# US 2018/0024295 A1 · Optical Coupling of Embedded Optical Fibers

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- Number: US 2018/0024295 A1
- Document ID: US20180024295A1
- Status: Published application
- Kind: A1
- Application number: 15/656,737
- Filed: 2017-07-21
- Published: 2018-01-25
- Earliest claimed: 2016-07-25
- Assignees: Com&Sens; Imec Vzw; Universiteit Gent
- Applicants: Com&Sens; Imec Vzw; Universiteit Gent
- Inventors: Jeroen Missinne; Geert Van Steenberge; Geert Luyckx; Eli Voet
- Web page: https://patentgrep.com/patent/US20180024295A1

## CPC

- G02B 6/262: {Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements}
- G02B 6/138: by using polymerisation
- G02B 6/3616: {Holders, macro size fixtures for mechanically holding or positioning fibres, e.g. on an optical bench (supporting carriers of a microbench type G02B6/3648; micromanipulators B25J7/00; cassettes, bobbins G02B6/4439)}
- G02B 6/3644: {the coupling means being through-holes or wall apertures}
- G02B 6/3825: {with an intermediate part, e.g. adapter, receptacle, linking two plugs}
- G02B 6/382: {with index-matching medium between light guides (provisionally see G02B6/4212)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical system and method for connecting two optical fibers is described in the present disclosure. An example optical system includes a first optical fiber embedded in an embedding material, the first optical fiber comprising side walls extending in a longitudinal direction in contact with the embedding material, a second, external, optical fiber, and a self-written waveguide in optical contact with the first and second optical fibers. Only a cross section perpendicular to the side walls of the first optical fiber is outside the embedding material, in contact with the self-written waveguide.

## Claims

### Claim 1

An optical system, the optical system comprising:
an embedded optical fiber embedded in an embedding material, the embedded optical fiber comprising side walls extending in a longitudinal direction in contact with the embedding material;
an external optical fiber; and
a self-written waveguide in optical contact with the embedded optical fiber and the external optical fiber thus forming an optical connection between the embedded optical fiber and the external optical fiber,
wherein only an end-face perpendicular to the side walls of the embedded optical fiber is outside the embedding material, in contact with the self-written waveguide.

### Claim 2 (depends on 1)

The optical system of claim 1, wherein the embedding material is a composite.

### Claim 3 (depends on 1)

The optical system of claim 1, wherein the embedded optical fiber comprises a first fiber core and wherein the external optical fiber comprises a second fiber core.

### Claim 4 (depends on 3)

The optical system of claim 3, wherein the first fiber core and the second fiber core are optically aligned.

### Claim 5 (depends on 1)

The optical system of claim 1, wherein the self-written waveguide comprises a core and a cladding.

### Claim 6 (depends on 1)

The optical system of claim 1, further comprising a strain relief element decoupling a stress acting on the external optical fiber from the optical connection.

### Claim 7 (depends on 1)

The optical system of claim 1, further comprising a ferrule, a block, a connector, a base plate, or a combination thereof attached to the self-written waveguide.

### Claim 8 (depends on 7)

The optical system of claim 7, wherein the ferrule is adapted to cooperate with an external ferrule of a removable optical fiber to thereby provide optical contact between the external optical fiber and the removable optical fiber.

### Claim 9 (depends on 8)

The optical system of claim 8, wherein both ferrules have an angled termination.

### Claim 10 (depends on 1)

The optical system of claim 1, wherein the embedded optical fiber and the external optical fiber are single mode optical fibers.

### Claim 11 (depends on 1)

The optical system of claim 1, wherein the embedded optical fiber is an optical fiber sensor for detecting deformations in the embedding material, and wherein the external optical fiber is an optical fiber adapted for information transmission.

### Claim 12 (depends on 1)

The optical system of claim 1, wherein the self-written waveguide is located between the embedded optical fiber and the external optical fiber.

### Claim 13 (depends on 1)

A method for optically coupling the external optical fiber with the embedded optical fiber embedded in the embedding material, thereby obtaining an optical system of claim 1, the method comprising:
exposing an end-face of the embedded optical fiber without exposing the side walls of the embedded optical fiber out of the embedding material;
aligning an end-face of the external optical fiber with the exposed end-face of the embedded optical fiber; and
providing an optical intermediate waveguide material between the end-face of the embedded optical fiber and the end-face of the external optical fiber, thereby obtaining the self-written waveguide between the embedded optical fiber and the external optical fiber.

### Claim 14 (depends on 13)

The method of claim 13, wherein aligning the end-faces of the respective optical fibers comprises transmitting a signal through the external optical fiber and measuring a difference in reflectivity between the end-face of the embedded optical fiber and the embedding material, thus revealing a location of the embedded optical fiber.

### Claim 15 (depends on 13)

The method of claim 13, wherein obtaining the self-written waveguide comprises the steps of dispensing an optical polymer between the end-face of the embedded optical fiber and the end-face of the external optical fiber, forming a core of the self-written waveguide, and forming a cladding of the self-written waveguide.

### Claim 16 (depends on 15)

The method of claim 15, wherein forming the core of the self-written waveguide comprises transmitting a UV signal through the respective optical fibers, and wherein forming the cladding comprises applying flood UV exposure to the optical polymer.

### Claim 17 (depends on 13)

The method of claim 13, wherein alignment is performed with support of a base plate.

### Claim 18 (depends on 13)

The method of claim 13, further comprising a ferrule for facilitating connection with an external sensor, an external reader, or an external fiber.

### Claim 19 (depends on 13)

The method of claim 13, further comprising providing structural reinforcement.

### Claim 20 (depends on 19)

The method of claim 19, wherein the structural reinforcement comprises a strain relief element.