JPH06109640A - Manufacture of optical fiber opt0-load - Google Patents

Abstract

PURPOSE:To manufacture an optical fiber opto-load having a functional film of high quality at its tip, with no trained skill required, easily and at low costs. CONSTITUTION:An end of long optical fiber F is introduced in a film forming vacuum bath X so that its end face 2 at least exposes itself in the bath X, while a sealing means 3 is also provided. Then, by a film farming means, a functional film is formed on the end face 2 of the optical fiber F. It is recommended that an end of the long optical fiber F is inserted into a cylindrical holder, and the gap between the inner periphery wall of the holder and the optical fiber F is sealed up far air-tight. Then the holder is inserted into an opening provided at a vacuum bath A for fixing, and the end face 2 of the optical fiber F is introduced into the film forming vacuum bath X.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended for detection of physical quantities such as heat, magnetic field and electric field, and measured quantities such as chemical quantities such as ions and concentrations. The present invention relates to a method for manufacturing an optical fiber optrode in which a functional thin film capable of obtaining detection signals such as phase, frequency, etc. is formed on the tip surface of an optical fiber.

[0002]

2. Description of the Related Art A thin film (hereinafter, referred to as a functional thin film) that changes its state in response to a specific ion or temperature change is provided at the tip of an optical fiber, and the change is detected as an optical change. Fiber optrodes are known.

On the other hand, as a thin film forming method, for example, in a known thin film forming method such as sputtering, a vacuum chamber is required in order to use gas or vacuum in the processing process. However, when the functional thin film is formed on the tip surface of the optical fiber by these methods, it is difficult to put the entire long optical fiber main body in the vacuum chamber and form the functional thin film on the tip portion. A method of adhering a separately formed functional thin film to the tip surface of a long optical fiber, or forming a functional thin film on the tip surface of a short optical fiber cut to a length that can be stored in a vacuum chamber by the above method, and then There is known a method of fusing the fiber to the long fiber body.

However, the former method requires a skilled skill, has a low yield, is expensive, and has a problem in productivity. Further, in the latter method, in addition to the above problems, it is necessary to perform mirror polishing of the end face of the optical fiber not only on the short tip surface but also on the short and long joint surfaces, so that there are many steps. However, there is a quality problem that fusion loss occurs.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to easily and inexpensively require no skill, and to provide an optical fiber optrode having a high-quality functional thin film at its tip. Is to provide a method for manufacturing the same.

[0006]

In order to achieve the above object, the inventors of the present invention focused on a method of setting an optical fiber in a vacuum chamber for forming a thin film, and examined only the end face of the long optical fiber. The optical fiber is introduced into the vacuum chamber and exposed, and a sealing means is applied to the introduction part of the optical fiber to keep the vacuum chamber airtight and the optical fiber is supported, and the thin film forming means facilitates the optical fiber tip surface. The present invention has been completed by finding that a functional thin film can be formed.

That is, in the method of manufacturing an optical fiber optrode of the present invention, a sealing means is provided so that one end of a long optical fiber is exposed in a vacuum chamber for forming a thin film and its tip end surface is exposed at least in the chamber. Is attached and introduced, and then a functional thin film is formed on the distal end face of the optical fiber by a thin film forming means. Desirably, one end of the long optical fiber is inserted into a cylindrical holder and the inner wall of the holder is inserted. The gap between the optical fiber and the optical fiber is hermetically sealed, and the holder is tightly fitted in the opening provided in the vacuum chamber to introduce the tip end surface of the optical fiber into the vacuum chamber for thin film formation.

The functional thin film formed on the front end surface of the optical fiber of the present invention is used for detection of physical quantities such as heat, magnetic field and electric field and measured quantities such as chemical quantities such as ions and concentrations. The physical characteristics change, and each measured amount is detected as a change in light intensity, phase, frequency, or the like. More specifically, for example, a GaAs thin film has optical characteristics that change with changes in temperature, so that heat can be detected.
Further, since the SiO ₂ and Si ₃ N ₄ thin films react with hydrogen ions and change their optical characteristics, the presence of hydrogen ions can be detected. Table 1 below shows other functional thin film substances, their detection targets, and thin film forming methods.

[0009]

[Table 1]

The method of manufacturing the optical fiber optrode of the present invention will be described in detail below. FIG. 1 is a schematic cross-sectional view showing a basic method for forming a functional thin film on the tip surface of a long optical fiber. In the figure, F is an optical fiber,
The one end portion in the vacuum chamber A within X, the front end surface 2 is introduced so as to be exposed to at least the tank X, and is fixed by attaching a sealing means 3. In the present invention, a thin film forming means (not shown) is applied to the front end surface 2 of the optical fiber F,
An optical fiber optrode is manufactured by forming the functional thin film.

According to the above manufacturing method, the long optical fiber F
Even when the film is wound on the spool, one end of the film can be introduced into the vacuum chamber X and the functional thin film can be directly formed on the tip surface 2.

The sealing means 3 may be any means capable of hermetically fixing one end of an optical fiber in a vacuum chamber.
For example, a gel-like grease sealing material such as silicon vacuum grease or a combination of this grease sealing material and a spacer can be used.

Examples of the thin film forming means that can be used in the present invention include the CVD method, the vacuum vapor deposition method, the molecular beam epitaxial method, the ionization vapor deposition method and the like, in addition to the above-mentioned sputtering. In the present invention, the functional thin film is 0.1-10
It is formed to a thickness of μm, preferably 1 to 5 μm. If the thickness of this functional thin film is less than 0.1 μm, the influence of grain boundaries and defects in the thin film becomes large, while if it exceeds 10 μm, the light transmittance is deteriorated and the residual stress in the film increases, which is not preferable.

In the present invention, as shown in FIG. 2, a cylindrical holder (hereinafter referred to as a capillary) 4 is tightly fitted in a vacuum chamber A, and one end of a long optical fiber F is placed in the capillary 4. The end face 2 of the optical fiber in the bath X
May be introduced, and the sealing means 3 may be provided in the gap between the inner peripheral wall of the capillary 4 and the optical fiber F. The use of the above-mentioned capillary 4 is preferable because the tip end surface 2 of the optical fiber can be easily fixed in the vacuum chamber X while being exposed.

Further, in the present invention, as shown in FIG. 3, an optical fiber holder 6 in which a plurality of capillaries 4 are tightly fitted is provided.
Can be detachably and airtightly fixed to the opening 7 provided in the vacuum chamber A. According to this method, the tip surfaces 2 of a plurality of optical fibers can be easily fixed in the vacuum chamber X at one time , which is preferable.

Therefore, the optical fiber optrode can be mass-produced, and the working efficiency can be greatly improved.

Further, in the present invention, as another method of fixing the optical fiber to the optical fiber holder 6, as shown in FIG. 4, in a large-diameter capillary 4 tightly fitted to the optical fiber holder 6, Rubber for high vacuum with multiple optical fibers 5
Alternatively, the grease 3 may be used to hermetically fix it. According to this method, a plurality of optical fibers can be fixed in a single capillary, work efficiency can be significantly improved, and cost can be reduced.

[0018]

According to the above-mentioned manufacturing method, even when the long optical fiber is wound on the spool, one end of the long optical fiber can be introduced into the vacuum chamber and the functional thin film can be directly formed on the tip surface thereof. become able to. Further, since the optical fiber is fixed using the capillary, the tip end surface of the optical fiber can be easily exposed and fixed in the vacuum chamber.

Further, since the optical fiber holder in which a plurality of capillaries are tightly fitted is used, the tip surfaces of a plurality of optical fibers can be easily exposed and fixed in the vacuum chamber at one time. Greatly improves efficiency. Furthermore, since a large-diameter capillary is tightly fitted to the optical fiber holder and a plurality of optical fibers are airtightly fixed to this, working efficiency is greatly improved and cost can be reduced.

[0020]

EXAMPLES Hereinafter, the present invention will be described more specifically by showing examples. Needless to say, the present invention is not limited to this embodiment. (Fixation of optical fiber) First, diameter 150 μm (core diameter 1
(00 μm) step-index type optical fiber is mirror-polished at its tip and then inserted into a capillary 4 having a hole diameter of 0.5 mm, and silicon-based vacuum grease 3 is filled and fixed in the gap between the capillary 4 and the optical fiber F. did. Then, a steel disk-shaped holder 6 in which 20 capillaries 4 were tightly fitted was airtightly attached to the opening 7 provided in the vacuum chamber A with bolts, and the tip surfaces 2 of the 20 optical fibers were placed in the vacuum chamber. It was fixed while being exposed to X.

(Formation of Thin Film) The disk holder 6 was connected to a high frequency power source (not shown) so as to also serve as the lower electrode of the parallel plate type sputtering apparatus A. Further, GaAs was used as the target. In this state, the inside of the closed tank is 2.0
Vacuum down to × 10 ^-7 Torr, and then use an effusion cell 260 in which 25 g of arsenic metal is previously inserted.
It was heated to ° C and an arsenic pressure of 1.6 x 10 ^-6 Torr was applied. This is because As from the deposited film during GaAs sputtering.
This is to prevent omission. After that, argon gas was introduced into the sealed tank, the pressure in the tank was maintained at 3.6 × 10 ^-2 Torr, plasma was generated at an anode voltage of 1.5 KV, traveling wave power of 110 W, reflected wave power of 10 W, and anode current of 100 mA. Was generated, pre-sputtering was performed for 20 minutes with the shutter closed, the shutter was opened, and main sputtering was performed for 3 hours. By this operation, 20 optical fiber optrodes in which a GaAs thin film having a thickness of about 3 μm was formed on each tip surface 2 of the optical fiber could be manufactured.

(Functional Test of Optical Fiber Optrode) From the opposite end of the optical fiber optrode, AlA is used as a light source.
The sGaLED light (wavelength 0.86 μm) was incident, and the intensity of light reflected by passing through the optrode was measured. When one optrode prepared above was placed in a thermostat and the temperature of the thermostat was changed from 50 ° C to 100 ° C, the light absorption edge of the GaAs thin film shifted to the long wavelength side and the intensity of reflected light decreased. did.

As a result, it was confirmed that the optical fiber optrode obtained in the example can detect the temperature change of the liquid.

In the above embodiment, the optical fiber is fixed to the closed chamber by using the capillary. However, the same optical property can be obtained by exposing and fixing the end face of the optical fiber in the vacuum chamber without the capillary. A fiber optrode was obtained. Further, in the above-mentioned embodiment, the example of the GaAs thin film capable of detecting the temperature change is shown, but even if the other functional thin films shown in Table 1 are formed, the respective detection objects can be detected.

[0025]

According to the manufacturing method of the optical fiber optrode of the present invention, even if the long optical fiber is wound on the spool, one end of the long optical fiber is introduced into the vacuum chamber and is directly attached to the front end surface thereof. It becomes possible to form a functional thin film.
Further, since the optical fiber is fixed using the capillary, the tip end surface of the optical fiber can be easily exposed and fixed in the vacuum chamber. Moreover, since an optical fiber holder in which a plurality of capillaries are tightly fitted is used,
The tip surfaces of a plurality of optical fibers can be easily exposed and fixed in the vacuum chamber at one time, and work efficiency is significantly improved. Furthermore, since a large-diameter capillary is tightly fitted to the optical fiber holder and a plurality of optical fibers are airtightly fixed to this, working efficiency is greatly improved and cost can be reduced.

Therefore, the step of forming a functional thin film on the end face of a long optical fiber does not require the conventional skill and splicing of the optical fiber, and a high-quality and stable optical fiber optrode is inexpensive and large in volume. Can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a basic manufacturing method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a method using a capillary.

FIG. 3 is a schematic cross-sectional view showing a method using a plurality of capillaries.

FIG. 4 is a schematic cross-sectional view showing a method of fixing a plurality of optical fibers to one capillary.

[Explanation of symbols]

A vacuum chamber F optical fiber X inside of vacuum chamber 1 introduction part 2 tip surface 3 sealing means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // G01N 21/00 Z 7370-2J G01R 33/032 8203-2G

Claims (2)

[Claims] 1. An end portion of a long optical fiber is introduced into a vacuum chamber for forming a thin film, with a sealing means attached so that its tip surface is exposed at least in the chamber, and then the optical fiber of the optical fiber is introduced. A method for manufacturing an optical fiber optrode, characterized in that a functional thin film is formed on the front end surface by a thin film forming means. 2. An end portion of a long optical fiber is inserted into a cylindrical holder, a gap between an inner peripheral wall of the holder and the optical fiber is hermetically sealed, and the holder is tightly fitted in an opening provided in a vacuum chamber. The leading end surface of the optical fiber is introduced into the vacuum chamber for thin film formation by performing the above.
A method for manufacturing the optical fiber optrode described.