JPS623922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical transmission body having excellent transmission characteristics in the infrared spectral region.

With the development of lasers compatible with long wavelength ranges, there has recently been a desire for lasers that can transmit light in the infrared spectral range.

Therefore, even in the past, we focused on the fact that thallium halide is transparent in the infrared spectrum region,
For example, an attempt has been made to provide a linear optical transmitter having a structure in which the above-mentioned halide is filled into a plastic tube by an extrusion method, but such means do not allow the so-called optical transmitter to accurately distinguish between the core and the cladding. A two-layer structure cannot be obtained as the main part of the transmitter, and since thallium halide is an ionic crystal, it is extremely fragile in terms of mechanical strength, and its strength depends on the plastic tube.
Since the tube and its interior were not in close contact, it was not possible to expect anything at all.

Furthermore, in addition to the above-mentioned strength problem, the light transmitting body produced by the extrusion method has major problems such as the inability to reduce the wire diameter and the slow extrusion speed.

In view of the above problems, it is an object of the present invention to provide an optical transmission body that is highly reliable in terms of strength and chemical stability, is easy to manufacture, and has excellent transmission characteristics in the infrared spectral region. The specific configuration and embodiments thereof will be described below.

In the figure, 1 is the core part, 2 is the clad part, and 3
is a metal layer.

Here, the core portion 1 and the cladding portion 2 are made of at least one thallium halide selected from the thallium halide group consisting of thallium iodide, thallium bromide, and thallium chloride.
The halide composition comprises one or more species.

In this case, since the core part 1 must have a higher refractive index than the cladding part 2, it is desirable that the core part 1 contains a large amount of thallium iodide and thallium bromide. The refractive index will be obtained.

The cladding portion 2, which has a lower refractive index than the core portion 1, contains a large amount of thallium bromide and thallium chloride, and in particular contains a large amount of thallium chloride, resulting in a low refractive index.

Further, in the above, for example, the core part 1 is made of thallium iodide or thallium bromide, and the clad part 2 is made of thallium iodide or thallium bromide.
Each of these parts 1 and 2 may be composed of a single compound such as thallium chloride.

In addition, each of the compositions of the core part 1 and the cladding part 2 may be composed of a ternary composition consisting of thallium iodide, thallium bromide, and thallium chloride. thallium,
By appropriately setting each content of thallium chloride that can lower the refractive index, a predetermined refractive index of each of these parts 1 and 2 can be obtained.Furthermore, depending on the content of thallium bromide, a similar refractive index can be obtained. Settings can be controlled.

In addition, when the core part 1 and the clad part 2 are composed of compositions of thallium iodide, thallium bromide, and thallium chloride, a combination of a binary system and a unicomponent system, a combination of a ternary system and a unicomponent system, Any combination of a ternary system and a binary system can be adopted.

On the other hand, the metal layer 3 described above is made of a metal that can be stretched at a temperature lower than the melting point of the halide composition constituting the core portion 1 and the cladding portion 2, and examples of this metal include aluminum, aluminum alloy, Appropriate materials are used from copper, copper alloys, silver, silver alloys, gold, gold alloys, palladium, palladium alloys, platinum, platinum alloys, and the like.

Hereinafter, one of the optical transmission bodies constructed in this way will be explained.
To briefly describe a manufacturing example, a rod of a thallium halide composition that is to become the core part 1 and the clad part 2 is inserted into a metal tube with a bottom that is to become the metal layer 3, and the metal tube is sealed. A linear optical transmitter is obtained by processing the material into a desired wire diameter using methods such as swaging, groove roll rolling, die drawing, and die drawing.

In the present invention, since the core portion 1 and the cladding portion 2, which are the main parts of the optical transmitter, are composed of the above-mentioned thallium halide composition, the infrared spectral region can be effectively utilized by utilizing the properties of these compositions. Not only does it provide excellent optical transmission characteristics, but also the metal layer 3 is tightly coated on the outer periphery of the main part where lack of mechanical strength is fatal, so the core part 1 In addition, mechanical strength capable of sufficiently protecting the cladding portion 2 can be ensured.

Moreover, this metal layer 3 can be stretched at a temperature lower than the melting point of the composition of the core part 1 and the cladding part 2, so low-temperature processing can be performed without damaging the positional relationship between the two parts 1 and 2. In a state that depends on the mechanical strength of the layer 3, it is possible to process the wire into a small diameter without any problems, and at the same time, the wire drawing speed at that time can be increased to increase the manufacturing efficiency of the optical transmission body.

Next, embodiments of the present invention will be described.

Example 1 50 mol% thallium iodide and 50 mol% thallium bromide
The core part 1 is formed by the halide composition in mol%.
A round rod (outer diameter 1 cm, length 5 cm) was made, and the cladding part 2 was made with a halide composition containing 40 mol% thallium bromide and 60 mol% thallium chloride.
A tube (inner diameter 1 cm, outer diameter 1.8 cm, length 5 cm) was made, and the above round rod was inserted into this tube to integrate the two.

Next, this integrated product is enclosed in an oxygen-free copper tube (inner diameter 1.8 cm, outer diameter 2.2 cm) that will become the metal layer 3, and after integrating each component that will become these 1, 2, and 3, this The outer diameter is 10mm by swaging process.
Then, the outer diameter was 1 mm by die processing to obtain an optical transmission body with the desired wire diameter.

Optical transmitter obtained in this way (length 10m)
When tested, it was confirmed that it could transmit infrared rays in the wavelength range of 2μ to 11μ.

Example 2 Thallium bromide 90 mol% and thallium iodide 10
A round rod (outer diameter 0.8 cm, length 10 cm) that will become the core part 1 is made from a halide composition of
The aluminum tube was sealed by filling the gap between the round rod and the aluminum tube with thallium chloride powder, which was to become the cladding part 2.

Then, the aluminum tube with the halide composition inside is drawn down to an outer diameter of 6 mm using a die on a draw bench, and then further drawn to an outer diameter of 6 mm using a die on a wire drawing machine.
The wire was processed into a thin wire of 0.5 mm to obtain an optical transmission body with the desired wire diameter.

Optical transmitter obtained in this way (length 10m)
When tested, it was confirmed that it could transmit a carbon dioxide laser beam with a wavelength of 10.6μ.

As described in detail above and illustrated in the examples, the present invention provides an optical transmitter having excellent transmission characteristics in the infrared spectral region, which has excellent strength, chemical stability, ease of manufacture, It can be provided in a state that satisfies requirements such as high efficiency.

[Brief explanation of the drawing]

The drawing is a sectional view of the optical transmission body of the present invention. 1...Core part, 2...Clad part, 3...Metal layer.

Claims (1)

[Claims] 1. A linear optical transmission body having a core portion and a cladding portion made of a thallium halide composition containing at least one member selected from the thallium halide group consisting of thallium iodide, thallium bromide, and thallium chloride. Infrared spectrum, characterized in that the outer periphery of the main part consisting of the core part and the cladding part is covered with a metal layer that can be stretched at a temperature lower than the melting point of the above-mentioned composition constituting the core part and the cladding part. Optical transmission body for area.