JPH0394216A - Production of faraday rotor - Google Patents

Abstract

PURPOSE:To obviate the generation of cracks, etc., in the Faraday rotor by taking out a single crystal which does not crack in the state in which a flux is dissolved. CONSTITUTION:The single crystal which grows and does not crack in the state in which the flux is dissolved. Raw materials and the flux are mixed in the range of 4.5 to 9.1mol% Gd2O3, 37 to 46mol% Fe2O3, 36 to 50mol% Bi2O3 and 5.5 to 23.5mol% B2O3 to grow bismuth-substd. gadolinium iron garnet. Namely, the sp. gr. of the B2O3 is lighter than the sp. gr. of the Faraday rotor and, therefore, when the mol% of the B2O3 to be used is increased, the film of the B2O3 is then formed in the upper part of the floated Faraday rotor and the Faraday rotor is kept free from direct contact with the atm. The dissipation of the heat from the Faraday rotor is prevented in this way and the growth of the Faraday rotor in the soln. is enabled. The generation of the cracks, etc., in the Faraday rotor is thus obviated.

Description

[Detailed Description of the Invention] (Industrial Application Field) The invention relates to a method for manufacturing a Faraday rotator used in optical inulators, optical switches, etc., and particularly relates to a magneto-optic garnet material used in the rotor. ．． (Prior art) A method for manufacturing this type of rotor is disclosed in Japanese Patent Application Laid-Open No. 59-164699.
It is disclosed in the issue. As a manufacturing method of the Faraday rotator of this prior art, raw materials and flags are mixed with Gd203 of 8 anal% or less (excluding 0%),
30-53 mol% Fe2Q3, Bi203
40 to 61 mol%, and B2 as Franks
The molar ratio of 03 and Bi203 is 13203 (mo
l%) /Bi? In the flux method, the raw material and flux are mixed and melted so that 03 (mol%)≦008, and a single crystal is precipitated and elongated while slowly cooling.
A manufacturing method is described in which the elongated single crystal is extracted while the flux is molten. (Problems to be Solved by the Invention) In the prior art Faraday rotator manufacturing method,
During manufacturing, the Faraday rotator floats due to its specific gravity, and heat is dissipated from the floated part, creating a temperature difference between the temperature in the solution and the floating part, which causes cracks to occur in the Faraday rotator. Furthermore, flux is mixed into the cracks, promoting the cracks. A Faraday rotator with cracks could not satisfy the effective diameter of light, causing light leakage, and there was a problem that it could not be used as a completed Faraday rotator. Therefore, the manufacturing yield is poor, leading to a decrease in manufacturing efficiency. The present invention aims to solve the above-mentioned problems and provides a method of manufacturing a Faraday rotator that does not cause cracks or the like. (Means for Solving the Problems) The method for producing a Faraday rotator of the present invention is a flux method in which a raw material and a flux are mixed and melted, and a single crystal is precipitated and lengthened while being slowly cooled. This method extracts a single crystal that does not have any prominent cracks in the melted state, and the raw material and the flux are mixed with Gd.
203 4.5-9.1not%, Fez03 3 7
~46 mol%, Bi20336~50 mol%
, B203 575 to 23.5 mat% to grow bismuth-substituted gadolinium iron garnet at 4.1F'61. (Function) According to the present invention, Faraday rotation B20 than the child's specific gravity
Since the specific gravity of B203 is light, the mol% of B203 used is
By increasing the amount, a film of 8203 is formed on the upper part of the floating Faraday rotator. B at the top of the Faraday rotator? Since the 03 membrane is used, the Faraday rotator does not come into direct contact with the atmosphere. Therefore, it is possible to prevent heat dissipation from the Faraday rotator and to grow the Faraday rotator in a solution. As a result, cracks and the like will not occur within the Faraday rotator.

(Example) Examples of the present invention will be described below. Flux and raw materials are placed in a crucible, the temperature in the furnace is raised to sufficiently mix and melt the materials, and then the melt is cooled to lengthen the single crystal in the melt. This single crystal is
The flags are separated from the crucible at the lowest slow cooling temperature, cooled to room temperature in the furnace for 24 hours, and then taken out. As for flux, Bi203 and B
Experiments were conducted using both Gd203 and Fe203 as raw materials, and changing the growth conditions of the mixing ratio of raw material components and flux, and the mixing ratio of raw materials. In this experimental example. Gd3xBixFe50+
Since the purpose is to cultivate the single crystal of Bi20
3 is a flux and also serves as a raw material. The single crystal obtained was fixed using an X-ray diffraction device. Furthermore, the Faraday rotation angle at a wavelength of 1.31 Lm was measured. The above crystal growth conditions and single crystal characteristic values are
Shown in the table.

In Table 1, the single crystal was fixed as follows. The obtained single crystal is powdered, the diffraction angle of the diffraction pattern is measured using an X-ray diffractometer, and the interplanar spacing is determined from the diffraction angle.
Society for Testing Mate
Rials powder and line data ( [Powdsr Dif
fraction FileInorganic
Volume] Joint Committee
Powder Diffraction Standa
rds Sets +9-20, P. 449,P
．． 521, Sets 11=l5 P. The measurement was performed by comparing with 503). In the grown crystal column of Table 1, G indicates a garnate 7-type single crystal, and α indicates α-Fe, +lh. Experimental example 1 in Table 1,
In the combinations shown in 2, 4.7, and 8.9, the garnet type single crystal (GdBiIG) is centered and has a length of f&, and Experimental Example 3
, Kumikai with many B203 like 5.6, or Bi2
In a group with a large amount of 03, α-Fe203 has a large amount of α-Fe203 in the center. When this grown crystal was polished and the Faraday rotation angle, which is one of the magneto-optical properties, was measured, it was found to be 22
00 (degrees/cm), and is shown at almost the same rotation angle as that described in JP-A-59-164692, which discloses the prior art. When several dozen pieces were further polished and the effective diameter of light was measured, many perfect single crystals with no cracks were obtained. Therefore, it is clear that the yield has improved.

(Effects of the Invention) According to the present invention, even if the composition ratio of B203 is changed by 5.5 mat% or more, the garnet type single crystal (Gd3-x
BixFe50+z) can be cultivated, and B
Since 203 is present on the top surface of the scoop due to its specific gravity, the garnet type single crystal can be grown in the liquid without floating. Therefore, the formation of cracks due to heat dissipation in the single crystal is reduced, and a Faraday rotator that satisfies the effective diameter of light can be efficiently obtained.

Claims (1)

[Scope of Claims] 1. In a flux method in which a raw material and a flux are mixed and melted, and a single crystal is precipitated and grown while being slowly cooled, a single crystal that does not generate cracks while the flux is molten. A method for producing a Faraday rotator, characterized by taking out a crystal. 2. The raw material and the flux were mixed with Gd_2O_34.
5-9.1 mol%, Fe_2O337-46 mol%
, Bi_2O_336-50mol%, B_2O_35
．． The method for manufacturing a Faraday rotator according to claim 1, characterized in that bismuth-substituted gadolinium iron garnet is grown by mixing 5 to 18.4 mol% in the above mol% range.