Connector for multilayered optical waveguide

Abstract

Methods for fabricating connectors for multilayered optical waveguides, as well as apparatuses for multilayered optical waveguides that embody ferrules and connectors. The method of fabricating a connector includes the steps of: stacking in a containing unit of a ferrule, a plurality of optical waveguides that are each preliminarily formed in the shape of layers; and injecting resin or adhesive through a space lying between the plurality of optical waveguides and the containing unit of the ferrule, with the plurality of optical waveguides contained in a stacked manner so that resin or adhesive reaches each of the plurality of optical waveguides.

Claims

1. A method of fabricating a connector, the method comprising the steps of: stacking in a containing unit of a ferrule, which has two parallel side walls, a plurality of optical multi-core waveguides and a lid; and injecting resin or adhesive through a space lying between the plurality of optical multi-core waveguides and the containing unit of the ferrule, wherein the resin or adhesive that is injected into the space contacts only sidewalls of the lid and only cladding sidewalls of each of the plurality of optical multi-core waveguides within the ferrule to secure the lid to the sidewalls of the ferrule.

2. The method according to claim 1, wherein: the ferrule includes a plurality of holes; the ferrule includes the containing unit; the containing unit is capable of containing, in a stacking manner, the plurality of optical waveguides; and the containing unit includes a fiducial face relative to all of the plurality of holes.

3. The method according to claim 1, wherein: the connector is a Mechanically Transferable (MT) connector; the ferrule is a multiple-core optical ferrule (MT ferrule) the ferrule includes a plurality of holes formed to serve as a plurality of position guides; and the containing unit is capable of containing, in a stacking manner, the plurality of optical waveguides.

4. The method according to claim 1, further comprising the step of: applying a pressure, toward the containing unit of the ferrule, on the plurality of optical waveguides stacked.

5. The method according to claim 1, wherein, as the space lying between the plurality of optical waveguides and the containing unit of the ferrule, grooves are arranged along a multilayered direction to produce active capillary phenomena.

6. The method according to claim 5, wherein the grooves are formed as a trimming on the side of the ferrule to consecutively communicate with the plurality of optical waveguides stacked.

7. The method according to claim 5, wherein the grooves are formed as a trimming on the side of the optical waveguide to consecutively communicate with the plurality of optical waveguides stacked.

8. The method according to claim 6, wherein: the length of the cross section in a multilayered direction, measured in a direction orthogonal to the waveguide direction, is smaller than 100 m; and the viscosity of resin or adhesive injected is from about 105 cps to about 195 cps and ranges there between.

9. The method according to claim 6, wherein: the length of the cross section in a multilayered direction, measured in a direction orthogonal to the waveguide direction, is from about 35 m to about 65 m and ranges there between, and the length in a waveguide direction is from about 350 m to about 650 m and ranges there between; and the viscosity of resin or adhesive injected is from about 105 cps to about 195 cps and ranges there between.

10. The method according to claim 7, wherein: the length of the cross section in a multilayered direction, measured in a direction orthogonal to the waveguide direction, is smaller than about 194.25 m to about 360.75 m and ranges there between.

11. A ferrule comprising: a containing unit having two parallel side walls, arranged so as to contain, in a stacking manner, a plurality of optical multi-core waveguides that are each preliminarily formed in the shape of layers, a space lying between the plurality of optical multi-core waveguides and the containing unit of the ferrule, and a lid that fits entirely between the side walls, wherein the space is formed by grooves which are formed in a direction perpendicular to the layers, and wherein injected resin or adhesive within the grooves contacts only sidewalls of the lid and only cladding sidewalls of the plurality of optical multi-core waveguides within the ferruled to secure the lid to the sidewalls of the ferrule.

12. The ferrule according to claim 11, further comprising a plurality of holes, and wherein: the plurality of holes serves as a fiducial; and the containing unit includes a fiducial face relative to all of the plurality of holes.

13. The ferrule according to claim 11, further comprising a plurality of holes, and wherein: the ferrule is a multiple-core optical ferrule, such that the ferrule is a Mechanically Transferable (MT) ferrule; and the plurality of holes serves as a plurality of position guides.

14. The ferrule according to claim 11, wherein the containing unit has a concave shape.

15. A connector utilizing a ferrule according to claim 11, wherein the grooves are filled with injected resin or adhesive.

16. A connector utilizing a ferrule according to claim 11, wherein the lid is placed on the plurality of optical waveguides stacked.

17. The ferrule according to claim 11, wherein the waveguides are for single mode, capable of being collectively connected.

18. The ferrule according to claim 11, wherein the waveguides are for multimode, capable of being collectively connected.

19. A connector utilizing a ferrule according to claim 11, wherein the waveguides are for single mode, capable of being collectively connected.

20. A connector utilizing a ferrule according to claim 11, wherein the waveguides are for multimode, capable of being collectively connected.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view illustrating a structure of an MT (Mechanically Transferable) connector for multimode multilayered waveguide, developed by the present applicant in the past, the structure using in combination a dummy-core structure and a waveguide tray;

(2) FIG. 2 is a view illustrating an MT ferrule or a ferrule according to the present invention;

(3) FIG. 3 is a view for explaining a method of fabricating the MT connector by use of a multiple-core optical ferrule (MT ferrule);

(4) FIG. 4 is a view for explaining a method of irradiating the MT connector with UV light after injection of resin or adhesive when the MT connector is fabricated using the multiple-core optical ferrule (MT ferrule);

(5) FIG. 5 is a cross-sectional view of the MT connector;

(6) FIG. 6 is a view for explaining the grooves;

(7) FIG. 7 is a view showing the specific dimensions of the MT ferrule;

(8) FIG. 8 is a view showing the dimensions of the grooves; and

(9) FIG. 9 is a view showing an example of experiment in which resin or adhesive different in viscosity is used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) FIG. 2 is a view illustrating an MT ferrule or a ferrule according to the present invention.

(11) All fundamental constituent elements are included which perform functions required of the multiple-core optical ferrule (MT ferrule).

(12) As a plurality of position guides, a plurality of holes are provided; this structure is the same as one described in FIG. 1.

(13) A containing unit is included which is arranged so that a plurality of optical waveguides, each preliminarily formed in a shape of layer, are contained therein in a stacked manner.

(14) The bottom face and the side face of the containing unit have a concave shape act as a containing unit face; these containing unit faces serve as a fiducial face.

(15) In this way, the containing unit is arranged so that a plurality of optical waveguides, each preliminarily formed in a shape of layer, are contained therein in a stacked manner, and also includes the fiducial face relative to all of the plurality of holes.

(16) The present invention is characterized in that grooves are arranged along a multilayered direction so that resin or adhesive injected reaches each of the plurality of optical waveguides contained in a stacked manner.

(17) The end face of the optical waveguide in the multiple-core optical connector is usually smoothed by lapping and polishing. Thus, connection loss was measured after the lapping and also after the subsequent polishing; it was found that, after the polishing, the degree of loss was smaller.

(18) FIG. 3 is a view for explaining a method of fabricating the MT connector by use of a multiple-core optical ferrule (MT ferrule).

(19) The MT ferrule includes a plurality of holes serving as a plurality of position guides and a containing unit in which a plurality of optical waveguides, each preliminarily formed in a shape of layer, can be contained in a staked manner.

(20) Injected into the groove is resin or adhesive.

(21) Stacked in the containing unit of the MT ferrule is a plurality of optical waveguides, each preliminarily formed in the shape of layers.

(22) Then, with the plurality of optical waveguides contained in a stacked manner, resin or adhesive is injected through a space lying between the plurality of optical waveguides and the containing unit of the MT ferrule, so that the resin or adhesive reaches each of the plurality of optical waveguides.

(23) As the space lying between the plurality of optical waveguides and the containing unit of the ferrule, grooves are arranged along a multilayered direction to produce active capillary phenomena.

(24) However, if there is a space allowing capillary phenomena on the side face of the containing unit face having a shape of concave, it can be expected that resin or adhesive injected reaches each of the plurality of optical waveguides contained in the containing unit.

(25) Thus, the meaning of the term space or groove according to the technical idea of the present invention should be broadly interpreted.

(26) The viscosity of the injected resin or adhesive also has importance.

(27) The viscosity of UV adhesive is 150 cps30% or less (from about 105 cps to about 195 cps and ranges there between) that is, UV adhesive having a significantly low viscosity is used.

(28) FIG. 4 is a view for explaining a method of irradiating the MT connector with UV light after injection of resin or adhesive when the MT connector is fabricated using the multiple-core optical ferrule (MT (Mechanically Transferable) ferrule).

(29) Ultraviolet (UV) light-cured resin is injected by use of a pipette and then UV light of a wavelength of 365 nm is irradiated, whereby the plurality of optical waveguides stacked are unfailingly secured.

(30) When desired, a pressure may be applied in the injection, or the injection may be encouraged by suction.

(31) A lid may be placed on the plurality of optical waveguides stacked to maintain the secured state.

(32) A pressure may be applied, toward the containing unit of the ferrule, on the plurality of optical waveguides stacked, or a pressure may be applied through the lid.

(33) FIG. 5 is a cross-sectional view of the MT connector.

(34) In FIG. 5, four layers of 24-channel waveguides are stacked; that is, a structure for 96 channels is formed.

(35) This means that the number of cores in the multiple-core structure is 96.

(36) In FIG. 5, a plurality of holes is provided; guide-pin holes are formed to serve as a plurality of position guides.

(37) The positional relation (the actual size being 375) between the center of the guide-pin hole and the center of the core in the optical waveguide has importance.

(38) Implementation of high-precision positioning allows collective connection of multiple cores even in the case of a single-mode optical waveguide.

(39) The distance (the actual size being 572.5) between the center of the guide-pin hole and the fiducial face, indicated by the shape of concave, with respect to all of the plurality of holes in the containing unit also has importance.

(40) FIG. 6 is a view for explaining the grooves.

(41) It is to be noted that the grooves are drawn in an exaggerated form.

(42) The grooves may be formed as a trimming on the side of the ferrule to consecutively communicate with the plurality of optical waveguides stacked.

(43) In this case, it was verified that, when the length (B) of the cross section in a multilayered direction, measured in a direction orthogonal to the waveguide direction, is smaller than 100 m, and in addition when the viscosity of resin or adhesive injected is 150 cps30% (from about 105 cps to about 195 cps and ranges there between) or less, then this combination of size and viscosity achieves effectiveness.

(44) Further, it was verified that, when the length (B) of the cross section in a multilayered direction, measured in a direction orthogonal to the waveguide direction, is 50 m30% (from about 35 m to about 65 m and ranges there between) and the length in a waveguide direction is 500 m30% (from about 350 m to about 650 m and ranges there between), and in addition when the viscosity of resin or adhesive injected is 150 cps30% (from about 105 cps to about 195 cps and ranges there between) or less, then this combination of size and viscosity achieves effectiveness.

(45) The grooves may be formed as a trimming on the side of the optical waveguide to consecutively communicate with the plurality of optical waveguides stacked.

(46) The length (A) of the cross section in a multilayered direction, measured in a direction orthogonal to the waveguide direction, may be smaller than 277.5 m30% (from about 194.25 m to about 360.75 m and ranges there between).

(47) FIG. 7 is a view showing the specific dimensions of the MT ferrule.

(48) The present invention is applied to the MT ferrule of these dimensions to achieve the advantageous effect; thus the actual dimensions and the reduction scale based on the actual dimensions have numerical importance.

(49) As the datum by which the fiducial is indicated in FIG. 7, and by which a theoretically accurate geometric fiducial is considered, the centers of the two guide-pin holes and the side face of the containing unit having a shape of concave are used.

(50) FIG. 8 is a view showing the dimensions of the grooves.

(51) FIG. 9 is a view showing an example of experiment in which resin or adhesive different in viscosity is used.

(52) It was found that the in-pouring of resin or adhesive having a viscosity of 150 cps30% (from about 105 cps to about 195 cps and ranges there between) or smaller is easy, but when the viscosity reaches 5000 cps, the in-pouring is not easy.