JP3095622B2 - Manufacturing method of fiber with optical components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to manufacture a fiber with an optical component in which an optical component such as a cylindrical refractive index distribution lens (rod lens) or a filter is attached to the tip of an optical fiber such as an image fiber. On how to do it.

[0002]

2. Description of the Related Art A cylindrical refractive index distribution type lens called a cell hook lens or a rod lens is attached to an objective portion of an image fiber for image formation.
Such a connection between the lens and the image fiber is performed by holding the lens and the image fiber with appropriate holding means, performing alignment such as axis alignment, and then bonding using an adhesive such as an epoxy resin adhesive for optics. how to,
Alternatively, it is performed by a method of connecting both using a sleeve such as a heat-shrinkable sleeve.

However, in such a method, when the outer diameter of the lens becomes small, the length becomes very short, so that it becomes difficult to hold the lens. For this reason,
There are drawbacks that the installation work requires time and a long time is required to maintain the mounting accuracy. In addition, the reliability of the connection using an adhesive may remain uneasy. Further, in the case of using a sleeve, there is a problem that the outer diameter becomes large.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to easily, accurately and efficiently attach a small optical component such as a rod lens to the tip of a fiber such as an image fiber. It is in.

[0005]

The object of the present invention is to prepare a precursor to be an optical component having a length that can be gripped in advance, and fusion-splicing the precursor to the fiber tip, and then cutting the precursor to a predetermined length. Thus, the problem can be solved by using the precursor as an optical component. For fusion splicing, use a precursor and
Simply contact the end face of the iva or with a precursor
A method of leaving a gap of 10 μm or less between fiber end faces
Used.

Hereinafter, specific examples of the present invention will be described in detail. In this example, a case will be described in which a silica-based refractive index distribution type lens (hereinafter abbreviated as a rod lens) is used as an optical component and a small-diameter quartz-based image fiber is used as a fiber. First, as shown in FIG. 1, a precursor (precursor) 1 serving as a rod lens and an image fiber 2 are prepared. As the precursor 1, a glass rod whose refractive index distribution in the diameter direction is a square distribution is used.

This glass rod is manufactured by VAD method, external method,
A glass base material having the above-mentioned refractive index distribution is prepared by a CVD method such as an internal method, and the glass base material is obtained by melt-drawing. The outer diameter of the glass base material is substantially the same as the outer diameter of the image fiber 2. The length is a length that can be gripped by the gripping device, and usually has an outer diameter of 1 to 2 mm and a length of 5 to 30 c
m. One end face of the precursor 1 is in an optically polished state, and serves as an end face for connection.

As the image fiber 2, various types such as a multi-core fiber type for normal observation are used. The length of the image fiber 2 is appropriately determined depending on the application, but is longer than the length that can be gripped by the gripping device. It is necessary to be.

Next, the precursor 1 and the image fiber 2 are aligned and connected. In this example, since both are made of silica glass, fusion splicing which is widely used for connection of communication optical fibers is used. Equipment is available
You. As the fusion splicing device, a known optical fiber fusion device for communication as shown in FIG. 1 can be used, and the precursor 1 is attached to one grip 4 of the fusion device 3 and the image fiber is attached to the other grip 5. Each of them can be connected by gripping each of them, bringing their end faces close to each other, performing alignment such as optical axis alignment using the optical microscope 6, and then performing arc discharge and fusing.

In this fusion splicing, alignment, preheating, and indentation are performed in the same manner as in the ordinary fusion splicing of an optical fiber for communication, so that the refractive index distribution of the precursor 1 serving as a rod lens is not adversely affected. → A method of setting the precursor 1 and the image fiber 2 at any one of the following conditions in an aligned state without taking each step of melting, and then melting (arc discharge).
That is, any method of simply bringing the precursor 1 and the end face of the image fiber 2 into contact with each other or leaving a gap of 10 μm or less between both end faces is adopted.

Thus, as shown in FIG. 2, when the precursor 1 serving as a rod lens is connected to the tip of the image fiber 2, the precursor 1 is sized to obtain a predetermined imaging characteristic and a fiber cutter or the like is used. If the cut surface is optically polished as necessary after cutting or polishing to obtain a predetermined imaging characteristic after the cutting, the tip of the image fiber 2 as shown in FIG. An image fiber 8 with a rod lens having the rod lens 7 attached thereto is obtained.

In this mounting method, the precursor 1 serving as a rod lens is used, and the length of the precursor 1 is set to a length sufficient for gripping, so that alignment and connection such as optical axis alignment are extremely performed. It can be performed easily and accurately. Also, since fusion splicing is performed,
The connection strength and reliability are also high.

In the present invention, as the fiber, in addition to the above-described image fiber, a communication optical fiber, a light guide, a polarization maintaining optical fiber, a plastic fiber, or the like is used. In addition, a filter, a birefringent plate, a polarizer, an analyzer, and the like that can form a rod-shaped precursor having a grippable length can be used.

Further, as shown in FIG. 4, by repeating the above method, the birefringent plate 1
2. Various optical components having different characteristics such as the first lens 13, the second lens 14, and the filter 15 can be sequentially attached. As in the above example, the image fiber 2 with the precursor 2 serving as a rod lens attached thereto may be assembled into a fiber scope, and then the precursor 2 may be cut into a predetermined length. It may be cut and polished simultaneously with the other members. Further, it is also possible to attach a rod lens having the same diameter to the tip of the communication optical fiber to increase the mode field diameter.

[0015]

As described above, according to the manufacturing method of the present invention, small and difficult-to-hold optical components such as rod lenses and filters are easily and accurately attached to the tips of image fibers and communication optical fibers. Will be able to do it. In addition, when the precursor to be an optical component and the fiber are fusion spliced, the precursor and the end face of the fiber are simply contacted.
10 μm between the precursor and the end face of the fiber
Since a method of forming a gap of m or less is employed, there is no adverse effect on the refractive index distribution of the precursor, and the connection strength and reliability are increased.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a connection method according to the present invention.

FIG. 2 is a schematic configuration diagram illustrating an example of a connection method according to the present invention.

FIG. 3 is a schematic configuration diagram showing an example of a fiber with an optical component obtained by the manufacturing method of the present invention.

FIG. 4 is a schematic configuration diagram showing another example of a fiber with an optical component obtained by the manufacturing method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Precursor, 2 ... Image fiber, 3 ... Fusion device, 4 ... Grip part, 5 ... Grip part, 7 ... Rod lens, 8 ...
Image fiber with rod lens

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-210405 (JP, A) JP-A-4-288509 (JP, A) JP-A 1-282509 (JP, A) JP-A-63- 167310 (JP, A) Hikaru Hei 3-42104 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 6/32 G02B 6/255

Claims (1)

(57) [Claims] When attaching an optical component such as a lens or a filter to the tip of a fiber, a precursor having a grippable length serving as an optical component is first fusion-spliced to the tip of the fiber.
The precursor is cut to a predetermined length and
Simply contact a method, the fusion splicing is the end surface of the precursor and the fiber to
Contact method or between the precursor and the end face of the fiber
What should be done by a method with a gap of 10 μm or less
Preparation of an optical component with fibers according to claim.