JP7133996B2 - Optical module and its manufacturing method - Google Patents

Description

The present invention relates to an optical module and its manufacturing method.

Optical modules using optical fibers are used as light emitting modules, light receiving modules, multiplexing modules, demultiplexing modules, etc. in optical communication systems, light source modules for medical fundus cameras, laser processing devices, and the like.

FIG. 6 shows a first conventional optical module, (A) is an overall perspective view of the upper side, (B) is an overall perspective view of the lower side, and (C) is a cross-sectional view of the sleeve (see Patent Document 1, 2).

6, the optical module includes an optical fiber 1, a ferrule 2 for hermetically fixing one end of the optical fiber 1 to improve optical connectivity of the optical fiber 1, and a ferrule 2 for inserting and fixing the ferrule 2. and a lens holder 4 fixed to the sleeve 3 and containing a lens.

In FIG. 6, optical fiber 1 and ferrule 2 are inserted into sleeve 3 . At this time, in order to align the optical axis of the optical fiber 1 and the optical axis of the lens of the lens holder 4 with high precision and fix them, the fixation is performed by spot welding using a YAG laser. For example, as shown in FIG. 6A, the ferrule ₂ and sleeve ₃ are welded at weld point P1 and penetration welded at penetration weld point P2. On the other hand, as shown in FIG. 6B, the sleeve ₃ and the lens holder 4 are welded together at the welding point P3. In this case, in order to reduce the welding energy at the through _- welding point P2, the sleeve 3 has a three-stage structure of a small-diameter portion 31, a medium-diameter portion (flange portion) 32, and a large-diameter portion (base portion) 33. _The small diameter portion 31 where P2 is provided is made as thin as possible. For example, the thickness of the small-diameter portion 31 is about 0.25 mm. As a result, penetration welding between the ferrule 2 and the small diameter portion 31 of the sleeve 3 can be easily performed. Note that the ferrule 2 and the sleeve 3 are made of the same or similar metal material for penetration welding between opposing surfaces (contact surfaces).

As shown in FIG. 6C, the formation of the sleeve 3 in FIG. The outer diameters of the medium diameter portion 32 and the large diameter portion 33 are formed by a lathe machining process. The manufacturing cost is low, and it is relatively easy to make the small diameter portion 31 as thin as possible, for example, to a thickness of about 0.25 mm.

On the other hand, in the optical fiber 1, the end face of the optical fiber is inclined at 8°, for example, in order to suppress reflected return light (see: paragraph 0003 of patent document 3, paragraph 0004 of patent document 4). An inclined-end optical fiber having an inclined end face is particularly effective for a single-mode optical fiber having a small core diameter, but it may also be applied to a multi-mode optical fiber.

FIG. 7 shows a second conventional optical module, where (A) is a front view and (B) is a cross-sectional view of a sleeve (see Patent Documents 3 and 5). The optical module of FIG. 7 adopts an inclined end face optical fiber 1'.

In FIG. 7, the end face of the inclined end face optical fiber 1' is, for example, an 8[deg.] inclined face. Therefore, the light emitted from the inclined end face (not shown) of the inclined end face optical fiber 1' travels through the large diameter portion 33 of the sleeve 3 while being inclined by about 4° (=8°/2). In this case, in order to align the optical axis of the inclined end face optical fiber 1' and the optical axis of the lens of the lens holder 4 with high accuracy, the center of the inclined end face optical fiber 1' and the center of the lens of the lens holder 4 are shifted. , adjusting the beam position.

The formation of the sleeve 3 in FIG. 7 is similar to the sleeve 3 in FIG. The outer diameters of the portion 31, the medium diameter portion 32 and the small diameter portion 31 are formed by a lathe machining process. For example, the thickness of the small-diameter portion 31 is about 0.25 mm. As a result, penetration welding between the ferrule 2 and the small diameter portion 31 of the sleeve 3 can be easily performed. Also in this case, the ferrule 2 and the sleeve 3 are made of the same or similar metal material for penetration welding between the opposing surfaces (contact surfaces).

FIG. 8 shows a third conventional optical module, (A) is an overall perspective view, (B) is an overall front view, and (C) is a cross-sectional view of a sleeve (see Patent Documents 4 and 6).

In FIG. 8, an inclined end face optical fiber 1' and a ferrule 2' having an 8° inclined end face are inclined by 4° (=8°/2) with respect to the sleeve 3', and the inclination angle of the inclined end face with respect to the sleeve 3' is 4°. In this case, the inclined through holes 31'a and 32'a for inserting the inclined end face optical fiber 1' and the ferrule 2' in the sleeve 3' are also inclined by 4°. Therefore, the emitted light from the inclined end face of the inclined end face optical fiber 1' becomes substantially vertical within the large diameter portion 33' of the sleeve 3'. As a result, the optical axis of the inclined end surface optical fiber 1′ and the lens holder (not shown) can be adjusted without adjusting the deviation between the center of the inclined end surface optical fiber 1′ and the center of the lens (not shown) of the lens holder 4. ) can be aligned with the optical axis of the lens with high accuracy. Therefore, beam quality can be improved. Also in this case, the ferrule 2' and the sleeve 3' are made of the same or similar metal material for penetration welding between the opposing surfaces (contact surfaces).

The formation of the sleeve 3 of FIG. 8 is similar to that of the sleeve 3 of FIG. and a lathe machining process for forming the outer diameters of the small diameter portion 31', the medium diameter portion 32' and the large diameter portion 33', and the manufacturing cost is low.

Japanese Utility Model Laid-Open No. 6-76908 Japanese Unexamined Patent Application Publication No. 2003-344698 Japanese Patent Application Laid-Open No. 2002-196180 JP-A-7-151934 Japanese Patent Application Laid-Open No. 2004-219756 JP-A-9-1371

However, the optical module shown in FIGS. 7 and 8 using the inclined end face optical fiber 1' has the following problems.

That is, in the second conventional optical module shown in FIG. 7, it is still not easy to adjust the beam position due to the deviation between the center of the optical fiber 1' and the center of the lens holder 4, and as a result, the beam quality is low. There is a problem.

Also, in the third conventional optical module shown in FIG. Furthermore, the thickness d of the small diameter portion 31' of the sleeve ₃ ' varies within the range of d1 to _d2 . Therefore, it is difficult to specify the thinnest place of the small diameter portion 31', and as a result, there is a problem that the penetration welding between the ferrule 2' and the small diameter portion 31' of the sleeve 3' is difficult.

In order to solve the above-mentioned problems, an optical module according to the present invention comprises an inclined end face optical fiber, a ferrule to which one end of the inclined end face optical fiber is attached, a diameter portion into which the ferrule is inserted with an inclination and fixed, and a diameter portion. and a sleeve having a base portion for holding , wherein the diameter portion has an inclined through-hole inclined in an inclined direction with respect to the axial direction of the sleeve, and the diameter portion is defined by the axial direction and the inclined direction of the sleeve. A ferrule having two flat surfaces formed so as to sandwich the inclined through hole in a vertical direction perpendicular to the surface, the distance between the two flat surfaces being smaller than the diameter of the diameter portion in the vertical direction, and and two flat surfaces are fixed by penetration welding.

In addition, the method of manufacturing an optical module according to the present invention comprises a first step of inserting and mounting an inclined end face optical fiber into a ferrule, and forming a diameter portion of a sleeve made of the same or similar metal material as the ferrule and an outer side of the base portion. and a second step for forming an inclined through-hole inclined with respect to the axial direction of the sleeve in the radial portion and forming a vertical through-hole in the axial direction of the sleeve in the base portion In step 3 , two flat surfaces are formed in the radial portion so as to sandwich the inclined through hole in the vertical direction perpendicular to the plane formed by the axial direction and the inclined direction of the sleeve, and the two flat surfaces in the vertical direction are formed. is smaller than the diameter of the diameter portion, and after the first, second, third and fourth steps, inserting the ferrule with the slanted end face optical fiber into the sleeve and a sixth step, after the fifth step, for through-welding the ferrule and the location of the flat surface facing the ferrule.

For penetration welding, the ferrule and sleeve may be made of the same or the same resin material instead of the same or the same kind of metal material. In this case, in the method of manufacturing an optical module described above, instead of the second and third steps, a sleeve comprising a diameter portion having an inclined through-hole and a base portion having a vertical through-hole is formed by a mold. Establish a process for

According to the present invention, penetration welding between the ferrule and the diameter of the sleeve can be facilitated while improving beam quality.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of an optical module according to the present invention, where (A) is an overall perspective view and (B) is an overall front view. Details of the sleeve in FIG. 1 are shown, (A) is a top view, (B) is a right side view, (C)-1 is a front view, (C)-2 is a front view explaining penetration welding, (D) is a cross-sectional view taken along line DD of (A). 2 is a flow chart for explaining a method of manufacturing the optical module of FIG. 1; An optical module as a first comparative example is shown, (A) is an overall perspective view, and (B) is an overall front view. An optical module as a second comparative example is shown, (A) is an overall perspective view, (B) is a top view of a sleeve, and (C) is a front view of a sleeve. A first conventional optical module is shown, (A) is an overall upper perspective view, (B) is an overall lower perspective view, and (C) is a cross-sectional view of a sleeve. A second conventional optical module is shown, (A) is an overall front view, and (B) is a cross-sectional view of a sleeve. FIG. 3 shows a third conventional optical module, (A) is an overall perspective view, (B) is an overall front view, and (C) is a cross-sectional view of a sleeve.

FIG. 1 shows an embodiment of an optical module according to the present invention, (A) is an overall perspective view, and (B) is an overall front view.

In FIG. 1, a sleeve 3'' is provided instead of the sleeve 3' of FIG. 8, and the sleeve 3'' has a small diameter portion 31'' instead of the small diameter portion 31' of FIG. 1 differs from the component shown in FIG. 8 only in the small diameter portion 31'' of the sleeve 3''. Therefore, similarly to the optical module shown in FIG. There is no need to adjust the deviation of the holder 4 from the center of the lens (not shown), and the beam quality can be improved.

In the small-diameter portion 31 ″ of FIG. 1, the I-cut surface, that is, the sleeve 3 ″ (small-diameter Flat surfaces 31″b and 31″c parallel to the plane formed by the _axis Ax of the portion 31″) and the ferrule 2′ (inclined through hole 31″a) are formed, and the tube thickness of the small diameter portion 31″ is partially In this case, the flat surfaces 31''b and 31''c extend over the entire axial direction of the small diameter portion 31'', thereby reducing the manufacturing cost.

Details of the sleeve 3″ in FIG. 1 will be described in detail with reference to FIG. 2. In FIG. 2, (A) is a top view, (B) is a right side view, (C)-1 is a front view, (C) _-2 is a front view showing the penetration welding point P2, and (D) is a cross-sectional view taken along line DD of (A).

As shown in FIG. 2D, in order to tilt the inserted 8° inclined end face optical fiber 1′ by 4°, the inclined through holes 31″a and 32′a of the small diameter portion 31″ and the medium diameter portion 32′ are formed. is tilted 4° with respect to the vertical direction. As shown in FIGS. 2A, 2B, and 2C-1, the flat surfaces 31''b and 31''c are planes (inclined 1B, the flat surfaces _31''b and 31''c are parallel to the axis Ax of the sleeve 3'' (small diameter portion 31'') and the ferrule 2' (inclined plane). It is parallel to the plane formed by the through hole 31''a). Therefore, as shown in FIG. 2B, the thickness of the inclined through hole 31''a portion of the small diameter portion 31'' can be minimized, for example, 0.25 mm. As a result, as shown in FIG. 2(C)-2, when the through welding points P2 _are provided at the flat surfaces 31''b and 31''c facing the inclined through hole 31''a of the small diameter portion 31'', Penetration welding can be easily performed.

In FIGS. 1 and 2, the ferrule 2' and the sleeve 3'' are made of the same or similar metal material for penetration welding between the opposing surfaces (contact surfaces).
・Austenitic stainless steel (SUS304, SUS303, etc.)
・Martensitic stainless steel (SUS403, etc.)
・Mild steel (SPCC, SS400C, etc.)
·cast iron
・Aluminum alloy (A5052 etc.)
etc. Choose one or two of these metals. SUS304 and/or SUS403 are used as the optimum metal.

A method of manufacturing the optical module of FIG. 1 will be described with reference to FIG.

First, in the inclined end face optical fiber mounting step 301, the 8° inclined end face optical fiber 1' is inserted into the ferrule 2' and mounted.

Next, in a sleeve small-diameter, medium-diameter, and large-diameter forming step 302, the outer diameters of the small-diameter portion 31'', medium-diameter portion 32', and large-diameter portion 33' of the sleeve 3'' are formed by lathe processing. .

Next, in a sleeve through hole forming step 303, the small diameter portion 31'' of the sleeve 3'', the oblique through holes 31''a and 32'a of the medium diameter portion 32', and the vertical through hole 33'a of the large diameter portion 33' are formed. is formed by a drilling process. In this case, the oblique through-holes 31''a, 32'a are inclined by 4° with respect to the axis A _x direction of the sleeve 3'', while the vertical through-hole 33'a is formed by the sleeve 3''. is the axis A in the _x -direction.

Next, in a sleeve flat surface forming step 304, the flat surfaces 31''b and 31''c of the small diameter portion 31'' of the sleeve 3'' are formed by a general-purpose end milling process. In this case, since the flat surfaces 31''b and 31''c extend over the entire axis _Ax direction of the small diameter portion 31'', grooving according to each product is not required, and flattening can be achieved by one reciprocating general-purpose end milling process. Surfaces 31''b and 31''c can be machined.

Next, in a ferrule inserting step 305, the ferrule 2' to which the inclined end face optical fiber 1' is mounted is inserted into the inclined through-hole 31''a of the small diameter portion 31'' of the sleeve 3'' and the inclined through-hole 32' of the medium diameter portion 32' of the sleeve 3''. 1A and the vertical through hole 33'a of the large diameter portion 33'.In this case, the tips of the inclined end face optical fiber 1' and the ferrule 2' have a large diameter as indicated by the dotted line in FIG. It is inserted up to the vicinity of the center of the portion 33' (base portion).

Finally, in a through-welding step 306, the flat surfaces 31″b and 31″c facing the through-holes 31″a and 32′a at locations P ₂ (see (C)-2 of FIG. 2) are made of the same kind of material. YAG laser penetration welding is performed between the ferrule 2 ′ and the small diameter portion 31 ″ of the sleeve 3 ″. At this time, other welding such as welding at welding points P ₁ and P ₃ in FIG. 6 is performed as necessary. also do

Thus, in FIGS. 1 and 2, even if the flat surfaces 31''b and 31''c are added, there is no increase in the number of difficult manufacturing steps, and therefore there is no increase in manufacturing cost.

The order of the sleeve through-hole forming step 303 and the sleeve flat surface forming step 304 in FIG. 3 is not limited to this order, and either step may be performed first.

In the above-described embodiment, the ferrule 2' made of the same or similar metal material and the small-diameter portion 31'' of the sleeve 3'' are welded through. Or even if it is composed of the same kind of resin material, penetration welding is possible.As the same kind of resin that can be penetrated (welded),
・Polycarbonate (PC)
・Polypropylene (PP)
・Polyvinyl chloride (PVC)
・Acrylic resin (PMMA)
・Polyfinylene sulfide (PPS)
・Poly ether ether ketone (PEEK)
・Polyolefin resin (POM)
・Polyvinylidene fluoride (PVDF)
・Tetrafluoroethylene resin (Teflon (registered trademark)) (PTFE)
etc. One or two of these resins are selected. PPS is used as the most suitable resin. In this case, the small diameter portion, medium diameter portion, and large diameter portion forming step (lathe processing step) 302 of FIG. ) 304, the outer diameter of the small diameter portion 31″, medium diameter portion 32′, large diameter portion 33′, inclined through holes 31″a, 32′a, vertical through holes 33′a and flat surface 31″b, 31″c is formed by injection molding with a mold. At this time, since the thickness of the small-diameter portion 31″ is relatively large (see FIG. 2D), the molten material is placed inside the flat surfaces 31″b and 31″c of the small-diameter portion 31″ of the mold. It can be turned evenly, including, and is therefore easy to manufacture.

FIG. 4 shows an optical module as a first comparative example, (A) is an overall perspective view, and (B) is an overall front view.

In the optical module of FIG. 4, a window portion 31'd is formed in the small diameter portion 31' of the sleeve 3' of the optical module of FIG. As a result, the window portion 31'd of the small diameter portion 31' corresponds to the flat surfaces 31''b and 31''c in FIGS. Therefore, it is possible to weld the location of this window portion 31'd and the ferrule 2' in the same manner as in the present invention.

However, in the optical module of FIG. 4, the window portion 31'd is formed only partially in the direction of the _axis Ax of the small diameter portion 31'. As a result, the formation of the window portion 31'd requires grooving, and therefore a general-purpose end milling process cannot be applied, resulting in an increase in manufacturing cost compared to the present invention.

FIG. 5 shows an optical module as a second comparative example, where (A) is an overall perspective view, (B) is a top view of the sleeve, and (C) is a front view of the sleeve.

In FIG. 5, the small-diameter portion 31' of FIG. 8 is also inclined by 4°, and the small-diameter portion 31' is evenly thinned to a thickness of about 0.25 mm. This facilitates penetration welding between the ferrule 2' and any location of the small diameter portion 31' of the sleeve 3', as in the present invention.

However, in the optical module of FIG. 5, since the outer diameter axis of the small diameter portion 31' is inclined with respect to the outer diameter axes of the medium diameter portion 32' and the large diameter portion 33', NC end mill processing is difficult, and therefore the manufacturing cost of the sleeve 3' of the optical module increases compared to the present invention. In this case, it is conceivable that the ferrule 2' and the sleeve 3' are made of the same or similar resin material, and the sleeve 3' is formed by injection molding using a metal mold. Since it is as small as 25 μm, the melted material does not spread evenly around the small-diameter portion 31′ of the mold, making the manufacturing itself difficult.

In the above embodiment, the small diameter portion 31'' of the sleeve 3'' is provided with two flat surfaces 31''b and 31''c, but only one of them may be provided. Further, the sleeve 3'' has a three-stage structure of a small diameter portion, a medium diameter portion (flange portion), and a large diameter portion (base portion), but it may have a two-stage structure of a small diameter portion and a large diameter portion (base portion). Furthermore, the large-diameter portion (base portion) may be rectangular with a cavity instead of being cylindrical.

Also, the present invention can be applied to any modifications within the obvious scope of the above embodiments.

1: optical fiber 1': inclined end face optical fibers 2, 2': ferrules 3, 3', 3": sleeves 31, 31', 31": small diameter portions 32, 32': medium diameter portions (flanges)
33, 33': large diameter portion (base portion)
31a, 32a, 33a: vertical through holes 31′a, 31″a, 32′a: inclined through holes 33′a: vertical through holes 4: lens holder

Claims (10)

An optical module comprising an inclined-end-face optical fiber, a ferrule to which one end of the inclined-end-face optical fiber is attached, and a sleeve having a diameter portion into which the ferrule is inserted and fixed at an angle and a base portion that holds the diameter portion ,
the diameter portion has an inclined through hole inclined in an inclined direction with respect to the axial direction of the sleeve,
The radial portion has two flat surfaces formed so as to sandwich the inclined through-hole in a vertical direction perpendicular to a plane defined by the axial direction of the sleeve and the inclined direction. so that the distance between two flat surfaces is less than the diameter of the radii;
An optical module, wherein the ferrule and the two flat surfaces are fixed by penetration welding. 2. The optical module according to claim 1, wherein the two flat surfaces are present along the entire axial direction of the diameter portion. The sleeve further has a flange portion having a diameter larger than that of the diameter portion and smaller than that of the base portion between the diameter portion and the base portion, and the flange portion inserts the ferrule with an inclination. Item 3. The optical module according to Item 1 or 2. Further comprising a lens holder fixed to the base,
4. The optical module according to any one of claims 1 to 3, wherein the center of the inclined end face optical fiber and the center of the lens of the lens holder are aligned in the base portion of the sleeve. a first step for inserting and mounting an inclined end face optical fiber into a ferrule made of a metal material;
a second step for forming the diameter of the sleeve and the outer diameter of the base made of the same or similar metal material as the ferrule;
a third step for forming an inclined through-hole inclined in an inclined direction with respect to the axial direction of the sleeve in the diameter portion and forming a vertical through-hole in the axial direction of the sleeve in the base portion;
Two flat surfaces are formed in the radial portion so as to sandwich the inclined through hole in a vertical direction perpendicular to a plane formed by the axial direction of the sleeve and the inclined direction, and the two flat surfaces in the vertical direction. a fourth step for ensuring that the distance between is less than the diameter of the radii ;
a fifth step for inserting the ferrule with the inclined end face optical fiber mounted thereon into the sleeve after the first, second, third and fourth steps;
and a sixth step of, after the fifth step, performing penetration welding of the ferrule and the location of the two flat surfaces facing the ferrule. The second step further forms an outer diameter of a flange portion between the diameter portion and the base portion that is larger than the diameter of the diameter portion and smaller than the base portion,
6. The optical module according to claim 5, wherein said third step forms an inclined through-hole in said flange portion which communicates with said inclined through-hole of said radial portion and is inclined in said inclined direction with respect to the axial direction of said sleeve. Production method. a first step for inserting and attaching the inclined end face optical fiber to a ferrule made of a resin material;
A sleeve having a diametrical portion and a base portion, wherein the diametrical portion has an inclined through-hole inclined in an oblique direction with respect to the axial direction of the sleeve, and the base portion defines a vertical through-hole in the axial direction of the sleeve. a second step of molding a sleeve made of the same or similar resin material as the ferrule with a mold;
Two flat surfaces are formed in the radial portion so as to sandwich the inclined through hole in a vertical direction perpendicular to a plane formed by the axial direction of the sleeve and the inclined direction, and the two flat surfaces in the vertical direction. a third step for ensuring that the distance between is less than the diameter of the radii ;
a fourth step for inserting the ferrule with the inclined end face optical fiber mounted thereon into the sleeve after the first, second and third steps;
and a fifth step for performing penetration welding between the ferrule and the location of the two flat surfaces facing the ferrule after the fourth step. In the second step, a flange portion having an outer diameter larger than the diameter of the diameter portion and smaller than the base portion is formed between the diameter portion and the base portion, and the diameter portion is inclined to the flange portion. 8. The method of manufacturing an optical module according to claim 7, wherein an inclined through-hole communicating with the through-hole and inclined in the inclined direction with respect to the axial direction of the sleeve is formed. 9. The method of manufacturing an optical module according to claim 5, wherein the two flat surfaces are present along the entire axial direction of the diameter portion. The optical module further comprises a lens holder fixed to the base,
10. The method for manufacturing an optical module according to claim 5, wherein the center of the inclined end face optical fiber and the center of the lens of the lens holder are aligned in the vertical through-hole of the base portion of the sleeve. .

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