JPH05158079A - Optical deflecting element - Google Patents

Abstract

PURPOSE:To enable setting of the polarization angle of extraordinary light at a large angle by providing an optical medium which changes the polarization angle of incident light by the heat generation of a heating element and forming the optical medium of SrxBa1-xNb2O6. CONSTITUTION:The optical deflecting element 10 has the planar optical medium 11 consisting of the SrxBa1-xNb2O6 which is a ferroelectric crystal having a solid soln. compsn. region and the heating element 12. The value of X is preferably set at nearly a 0.25<=X<=0.5 range. The reason for setting the value of X in such range lies in that the Curie temp. of the SrxBa1-xNb2O6 when the value of x is set at about 0.25 is 200 deg.C and the Curie temp. when the value of X is set at nearly 0.5 is 130 deg.C and, therefore, the transformation from the ferroelectric crystal to an ordinary electric crystal does not arise at the ordinary environmental temp. at which the element is used (for example, the temp. at the time of heat generation of the heating element). A temp. gradient is generated in the thickness direction of the optical medium 11 by the heat generation in the heating element 12 with such constitution, by which a refractive index gradient is generated and the extraordinary ray is deflected in the a-axis direction and outputted.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION The present invention relates to an optical disc player,
The present invention relates to an optical deflector used for an optical communication switch, a laser printer, etc. to deflect incident light.

2. Description of the Related Art FIG. 4 shows a schematic structure of a light deflection element. The figure is a schematic external perspective view of the light deflection element. Also, FIG.
4 is a table showing characteristics of materials of the optical medium shown in FIG. The light deflection element 1 shown in FIG. 4 is provided with a plate-shaped optical medium 2 made of soda glass, lithium niobate, rutile, etc., and a single heater 3 formed on the upper surface of the figure.
A DC or AC power source 4 is connected to the heater 3. In the above configuration, a temperature gradient is generated in the thickness direction of the optical medium 2 due to heat generated by energizing the heater 3. With this temperature gradient, a thermo-optical effect is generated in the optical medium 2 and a refractive index gradient is generated. The incident light 5 from the left end surface in the figure is deflected by this refractive index gradient.

By the way, in the case of the optical medium 2 made of the above-mentioned material, the refractive index ne of extraordinary light is in the range of 2.2 to 2.865 as shown in FIG.
Change in refractive index with respect to temperature change (δn / δT (× 1
0 ^{- 5)),} the soda glass is 1 to 1.5, lithium niobate is 5.3, rutile is -7.2. However,
The deflection angles in the case of using such a material are all about 1 °, and even if such an optical deflection element 1 is applied to an optical disc player, an optical communication switch, a laser printer, etc., the deflection angle is small. There is a problem when considering practical application. Therefore, it is an object of the present invention to provide a light deflection element having a large deflection angle of abnormal light.

In order to achieve the above-mentioned object, the structure of the present invention according to claim 1 changes the deflection angle of incident light by a heating element that generates heat by energization and the heating of this heating element. in the optical deflecting element including an optical medium, said optical medium Sr _x Ba _{1 -} is formed by _x Nb ₂ O _6. According to a second aspect of the present invention for achieving the same object, the value of x described in the first aspect is approximately 0.25 ≦ x ≦ 0.
The range is 5.

According to the above claim 1, the light deflector of the present invention, the refractive index of extraordinary light with respect to a temperature larger Sr _x Ba ₁ as an optical medium _- so _x Nb ₂ O ₆ is used, the light The deflection angle can be increased. That is, according to the optical deflector of the present invention, the heat generated by the heating element causes Sr _x Ba <sub>1
- x</sub> when the temperature gradient in the thickness direction of the optical medium results consisting of Nb ₂ O _6, the deflection angle of the so large thermo-optic effect with the temperature gradient in the optical medium occurs, abnormal light for refractive index gradient is increased Can be set large. According to claim _{2, Sr x Ba 1 - x} Nb 2 O 6 in x approximately 0.25 ≦ x the value of
Since the range of ≦ 0.5 is set, the ferroelectric crystal does not transform into the paraelectric crystal at a normal operating environment temperature, and thus stable operation can be performed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
It FIG. 1 is a schematic perspective view showing an embodiment of a light deflection element,
2 is Sr_xBa_{1 - x}Nb₂O₆When x is a parameter
FIG. 3 is a characteristic diagram showing the relationship between the refractive index and the temperature. Shown in Figure 1
The optical deflection element 10 has a ferroelectric composition having a solid solution composition region.
Crystal Sr_xBa_{1 - x}Nb₂O₆A plate-shaped optical medium composed of
11 is formed on the upper surface of the drawing by sputtering or the like.
Heat generating element 12 made of tantalum, aluminum, etc.
This heating element 12 is equipped with direct current or alternating current.
Source 13 is connected. In such a configuration, the heating element
The temperature gradient in the thickness direction of the optical medium 11 due to the heat generated by
Occurs, and this temperature gradient creates a refractive index gradient. this
Due to the refractive index gradient, the extraordinary light of the incident light 14 is directed upward in the drawing.
It is deflected in the a-axis direction and output. By the way, this embodiment
Then Sr_xBa_{1 - x}Nb₂O₆X of optical medium 11 consisting of
The value is set in the range of approximately 0.25 ≦ x ≦ 0.5. this
To set the value of x in such a range, the value of x is set to approximately 0.
Sr when set to 25_xBa_{1 - x}Nb₂O₆Curi
-Temperature is 200 ° C, and the value of x is set to about 0.5.
If the Curie temperature is 130 ℃,
Strong at the operating environment temperature (for example, the temperature when the heating element generates heat)
Inducing transformation from a dielectric crystal to a paraelectric crystal
Because there is nothing. If the value of x is less than 0.25,
Sr_xBa_{1 - x}Nb₂O₆Is hard to obtain crystals. Therefore, this
By setting x in such a range, stable operation can be performed.
You can make it. Also, Sr_xBa_{1 - x}Nb₂O₆The difference
The temperature coefficient δn / δT of the refractive index ne of ordinary light depends on the value of x.
Although it changes, it is about 2.5 × 10^{- Four}So this S
r_xBa_{1 - x}Nb₂O₆Deflection Element Using Optical Medium 11
Set the deflection angle of 10 to a large value of 3 to 5 degrees.
You can Therefore, the light deflection element 1 according to the present embodiment
0 for optical disk player, optical communication switch and laser
It can be easily applied to a printer or the like. Sr in Figure 2
_xBa_{1 - x}Nb₂O₆Refractive index with x as a parameter
Shows the relationship between temperature and temperature. In FIG. 2, the horizontal axis represents temperature (T
℃), the vertical axis shows the refractive index, no is Sr_xBa_{1 - x}Nb₂O
₆Change of the refractive index with respect to the temperature of ordinary light, ne is the temperature of extraordinary light
The change of the refractive index with respect to the degree is shown. Abnormal from this figure
It can be seen that light has a large change in refractive index with temperature.
Next, referring to FIG. 3, another embodiment of the optical deflector will be described.
Explain. The optical deflector 20 shown in FIG. 3 is a waveguide type device.
The glass substrate 21 and
Optical medium adhered on the glass substrate 21 of the above with an optical adhesive
Waveguide 22 composed of a solid solution composition
Sr which is an electric crystalline_xBa_{1 - x}Nb₂O₆Waveguide consisting of
22 and titanium oxide and pentoxide formed on the upper surface in the figure
Material containing tantalum or niobium pentoxide as the main component
On the buffer layer 23 of quality and on this buffer layer 23
A pair of heating elements 24, 25 formed in parallel with each other,
Power sources 26 and 27 connected to the heating elements 24 and 25 of
Be prepared. In this embodiment also, Sr_xB
a_{1 - x}Nb₂O₆The value of x in the range of 0.25 ≦ x ≦ 0.5
It is surrounded. The light deflection element 20 shown in FIG. 3 has a large heat capacity.
Since a fine optical medium is used as the waveguide 22, the response
The speed can be set to a few ms or less. Configuration above
Then, the heating element 24 and the heating element 25 are alternately heated.
It For example, when the heating element 24 is in a heated state, the waveguide
22 shows the temperature gradient generated from the back side to the front side of the paper.
Therefore, a refractive index gradient is generated. In this state, the incident light 28 is guided
When incident on the waveguide 22, the incident light 28 is reflected on the back side of the paper.
(Shown in (a)). In addition, the heating element 25 is added.
When in the heat state, the waveguide 22 has a front side to a back side in the drawing.
The refractive index gradient is generated by the temperature gradient
Therefore, when the incident light 28 enters the waveguide 22, the incident light 2
8 is deflected to the front side of the paper (shown by (b)). By the way
In this embodiment, titanium oxide is provided on the upper surface of the waveguide 22 in the drawing.
Buff containing tantalum pentoxide or niobium pentoxide as the main component
The layer 23 is formed by the sputtering method. this
The buffer layer 23 made of such a material has a refractive index higher than that of air.
It is also larger than the refractive index of the waveguide 22.
Next, the specific manufacturing method of each embodiment and its function will be described.
And explain. First, an example of manufacturing the optical deflection element 10 of FIG.
As Sr_{0 . Five}Ba_{0 . Five}Nb₂O₆Vertical to the a-axis
14mm × 14mm × 3mm by cutting on the flat surface 10a
Then, the both sides 10a are polished to be parallel.
It was A heating element 1 made of Ta or Al is formed on the upper surface of the wafer.
2 was formed by the sputtering method. The length of this heating element is 1
It is 0 mm. The direction of the plane of polarization is c on the polished surface 10a.
Linearly polarized light parallel to the axial direction (wavelength of light is 0.633μ
m) and the temperature of the heating element 12 is 50 ° C higher than room temperature.
I adjusted the power supply so that As a result, deflection of about 3 degrees
I got the horn. Manufacture of the light deflection element 20 shown in FIG.
As an example, Sr_{0 . Five}Ba_{0 . Five}Nb₂O₆With the crystal of a
14mm x 14mm x by cutting at the vertical surface 22a
Obtain a 0.5 mm wafer and polish both sides 22a
I made them parallel. Optically contact this with a quartz glass substrate 21.
It adhered using the adhesive. After adhesion Sr_{0 . Five}Ba_{0 . Five}Nb₂O₆
Optical polishing process of the crystal of
It was A buffer layer 23, Ta, is formed on the crystal.₂O_FiveThin film
Was formed by the sputtering method. On top of that, heating elements 24, 2
5 is a spade resistance electrode made of Ta or Al.
It was formed by the Tatta method. Sr_{0 . Five}Ba_{0 . Five}Nb₂O₆Crystal of
The direction of the plane of polarization is c-axis on the end face 22a of the waveguide 22 made of
Linearly polarized light (wavelength 0.633 μm) parallel to the direction
It was incident and about 0.5 W of electric power was applied to the heating element.
A deflection angle of about 2.5 ° C. could be obtained. In addition, this
The description is not limited to the embodiment shown or described above.
No, various modifications can be implemented within the scope of the gist
Is. For example, the refractive index of the buffer layer is titanium oxide,
Combination of tantalum oxide or niobium pentoxide with other ingredients
Within the range of 2.0 to 2.5 depending on the sponge and sputtering conditions
Since it can be set at
By reducing the difference between the refractive index of the
In the optical deflection element that guides the waveguide,
Thicker and therefore easier to manufacture and assemble
It can be easy.

According to the present invention, it is possible to provide a light deflection element capable of setting a large deflection angle of abnormal light.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a light deflection element.

[Figure 2] Sr _x Ba _{1 -} characteristic diagram showing the relationship of x of _x Nb ₂ O ₆ and the refractive index and the temperature when a parameter.

FIG. 3 is a schematic perspective view showing another embodiment of the light deflection element.

FIG. 4 is a schematic external perspective view of a light deflection element.

5 is a table showing the characteristics of the material of the optical medium of the light deflection element shown in FIG.

[Explanation of symbols]

 11,22 Optical medium 12,24,25 Heating element 13 Power supply 22 Waveguide 23 Buffer layer

Claims (2)

[Claims] 1. An optical deflection element comprising a heating element that generates heat when energized and an optical medium that changes the deflection angle of incident light by the heating of the heating element, wherein the optical medium is Sr _x B
An optical deflecting element formed of a _{1 - x} Nb ₂ O ₆ . 2. The value of x is approximately 0.25 ≦ x ≦ 0.5.
The light deflection element according to claim 1, wherein