completed, the first optical component 201 coupled and aligned with the second waveguide 40 can be removed. Since the second waveguide 40 only serves as an auxiliary alignment reference and does not need to exist continuously in the formal working state, removing the first optical component 201 can simplify the device structure, avoid potential interference of the auxiliary optical path to the main optical path, and also reserve space for adjusting the horizontal deflection angle of the first target optical component 203.

[0086] Step S4: Based on the preset distance and preset alignment coordinates, determine the third alignment coordinates of the second target optical component 204 aligned with the second end face 302 of the first waveguide 30.

[0087] In one embodiment, the preset alignment coordinates are either the first alignment coordinates or the second alignment coordinates. The third alignment coordinates can be determined based on the second distance between the first waveguide 30 and the second waveguide 40 at the second coupling end face 102, the first alignment coordinates or the second alignment coordinates, and the cavity length of the optical amplifier 100.

[0088] If the first alignment coordinate is set as (X0, Y0), then the second alignment coordinate can be expressed as (X0, Y0 ± d1). The cavity length of the optical amplifier 100 is L, and the second distance between the first waveguide 30 and the second waveguide 40 at the second coupling end face 102 is d2. Then the third alignment coordinate can be derived as (X0 ± L, Y0 ± d2). The specific sign is also determined by the relative position of the two waveguides and the relative position of the coupling end face of the optical amplifier 100.

[0089] In another embodiment, the preset alignment coordinates are the fourth alignment coordinates when the second optical component 202 is coupled and aligned with the second waveguide 40. Consistent with the calculation logic of the first alignment coordinates, the third alignment coordinates can be directly calculated based on the second distance d2 between the first waveguide 30 and the second waveguide 40 at the second coupling end face 102, combined with the fourth alignment coordinates.

[0090] If the fourth alignment coordinate is set as (X1, Y1), and the first waveguide 30 and the second waveguide 40 are arranged horizontally at the second coupling end face 102, then the third alignment coordinate is (X1, Y1±d2), and the specific sign is determined by the relative positional relationship of the two waveguides.

[0091] Step S4 further includes actively coupling the second target optical component 204, aligning it with the second end face 302 of the first waveguide 30. Specifically, this involves adjusting the deflection angle of the second target optical component 204 relative to the second end face 302 of the first waveguide 30, using a third alignment coordinate as a reference, until the received optical power of the first target optical component 203 reaches its maximum value, thus determining the coupling position of the second target optical component 204. This completes all coupling operations between the coupling end faces on both sides of the optical amplifier and the optical components.

[0092] In one embodiment, the step of actively coupling and adjusting the second target optical component to couple and align the second target optical component with the second end face of the first waveguide includes: acquiring the second optical power of the second waveguide and the first optical power of the first waveguide; adjusting the third alignment coordinates based on the first optical power until the difference between the first optical power and the second optical power is less than a preset value.

[0093] In this invention, the second waveguide 40, in addition to serving as a coupling alignment reference, can also be used for preliminary judgment and evaluation of the overall performance of the optical amplifier 100.

[0094] Since the first waveguide 30 and the second waveguide 40 differ only in the optical transmission path along the length of the resonant cavity, and both share the same epitaxial structure 20, the optoelectronic properties of the second waveguide 40, i.e., the straight waveguide, can reflect the intrinsic characteristics of the epitaxial layer. Compared to skewed and curved waveguides, the straight waveguide effectively shortens the effective optical path of optical transmission and reduces the additional transmission loss introduced by the path, thus reflecting the intrinsic optical and electrical properties of the epitaxial layer in the growth direction more intuitively and realistically.

[0095] In practical applications, the output photoelectric parameters, such as threshold current, slope efficiency, and gain spectrum, can be detected by injecting test current or test optical signal into the second waveguide 40. The detection results can be compared with preset standard values ​​to quickly determine whether the epitaxial layer quality is qualified.

[0096] Furthermore, by comparing the test results of the second waveguide 40 with the performance parameters of the first waveguide 30, it is possible to distinguish between epitaxial material quality problems and loss problems introduced by waveguide structure design, providing key basis for the analysis, problem location and performance interpretation of the optical amplifier 100 manufacturing process.

[0097] In one embodiment of the present invention, when the optical amplifier 100 is operating normally, the first waveguide 30 serves as the main working waveguide, undertaking the functions of optical signal amplification and transmission. The second waveguide 40 may not be powered; its two ends may be connected to isolators or left floating, and it does not participate in the amplification and transmission of signal light. In this mode, the second waveguide 40 is used only as an auxiliary structure.

[0098] In another embodiment of the present invention, the second waveguide 40 can also be powered on to emit light, but since it does not participate in the main signal transmission path, its light emission will not affect the actual application function of the optical amplifier 100.

[0099] It should be understood that whether the second waveguide 40 is powered on can be flexibly selected according to the specific application scenario and design requirements, and the present invention does not impose any restrictions on this.

[0100] In summary, this invention simultaneously sets a first waveguide 30 as the main waveguide and a second waveguide 40 as an auxiliary alignment reference on the optical amplifier 100. By using the second waveguide 40 as an auxiliary alignment reference and leveraging the high-precision positional relationship of semiconductor photolithography, the complex alignment problem of special waveguide structures is transformed into a simple alignment of the second waveguide 40 combined with fixed offset calculation. This significantly reduces the difficulty of coupling alignment and improves coupling efficiency. At the same time, the second waveguide 40 reduces the impact of strong backlight on the optical amplifier 100 during coupling, improving device yield and long-term reliability. The second waveguide 40 can also serve as a node for rapid evaluation of epitaxial quality, providing a convenient detection method for process control of the optical amplifier 100.

[0101] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0102] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A coupling method between an optical amplifier and an optical component, characterized in that, The optical components include a first optical component (201), a first target optical component (203), and a second target optical component (204), and include the following steps: An optical amplifier is provided, the optical amplifier including a substrate (10), an epitaxial structure (20) formed on the substrate (10), a first waveguide (30) and a second waveguide (40) formed on the epitaxial structure (20). The end face of the first waveguide (30) forms an acute angle with the coupling end face of the optical amplifier, and any part of the second waveguide (40) forms a right angle with the coupling end face of the optical amplifier. The second waveguide (40) and the first waveguide (30) are spaced apart by a preset distance. The coupling end face includes a first coupling end face (101) and a second coupling end face (102) respectively. The end face includes a first end face (301) and a second end face (302) respectively corresponding to the first coupling end face (101) and the second coupling end face (102). The first optical component (201) is coupled and aligned with the first coupling end face (101) of the second waveguide (40) to determine the first alignment coordinates of the first optical component (201); Based on the preset distance and the first alignment coordinates, the second alignment coordinates of the first target optical component (203) and the third alignment coordinates of the second target optical component (204) are determined; Active coupling adjusts at least one of the target optical component and the optical amplifier until the target optical component is coupled and aligned with the first waveguide (30). The target optical component includes the first target optical component (203) and the second target optical component (204); the alignment of the target optical component with the first waveguide (30) includes coupling the first target optical component (203) to the first end face (301) of the first waveguide (30) and coupling the second target optical component (204) to the second end face (302) of the first waveguide (30).

2. The coupling method according to claim 1, characterized in that, Active coupling adjustment of at least one of the target optical component and the optical amplifier until the target optical component is coupled and aligned with the first waveguide (30) includes: Based on the preset distance and the first alignment coordinates, after determining the second alignment coordinates of the first target optical component (203), the first target optical component (203) is actively coupled and adjusted to couple the first target optical component (203) to the first end face (301) of the first waveguide (30). Based on the preset distance and preset alignment coordinates, after determining the third alignment coordinates of the second target optical component (204), the second target optical component (204) is actively coupled and adjusted to couple the second target optical component (204) to the second end face (302) of the first waveguide (30).

3. The coupling method according to claim 2, characterized in that, The first optical component (201) is coupled and aligned with the first coupling end face (101) of the second waveguide (40), and the first alignment coordinates of the first optical component (201) are determined, including: Active coupling aligns the first optical component (201) with the first coupling end face (101) of the second waveguide (40). The position coordinates at which the maximum output optical power of the second waveguide (40) is determined are the first alignment coordinates.

4. The coupling method according to claim 2 or 3, characterized in that, The step of actively coupling and adjusting the first target optical component (203) to couple and align the first target optical component (203) with the first end face (301) of the first waveguide (30) includes: using the position corresponding to the second alignment coordinate as a reference, adjusting the deflection angle of the first target optical component (203) relative to the first end face (301) of the first waveguide (30), performing active coupling adjustment on the first waveguide (30) until the optical power received by the first target optical component (203) reaches the maximum value, and determining the position of the first target optical component (203); The steps of actively coupling and adjusting the second target optical component (204) to couple and align the second target optical component (204) with the second end face (302) of the first waveguide (30) include: using the third alignment coordinate as a reference, adjusting the deflection angle of the second target optical component (204) relative to the second end face (302) of the first waveguide (30), performing active coupling adjustment on the first waveguide (30) until the optical power received by the first target optical component (203) reaches the maximum value, and determining the position of the second target optical component (204).

5. The coupling method according to claim 2, characterized in that, The distance between the first waveguide (30) and the second waveguide (40) at the first coupling end face (101) of the optical amplifier is a first distance; The first distance is determined based on the distance from the first target optical component (203) to the first coupling end face (101) of the optical amplifier, the horizontal divergence angle of the emitted light spot of the first waveguide (30), and the radial dimension of the first target optical component (203).

6. The coupling method according to claim 5, characterized in that, The preset alignment coordinates include a first alignment coordinate or a second alignment coordinate. The third alignment coordinate is determined based on the second distance between the first waveguide (30) and the second waveguide (40) at the second coupling end face (102) of the optical amplifier, the preset alignment coordinates, and the cavity length of the optical amplifier. Alternatively, the second optical component (202) is actively coupled and aligned with the second coupling end face (102) of the second waveguide (40), and the position coordinates at which the maximum output optical power of the second waveguide (40) is determined are the fourth alignment coordinates; the preset alignment coordinates are the fourth alignment coordinates; the third alignment coordinates are determined based on the second distance between the first waveguide (30) and the second waveguide (40) at the second coupling end face (102) of the optical amplifier and the fourth alignment coordinates.

7. The coupling method according to claim 4, characterized in that, The steps of actively coupling and adjusting the second target optical component (204) to couple and align the second target optical component (204) with the second end face (302) of the first waveguide (30) include: Obtain the second optical power of the second waveguide (40) and the first optical power of the first waveguide (30); The third alignment coordinates are adjusted based on the first optical power until the difference between the first optical power and the second optical power is less than a preset value.

8. An optical amplifier, characterized in that, include: Substrate (10); An epitaxial structure (20) is formed on the substrate (10); The first waveguide (30) and the second waveguide (40) are both formed on the epitaxial structure (20); The end face of the first waveguide (30) forms an acute angle with the coupling end face of the optical amplifier, and any part of the second waveguide (40) forms a right angle with the coupling end face. The second waveguide (40) and the first waveguide (30) are spaced apart by a preset distance. The coupling end face includes a first coupling end face (101) and a second coupling end face (102) that are respectively provided. The second waveguide (40) and the first waveguide (30) both extend from the first coupling end face (101) of the optical amplifier to the opposite second coupling end face (102).

9. The optical amplifier according to claim 8, characterized in that, An electrical isolation region (50) is provided between the second waveguide (40) and the first waveguide (30).

10. The optical amplifier according to claim 9, characterized in that, The epitaxial structure (20) includes an active layer (23), and the electrical isolation region (50) includes an electrical isolation trench extending at least to the active layer (23) and an insulating region formed in the electrical isolation trench; Alternatively, the optical amplifier may further include a metal electrode disposed on the epitaxial structure (20), wherein the electrical isolation region (50) is a region between the first waveguide (30) and the second waveguide (40) where the metal electrode is at least partially stripped to expose the epitaxial structure (20).

11. The optical amplifier according to claim 9 or 10, characterized in that, The distance between the electrically isolated region (50) and the second waveguide (40) is 20-30 μm; And / or, the distance between the second waveguide (40) and the first waveguide (30) is greater than twice the ridge width of the first waveguide (30).

12. The optical amplifier according to claim 8, characterized in that, The distance between the first waveguide (30) and the second waveguide (40) on the first coupling end face (101) is greater than or equal to a threshold C; wherein the threshold C is determined based on the lateral diffusion width A of the first waveguide (30) on the first coupling end face (101) and the radial dimension of the optical component to be coupled, the lateral diffusion width A is determined based on the distance between the optical component and the first coupling end face (101), the horizontal divergence angle of the emitted light spot of the first waveguide (30) and a first included angle, the first included angle being the angle between the line connecting the two ends of the first waveguide (30) and the cavity length direction of the optical amplifier.

13. The optical amplifier according to claim 12, characterized in that, The distance between the first waveguide (30) and the second waveguide (40) on the second coupling end face (102) is greater than or equal to a threshold E; wherein the threshold E is determined based on the threshold C, the cavity length of the optical amplifier and the first included angle.

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