Chip end face coupling packaging structure and method

Abstract

The invention discloses a chip end face coupling packaging structure and method, and relates to the field of chip packaging, the chip end face coupling packaging structure comprises an optical fiber array structure and a chip, the optical fiber array structure comprises an upper cover plate, a lower cover plate and an optical fiber body, and the to-be-coupled end of the optical fiber body extends to the outer side of the upper cover plate and the outer side of the lower cover plate; the chip is provided with a first surface, one end of the chip is provided with a scribing channel, and the scribing channel extends from the first surface to the direction, away from the first surface, of the chip; the end, provided with the scribing channel, of the chip is opposite to the to-be-coupled end of the optical fiber body, and the to-be-coupled end of the optical fiber body crosses the scribing channel to be in butt joint and coupled with the end face coupler on the first surface of the chip. The to-be-coupled end protrudes out of the end faces, close to the chip, of the upper cover plate and the lower cover plate, so that the to-be-coupled end of the optical fiber body can cross an existing scribing channel on the chip to achieve butt joint coupling with an end face coupler, grinding and polishing of a substrate at the scribing channel end are not needed, the packaging process is simplified, the production efficiency can be improved, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chip packaging, in particular to a chip end face coupling packaging structure and method. BACKGROUND

[0002] Silicon photonics chip and integrated circuit CMOS (Complementary Metal-Oxide-Semiconductor) process are highly compatible, and have broad application prospects in the fields of communication, sensing, optical computing, etc. In recent years, it has developed rapidly and become a research hotspot. Optical coupling packaging technology is committed to realizing efficient connection between chips and external optical fibers, and is one of the key technologies for silicon photonics chip to realize large-scale application. The waveguide end face coupling technology has become the mainstream direction in this field because of its advantages such as compact structure, low loss, polarization insensitivity, large bandwidth and mature process. However, due to the existence of deep etched groove type notch (slicing channel reserved during wafer slicing to ensure that the end face coupler is not damaged during slicing) on the end face of the silicon photonics chip, the ordinary 0° optical fiber array cannot be tightly fitted with the end face coupler. Specifically, the existing optical fiber array to be coupled end is flush with the end face of the upper and lower cover plates of the optical fiber array, that is, the optical fiber array to be coupled end does not protrude from the end face of the upper and lower cover plates, which causes the optical fiber array to be unable to directly couple with the end face coupler behind the groove type notch. At present, when the chip end face is coupled and packaged, the protruding front edge of the chip corresponding to the groove type notch needs to be ground and polished first, so that the end face of the silicon photonics chip forms a smooth end face, so that the to-be-coupled end of the end face coupler is located on the smooth end face plane, and then the silicon photonics chip and the optical fiber array are coupled. The existing chip end face coupling packaging process is complicated and costly. SUMMARY

[0003] The purpose of the present application is to provide a chip end face coupling packaging structure and method to solve the problems existing in the prior art, simplify the packaging process, improve production efficiency, and significantly reduce packaging cost.

[0004] To achieve the above purpose, the present application provides the following solutions:

[0005] The present application provides a chip end face coupling packaging structure, comprising an optical fiber array structure and a chip, wherein:

[0006] The optical fiber array structure comprises an upper cover plate, a lower cover plate and an optical fiber body, the optical fiber body is arranged between the upper cover plate and the lower cover plate, and the to-be-coupled end of the optical fiber body protrudes outside the upper cover plate and the lower cover plate;

[0007] The chip has a first surface, and a scribe line is provided at one end of the chip, and the scribe line extends from the first surface toward the chip away from the first surface; the end of the chip provided with the scribe line is arranged opposite to the end to be coupled of the optical fiber body, and the end to be coupled of the optical fiber body crosses the scribe line and is docked and coupled with the end face coupler on the first surface of the chip.

[0008] Preferably, it also includes a connecting cover plate, which is fixedly connected to the end of the upper cover plate close to the chip, and the connecting cover plate is fixedly connected to the first surface. A groove is provided on the surface of the connecting cover plate close to the first surface, and the groove is arranged at the end of the connecting cover plate close to the chip. The groove and the dicing road form an avoidance groove, and the end to be coupled of the optical fiber body is arranged in the avoidance groove and is fitted with the side wall of the end face coupler close to the optical fiber body, and a gap is left between the end to be coupled of the optical fiber body and the two inner walls of the avoidance groove.

[0009] Preferably, the connecting cover plate is a glass cover plate, the optical fiber body is a single-mode optical fiber, the end to be coupled of the single-mode optical fiber is tapered, and the chip is a silicon photonic chip.

[0010] Preferably, the distance between the inner wall of the avoidance groove away from the chip and the plane where the first surface is located is the height of the avoidance groove, and the height of the avoidance groove is greater than half the diameter of the optical fiber body; the width of the avoidance groove is greater than the length of the part of the optical fiber body protruding from the upper cover plate.

[0011] Preferably, the thickness of the connecting cover plate is greater than or equal to the thickness of the upper cover plate.

[0012] Preferably, a plurality of V-shaped grooves extending toward the chip are provided on a side of the lower cover plate close to the upper cover plate, and one of the optical fiber bodies is provided in each of the V-shaped grooves.

[0013] Preferably, a metal heat sink is further included, which is arranged on a side of the chip away from the connecting cover plate, a metal boss is arranged between the metal heat sink and the chip, and the chip protrudes from the end of the metal boss close to the lower cover plate.

[0014] Preferably, one end of the optical fiber array structure close to the chip, one end of the chip close to the optical fiber array structure, one end of the connecting cover plate close to the optical fiber array structure, and one end of the metal heat sink close to the optical fiber array structure are fixedly connected by a refractive index matching gel.

[0015] The present invention also provides a chip end face coupling packaging method based on the chip end face coupling packaging structure, comprising the following steps:

[0016] The optical fiber body is arranged between the upper cover plate and the lower cover plate, and the to-be-coupled end of the optical fiber body protrudes outside the upper cover plate and the lower cover plate; the to-be-coupled end of the optical fiber body is arranged opposite to one end of the chip provided with the scribe lane, and the to-be-coupled end of the optical fiber body is coupled to the end face coupler on the first surface of the chip through the scribe lane.

[0017] Preferably, further comprising: arranging a connecting cover plate at one end of the chip close to the upper cover plate, a groove is arranged on a first end face of the connecting cover plate, and the groove penetrates through one side of the connecting cover plate close to the first end face; the groove is arranged opposite to the scribe lane, and the groove and the scribe lane form an avoiding groove; the connecting cover plate is fixedly connected to one end of the upper cover plate close to the chip and the first surface; the to-be-coupled end of the optical fiber body is arranged in the avoiding groove, and the optical fiber body is attached to the end face coupler close to the side wall of the optical fiber body; and a gap is left between the to-be-coupled end of the optical fiber body and the two inner walls of the avoiding groove.

[0018] The present application has the following technical effects relative to the prior art:

[0019] The present application provides a chip end face coupling packaging structure and method, comprising an optical fiber array structure and a chip, wherein: the optical fiber array structure comprises an upper cover plate, a lower cover plate and an optical fiber body, the optical fiber body is arranged between the upper cover plate and the lower cover plate, and the to-be-coupled end of the optical fiber body protrudes outside the upper cover plate and the lower cover plate; the chip has a first surface, one end of the chip is provided with a scribe lane, and the scribe lane extends away from the first surface of the chip in a direction away from the first surface; the one end of the chip provided with the scribe lane is arranged opposite to the to-be-coupled end of the optical fiber body, and the to-be-coupled end of the optical fiber body is coupled to the end face coupler on the first surface of the chip through the scribe lane. By making the to-be-coupled end of the optical fiber body protrude outward from the end face of the upper and lower cover plates close to the chip, the to-be-coupled end of the optical fiber body can pass through the existing scribe lane on the chip, realize butt coupling with the end face coupler, and there is no need to grind and polish the substrate part corresponding to the scribe lane on the chip, thereby simplifying the packaging process, improving production efficiency and reducing cost. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0021] Fig. 1 The structural schematic diagram of the chip end face coupling packaging structure provided for embodiment 1.

[0022] Fig. 2 Structure diagram of part structure of chip end face coupling package structure provided for embodiment 1;

[0023] Fig. 3 Structure diagram of chip provided for embodiment 1;

[0024] Fig. 4 Structure diagram of fiber array structure provided for embodiment 1;

[0025] Fig. 5 Structure diagram of connecting cover plate provided for embodiment 1;

[0026] Fig. 6 Diagram of avoiding groove and scribing groove provided for embodiment 1;

[0027] In the figure: 1000, chip end face coupling package structure; 100, fiber array structure, 101, upper cover plate; 102, solidified glue; 103, fiber body; 104, lower cover plate; 200, connecting cover plate; 201, avoiding groove; 300, chip; 301, scribing groove; 302, end face coupler; 400, metal heat sink; 500, refractive index matching gel. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0029] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer", "front", "back", "center", "longitudinal", "transverse", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "clockwise", "counterclockwise" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", "fourth" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0030] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] The purpose of the present invention is to provide a chip end face coupling packaging structure and method to solve the problems existing in the prior art, simplify the packaging process, improve production efficiency, and significantly reduce packaging costs.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figs. 1-6 As shown, this embodiment provides a chip end-face coupling packaging structure 1000, including an optical fiber array structure 100 and a chip 300, wherein: the optical fiber array structure 100 includes an upper cover plate 101, a lower cover plate 104 and an optical fiber body 103, the optical fiber body 103 is arranged between the upper cover plate 101 and the lower cover plate 104, and the end to be coupled of the optical fiber body 103 extends to the outside of the upper cover plate 101 and the lower cover plate 104; the chip 300 has a first surface ( Fig. 1 The upper surface of the chip 300 is provided with a scribe line 301 at one end of the chip 300, and the scribe line 301 extends from the first surface toward the direction of the chip 300 away from the first surface; the end of the chip 300 provided with the scribe line 301 is arranged opposite to the end to be coupled of the optical fiber body 103, and the end to be coupled of the optical fiber body 103 crosses the scribe line 301 and is docked and coupled with the end face coupler 302 on the first surface of the chip 300.

[0035] By making the end of the optical fiber body 103 to be coupled protrude outward from the upper and lower cover plates 104 close to the end face of the chip 300, the end of the optical fiber body 103 to be coupled can pass over the existing dicing street 301 on the chip 300 and achieve docking coupling with the end face coupler 302. That is, after the chip 300 is cut, there is no need to grind and polish the base portion corresponding to the dicing street 301 on the chip 300, and the coupling operation can be carried out directly, which simplifies the packaging process, can improve production efficiency, and significantly reduce the packaging cost.

[0036] In the embodiment, a connecting cover plate 200 is further included, which is fixedly connected with the upper cover plate 101 at one end close to the chip 300, and is fixedly connected with the first surface. A groove is formed on the surface of the connecting cover plate 200 close to the first surface, and the groove is arranged at the one end of the connecting cover plate 200 close to the chip 300. The groove and the scribe line 301 form an avoiding groove 201. The to-be-coupled end of the optical fiber body 103 is arranged in the avoiding groove 201 and is attached to the sidewall close to the optical fiber body 103 of the end face coupler 302. A gap is left between the to-be-coupled end of the optical fiber body 103 and the two inner walls of the avoiding groove 201. Since the contact area between the end face coupler 302 and the optical fiber body 103 is small, and the gap between the chip 300 and the lower cover plate 104 cannot be 0, the connecting cover plate 200 is arranged between the chip 300 and the optical fiber array structure 100, and the chip 300 and the optical fiber array structure 100 are further connected through the connecting cover plate 200, so that the attachment area of the chip 300 and the optical fiber array structure 100 is increased, the slight displacement of the optical fiber array structure 100 caused by directly adding the refractive index matching liquid for curing is reduced, the structure is more stable, and the coupling efficiency is higher. The avoiding groove 201 can prevent the connecting cover plate 200 from directly pressing on the optical fiber body 103 and damaging or deviating the optical fiber body 103.

[0037] In the embodiment, as shown in FIG. 2, the connecting cover plate 200 is L-shaped. Fig. 1

[0038] In the embodiment, the connecting cover plate 200 is a glass cover plate, preferably an ultrathin glass cover plate, and the thickness is 0.3-2 mm. The optical fiber body 103 is a single-mode optical fiber, and the to-be-coupled end of the single-mode optical fiber is tapered. Since the tapered single-mode optical fiber is used, the tapered tip mode field is a small mode field, and the small mode field optical fiber does not need to be fused with the single-mode optical fiber, so that the packaging process is further simplified. The chip 300 is a silicon optical chip 300. Further, the optical fiber array structure 100 is a special-shaped optical fiber array, which is arranged by small mode field tapered optical fibers (the mode field diameter is about 2-4 μm, preferably about 3.5 μm, and the length of the tapered tip is 0.1-0.5 mm). The tapered tip part protrudes from the upper and lower cover plates 104. Preferably, the coupling end of the single-mode optical fiber is ground into a taper to convert the light-emitting mode field into a small mode field.

[0039] In the embodiment, the distance between the inner wall of the avoiding groove 201 away from the chip 300 and the plane where the first surface is located is the height (h1 in the figure) of the avoiding groove 201. The height of the avoiding groove 201 is greater than half of the diameter of the optical fiber body 103, and is generally between 0.1-0.3 mm. The width (w3 in the figure) of the avoiding groove 201 is greater than the length of the part of the optical fiber body 103 protruding from the upper cover plate 101. ​

[0040] In the embodiment, the thickness of the connecting cover plate 200 is greater than or equal to the thickness of the upper cover plate 101.

[0041] In the embodiment, the lower cover plate 104 is provided with a plurality of V-shaped grooves extending towards the chip 300 on the side close to the upper cover plate 101, and one optical fiber body 103 is arranged in each V-shaped groove. The end face coupler 302 is a multi-channel coupler.

[0042] In the embodiment, a metal heat sink 400 is further included, which is arranged on the side of the chip 300 away from the connecting cover plate 200, and a metal boss is arranged between the metal heat sink 400 and the chip 300, and the chip 300 protrudes from the end of the metal boss close to the lower cover plate 104.

[0043] In the embodiment, the end of the optical fiber array structure 100 close to the chip 300, the end of the chip 300 close to the optical fiber array structure 100, the end of the connecting cover plate 200 close to the optical fiber array structure 100, and the end of the metal heat sink 400 close to the optical fiber array structure 100 are fixedly connected by the refractive index matching gel 500.

[0044] In the embodiment, the material of the metal heat sink 400 is copper, iron, aluminum, Kovar alloy, etc. The chip 300 is attached to the metal boss, and the width w4 of the chip packaging end face protruding from the metal heat sink 400 is 0.1-0.5 mm, which prevents overflow of the bottom surface during the attachment of the chip, and ensures that the optical fiber array structure 100 can be well attached to the chip 300. The height of the metal heat sink 400 should not be too high or too low, and the distance between the lower cover plate 104 of the optical fiber array structure 100 and the metal heat sink 400 is 0.1-2 mm.

[0045] In the embodiment, the diameter of the optical fiber body 103 is preferably 125 μm.

[0046] In the embodiment, the height (h2 in the figure) of the scribe groove 301 is greater than half the diameter of the optical fiber body 103, and is generally about 100 μm; and the width (w1 in the figure) of the scribe groove 301 is about 70 μm.

[0047] In the embodiment, the smaller the distance (w2 in the figure) between the end face of the chip 300 close to the lower cover plate 104 and the end face of the lower cover plate 104 close to the chip 300, the better, but due to the processing precision of the optical fiber array, it is generally within the range of 0.1-0.3 mm.

[0048] In the embodiment, the length (w1+w2 in the figure) of the optical fiber body 103 protruding out of the upper and lower cover plates 104 is 0.1-0.5 mm.

[0049] In the embodiment, the length of the connecting cover plate 200 is greater than the width of the chip 300 array coupler, for example, the pitch of the coupler is 127 μm, and for 12 channels, the width of the array coupler is about 1.4 mm.

[0050] In the embodiment, the lower cover plate 104 is connected to the upper cover plate 101 through the cured glue 102.

[0051] Embodiment 2

[0052] The embodiment provides a chip end face coupling packaging method of the chip end face coupling packaging structure 1000 based on the embodiment 1, and the method comprises the following steps.

[0053] The fiber body 103 is arranged between the upper cover plate 101 and the lower cover plate 104, and the to-be-coupled end of the fiber body 103 protrudes to the outside of the upper cover plate 101 and the lower cover plate 104; the to-be-coupled end of the fiber body 103 is arranged opposite to one end of the chip 300 provided with the scribe lane 301, and the to-be-coupled end of the fiber body 103 is docked and coupled with the end face coupler 302 on the first surface of the chip 300 beyond the scribe lane 301. The fiber array structure 100 of the embodiment adopts the design of the upper and lower cover plates 104 being retracted and the fiber body 103 being protruded outward, so that the bare fiber of the fiber array structure 100 protrudes accurately from the end face of the fiber array structure 100, the traditional grinding and polishing process is not needed for the end face of the chip 300, the original etching end face of the chip 300 can be directly reserved for coupling, the key processes such as grinding, polishing and detection are reduced, the large-scale packaging efficiency of the silicon optical chip 300 is significantly improved, the manpower and material resources are saved, and the packaging cost is reduced.

[0054] In the embodiment, the connecting cover plate 200 is arranged at one end of the chip 300 close to the upper cover plate 101, a groove is formed in the first end face of the connecting cover plate 200, and the groove penetrates through one side face of the connecting cover plate 200 connected to the first end face; the groove is arranged opposite to the scribe lane 301 and forms an avoiding groove 201 with the scribe lane 301, the connecting cover plate 200 is fixedly connected to one end of the upper cover plate 101 close to the chip 300 and the first surface; the to-be-coupled end of the fiber body 103 is arranged in the avoiding groove 201, and the fiber body 103 is attached to the end face coupler 302 close to the side wall of the fiber body 103, and there is a gap between the to-be-coupled end of the fiber body 103 and the two inner walls of the avoiding groove 201.

[0055] In the embodiment, the connecting cover plate 200 is tightly attached to the upper cover plate 101, the refractive index matching liquid is arranged at the connecting cover plate 200, the fiber array structure 100, the chip 300 and the metal heat sink 400, the coupling is solidified through the refractive index matching liquid, the connecting cover plate 200, the fiber array structure 100 and the metal heat sink 400 are three-dimensionally reinforced through the refractive index matching liquid, and a stable packaging structure is formed.

[0056] In the embodiment, the chip 300 cut from the wafer is attached to the metal boss by the conductive silver glue, the end surface part of the chip 300 is ensured to protrude outward from the end part of the metal boss close to the chip 300 array structure, and the fiber array structure 100 cannot be tightly attached to the chip 300 is prevented; then the fiber array structure 100 is aligned with the end surface coupler 302, and the coupling efficiency reaches the highest alignment mark.

[0057] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above embodiment is only used for helping to understand the method of the present application and the core idea; meanwhile, for the general technical personnel in the field, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the present application should not be understood as the limitation of the present application.

Claims

1. A chip end-face coupling packaging structure, characterized in that: The invention comprises an optical fiber array structure and a chip, wherein: The optical fiber array structure includes an upper cover plate, a lower cover plate and an optical fiber body, wherein the optical fiber body is arranged between the upper cover plate and the lower cover plate, and the end to be coupled of the optical fiber body extends outward from the upper cover plate and the lower cover plate; The chip has a first surface, and a scribe line is provided at one end of the chip, and the scribe line extends from the first surface toward the chip away from the first surface; the end of the chip provided with the scribe line is arranged opposite to the end to be coupled of the optical fiber body, and the end to be coupled of the optical fiber body crosses the scribe line and is docked and coupled with the end face coupler on the first surface of the chip.

2. The chip end-face coupled packaging structure according to claim 1, wherein: It also includes a connecting cover plate, which is fixedly connected to the end of the upper cover plate close to the chip, and the connecting cover plate is fixedly connected to the first surface. A groove is provided on the surface of the connecting cover plate close to the first surface, and the groove is provided at the end of the connecting cover plate close to the chip. The groove and the dicing road form an avoidance groove, and the end to be coupled of the optical fiber body is provided in the avoidance groove and is fitted with the side wall of the end face coupler close to the optical fiber body, and a gap is left between the end to be coupled of the optical fiber body and the two inner walls of the avoidance groove.

3. The chip end-face coupled packaging structure according to claim 2, wherein: The connecting cover plate is a glass cover plate, the optical fiber body is a single-mode optical fiber, the end to be coupled of the single-mode optical fiber is tapered, and the chip is a silicon photonic chip.

4. The chip end-face coupled packaging structure according to claim 2, wherein: The distance between the inner wall of the avoidance groove away from the chip and the plane where the first surface is located is the height of the avoidance groove, and the height of the avoidance groove is greater than half the diameter of the optical fiber body; the width of the avoidance groove is greater than the length of the part of the optical fiber body protruding from the upper cover plate.

5. The chip end-face coupled packaging structure according to claim 2, wherein: The thickness of the connecting cover plate is greater than or equal to the thickness of the upper cover plate.

6. The chip end-face coupled packaging structure according to claim 1, wherein: A plurality of V-shaped grooves extending toward the chip are provided on one side of the lower cover plate close to the upper cover plate, and one optical fiber body is provided in each of the V-shaped grooves.

7. The chip end-face coupled packaging structure according to claim 2, wherein: It also includes a metal heat sink, which is arranged on a side of the chip away from the connecting cover plate. A metal boss is arranged between the metal heat sink and the chip, and the chip protrudes from the end of the metal boss close to the lower cover plate.

8. The chip end-face coupling packaging structure according to claim 7, characterized in that: One end of the optical fiber array structure close to the chip, one end of the chip close to the optical fiber array structure, one end of the connection cover plate close to the optical fiber array structure, and one end of the metal heat sink close to the optical fiber array structure are fixedly connected by a refractive index matching gel.

9. A chip end-face coupling packaging method based on the chip end-face coupling packaging structure according to any one of claims 1 to 8, characterized in that: The steps include: The optical fiber body is arranged between the upper cover plate and the lower cover plate, and the end of the optical fiber body to be coupled is extended to the outside of the upper cover plate and the lower cover plate; the end of the optical fiber body to be coupled is arranged opposite to the end of the chip where the dicing line is provided, and the end of the optical fiber body to be coupled is crossed over the dicing line and docked with the end face coupler on the first surface of the chip.

10. The chip end-face coupling packaging method according to claim 9, characterized in that: Also includes: A connecting cover plate is provided at one end of the chip close to the upper cover plate, and a groove is provided on the first end surface of the connecting cover plate, and the groove passes through a side surface of the connecting cover plate connected to the first end surface; the groove is arranged opposite to the scribe line and the groove and the scribe line form an avoidance groove, so that the connecting cover plate is fixedly connected to the end of the upper cover plate close to the chip and the first surface; the end to be coupled of the optical fiber body is arranged in the avoidance groove, and the optical fiber body and the end face coupler are fitted close to the side wall of the optical fiber body, and a gap is left between the end to be coupled of the optical fiber body and the two inner walls of the avoidance groove.

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