Alignment Method and Coupling Method for Optoelectronic Devices

Abstract

The present invention provides an alignment method and a coupling method for optoelectronic devices, wherein the alignment method for optoelectronic devices includes: a plane alignment step, adjusting the position of the beveled surface in a plane parallel to the photosensitive surface so that the beveled surface is above the normal of the photosensitive surface; a spacing alignment step, placing a reflector at an angle on the side of the chip, and observing and adjusting the normal spacing between the photosensitive surface and the optical fiber through the side view image of the chip reflected by the reflector collected by the imaging device. A deflection angle alignment step includes rotating and adjusting the angle of the optical fiber until the output power of the substrate is maximized. The alignment method for optoelectronic devices of the present invention uses a reflector to achieve the acquisition of side view images during the alignment process between the chip and the optical fiber, solving the problem that the lateral spacing cannot be directly observed due to the existence of the side wall of the tube shell. Moreover, the spacing alignment process and the horizontal alignment process can share a set of imaging devices, simplifying the structure and simplifying the operation process; thereby shortening the coupling time and improving the coupling efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic device coupling, and in particular to an alignment method and a coupling method of optoelectronic devices. Background Art

[0002] Optoelectronic devices in the field of optical communications include light emitters, light detectors, optical amplifiers, and other devices. These devices often utilize optical fibers of a certain standard specification to transmit light between them and the outside world, enabling the transfer of optical signals and light energy between the device and the outside world. Coupling, as used in this application, refers to the process of adjusting and securing the optical fiber and light detector to the correct position, enabling the detector to respond to the optical signal in the fiber and generate an output electrical signal.

[0003] The structure of existing optoelectronic devices with deep cavity shells is as follows Figure 1 An optical chip is mounted on the substrate, which generates an electrical signal by sensing the incident light. The substrate is also provided with peripheral circuits that match the optical chip. The substrate with the optical chip is located in a tube shell with side walls on all sides. The side wall of the tube shell is designed with a tail pipe to facilitate the optical fiber component to enter the tube shell through the tail pipe and couple with the optical chip. For optical detector coupling, it is divided into horizontal alignment and vertical alignment coupling. Vertical coupling is limited by the observation angle and structural space, and is mostly used in TO-type packaging. Generally, high-precision coupling adopts the horizontal coupling method of beveled optical fiber and detector chip.

[0004] The end face of an optical fiber is typically an angled surface. After the optical signal within the beam is totally reflected by this surface, it is reversed and emitted from the surface. The emitted optical signal is received by the photosensitive surface of the chip and converted into an electrical signal by the chip. Therefore, precise alignment and fixation of the relative position between the optical fiber's bevel and the chip's photosensitive surface is essential for signal transmission and conversion. This requires both the spatial position and rotational orientation of the bevel at the end of the optical fiber. Orthogonal positioning of the optical fiber on a surface parallel to the substrate is required, as is adjustment of the optical fiber's rotation angle around its axis to ensure coupling efficiency, with the bevel facing the photosensitive side of the optical chip.

[0005] Because optoelectronic devices require external high-frequency connectors, the housing used to package them must be designed with sidewalls, and the chip is housed within a cavity enclosed by these walls. Due to the obstruction of the housing walls, conventional coupling is limited to observing the offset between the optical fiber and the chip parallel to the substrate surface from above. This makes it impossible to observe the vertical distance between the fiber and the chip, nor is it possible to accurately measure the fiber's rotation angle. During insertion into the housing, the fiber may collide with the optical chip, causing component failure. Furthermore, the inability to observe the vertical distance between the fiber and the chip makes it impossible to ensure that the optical fiber's light-emitting surface is parallel to the chip's photosensitive surface, hindering rapid identification of the optimal coupling point. If the spacing between the fiber and the chip is not controlled, coupling efficiency will decrease if the fiber is too far from the chip. However, if the fiber is too close to the chip, the fiber may collide with the chip in shock and vibration environments, damaging it. Summary of the Invention

[0006] Existing optoelectronic devices with housings present difficulties in alignment and coupling. Due to the inconvenience of observation, components may collide and be damaged. Furthermore, it is difficult to accurately position optical fibers and quickly complete alignment and coupling. To address this issue, the present invention provides an alignment method and coupling method for optoelectronic devices.

[0007] The technical solution of the present invention provides an alignment method for an optoelectronic device, which is used for aligning an optoelectronic device. The optoelectronic device has a chip arranged in a cavity of a tube shell, and a tail tube for an optical fiber to pass through is arranged on the tube shell;

[0008] The alignment method of the optoelectronic device comprises the following steps:

[0009] Plane alignment steps: After inserting the optical fiber into the tail tube, adjust the position of the optical fiber's bevel in a plane parallel to the photosensitive surface so that the bevel is above the normal direction of the photosensitive surface;

[0010] Gap alignment steps: Place a reflector at an angle on the side of the chip to reflect the side view image of the chip to the imaging device. Observe the normal distance between the photosensitive surface and the optical fiber using the side view image captured by the imaging device. Move the optical fiber along the normal direction of the photosensitive surface with reference to the normal distance to within a predetermined height RH above the photosensitive surface.

[0011] Deflection angle alignment step: The deflection angle alignment step includes at least a fine-tuning step, that is, rotating and adjusting the angle of the optical fiber until the output power of the substrate is maximum.

[0012] Preferably, in the spacing alignment step, the angle between the photosensitive surface and the reflector is 45 degrees.

[0013] Preferably, the reflector is parallel to the extending direction of the optical fiber.

[0014] Preferably, the deflection angle alignment step includes at least one coarse adjustment step before the fine adjustment step, that is, observing and adjusting the angle of the optical fiber 13 by the projection shape of the beveled surface in the side view image.

[0015] Preferably, in the planar alignment step, the normal distance between the optical fiber and the tail tube is maintained to be greater than a first threshold value T1.

[0016] Preferably, the first threshold T1 is T1 ≥ 0.3 mm.

[0017] Preferably, the predetermined height range RH satisfies 0.1 mm ≤ RH ≤ 0.3 mm.

[0018] The present invention also provides a coupling method for an optoelectronic device, which includes any one of the above-mentioned methods for aligning an optoelectronic device.

[0019] Preferably, the method comprises the following steps:

[0020] Alignment step: completing the alignment operation between the optical fiber and the chip according to the alignment method of the optoelectronic device to obtain the optimal coupling point of the optical fiber;

[0021] Glue dispensing step: Move the aligned optical fiber to facilitate the glue application between the optical fiber and the tail tube;

[0022] Reset steps: After applying glue between the optical fiber and the tail tube, move the optical fiber in the opposite direction to the optimal coupling point.

[0023] Preferably, the resetting step repeats the operation of the aligning step.

[0024] Preferably, in the dispensing step, the movement of the optical fiber is limited to one of the movement parallel to the photosensitive surface or the movement along the normal direction of the photosensitive surface; correspondingly, in the resetting step, only one of the plane alignment step or the spacing alignment step of the alignment method of the optoelectronic device is performed.

[0025] The optoelectronic device alignment method of the present invention utilizes an auxiliary reflector during the alignment process to capture a side view image of the chip and optical fiber, resolving the issue of being unable to directly observe the lateral spacing during alignment due to the presence of the tube shell sidewall. Furthermore, even in optoelectronic devices without a tube shell, the reflector ensures that the side view image's optical path is parallel to the top view optical path during horizontal alignment. In actual alignment, given the limited size of optoelectronic devices, a shared imaging device can be used, simplifying both the structure and the operational process, thereby shortening coupling time and improving coupling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the optoelectronic device of the present invention;

[0027] Figure 2 Schematic diagram of the optical path of the optoelectronic device of the present invention;

[0028] Figure 3 It is a structural schematic diagram of the alignment method of the optoelectronic device of the present invention.

[0029] In the figure,

[0030] 1: Optoelectronic device 11: Substrate 12: Chip 121: Photosensitive surface 13: Optical fiber 131: Beveled surface 14: Housing 141: Tail pipe 2: Reflector 3: Imaging device DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. In this specification, the size ratios in the drawings do not represent the actual size ratios, but are only used to reflect the relative positional relationship and connection relationship between the various components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.

[0032] In the manufacture of optoelectronic devices, in order to avoid the influence of the external environment on the devices, the devices need to be integrated into a special tube shell and securely fixed. Figure 1 A simplified schematic diagram of the structure of such an optoelectronic device is shown. The conversion portion of the optoelectronic device 1 includes a substrate 11 and a chip 12 attached to and electrically connected to the substrate 11. The light transmission portion is an optical fiber 13 disposed above the photosensitive surface 121 of the chip 12. The optical fiber 13 extends in a plane parallel to the photosensitive surface 121, with its end located above the photosensitive surface 121. To allow light emitted by the optical fiber 13 to enter and project onto the photosensitive surface 121, the end of the optical fiber 13 is typically configured with a beveled surface 131. The beveled surface 131 faces the photosensitive surface 121 in the circumferential direction of the optical fiber 13 to maximize the optical signal input on the photosensitive surface 121. It should be noted that the angle of the beveled surface 131 is generally between 40 and 50 degrees in order to achieve total reflection and ensure reflection efficiency, with 40 or 45 degrees being the most common. Therefore, it can be understood that when the beveled surface is not 45 degrees, the reflected light is not actually parallel to the normal of the photosensitive surface 121 when irradiating the photosensitive surface 121. However, since the spacing between the photosensitive surface 121 and the beveled surface 131 after coupling is less than 0.3 mm, the angle deviation does not affect the alignment effect. In addition, in this application, the beveled surface 131 located directly above the photosensitive surface 121 should not be understood as a position where the geometric center coincides, but should be understood as the center point of the beveled surface 131 always being within a planar position range within the photosensitive surface 121.

[0033] The optoelectronic device 1 is also provided with a protective part, mainly including a tube shell 14 for protecting the substrate 11 and the chip 12. The substrate 11 is placed in the cavity of the tube shell 14 and is surrounded by the side walls of the tube shell, which effectively prevents the intrusion of foreign objects. In the subsequent packaging, the opening on the upper part of the tube shell 14 will also be closed. Therefore, the environment inside the optoelectronic device 1 is completely sealed, completely avoiding the interference of the external environment on the operation of the optoelectronic device.

[0034] Figure 2 Figure 1 is a schematic diagram of the optical path of optoelectronic device 1. As incident light propagates through optical fiber 13, it undergoes total internal reflection at the beveled surface 131 at the end of the fiber 13, where it is deflected and emitted from the fiber's surface. The deflected light is projected onto photosensitive surface 121 and converted into an electrical signal for output by chip 12. The dimensions of optical fiber 13 and chip 12 are typically in the micron range. To achieve optimal coupling and prevent collisions between optical fiber 13 and chip 12 during vibration, the coupling spacing between them is typically controlled between 0.1 and 0.3 mm.

[0035] The diameter of the tail tube 141 is larger than the diameter of the optical fiber 13, providing control for adjusting the position of the optical fiber, and is also used for subsequent glue coating to fix the optical fiber. The tube shell 14 assembled with the substrate 11 and the chip 12 is placed on a tube shell fixture and fixed so that the tube shell 14 as a whole no longer moves during the alignment and coupling process. The optical fiber 13 is fixed on a high-precision displacement stage by a fiber optic clamp. During the alignment and coupling process, the position and posture (posture) of the displacement stage that fixes the optical fiber 13 is adjusted so that the posture of the beveled surface 131 of the chip 12 to be coupled, which is gradually approached by the tail tube 141 and extends into the tube shell 14, changes accordingly until a larger output signal power is obtained. The measurement of the output power can usually be achieved by a detection instrument connected to the substrate.

[0036] In general, in order to achieve alignment coupling between the chip 12 and the optical fiber 13, the following problems need to be solved: first, the position adjustment of the bevel 131 in the plane parallel to the photosensitive surface 121; second, the spacing adjustment between the optical fiber 13 and the chip 12; third, the circumferential deflection angle adjustment of the bevel 131 along the axis of the optical fiber 13. Among them, the plane position adjustment of the bevel 131 can be achieved by directly observing the real-time image captured by the image device 3 (such as a CCD camera). However, the spacing adjustment between the optical fiber 13 and the chip 12 cannot be directly observed by the eye or the image device 3 due to the obstruction of the side wall. At the same time, the judgment of the rotation angle of the optical fiber 13 is only confirmed above the optical fiber 13. Due to the lack of reference, its accuracy is difficult to guarantee.

[0037] The optoelectronic device alignment method of the present invention utilizes a reflector 2 positioned on the side of chip 12 to reflect a side view image of chip 12 and optical fiber 13 to an imaging device 3, thereby obtaining an indication of the relative spacing between beveled surface 131 and photosensitive surface 121. Furthermore, through appropriate placement, the image of optical fiber 13 can be aligned with photosensitive surface 121 when entering reflector 2. This allows for improved accuracy in adjusting the circumferential deflection angle of beveled surface 131 by observing whether the side projection of beveled surface 131 forms a straight line.

[0038] The steps of the optoelectronic device alignment method of the present invention generally include:

[0039] Plane alignment steps.

[0040] After inserting the optical fiber 13 through the tail tube 141, maintain the normal distance between the optical fiber 13 and the tail tube 141 greater than a first threshold value T1. Adjust the position of the beveled surface 131 in a plane parallel to the photosensitive surface 121 so that the beveled surface 131 is above the normal direction of the photosensitive surface 121. This is to avoid the risk of device damage and scrapping caused by potential contact between the optical fiber 13 and the photosensitive surface 121 due to operational errors. The first threshold value T1 is generally set to T1>=0.3mm.

[0041] Pitch alignment step.

[0042] A reflector 2 is positioned at an angle to the side of the chip 12 to reflect the side view image of the chip 12 to the imaging device 3, thereby providing an output image from the imaging device 3 for observing the normal distance between the photosensitive surface 121 and the optical fiber 13. With reference to the side view image output by the imaging device 3, the optical fiber 13 is moved along the normal direction of the photosensitive surface 121 to within a predetermined height range RH above the photosensitive surface 121. Because the normal distance is greater than the first threshold value T1 during the planar alignment step, the normal movement along the photosensitive surface 121 here typically involves moving the optical fiber 13 normal to the photosensitive surface 121 to reduce the distance.

[0043] The preferred position of the reflector 2 is as follows: Figure 3 As shown, the reflector 2 is positioned at a 45-degree angle to the photosensitive surface 121, and non-human installation errors are acceptable. This ensures that the imaging light path entering the reflector 2 is parallel to the photosensitive surface 121, without compromising distance accuracy, and facilitates placement and verification. More preferably, the reflective surface of the reflector 2 is positioned at a 45-degree angle to the photosensitive surface 121 and parallel to the axial direction of the optical fiber 13.

[0044] The given height range RH can generally be taken as RH∈[0.1mm,0.3mm] (i.e. 0.1mm<=RH<=0.3mm)

[0045] Taking into account the small size of the chip 12, the distance between the reflector 2 and the chip 12 is reasonably set, so that the reflected light path of the reflector 2 is still within the field of view of the plane-aligned image device 3. Therefore, the spacing alignment step and the plane alignment step can share the image device 3. It is only necessary to adjust the focal length of the lens to ensure that the image of the target area is clear when switching. In fact, it can be seen that the above operation can be used not only for the alignment of optoelectronic devices with a tube shell, but also for optoelectronic devices without a tube shell and without the obstruction of the tube shell side wall. The image device 3 can be shared by the reflector 2 without the need to set up two independent image devices 3. This also simplifies the operation process and improves the operation efficiency.

[0046] Deflection angle alignment steps.

[0047] The deflection angle alignment step includes at least a fine adjustment step, wherein the optical fiber 13 is rotated to adjust the angle so that the circumferential angle of the beveled surface 131 changes until the substrate 11 stops at the maximum output power, which is the circumferential angle position of the beveled surface 131 .

[0048] Optionally, at least one coarse adjustment step can be completed before the fine adjustment step. That is, the approximate deflection angle of the beveled surface 131 is observed and adjusted through the projection of the beveled surface 131 in the side view image. Specifically, the reflector 2 is placed at an angle on the side of the chip 12, or, if it is performed after the subsequent spacing alignment step, the reflector 2 in this step can be shared. The side view image of the chip 12 reflected from the reflector 2 is obtained by the imaging device 3. Observe the projection features of the beveled surface 131 in the side view image. When it is almost distributed as a line in the side view image, the beveled surface 131 is basically facing the photosensitive surface 121. This can provide a better operating basis for the subsequent fine adjustment process, reduce the number of switching times, and improve the operating efficiency of the angle adjustment.

[0049] The above steps are repeated at least once, and can be repeated alternately depending on the specific situation.

[0050] Based on the above alignment steps, the present invention further provides a coupling method for optoelectronic devices, which includes the above alignment steps.

[0051] First of all, it is obvious that after the optical fiber 13 passes through the tail tube 141 and before the above-mentioned alignment method of the optoelectronic device is started, glue can be dispensed between the optical fiber 13 and the tail tube 141 for fixation, and then the alignment operation of the optical fiber 13 can be completed according to the above-mentioned alignment method of the optoelectronic device, so that the optical fiber 13 remains in the aligned position until the glue solidifies.

[0052] This solution still falls within the scope of protection of the present invention, but it should be noted that during product preparation, the possibility of defective optical fibers 13, substrates 11, and chips 12 cannot be ruled out. In this case, if glue is applied first and then aligned, once the component fails during the alignment fine-tuning process due to product defects or operational errors (such as friction between the chip 12 and the optical fiber 13), other parts can only be replaced to realign the coupling. However, it should be noted that the optical fiber 13 and the tube shell 14 are already contaminated with glue. If the optical fiber 13 fails, then in the process of reinserting the new optical fiber 13 into the tube shell 14, the glue will contaminate the end of the optical fiber 13, making it unusable. Therefore, the actual consequence is that applying glue first will cause the tube shell 14 including the chip 12 to be scrapped as a whole. Correspondingly, if the chip 12 is defective, when the optical fiber 13 is taken out after applying glue, the glue will contaminate the end of the optical fiber 13, resulting in unnecessary scrapping of the optical fiber 13.

[0053] Therefore, the steps of the optimized optoelectronic device coupling method include:

[0054] Alignment step: The alignment operation between the optical fiber 13 and the chip 12 is completed according to the above-mentioned alignment method of the optoelectronic device to obtain the optimal coupling point of the optical fiber 13.

[0055] Glue dispensing step: Move the aligned optical fiber 13 to facilitate the glue application between the optical fiber 13 and the tail tube 141. A gap is left on the tail tube 141 for glue dispensing. To ensure that the glue completely penetrates around the optical fiber 13 in the tail tube 141, it is recommended to move the optical fiber 13 upward appropriately.

[0056] Reset step. After applying glue between the optical fiber 13 and the tail tube 141, the optical fiber 13 is moved in the reverse direction to the optimal coupling point in the original position. Obviously, during the reverse movement after applying glue, it is necessary to ensure that the position of the optical fiber 13 is restored. Therefore, the reset step is optional, that is, repeating the above-mentioned alignment step.

[0057] Furthermore, in order to avoid the loss of efficiency caused by repeated alignment, during the glue dispensing step, the movement of the optical fiber 13 should only involve movement parallel to the photosensitive surface 121 or movement along the normal direction of the photosensitive surface 121. Therefore, during the resetting step after glue dispensing, only the plane alignment step or the pitch alignment step of the optoelectronic device alignment method can be performed.

[0058] The above content only describes the preferred embodiments of the present invention and does not limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solution of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for aligning an optoelectronic device, characterized in that: Used for aligning an optoelectronic device (1), wherein a chip (12) is arranged in a cavity of a tube shell (14) of the optoelectronic device (1). The tube shell (14) is provided with a tail tube (141) for the optical fiber (13) to pass through; The alignment method of the optoelectronic device comprises the following steps: Plane alignment step: after inserting the optical fiber (13) into the tail tube (141), adjusting the position of the oblique cut surface (131) of the optical fiber (13) in a plane parallel to the photosensitive surface (121) so that the oblique cut surface (131) is above the normal direction of the photosensitive surface (121); Pitch alignment step: Place a reflector (2) at an angle on the side of the chip (12), and the reflector (2) is used to reflect the chip (12) The side view image at the position is sent to the imaging device (3), and the normal distance between the photosensitive surface (121) and the optical fiber (13) is observed through the side view image collected by the imaging device (3); the optical fiber (13) is moved along the normal direction of the photosensitive surface (121) to within a predetermined height RH above the photosensitive surface (121) with reference to the normal distance; Deflection angle alignment step: The deflection angle alignment step includes at least a fine adjustment step, that is, rotating and adjusting the angle of the optical fiber (13) until the output power of the substrate (11) is maximum.

2. The method for aligning an optoelectronic device according to claim 1, wherein: In the spacing alignment step, the angle between the photosensitive surface (121) and the reflector (2) is 45 degrees.

3. The method for aligning an optoelectronic device according to claim 2, wherein: The reflector (2) is parallel to the extension direction of the optical fiber (13).

4. The method for aligning an optoelectronic device according to claim 3, wherein: The deflection angle alignment step includes at least one coarse adjustment step before the fine adjustment step, that is, observing and adjusting the angle of the optical fiber (13) through the projection shape of the beveled surface (131) in the side view image.

5. The method for aligning an optoelectronic device according to claim 1, wherein: In the planar alignment step, the normal distance between the optical fiber (13) and the tail tube (141) is maintained to be greater than a first threshold value T1.

6. The method for aligning an optoelectronic device according to claim 5, wherein: The first threshold T1 is T1≥ 0.3mm.

7. The method for aligning an optoelectronic device according to claim 1, wherein: The predetermined height RH satisfies 0.1 mm ≤ RH ≤ 0.3 mm.

8. A coupling method for an optoelectronic device, characterized in that: A method for aligning an optoelectronic device comprising the steps of claim 1 .

9. The optoelectronic device coupling method according to claim 8, wherein: The steps include: Alignment step: completing the alignment operation between the optical fiber (13) and the chip (12) according to the alignment method of the optoelectronic device according to any one of claims 1 to 7 to obtain the optimal coupling point of the optical fiber (13); Glue dispensing step: moving the aligned optical fiber (13) to facilitate glue dispensing between the optical fiber (13) and the tail tube (141); Resetting step: After applying glue between the optical fiber (13) and the tail tube (141), the optical fiber (13) is moved in the reverse direction to the optimal coupling point.

10. The optoelectronic device coupling method according to claim 9, wherein: The resetting step repeats the operation of the aligning step.

11. The optoelectronic device coupling method according to claim 9, wherein: In the dispensing step, the movement of the optical fiber (13) is limited to one of the movement parallel to the photosensitive surface (121) or the movement along the normal direction of the photosensitive surface (121); accordingly, in the resetting step, only the parallel movement of the alignment method of the optoelectronic device according to any one of claims 1 to 7 is performed. One of a face alignment step or a pitch alignment step.

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