JPS62105931A - Magneto-optical garnet - Google Patents

Abstract

PURPOSE:To maintain a stable isolation value at 1.3 and 1.5 micron bands without being influence by both a Faraday rotation coefficient and laser oscillation wavelength, by forming a magneto-optical garnet having a composition shown by a chemical formula of the formula. CONSTITUTION:For example, a magnetic garnet single crystal film having 12.438Angstrom lattice constant and a chemical formula shown by the formula Tb2.6Bi0.6 Fe8O12 is formed in about 850 micron thickness from lead oxide-bismuth oxide- boron oxide flux supported on a platinum crucible at about 770 deg.C on a nonmagnetic samarium.gallium garnet substrate [111] having 12.438Angstrom lattice constant by liquid-phase epitaxial method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magneto-optical garnet material used in a 7A/2 rotator such as an optical isolator or an optical switch. In particular, it relates to a magneto-optic garnet containing Tb and Bi at the 248 position.

(Prior art) In February 1985, the American Sundical Fiber Communications Conference 7 was held to eliminate reflection noise in optical fiber communications.
ptical Fioer Corrmunicati
on) ;@GdJj small (Je
It has been proposed to use AIGa )s Q* garnet thick films as Faraday rotators.

(Problem to be solved by the invention) However, since the Faraday rotation coefficient of garnet shows a significant dependence on the ambient temperature, even if the 45 degree Faraday rotation required for the isolator is guaranteed at room temperature. , the rotation angle changes due to changes in the ambient environment temperature, and the Ainlay's C 1〉width decreases. (GdBt)a (F
In the case of eA1()a)sO8,., taking as an example the value in the wavelength L3 μm band, the temperature dependence of the Faraday rotation is as shown in FIG.

When the Faraday rotation angle changes with a change in temperature, the value of isolation 1 changes as shown in FIG. 3.

On the other hand, since the laser oscillation wavelength also changes as the ambient temperature changes, the 7Alade rotation angle also changes.The purpose of the present invention is to calculate the Faraday rotation coefficient and the laser oscillation wavelength in the wavelength 1.3 μm and 1.5 μm bands. The present inventors aim to provide a magneto-optical garnet that can secure a stable isolation value without being affected by the temperature dependence of both. Noting that the sign of the Faraday rotation angle of We have experimentally discovered that garnet works stably as an optical isolator in the 1.3 μm and 1.5 μm wavelength bands, despite changes in ambient temperature and temperature changes in the laser wavelength, and we have achieved the present invention. Ta. That is, Tb.

It is a magneto-optical garnet characterized by having a composition represented by the chemical formula Bi@+ x Fesolt.

(Example) The present invention will be explained below using examples.

In a platinum crucible (...2 held hawkified limestone - tonismuth oxide - boron oxide thread 1 - Original Yoshi 77 O"C, the lattice constant is 12.1,' (8X non-magnetic samarium
1 on gallium garninet substrate 1uxl, lattice constant 12461A ”CT hLa river 0 for 4 k'ew
(J + t '7x Magnetic Gar-Nect single crystal film with the chemical formula ' 850 it Wavelength 14: 3μI
In II, C was measured as a function of the ambient temperature, and the results shown in FIG. 1 and Table 1 were obtained. The saw exhibits a Faraday rotation of 45° at a thickness of 850 μm. l) The Faraday rotation coefficients at C and 50'0 showed only no OJ rotation relative to the values at 25°C. This l direction is (cidiii 几(FeAIUa), compared to 4!(d) at 0°.
-,,)C is small, [)C is within the range of 50℃ 2 and 5
3 We were able to secure 1・f lane and 3 lanes of aJJ. -i, the temperature dependence of the rotation coefficient of the 7th rotation coefficient at the wavelength of 1.54 m was found in Table 2. 11207! It showed one rotation of 7 alades of 45 degrees with a thickness of m. The 7Alade rotation coefficient at o'c and 5°C showed only a 2.1% variation with respect to the value at 25°C.

Furthermore, even when a single material is used, no deterioration of the isolator is found in response to fluctuations in the oscillation wavelength of the light source laser due to changes in ambient temperature in optical fiber communications.
It was effective in removing reflection noise.

(Example 2) Lead oxide-bismuth oxide-boron thread flux held in platinum crucible
n,! On the top, the lattice constant is 712.474λ and Tb2.4
A magnetic garnet single crystal film having the chemical formula BiOJ Fe, Qt was formed to a thickness of 475 μm by liquid phase epitaxial method. When the Faraday rotation coefficient of this garnet film was measured as a function of the ambient temperature at a wavelength of 163 μm, the results shown in Table @1 were obtained. 4
It exhibited a Faraday rotation of 45 degrees at a thickness of 75 μm. 0
Faraday rotation coefficient at ゛C and 50℃ is 25℃
It was rare to see a variation of only 2.1% with respect to the value in . This direct is (GaHi)m(PeAIGa), love,
It is extremely small compared to 4% in o ”c to 5
3GdB isolation can be ensured in the 0°C range.6-+1'ii"'-% wavelength 15μm
The dependence of the Faraday rotation frequency on the ambient temperature is shown in Table 2, b) /'t7,6ty'1μm
It was shown that the thickness was 45 degrees Faraday rotation.

The Faraday rotation coefficient at 0°C and 50°C tζ is 25
Only J showed a variation of 2.9% with respect to the value at 0.

(Example 3) Lead oxide - bismuth oxide - oxide held in a platinum crucible was 752"C from a boron thread flux, and the lattice constant was x2
．． Non-magnetic calcium of 49 of A, 7 g of non-magnetic rim, zirconium wafer placed on a substrate 11111 with a lattice constant of 712-4S6
A magnetic garnet single crystal film having a chemical formula of TbL and 1316.11 k'ee OH in X was formed to a thickness of 330/an by a liquid phase epitaxial method. Faraday rotation coefficient of this garnet film? , at a wavelength of 1.3 μm, was determined as a function of the ambient temperature (~611), and the results shown in Table 1 were obtained/?, and a Faraday rotation of 45 degrees was obtained at a thickness of 330 μm. °C and 50'
The faradic rotation coefficient at O is 2. ．． It showed only a variation of 8%. This value is extremely small compared to 4% in (Gd4Ji)a (Fe, 1(Ja).Q), a<, O'0 to 50℃
It was possible to secure 33 dB of noise within the range of ↓-. Further, the dependence of the Faraday rotation coefficient at a wavelength of 15 μm on the temperature of the surrounding environment was as shown in Table 2 (%). A J height of 470 μm showed 45 feet of 7 azide one rotation. The Faraday rotation coefficients at 0°C and 50°C showed only a 3.3% variation with respect to the value at 25°C.

(Example 4) The lead oxide-bismuth oxide-oxidation lattice constant was 12.0 at 742"0 from the boron thread flux held on platinum rutsuho.
49oA non-magnetic calcium, magnesium, zirco;
−, Lamb replacement auto*um gallium garnet steamer 1
In 111L, the lattice constant is 12°, 499 people are 'Fby
76 BiL6 Fe, S2. A magnetic material with the following chemical formula:

A monocrystalline film with a thickness of 251μn1 was formed using the liquid nitrate coating method.
7. ．． 7′ One rotation coefficient is a function of the ambient temperature at wavelength 1:3 μm and j, 7t i! IJ Constant 1 - Also, the results shown in Table 1 were obtained. At a thickness of 251 μrn, it exhibited a Faraday rotation of 5 degrees. 0"O and 50゛c
The value of 2 in 2 shows a change of 3.296, which is 46). (The second value is (GaBiru(FeAIGa
), (JI, is smaller than 4% in +, 0°C
To ensure an isolation of 32 dB in the range from was as shown in Table 2 - 365 μm
It shows the Faraday rotation of 451 vines with a thickness of 1~.

Boualaday rotation coefficient at OC and 50'O -22
It showed a variation of 3.5% with respect to the value at 5°C, and only r''.

(Example 5) The lattice constant was 12 at 800°C from a lead oxide-bismuth oxide-boron oxide thread flux held in a platinum crucible.
, 4381. on a non-magnetic samarium-gallium-garnet substrate foxl with a lattice constant of 12.499X-, Tb, BjO, 111F'e, 0. A magnetic garnet single crystal film having the chemical formula , was formed to a thickness of 3.99thm by liquid phase epitaxial method. When the 7-Arad rotation coefficient of this garnet film was measured as a function of the ambient temperature at a wavelength of 1.5 μm, the results shown in Table 2 were obtained. It showed rotation. The 7Alade one rotation coefficient at 0'0 and 50'0 showed only 3.5♀ perturbation relative to the value at 25°C. This value is (GdB
r )3 (FeAIGa )s 4 in O+*
%, and was able to secure an isolation control of 31 dB in the range of 0°C to 50°C.

(Example 6) A lead oxide-bismuth oxide-boron thread flux held in a platinum crucible had a lattice constant of 12 at 787°C.
．． 4: On a non-magnetic samarium-gallium-garnet substrate 11.111 at 38 K, the lattice constant is 12.4ssX
A magnetic garnet single crystal film having a chemical formula of Tbty 13iaa k""J0111 was formed to a thickness of 1.421T by a bitaxial method. :,
The 7-γ Love-rotation coefficient of the glue-non-1 film is set to wavelength 1.
:(When measured as a function of the ambient temperature in μ1TIIIC, the results shown in Table 1 were obtained.1.
421 songs] shows a farade rotation of 45 degrees at the speed of / this. ()゛C, and the Faraday rotation coefficient at 50゛C is 25゛C? 2 for the value U'-J.
Only showing a 4% variation - C゛4゛7'? :o This 1
111 is (GaBi)s (FeAIOa), S1
．． This is significantly smaller than the 64% at 0°C to 5°C.
In the 0'('', ) range [21]: We were able to secure the 7L'-ion of Q Ec34aB. Also, at the wavelength of 1.5 μIll, we obtained the The dependence on ambient temperature was 4b as shown in Table 2.■
(45 g·l at a thickness of 19 μm) It showed Faraday synchronization. The Faraday rotation coefficient at 0°C and 50'Ci is 996 with respect to the value at 25'Ct'.
′).

(Example 7) At 736°C, a lead oxide-bismuth oxide flux held in a platinum crucible was deposited onto a nonmagnetic neodymium gallium garnet substrate [o] with a lattice constant of 12.509X. .511 X and 'l't314 Bi
A magnetic garnet single crystal film having a chemical formula of 1, pFelQ* was formed to a thickness of 204 μm by a liquid phase epitaxial method. When the Faraday rotation coefficient of this garnet a was measured as a function of the ambient temperature at a wavelength of 1.3 μm, the results shown in the first column were: 3.3%
It rarely showed only fluctuations in This value is (IJdBi
), (FeAIGa), 45'1 in U, ,
It was possible to secure an isolation of 32 dB in the range from 0°C to 50°C.

Ma/+:, Faraday at wavelength 1.5μm11
The dependence of the rotation coefficient on the temperature of the surrounding environment was rare, as shown in the second dog.

It has a thickness of 298 μm and exhibits 7 rotations of 45 degrees. The 77 rad one rotation coefficient at 0'0 and 50'(': 7) showed only a 3.6% variation with respect to the value at 25'C.

(Example 8) The platinum melt was held at 713'C! from a lead oxide-bismuth oxide flux, and the lattice constant was 12°fic.
) Squirrel=Q WIE A-sexual neodyno...Gallium...
ff-net, board +113. On l, the lattice constant is tz
, s3x X, 'l'l)! −,8λ1.1IFe,
0. , the chemical formula is, 8-right magnetic node single-linked structure 15 mm thick / 2 liquids, 4 fl shrimp 7 layers H-r: y: 1.'#:,. The Radhe rotation coefficient of the garnet film was measured as a function of the ambient temperature at a wavelength of 1.31p.
, I got the results shown in Table 1. 159μm
It showed a Faraday 19.1 turn of 45 degrees at a thickness of . O"
C, J and 50℃ The value of is ((month B1).

(F'e, A I (ia) (I can go to H()12,
It is small compared to 4%, and the range from 0゛( ) to 50°6 [1
4r(, oi-[31dl)-fi:)Reage(n is sure to be So-(%rwinterk・-6-up),
- Polishing length 1 = 5Brn (・t゛ru7a5・de・for the surroundings of one rotation coefficient) The temperature dependence of the stand was as shown in Table 2. It exhibited a Faraday rotation of 45 degrees at a thickness of 3234 μm. , 0°C and 50'C showed a variation of only 3.3% with respect to the value at 25°C.

(Example 9) Platinum gold? It is held at 688"C from a corrugated lead-bismuth oxide flux, and the lattice constant is 12.
On a 509A non-magnetic neodymium gallium-garnet substrate foxl, the lattice constant is 12.562λ, and 'I''
bLn BiIL.

A magnetic garnet single crystal film with the chemical formula Fe, On was formed at a speed of 116 μm using the liquid phase epitaxial method. The 7 azide rotation coefficient of this Carnet film was expressed as a function of the ambient temperature at a wavelength of 1.3 μn When measured, the results shown in Table 1 were obtained. 11
It exhibits a Faraday rotation of 45 degrees with a thickness of 6 μm and is 1-7.

The Faraday rotation coefficient at 0°C and 50°C is 2
There was only a change of ηt7 of C3 and 6% with respect to the value at 5°C. This value is (GdB 1)s(FeAIG
a), 0. , to J? It is small compared to 4%, which is 0″
Fi O'J from r3! I'-) Range 171fl>
Ei7:3], 4V-1 Noah, (71/-In).

Table 1 'FbxHiz -41)', 'e* Ots wave 21
34rn to k(・suru-7cho-':)f-one rotation coefficient humidity I (dependent Table 2 Tbx Bi, -!Fe, Ou l/) wavelength 1.5
1 of the 77 Radhe one rotation fraction in μsn. ! , degree dependence (effect of the invention) As explained above, using the present invention
It becomes possible to realize an optical isolator that is less susceptible to changes in ambient temperature and provides stable isolation.

[Brief explanation of drawings]

Figure 1 shows 'l'bs, s Faraday rotation coefficient of BiQ4F-011 garnet film at a wavelength of 1.5 μm.
Figure 2 shows the degree dependence on (GdBi) $ (FeA
IG;+), o+t garnet film wavelength 1.5μrn
Figure 3 showing the temperature dependence of the Faraday rotation coefficient in
The figure shows the change in the isolage control value due to the deviation of the Faraday rotation angle from 45°.

Claims (1)

[Claims] A magneto-optical garnet patented as having a composition represented by the chemical formula TbxBi_■_-_xFe_■O_1_2.