阅读说明：本技术 光学连接部件 (Optical connecting member ) 是由 高桥正典 岩屋光洋 斋藤恒聪 于 2019-03-15 设计创作，主要内容包括：光学连接部件具备：多个种类的光纤；多个高相对折射率差光纤,芯体与包层的相对折射率差比所述多个种类的光纤大,与所述多个种类的光纤熔接；和固定部件,具有将所述多个高相对折射率差光纤以去除了被覆的状态分别容纳的多个V字槽,对将处于与所述多个种类的光纤熔接的状态的所述多个高相对折射率差光纤与光学元件光学耦合时的、所述多个高相对折射率差光纤与所述光学元件的相对位置进行固定。所述多个高相对折射率差光纤是相互相同种类。(The optical connection component comprises: a plurality of kinds of optical fibers; a plurality of high relative refractive index difference optical fibers, having a relative refractive index difference between a core and a cladding larger than that of the plurality of types of optical fibers, and fusion-spliced with the plurality of types of optical fibers; and a fixing member having a plurality of V-grooves for respectively housing the plurality of high relative refractive index difference optical fibers in a state where the coatings thereof are removed, and fixing relative positions of the plurality of high relative refractive index difference optical fibers and the optical element when the plurality of high relative refractive index difference optical fibers in a state where the plurality of types of optical fibers are fusion-spliced are optically coupled with the optical element. The plurality of high relative refractive index difference optical fibers are of the same kind as each other.)

1. An optical connection component, comprising:

a plurality of kinds of optical fibers;

a plurality of high relative refractive index difference optical fibers, having a relative refractive index difference between a core and a cladding larger than that of the plurality of types of optical fibers, and fusion-spliced with the plurality of types of optical fibers; and

a fixing member having a plurality of V-grooves for respectively housing the plurality of high relative refractive index difference optical fibers in a state where the coatings thereof are removed, for fixing relative positions of the plurality of high relative refractive index difference optical fibers and the optical element when the plurality of high relative refractive index difference optical fibers in a state where the plurality of types of optical fibers are fusion-spliced are optically coupled with the optical element,

the plurality of high relative refractive index difference optical fibers are of the same kind as each other.

2. An optical connection component according to claim 1,

the plurality of types of optical fibers comprise polarization maintaining fibers,

the plurality of high relative refractive index difference fibers are polarization maintaining type high relative refractive index difference fibers.

3. Optical connection component according to claim 1 or 2,

the optical connection component further includes: and a ferrule that receives at least end portions of the plurality of types of optical fibers extending from the fixing member on a side opposite to the plurality of high relative refractive index difference optical fibers.

4. An optical connection component according to claim 3,

the ferrule houses the fixing member and the plurality of types of optical fibers extending from the fixing member in a state in which the end portions of the fixing member on the side of the plurality of high relative refractive index difference optical fibers are exposed.

5. An optical connection component according to claim 4,

the ferrule accommodates the plurality of types of optical fibers with the coating removed, together with the fixing member.

6. An optical connecting member according to any one of claims 3 to 5,

the ferrule is an MT ferrule.

Technical Field

The present invention relates to an optical connecting member.

Background

Conventionally, in an optical waveguide constituting an optical element such as a Planar Lightwave Circuit (PLC) or a silicon waveguide chip, reduction of connection loss with an optical fiber optically connected to the optical waveguide (hereinafter, appropriately referred to as a connected optical fiber) has been exemplified as one of the problems. In order to reduce the connection loss, it is necessary to reduce the mismatch between the Mode Field Diameter (MFD) of the optical waveguide having a very small Mode Field Diameter (MFD) compared to the optical fiber to be connected.

As a technique for this, a technique has been proposed in which a high relative refractive index difference optical fiber (hereinafter, referred to as a high Δ optical fiber, where appropriate) having a relative refractive index difference between a core and a cladding larger than that of a connected optical fiber is fusion-spliced to the connected optical fiber, and an optical waveguide of an optical element is connected to the connected optical fiber via the high Δ optical fiber (see, for example, patent document 1). In the technique described in patent document 1, the high Δ optical fiber in a state in which the coating is peeled off is fixed in a V-groove of a glass block-shaped fixing member, and the fixing member is connected to the optical element, whereby the optical waveguide of the optical element is optically coupled to the high Δ optical fiber in the V-groove. In general, since the mode field diameter of the high Δ optical fiber is closer to the mode field diameter of the optical waveguide than the mode field diameter of the connected optical fiber, the presence of the high Δ optical fiber between the connected optical fiber and the optical waveguide can reduce the connection loss.

Prior art documents

Patent document

Patent document 1: JP 6089147A

Disclosure of Invention

Problems to be solved by the invention

However, with the advancement of the functions of optical elements, etc., there is a possibility that a plurality of types of optical fibers to be connected may be connected to the optical elements. In this case, the types of high Δ optical fibers to be fusion-spliced with these plural types of connected optical fibers are generally plural according to the types of connected optical fibers to be fusion-spliced. For example, when a polarization maintaining fiber is included in these plural kinds of connected fibers, a polarization maintaining type high Δ fiber of the same type as the polarization maintaining fiber is fusion-spliced to the polarization maintaining fiber. The plurality of types of high Δ optical fibers to which the plurality of types of connected optical fibers are respectively fusion-spliced are fixed in the plurality of V-grooves formed in parallel in the fixing member in a state where the coatings are peeled off. By connecting the fixing member to the optical element, a plurality of optical waveguides constituting the optical element are optically coupled to the plurality of types of high Δ optical fibers.

However, since there is a possibility that the clad diameters are different between the high Δ optical fibers of different types in the high Δ optical fibers of the plurality of types, the position of the core in the V-groove may be deviated between the high Δ optical fibers of the plurality of types respectively fixed in the V-grooves of the fixing member. As a result, a shift of the central axis of the core (hereinafter, appropriately referred to as a mandrel shift) occurs between the optical waveguide of the optical element and the high Δ optical fiber in the V-groove, and as a result, there is a concern that a connection loss between the optical waveguide and the high Δ optical fiber increases.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical connecting member capable of reducing a connection loss between an optical waveguide of an optical element and an optical fiber optically coupled to the optical waveguide.

Means for solving the problem

In order to solve the above problems and achieve the object, an optical connection component according to the present invention includes: a plurality of kinds of optical fibers; a plurality of high relative refractive index difference optical fibers, having a relative refractive index difference between a core and a cladding larger than that of the plurality of types of optical fibers, and fusion-spliced with the plurality of types of optical fibers; and a fixing member having a plurality of V-grooves for respectively housing the plurality of high relative refractive index difference optical fibers with coatings removed, the fixing member fixing relative positions of the plurality of high relative refractive index difference optical fibers and the optical element when the plurality of high relative refractive index difference optical fibers in a state of being fusion-spliced with the plurality of types of optical fibers are optically coupled with the optical element, the plurality of high relative refractive index difference optical fibers being of the same type as each other.

In the optical connecting member according to the present invention, the plurality of types of optical fibers include polarization-maintaining optical fibers, and the plurality of high relative refractive index difference optical fibers are polarization-maintaining high relative refractive index difference optical fibers.

In addition, the optical connection member according to the present invention is characterized in that the above-described invention further includes: and a ferrule that receives at least end portions of the plurality of types of optical fibers extending from the fixing member on a side opposite to the plurality of high relative refractive index difference optical fibers.

In the optical connecting member according to the present invention, in the above-described invention, the ferrule houses the fixing member and the plurality of types of optical fibers extending from the fixing member in a state in which end portions of the fixing member on the side of the plurality of high relative refractive index difference optical fibers are exposed.

In the optical connecting component according to the present invention, the ferrule is configured to accommodate the plurality of types of optical fibers with the coatings removed, together with the fixing member.

In the optical connecting member according to the present invention, the ferrule is an MT ferrule.

Effect of invention

The optical connecting member according to the present invention has an effect of reducing a connection loss between an optical waveguide of an optical element and an optical fiber optically coupled to the optical waveguide.

Drawings

Fig. 1 is a diagram schematically showing a configuration example of an optical connection component according to embodiment 1 of the present invention.

Fig. 2 is a schematic diagram showing an example of the arrangement of optical fibers in the fixing member in embodiment 1 of the present invention.

Fig. 3 is a sectional view of the fixing member shown in fig. 2 taken along line a-a.

Fig. 4 is a schematic sectional view of the fixing member shown in fig. 2 taken along line B-B.

Fig. 5 is a diagram illustrating a problem that occurs when a plurality of high Δ optical fibers arranged in each V-groove of the fixing member are different in type from each other.

Fig. 6 is a diagram showing an example of the relationship between the mandrel offset and the connection loss when mutually the same type of optical fibers are connected to each other.

Fig. 7 is a schematic diagram showing a configuration example of an optical component to which the optical connection component 10 according to embodiment 1 of the present invention is applied.

Fig. 8 is a diagram schematically showing a configuration example of an optical connection member according to a modification of embodiment 1 of the present invention.

Fig. 9 is a diagram schematically showing a configuration example of an optical connection member according to embodiment 2 of the present invention.

Fig. 10 is a schematic cross-sectional view of the optical connection component shown in fig. 9 taken along line C-C.

Fig. 11 is a diagram schematically showing a configuration example of an optical connection member according to a modification example of embodiment 2 of the present invention.

Detailed Description

Embodiments of an optical connection component according to the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments described below. In the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate. Further, it is to be noted that the drawings are schematic, and the relationship of the sizes of the respective elements, the ratio, and the like may be different from those in reality. The drawings may contain portions having different dimensional relationships and ratios from each other. In the present specification, the cutoff wavelength refers to a 22 m-law cutoff wavelength defined by ITU-T (international telecommunication union) g.650.1. In addition, terms not specifically defined in the present specification are defined and measured as appropriate in ITU-T G.650.1.

(embodiment mode 1)

Fig. 1 is a diagram schematically showing a configuration example of an optical connection component according to embodiment 1 of the present invention. The optical connection component 10 is a component for connecting an optical fiber to be connected to an optical waveguide of an optical element with low loss. As shown in fig. 1, the optical connection member 10 includes: a plurality of kinds of optical fiber arrays 1, a plurality of same kinds of high- Δ optical fiber arrays 5, ferrules 9, and fixing members 11.

The plural kinds of optical fiber trains 1 include plural kinds of connected optical fibers. In embodiment 1, as shown in fig. 1, the plurality of types of optical fiber trains 1 include, for example: three optical fibers, single mode fibers 2, 3 and polarization maintaining fiber 4. The number of optical fibers included in the plurality of types of optical fiber arrays 1 is not limited to the three optical fibers.

The single- mode fibers 2, 3 are typical single-mode fibers according to ITU-t g.652 having a zero dispersion wavelength in the 1.3 μm band. In a typical single mode optical fiber, the relative refractive index difference between the core and the cladding is about 0.3%, and the mode field diameter at a wavelength of 1550nm is 10 to 11 μm. On the other hand, the polarization maintaining fiber 4 is an optical fiber that maintains a polarization plane and transmits light in a single mode. The single- mode fibers 2 and 3 and the polarization maintaining fiber 4 are arranged in parallel with each other so that the polarization maintaining fiber 4 is sandwiched between the single- mode fibers 2 and 3, as shown in fig. 1, for example. The single- mode fibers 2 and 3 and the polarization maintaining fiber 4 may be single-core fibers, or may be collectively covered to form a so-called optical fiber ribbon.

The plurality of high Δ optical fiber arrays 5 have a larger relative refractive index difference between the core and the cladding than the plurality of types of optical fiber arrays 1, and include a plurality of (specifically, the same number as the plurality of types of optical fiber arrays 1) high relative refractive index difference optical fibers of the same type. For example, as shown in fig. 1, the plurality of high Δ optical fibers 5 of the same kind includes three high Δ optical fibers 6, 7, and 8 of the same kind.

In embodiment 1, each of the high Δ fibers 6, 7, and 8 is a polarization-maintaining high Δ fiber. For example, the high Δ fibers 6, 7, and 8 have the same configuration as the polarization maintaining fiber 4, except that the relative refractive index difference between the core and the cladding is larger than that of each of the connected fibers included in the plurality of types of optical fiber 1 rows. In the high Δ optical fibers 6, 7, and 8, the relative refractive index difference between the core and the cladding is 2.0% or more and 3.0% or less, and the mode field diameter at a wavelength of 1550nm is 3.0 μm or more and 5.0 μm or less, for example.

The plurality of high Δ optical fiber rows 5 of the same kind are fusion-spliced to the plurality of kinds of optical fiber rows 1 described above. For example, as shown in fig. 1, the high Δ fiber 6 is fusion-spliced to the single-mode fiber 2, the high Δ fiber 7 is fusion-spliced to the single-mode fiber 3, and the high Δ fiber 8 is fusion-spliced to the polarization maintaining fiber 4. The high Δ optical fibers 6, 7, and 8 thus fused are present between a plurality of optical waveguides (not shown) constituting the optical element and the plurality of types of optical fiber arrays 1 in a state of being fixed to the fixing member 11, and are optically coupled to the plurality of optical waveguides, respectively.

The relative refractive index difference (Δ) between the core and the cladding is a value determined by the following equation.

Δ＝{(n_c-n_cl)/n_c}×100

In the formula, n_cIs the maximum refractive index of the core, n_clIs the refractive index of the cladding.

In addition, the respective connected optical fibers included in the plurality of types of optical fiber arrays 1 and the respective high Δ optical fibers included in the plurality of high Δ optical fiber arrays 5 of the same type are fusion-spliced so as to smooth the change in the mode field diameter at the fusion-spliced point and suppress the connection loss to a low level by examining the heating condition at the time of fusion-splicing, for example, by using TEC (Thermally-diffused Expanded Core) fusion or the like. Accordingly, it is preferable that the connection loss between the single-mode fiber 2 and the high Δ fiber 6, the connection loss between the single-mode fiber 3 and the high Δ fiber 7, and the connection loss between the polarization maintaining fiber 4 and the high Δ fiber 8 be reduced to 0.1dB or less.

Here, in the plurality of types of optical fiber arrays 1 and the plurality of high Δ optical fiber arrays 5 of the same type, the type of optical fiber (including the high Δ optical fiber) is determined according to characteristics such as the clad diameter, the core diameter, the relative refractive index difference, the position and number of cores in the clad, and the light transmission characteristics of the optical fiber. For example, in the same type of optical fiber, the difference in the clad diameter (outer diameter of the glass portion) converges to the allowable level or less described later. As a preferable example, the cladding diameters of the same kind of optical fibers are equal to each other. As an example of such a kind of optical fiber, a short optical fiber cut out from a long optical fiber of the same manufacturing lot is exemplified. On the other hand, the different types of optical fibers include, as exemplified by normal single-mode fibers and polarization maintaining fibers, optical fibers having different optical transmission characteristics, and even optical fibers having the same optical transmission characteristics (for example, normal single-mode fibers and polarization maintaining fibers), optical fibers having a size difference of a cladding diameter or the like exceeding the allowable level. As an example of such different types of optical fibers, there is exemplified a case where optical fibers having different lots are manufactured.

The ferrule 9 accommodates at least end portions of the plurality of types of optical fiber arrays 1 extending from the fixing member 11 on a side opposite to the plurality of types of high Δ optical fiber arrays 5. In embodiment 1, as shown in fig. 1, the ferrule 9 houses a portion (the end portion) of the single- mode fibers 2 and 3 and the polarization maintaining fiber 4 extending from the fixing member 11, the portion having a predetermined length from the end surface on the opposite side of the fusion-splicing point with the high Δ fibers 6, 7, and 8. That is, the respective middle portions of the single- mode fibers 2 and 3 and the polarization maintaining fiber 4 are exposed between the ferrule 9 and the fixing member 11 in a covered state. The ferrule 9 is bonded to the single- mode fibers 2 and 3 and the polarization maintaining fiber 4 by an adhesive or the like, and the relative positions of these are fixed. At this time, the single- mode fibers 2 and 3 and the polarization maintaining fiber 4 are arranged in parallel with each other, and the end faces of these fibers are in the same plane as the ferrule end face 9a (the end face of the ferrule 9 on the side opposite to the fixing member 11).

The fixing member 11 is a member for optically coupling the plurality of high Δ optical fiber arrays 5 of the same kind, which are fusion-spliced to the plurality of kinds of optical fiber arrays 1, and an optical element (not shown) to be connected. For example, the fixing member 11 is a glass block made of quartz glass. The fixing member 11 is not limited to the glass block, and may be a material having physical properties (linear expansion coefficient and the like) similar to those of the glass block so as not to apply unnecessary stress to the optical element and the optical fiber.

As shown in fig. 1, the fixing member 11 accommodates and fixes a plurality of high Δ optical fiber arrays 5 of the same kind and a part of a plurality of kinds of optical fiber arrays 1 to be fusion-spliced to them. At this time, the high Δ fibers 6, 7, and 8 included in the plurality of high Δ fiber rows 5 of the same type are fixed to the fixing member 11 in a state of being arranged in parallel to each other, and the end faces of these are in a state of being on the same plane as the block end face 11a (the end face on the opposite side of the ferrule 9 in the fixing member 11). The plurality of types of optical fiber arrays 1 are fixed to the fixing member 11 in a state where the plurality of high Δ optical fiber arrays 5 of the same type are fused so as to be aligned with the positions of the cores. In embodiment 1, a plurality of types of optical fiber arrays 1 are exposed extending from the fixing member 11 toward the ferrule 9 as shown in fig. 1. The fixing member 11 optically couples the plurality of high Δ optical fiber rows 5 of the same type to the optical element by connecting the block end face 11a to the optical element to be connected. The fixing member 11 fixes the relative positions of the plurality of high Δ optical fiber arrays 5 of the same kind and the optical element.

Fig. 2 is a schematic diagram showing an example of the arrangement of optical fibers in the fixing member in embodiment 1 of the present invention. Fig. 3 is a sectional view of the fixing member shown in fig. 2 taken along line a-a. Fig. 3 schematically shows a cross section of the fixing member 11 in the direction of the optical axis including the polarization maintaining fiber 4 and the high Δ fiber 8. Fig. 4 is a schematic sectional view of the fixing member shown in fig. 2 taken along line B-B. Fig. 4 schematically shows a cross section of the fixing member 11 and the high Δ fibers 6, 7, and 8 as viewed from the block end face 11a side.

As shown in fig. 1 to 4, the fixing member 11 includes a substrate 12 and an upper plate 13. The fixing member 11 has V-grooves 14 for accommodating the plurality of high Δ optical fiber rows 5 of the same type in a state where the coatings are removed. The V-grooves 14 are provided in the substrate 12 in a necessary number (three in embodiment 1) corresponding to the plurality of high Δ optical fiber rows 5 of the same kind, for example. The fixing member 11 sandwiches the high Δ optical fibers 6, 7, and 8 arranged in the V-grooves 14 between the flat surfaces of the substrate 12 (specifically, the V-grooves 14) and the upper plate 13.

In embodiment 1, as shown in fig. 2, a polarization maintaining high Δ fiber 6 is fusion-spliced to a single-mode fiber 2. The single-mode fiber 3 is fusion-spliced with a polarization-maintaining high Δ fiber 7. The polarization maintaining fiber 4 is fusion-spliced with a polarization maintaining high Δ fiber 8. For example, as shown in fig. 3, the polarization maintaining fiber 4 and the high Δ fiber 8 are fusion-spliced so that the cores 4a and 8a are aligned with each other. At this time, the heating conditions for fusion splicing are adjusted so as to smooth the change in mode field diameter at the fusion splice point 16c of the polarization maintaining fiber 4 and the high Δ fiber 8 and reduce the connection loss. This is also true for the fusion-spliced point 16a of the single-mode fiber 2 and the high Δ fiber 6, and the fusion-spliced point 16b of the single-mode fiber 3 and the high Δ fiber 7.

As shown in fig. 2 and 3, the fusion-splicing point 16c between the polarization maintaining fiber 4 and the high Δ fiber 8 is located inside the V-groove 14. In other words, the weld point 16c is sandwiched between the V-groove 14 and the upper plate 13. The polarization maintaining fiber 4 and the high Δ fiber 8 are in a state where the coatings thereof are peeled off in the region sandwiched between the V-groove 14 and the upper plate 13, and the glass portions (cladding) of the polarization maintaining fiber 4 and the high Δ fiber 8 are directly sandwiched between the V-groove 14 and the upper plate 13. Similarly, the fusion-spliced points 16a and 16b of the single mode fibers 2 and 3 and the high Δ fibers 6 and 7 are located inside the V-groove 14, and glass portions (cladding) of the single mode fibers 2 and 3 and the high Δ fibers 6 and 7 are directly sandwiched between the V-groove 14 and the upper plate 13.

As shown in fig. 2 to 4, an adhesive 15 is filled in each gap between the single- mode fibers 2 and 3, the polarization maintaining fiber 4, the substrate 12 (including the V-groove 14), and the upper plate 13. These optical fibers and components are fixed by the filled adhesive 15. Further, the single- mode fibers 2 and 3 and the polarization maintaining fiber 4 are fixed to the substrate 12 with an adhesive 15 from above the covering member (for example, the covering member 4b of the polarization maintaining fiber 4 shown in fig. 3) of each of the fibers in the region not sandwiched between the V-groove 14 and the upper plate 13.

In the above configuration, the outer diameters of the fusion-spliced points 16a and 16b are preferably set to be smaller than the outer diameters of the single-mode optical fibers 2 and 3 and the high Δ optical fibers 6 and 7 before and after the fusion-spliced points. Similarly, the outer diameter of the fusion-spliced point 16c is preferably made smaller than the outer diameters of the polarization maintaining fiber 4 and the high Δ fiber 8 before and after the fusion-spliced point. This is for the following reason. For example, as described above, since the weld points 16a are sandwiched between the V-groove 14 and the upper plate 13, stress may be received from the V-groove 14 and the upper plate 13. When the stress is applied to the welding point 16a, the connection loss at the welding point 16a increases. Therefore, by processing the fusion-spliced point 16a so that the outer diameter of the fusion-spliced point 16a becomes smaller than the outer diameters of the optical fibers before and after the fusion-spliced point 16a as described above, the stress received by the fusion-spliced point 16a from the V-groove 14 and the upper plate 13 can be relaxed, and an increase in connection loss can be suppressed. This is also the same for the remaining weld points 16b, 16 c.

Further, there is a fear that the mechanical reliability of the welding point 16a is lost due to the welding point 16a coming into contact with the upper plate 13. By making the outer diameter of the fusion-spliced point 16a smaller than the outer diameters of the optical fibers before and after the fusion-spliced point, the possibility of losing the mechanical reliability can be reduced. This is also the same for the remaining weld points 16b, 16 c.

As a method of controlling the outer diameters of the fusion-spliced points 16a, 16b, and 16c, a method of controlling the pushing amount and the retracting amount of each optical fiber to be fused, a method of etching the fusion-spliced point of the optical fiber after fusion-splicing, or the like can be used.

Here, the high Δ optical fibers 6, 7, and 8 disposed in the V-grooves 14 of the fixing member 11 are of the same type. For example, the high Δ fibers 6, 7, and 8 are fibers cut out from polarization-maintaining high Δ fibers of the same manufacturing lot. In this way, when the high Δ fibers 6, 7, and 8 are the same kind of fibers, the difference in the clad diameters between the high Δ fibers 6, 7, and 8 is smaller than the difference in the clad diameters between the different kinds of fibers. Therefore, as shown in fig. 4, when the high Δ optical fibers 6, 7, 8 are arranged in the V-grooves 14, the positions of the cores 6a, 7a, 8a of the high Δ optical fibers 6, 7, 8 are aligned in the height direction (the depth direction of the V-grooves 14) (state of small variation). That is, the amount of positional deviation of the central axes of the cores 6a, 7a, 8a between the high Δ optical fibers 6, 7, 8 (the core positional deviation amount H shown in fig. 4) is less than or equal to the allowable level from the viewpoint of reducing the connection loss between the high Δ optical fibers and the optical waveguide. As a result, since the amounts of misalignment between the optical waveguides of the optical element connected to the block end face 11a of the fixing member 11 and the high Δ optical fibers 6, 7, and 8 sandwiched between the V-groove 14 of the fixing member 11 and the upper plate 13 are reduced, the connection loss between the high Δ optical fibers 6, 7, and 8 and the optical waveguides can be reduced to the allowable level or less (for example, 1dB or less). By using the same kind of optical fibers such as the high Δ optical fibers 6, 7, and 8, the difference in the clad diameters can be reduced to an allowable level or less from the viewpoint of reducing the connection loss between the high Δ optical fibers 6, 7, and 8 and the optical waveguide.

On the other hand, when the high Δ optical fibers of different types are disposed in the V-grooves 14 of the fixing member 11, it is difficult to reduce the connection loss between the high Δ optical fibers of the V-grooves 14 and the optical waveguides of the optical element. Fig. 5 is a diagram illustrating a problem that occurs when a plurality of high Δ optical fibers arranged in each V-groove of the fixing member are different from each other. For example, in fig. 5, instead of the polarization-maintaining high Δ fibers 6 and 7 of the same type as the high Δ fiber 8, single-mode high Δ fibers 18 and 19 of a different type from the high Δ fiber 8 are disposed in the V-grooves 14. The single-mode high Δ optical fibers 18 and 19 have the same configuration as the normal single-mode optical fibers 2 and 3, except that the relative refractive index difference between the core and the cladding is larger than that of each of the connected optical fibers included in the plurality of types of optical fiber 1 rows.

As shown in fig. 5, since the high Δ fiber 8 is of a different type from the other high Δ fibers 18 and 19 arranged in parallel to each other, a difference in cladding diameter occurs between the high Δ fibers 18 and 19 of the same type and the high Δ fibers 8 of the different type. For example, if the dimensional tolerance of the designed clad diameters of the high Δ fibers 8, 18, and 19 is ± 1 μm, the difference in clad diameters between the high Δ fibers 18 and 19 and the high Δ fiber 8 may be about 2 μm. In the high Δ fibers 18 and 19 and the high Δ fiber 8 shown in fig. 5, a difference of more than 1 μm and not more than 2 μm occurs in the cladding diameter as an example.

When such different types of high Δ optical fibers 8, 18, and 19 are arranged in the respective V-grooves 14, core position shifts occur in the depth direction of the V-grooves 14 due to the difference in the clad diameters between the cores 18a and 19a of the high Δ optical fibers 18 and 19 and the core 8a of the high Δ optical fiber 8, as shown in fig. 5. The core position shift amount H increases as the difference in the clad diameters increases.

When the cores 18a and 19a of the high Δ optical fibers 18 and 19 of the same type are aligned with the cores of the optical waveguides of the optical element, among the high Δ optical fibers 8, 18, and 19 in which the core position shift occurs as described above, the core shift occurs between the core 8a of the high Δ optical fiber 8 of the different type and the cores of the optical waveguides of the optical element. Even when the core 8a of the high Δ optical fiber 8 is aligned with the core of the optical waveguide, a core misalignment occurs between the cores 18a and 19a of the different types of high Δ optical fibers 18 and 19 and the cores of the optical waveguides. In any case, a core axis shift occurs between the high Δ optical fibers 8, 18, and 19 and the optical waveguides of the optical element, and as a result, it is difficult to reduce a connection loss when the high Δ optical fibers 8, 18, and 19 are optically coupled to the optical waveguides of the optical element.

In fig. 5, the case where the cladding diameters of the different types of high Δ optical fibers 8 are larger than the cladding diameters of the same types of high Δ optical fibers 18 and 19 is illustrated, but the problem of the connection loss is not limited to this case. That is, even when the cladding diameter of the high Δ optical fiber 8 is smaller than that of the high Δ optical fibers 18 and 19, the core axis displacement occurs between the high Δ optical fibers 8, 18, and 19 and the optical waveguide of the optical element in the same manner except that the direction of the core position displacement is the opposite direction to the above, and the above-described problem of connection loss occurs. In addition, even if different types of high Δ optical fibers 8 are arbitrarily arranged in a plurality of (three in embodiment 1) V-grooves 14 provided in the substrate 12, the above-described problem of connection loss similarly occurs.

Further, as shown in fig. 5, when the different types of high Δ optical fibers 8, 18, and 19 are arranged in the V-grooves 14, there is a possibility that the upper plate 13, which sandwiches the high Δ optical fibers 8, 18, and 19 between the V-grooves 14, is inclined with respect to the substrate 12. In this case, the thickness of the adhesive 15 filled between the substrate 12 and the upper plate 13, etc. is different in the direction in which the upper plate 13 is inclined. This difference in the layer thickness of the adhesive 15 causes a variation in stress in the layer of the cured adhesive 15. This causes a difference in stress applied from the adhesive 15 to the high Δ optical fibers 8, 18, and 19, the substrate 12, the upper plate 13, and the like, and thus causes a problem of deterioration in optical characteristics of the high Δ optical fibers 8, 18, and 19, reliability of bonding between the substrate 12 and the upper plate 13, and the like. This problem similarly occurs even when different types of high Δ optical fibers 8 are arranged in any of the plurality of V-grooves 14 provided in the substrate 12.

Next, connection loss between the plurality of high Δ optical fiber arrays 5 of the same type and each optical waveguide of the optical element in the present invention will be described. Since the mode field diameters of the plurality of high Δ optical fiber arrays 5 of the same type are different from each other in the respective optical waveguides, first, the relationship between the core axis offset amount and the connection loss between the high Δ optical fibers and the optical waveguides having different mode field diameters is confirmed. Specifically, the size of the optical waveguide to which the high Δ optical fiber having a predetermined mode field diameter is connected is changed, and the connection loss with respect to the amount of misalignment between the core axes of the high Δ optical fiber and the optical waveguide is calculated for each of the sizes of the optical waveguides. As a result, it is found that even if the size of the optical waveguide to which the high Δ optical fiber is connected changes, the change in the connection loss with respect to the amount of misalignment between the core axes of the high Δ optical fiber and the optical waveguide is small. Therefore, there is no problem even if the connection loss with respect to the mandrel offset amount of the high Δ optical fiber and the optical waveguide having different mode field diameters is calculated using a model assuming the connection of the optical fibers of the same kind to each other.

Based on the above results, the connection loss with respect to the mandrel offset amount when connecting the optical fibers is calculated from a model assuming the connection of the optical fibers of the same kind to each other. Fig. 6 is a diagram showing an example of the relationship between the mandrel offset and the connection loss when mutually the same type of optical fibers are connected to each other. In fig. 6, a line L1 represents a relationship between the mandrel offset and the connection loss calculated for the connection of the single-mode optical fibers. Line L2 represents the relationship between the mandrel offset and the connection loss calculated for the connection of high Δ optical fibers having a mode field diameter of 4.5 μm to each other. Line L3 represents the relationship between the mandrel offset and the connection loss calculated for the connection of high Δ optical fibers having a mode field diameter of 3.5 μm to each other.

The mandrel offset X [ μm ] between the plurality of high- Δ optical fiber arrays 5 of the same kind arranged in the plurality of V-grooves 14 of the fixing member 11 and the optical waveguide of each optical element is expressed by the following formula (1) using the difference Δ R [ μm ] in the clad diameter between the high- Δ optical fibers included in the plurality of high- Δ optical fiber arrays 5 of the same kind and the angle θ [ rad ] formed by the bottom of the V-groove 14.

X＝ΔR÷sin(θ/2)÷2···(1)

Here, as the connection loss with respect to the mandrel offset amount of each optical waveguide of the plurality of high Δ optical fiber arrays 5 of the same kind and the optical element, the connection loss calculated from the model assuming the connection of the optical fibers of the same kind can be used as described above. For example, when the mode field diameters of the plurality of high Δ optical fiber arrays 5 of the same type are 4.5 μm, the connection loss with respect to the mandrel offset amount indicated by the line L2 in fig. 6 can be used as the connection loss with respect to the mandrel offset amount of each optical waveguide of the plurality of high Δ optical fiber arrays 5 of the same type and the optical element. When the connection loss between the plurality of high- Δ optical fiber arrays 5 of the same kind and each optical waveguide of the optical element is reduced to 1dB or less, the allowable mandrel offset X in these connections is 0.8 μm or less, as indicated by line L2 in fig. 6. In order to satisfy the condition that the mandrel offset X is equal to or less than 0.8 μm, for example, when the angle θ of the V-groove 14 is pi/2 rad (equal to 90 °), the difference Δ R between the cladding diameters of the high Δ optical fibers included in the plurality of high Δ optical fiber rows 5 of the same type needs to be equal to or less than 1 μm. Since the plurality of high Δ fiber arrays 5 of the same type include the same type of high Δ fibers as in the examples of the high Δ fibers 6, 7, and 8 described above, the condition for the difference Δ R in clad diameter can be easily satisfied.

In this way, the difference Δ R between the cladding diameters allowed from the viewpoint of reducing the connection loss between the high Δ optical fiber and the optical waveguide is not limited to the case where the mode field diameter is 4.5 μm, and can be easily satisfied in the range (for example, 3.0 μm or more and 5.0 μm or less) where the mode field diameter of the high Δ optical fiber can be obtained, by making the plurality of high Δ optical fibers arranged in the plurality of V-grooves 14 to be of the same kind. Further, by reducing the difference Δ R in the clad diameter to the permissible level or less, the inclination of the upper plate 13 of the fixing member 11 with respect to the substrate 12 can be suppressed, and as a result, the above-described problem caused by the inclination of the upper plate 13 can be solved.

Next, an application example of the optical connecting member 10 to an optical element will be described. Fig. 7 is a schematic diagram showing a configuration example of an optical component to which the optical connection component 10 according to embodiment 1 of the present invention is applied. As shown in fig. 7, the optical member 110 includes the optical connection member 10 and the optical element 100. The optical element 100 functions as a coherent mixer used for coherent modulation of the DP-QPSK system, for example. The optical connection member 10 is connected to the input end surface of the optical element 100 via a block end surface 11a (see fig. 1) of the fixing member 11, and optically couples the high Δ optical fibers 6, 7, and 8 to the optical waveguides 101a, 101c, and 101b of the optical element 100, respectively. Although not shown in particular, a plurality of optical waveguides or array-type optical fibers optically coupled to the single- mode fibers 2 and 3 and the polarization maintaining fiber 4 are connected to the ferrule 9. The circuit diagram shown in fig. 7 is an example of a circuit used for the optical element 100, and the present invention is not limited to this circuit.

As shown in fig. 7, the optical element 100 includes: 2 signal ports, a local oscillator optical port, and 8 output ports P1-P8. These 2 signal ports and local oscillation optical ports are ports into which light is input from the single mode fibers 2 and 3 and the polarization maintaining fiber 4 of the optical connection member 10 via the high Δ fibers 6, 7, and 8, respectively. The 8 output ports P1 to P8 are ports for outputting light to a plurality of optical fibers (not shown) connected to the ports.

In the optical element 100 shown in fig. 7, 2 signal lights which are polarization-separated in advance and whose polarization planes are adjusted to TM polarization are input from 2 single mode fibers 2 and 3 to the optical waveguides 101a and 101c through the high Δ fibers 6 and 7, respectively. The signal light input to the optical waveguide 101a is guided to the 90-degree mixing element 103a, and the signal light input to the optical waveguide 101c is guided to the 90-degree mixing element 103 b.

On the other hand, TM-polarized local oscillation light is input from the polarization maintaining fiber 4 to the optical waveguide 101b via the high Δ fiber 8. The local oscillation light input to the optical waveguide 101b is branched into two by the power splitter 102 and guided to the 90-degree mixing elements 103a and 103b, respectively.

In the 90-degree hybrid elements 103a and 103b, the signal light is separated into the signal light of the I-channel component and the signal light of the Q-channel component due to interference of the signal light with the local oscillation light, and output light is output from the 8 output ports P1 to P8.

As described above, in the optical connection component 10 according to embodiment 1 of the present invention, the plurality of high Δ optical fibers fusion-spliced to the plurality of types of optical fiber arrays 1 are the plurality of same type of high Δ optical fiber arrays 5, the plurality of same type of high Δ optical fiber arrays 5 are disposed in the plurality of V-grooves 14 of the fixing member 11 in a state where the coatings are removed, and the relative positions of the plurality of same type of high Δ optical fiber arrays 5 and the optical element when the plurality of same type of high Δ optical fiber arrays 5 fusion-spliced to the plurality of types of optical fiber arrays 1 are optically coupled to the optical element are fixed by the fixing member 11.

Therefore, the difference in the cladding diameter between the plurality of high Δ optical fiber arrays 5 of the same type can be suppressed to the allowable level or less from the viewpoint of reducing the connection loss between the high Δ optical fiber and the optical waveguide. As a result, since it is possible to reduce the misalignment between the respective mandrels of the plurality of high- Δ optical fiber arrays 5 of the same kind and the plurality of optical waveguides of the optical element to be connected, which are arranged in the plurality of V-grooves 14, respectively, it is possible to reduce the connection loss between the optical waveguide of the optical element and the optical fiber such as the high- Δ optical fiber optically coupled to the optical waveguide to the allowable level or less (for example, 1dB or less).

In the optical connection component 10 according to embodiment 1 of the present invention, the fusion-splicing points between the plurality of high Δ optical fiber rows 5 of the same type and the plurality of optical fiber rows 1 of the same type and the plurality of high Δ optical fiber rows 5 of the same type are accommodated in the fixing member 11. Therefore, when a plurality of high Δ optical fiber arrays 5 of the same kind are fusion-spliced to a plurality of kinds of optical fiber arrays 1, a member such as a reinforcing sleeve, which has been conventionally necessary, is not required, and therefore, the optical connection member 10 can be more downsized.

(modification of embodiment 1)

Next, a modified example of embodiment 1 of the present invention will be described. Fig. 8 is a diagram schematically showing a configuration example of an optical connection member according to a modification of embodiment 1 of the present invention. As shown in fig. 8, the optical connection member 10A includes a plurality of kinds of optical fiber arrays 1A including 4 times as many optical fibers instead of the plurality of kinds of optical fiber arrays 1, and includes a plurality of kinds of high Δ optical fiber arrays 5A including the same number of high Δ optical fibers as the plurality of kinds of optical fiber arrays 1A instead of the plurality of kinds of high Δ optical fiber arrays 5. In the optical connection component 10A, the ferrule 9 is an MT ferrule. The other structures are the same as those in embodiment 1, and the same structural parts are given the same reference numerals.

The plural kinds of optical fiber arrays 1A include plural kinds of the connected optical fibers. The number of connected optical fibers included in the plurality of types of optical fiber array 1A is a multiple of 4 (for example, 8 as shown in fig. 8). It is preferable that the plurality of types of optical fiber arrays 1A are collectively covered in a state where a number of connected optical fibers equal to 4 of these optical fibers are arrayed, and are configured as so-called optical fiber ribbons. The plurality of types of optical fiber arrays 1A may include 1 or more polarization maintaining optical fibers and a plurality of normal single-mode optical fibers, or may include a plurality of polarization maintaining optical fibers and 1 or more normal single-mode optical fibers. The plurality of types of optical fiber arrays 1A may include one or more polarization maintaining fibers, normal single-mode fibers, and single-mode fibers other than these, may include one or more normal single-mode fibers and single-mode fibers other than these, and may include any of the polarization maintaining fibers, the normal single-mode fibers, and the single-mode fibers other than these.

The plurality of high Δ optical fiber arrays 5A of the same kind include a plurality of (specifically, the same number as the plurality of kinds of optical fiber arrays 1A) high Δ optical fibers of the same kind, in which the relative refractive index difference between the core and the cladding is larger than that of the plurality of kinds of optical fiber arrays 1A. The type of the high Δ optical fibers included in the plurality of high Δ optical fiber arrays 5A of the same kind (optical fiber types classified by the structures of the core and the cladding) is not particularly limited as long as the high Δ optical fibers are of the same kind, but is preferably of the same kind as any connected optical fibers included in the plurality of kinds of optical fiber arrays 1A. For example, when the plurality of types of optical fiber arrays 1A include only normal single-mode optical fibers, it is preferable that each of the plurality of high Δ optical fiber arrays 5A of the same type is a high Δ optical fiber in which a relative refractive index difference between a core and a cladding of the normal single-mode optical fiber is increased. When the plurality of types of optical fiber arrays 1A include a normal single-mode fiber and a polarization maintaining fiber, it is preferable that each of the plurality of high Δ optical fiber arrays 5A of the same type is a polarization maintaining high Δ optical fiber (for example, the same as the high Δ optical fibers 6, 7, and 8 described above) from the viewpoint of maintaining the polarization plane. In each of the plurality of high Δ optical fiber arrays 5A of the same type, the relative refractive index difference between the core and the cladding is 2.0% or more and 3.0% or less, and the mode field diameter at a wavelength of 1550nm is, for example, 3.0 μm or more and 5.0 μm or less.

The plurality of high Δ optical fiber rows 5A of the same kind are fusion-spliced to the plurality of kinds of optical fiber rows 1A described above. The plurality of high Δ optical fiber arrays 5A of the same type thus fused are present between a plurality of optical waveguides (not shown) constituting the optical element and the plurality of types of optical fiber arrays 1A in a state of being fixed to the fixing member 11, and are optically coupled to the plurality of optical waveguides, respectively, as in the case of embodiment 1.

The above-described plurality of types of optical fiber arrays 1A and the plurality of high Δ optical fiber arrays 5A of the same type are fusion-spliced by applying heating conditions at the time of fusion splicing such as TEC fusion, for example, so as to smooth the change in mode field diameter at the fusion-spliced point, thereby suppressing the connection loss to a low level. Accordingly, it is preferable that the connection loss between each connected optical fiber included in the plurality of types of optical fiber arrays 1A and each high Δ optical fiber included in the plurality of high Δ optical fiber arrays 5A of the same type be reduced to 0.1dB or less.

Although not particularly shown, the optical member according to the present modification can be configured by applying the optical connection member 10A having the above-described configuration to an optical element. Examples of the optical element include: PLC elements, silicon optical waveguide chips, coherent mixers, etc.

As described above, in the optical connecting member 10A according to the modification of embodiment 1 of the present invention, the plurality of high Δ optical fibers to be fusion-spliced to the plurality of types of optical fiber arrays 1A are the plurality of types of high Δ optical fiber arrays 5A of the same type, and the ferrule 9 is an MT ferrule, and the configuration is otherwise the same as that of embodiment 1. Therefore, the optical connection component to which the MT ferrule is applied can be configured to enjoy the same operational effects as those of embodiment 1.

(embodiment mode 2)

Next, embodiment 2 of the present invention will be explained. Fig. 9 is a diagram schematically showing a configuration example of an optical connection member according to embodiment 2 of the present invention. As shown in fig. 9, the optical connection member 20 includes a ferrule 29 instead of the ferrule 9. Other structures are the same as embodiment 1, and the same structural parts are given the same reference numerals.

The ferrule 29 accommodates at least the end portions of the plurality of types of optical fiber arrays 1 extending from the fixing member 11 on the opposite side to the plurality of high Δ optical fiber arrays 5 of the same type. In embodiment 2, as shown in fig. 9, the ferrule 29 houses the fixing member 11 and the plurality of types of optical fiber arrays 1 extending from the fixing member 11 in a state in which the end portions (i.e., the block end surfaces 11a and the vicinity thereof) on the high Δ optical fiber arrays 5 side of the plurality of types of the fixing member 11 are exposed.

Fig. 10 is a schematic cross-sectional view of the optical connection component shown in fig. 9 taken along line C-C. Fig. 10 schematically illustrates a cross section of the optical connection member 20 in the direction of the optical axis including the polarization maintaining fiber 4 and the high Δ fiber 8. As shown in fig. 9 and 10, the ferrule 29 includes a housing portion 29b and a restricting portion 29 c. The housing 29b is an internal space for housing the fixing member 11 and the ferrules 29 of the plurality of types of optical fiber arrays 1. The regulating portion 29c regulates the storage position of the fixing member 11 when the fixing member 11 and the plurality of types of optical fiber arrays 1 are stored in the storage portion 29b of the ferrule 29.

The fixing member 11 is pushed into the housing portion 29b of the ferrule 29 from the side of the plurality of types of optical fiber arrays 1. Specifically, as shown in fig. 10, the fixing member 11 is pushed into a position where its end portion abuts against the regulating portion 29 c. Thereby, the storage position of the fixing member 11 in the storage portion 29b is determined. As shown in fig. 9 and 10, the ferrule 29 is housed in the housing portion 29b so that the end portion of the fixing member 11 pressed in this manner on the block end surface 11a side is exposed outside the ferrule 29. In common with the housing of the fixing member 11, the ferrule 29 houses a plurality of types of optical fiber arrays 1 (for example, single- mode fibers 2 and 3 and polarization-maintaining fiber 4) extending from the fixing member 11. At this time, the ferrule 29 fixes the relative positions of the respective connected optical fibers of the plurality of types of optical fiber arrays 1 stored therein. At this stage, the plural kinds of optical fiber arrays 1 are arranged in parallel with each other in the housing 29b, and the end faces thereof are in a state of being flush with the ferrule end face 29a (end face on the opposite side of the fixing member 11 in the ferrule 29) as in the polarization maintaining optical fiber 4 shown in fig. 10, for example. In embodiment 2, the ferrule 29 preferably houses the plurality of types of optical fiber arrays 1 from which the coatings have been removed in the housing section 29b together with the fixing member 11.

As shown in fig. 10, the adhesive 15 is filled between the housing portion 29b of the ferrule 29, the fixing member 11, and the plurality of types of optical fiber arrays 1. The fixing members 11 and the plurality of types of optical fiber arrays 1 are fixed in the housing 29b by the filled adhesive 15.

Although not particularly shown, the optical connection member 20 can be applied to the optical element 100 (see fig. 7) as in embodiment 1 described above. Thus, the optical component of embodiment 2 including the optical connection member 20 and the optical element 100 can be configured.

As described above, in the optical connection member 20 according to embodiment 2 of the present invention, the fixing member 11 and the plurality of types of optical fiber arrays 1 extending from the fixing member 11 are accommodated in the accommodating portion 29b of the ferrule 29 in a state where the end portions of the fixing member 11 on the high Δ optical fiber arrays 5 side of the same type are exposed, and the other configuration is the same as that of embodiment 1. Therefore, the fixing member 11 housed in the housing portion 29b of the ferrule 29 and the housing lengths of the plurality of types of optical fiber arrays 1 can be absorbed by the length of the ferrule 29 while enjoying the same operational effects as those of the above-described embodiment 1, and thereby the optical connection member 20 can be configured to be downsized in the housing lengths.

In the optical connection component 20 according to embodiment 2 of the present invention, the plurality of types of optical fiber arrays 1 with coatings removed are stored in the storage section 29b of the ferrule 29 together with the fixing member 11. Therefore, when the optical element connected to the optical connection member 20 is subjected to a heating process or the like, even if the optical connection member 20 is subjected to a high-temperature heating process, it is possible to prevent deterioration of the covering member that originally covers each of the plurality of types of optical fiber arrays 1.

(modification of embodiment 2)

Next, a modified example of embodiment 2 of the present invention will be explained. Fig. 11 is a diagram schematically showing a configuration example of an optical connection member according to a modification example of embodiment 2 of the present invention. As shown in fig. 11, the optical connection member 20A includes a plurality of kinds of optical fiber arrays 1A including 4 times as many optical fibers instead of the plurality of kinds of optical fiber arrays 1, and includes a plurality of kinds of high Δ optical fiber arrays 5A including as many high Δ optical fibers as the plurality of kinds of optical fiber arrays 1A instead of the plurality of kinds of high Δ optical fiber arrays 5. In the optical connection component 20A, the ferrule 29 is an MT ferrule. The plurality of types of optical fiber arrays 1A and the plurality of the same types of high Δ optical fiber arrays 5A are the same as the modification of embodiment 1 described above. Other structures are the same as embodiment 1, and the same structural parts are given the same reference numerals.

In the optical connection member 20A, as shown in fig. 11, the ferrule 29 stores the plural kinds of optical fiber arrays 1A extending from the fixing member 11 together with the fixing member 11, and fixes the relative positions of the connected optical fibers included in the stored plural kinds of optical fiber arrays 1A. At this stage, the plural types of optical fiber arrays 1A are arranged in parallel with each other in the ferrule 29 (specifically, in the housing portion 29b shown in fig. 10), and the end surfaces thereof are in a state of being flush with the ferrule end surface 29 a. In the present modification, the ferrule 29 preferably houses the plurality of types of optical fiber arrays 1A from which the coatings are removed together with the fixing member 11.

Note that, although not particularly shown, the optical member according to the present modification can be configured by applying the optical connection member 20A having the above-described configuration to an optical element. Examples of the optical element include: PLC elements, silicon optical waveguide chips, coherent mixers, etc.

As described above, in the optical connection component 20A according to the modification of embodiment 2 of the present invention, the plurality of high Δ optical fibers to be fusion-spliced to the plurality of types of optical fiber arrays 1A are the plurality of same types of high Δ optical fiber arrays 5A, and the ferrule 9 is an MT ferrule, which is otherwise the same as that of embodiment 2. Therefore, an optical connection component to which the MT ferrule is applied, that is, the same operational effects as those of embodiment 2 can be obtained.

In embodiments 1 and 2, a plurality of types of optical fiber arrays 1 in which normal single-mode optical fibers 2 and 3 and polarization maintaining optical fiber 4 are mixed are illustrated, but the present invention is not limited to this. For example, the plurality of types of optical fiber arrays 1 may include any of polarization maintaining fibers, normal single-mode fibers, and single-mode fibers other than these, or 2 or more of these fibers may be mixed.

In embodiments 1 and 2, the high Δ fiber arrays 5 of the same type including the polarization-maintaining high Δ fibers are illustrated, but the present invention is not limited thereto. For example, each of the plurality of high Δ fiber arrays 5 of the same type may be a high Δ fiber of the same type as any of the fibers included in the plurality of types of fiber arrays 1 (for example, a high Δ fiber in which the relative refractive index difference between the core and the cladding of a normal single-mode fiber is increased), or may be a high Δ fiber of the same type as a fiber not included in the plurality of types of fiber arrays 1.

In embodiments 1 and 2 and the modifications described above, the fusion-splicing points of the plurality of types of optical fiber arrays and the plurality of types of high Δ optical fiber arrays are disposed in the V-grooves of the fixing member, but the present invention is not limited to this. For example, the welding point may be disposed in a V-groove of the fixing member. In this case, the welding point may be disposed on the substrate of the fixing member in a state of being covered with a covering member such as a reinforcing sleeve, or may be covered with an adhesive and fixed to the substrate of the fixing member.

In embodiments 1 and 2 described above, a coherent mixer is used as the optical element 100 connecting the optical connection members 10 and 20, but the present invention is not limited to this. For example, the optical element 100 connecting the optical connection members 10 and 20 may be an optical element other than a coherent mixer such as a PLC element or a silicon optical waveguide chip.

The present invention is not limited to the above embodiments. An embodiment in which the above-described components are combined as appropriate is also included in the present invention. Other embodiments, examples, operation techniques, and the like, which are made by those skilled in the art based on the above-described embodiments, are all included in the scope of the present invention.

Industrial applicability

As described above, the optical connection component according to the present invention is useful for connecting an optical element and an optical fiber, and is particularly suitable for an optical connection component capable of reducing a connection loss between an optical waveguide of an optical element and an optical fiber optically coupled to the optical waveguide.

-description of symbols-

1. 1A multiple kinds of optical fiber arrays

2. 3 single mode optical fiber

4 polarization maintaining optical fiber

4a, 6a, 7a, 8a, 18a, 19a core

4b coated Member

5. 5A multiple homogeneous high-delta optical fiber arrays

6. 7, 8, 18, 19 high delta optical fiber

9. 29 ferrule

9a, 29a ferrule end faces

10. 10A, 20A optical connection component

11 fixing part

11a end face

12 substrate

13 upper plate

14V-shaped groove

15 adhesive

16a, 16b, 16c weld points

29b receiving part

29c restriction part

100 optical element

101a, 101b, 101c optical waveguide

102 power divider

103a, 103b 90 degree mixing element

110 optical component

P1, P2, P3, P4, P5, P6, P7, P8 output ports.