JP2003270602A - Electrooptical effect element using single crystal of lead zinc niobate - lead titanate mixed crystal ferroelectric material and optical switch using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical effect element using single crystal of lead zinc niobate - lead titanate mixed crystal ferroelectric material and an optical switch using the same which allows the low-voltage drive of a light deflecting element using electrooptical effect without deteriorating light propagation characteristics. <P>SOLUTION: This electrooptical effect element has an optical wave guide structure of which at least one side clad layer 1 consists of Pb ä(Zn<SB>1-u</SB>Nb<SB>u</SB>)<SB>1-v</SB>Ti<SB>v</SB>}<SB>w</SB>O<SB>3</SB>and core layer 2 consists of Pbä(Mg<SB>1-x</SB>Nb<SB>x</SB>)<SB>1-y</SB>Ti<SB>y</SB>}<SB>z</SB>O<SB>3</SB>. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to lead zinc niobate (P
The present invention relates to an electro-optic effect element using a ZN) -lead titanate (PT) mixed crystal type ferroelectric single crystal and an optical switch using the same, and in particular, it relates to an optical wave propagating in an optical waveguide, a phase and an intensity. An optical signal that uses an optical modulation element that changes according to the applied voltage, an optical deflection element that changes the direction of light, and an optical switch that switches the propagation destination of the optical signal between a plurality of input ports and a plurality of output ports TECHNICAL FIELD The present invention relates to an electro-optical effect element using a zinc zinc niobate-lead titanate mixed crystal ferroelectric single crystal characterized by a material forming an optical waveguide for driving a switching device at a low voltage, and an optical switch using the same. It is a thing.

[0002]

2. Description of the Related Art In recent years, the transmission band of optical communication has been increasing, and wavelength multiplexing (WDM: Wavelength) has been adopted.
High-speed and large-capacity combined with Division Multiplex technology, and an optical deflector for switching the transmission destination of optical signals is required to build the hardware infrastructure of the optical fiber network in the backbone communication network. is there.

A mechanical micromirror is used in a conventional optical deflector, but in order to realize higher integration, higher speed, and lower loss, a change in the refractive index due to the electro-optic effect of a ferroelectric substance is used. An optical deflector using the same has also been developed.

For example, a prism type domain inversion light deflecting element or a prism type electrode light deflecting element using a LiNbO ₃ single crystal wafer having a Ti diffusion type waveguide and a proton exchange type waveguide has been proposed (required). Then Q.
Chec et al. J. Lightwave T
ech. , Vol. 12, p. 1401, 1994).

However, these light deflection elements are
Since the electrode spacing of about 0.5 mm, which is the thickness of the NbO ₃ single crystal wafer, is required, the driving voltage is still high,
Even if the drive voltage is 600 V, the deflection angle θ is only about 0.5 °, and there is a problem that a practical deflection angle cannot be obtained.

Therefore, the Nb-doped SrTiO ₃ conductive single crystal substrate has a thickness of, for example, 600 on the (100) plane.
nm of Pb (Zr _0.52 Ti _0.48 ) O ₃ composition having a high electro-optic constant is epitaxially grown to form a thin film optical waveguide, and an applied voltage of -1 is applied to this optical deflection element.
It has been proposed to obtain a deflection angle of 10.8 ° by sweeping from 2V to 12V (if necessary, see Japanese Patent Laid-Open No. 9-5795).

[0007]

[Problems to be Solved by the Invention] However, SrTiO ₃
To use the substrate as a conductive substrate, at least 1
% Of Nb must be doped, but the substrate is blackened by high-concentration doping of Nb, and absorption of propagating light is unavoidable, and it is not necessarily a method suitable for propagating an optical signal over a long distance.

Also, when a conductive oxide film such as SrRuO ₃ is formed on a non-doped SrTiO ₃ substrate, the same light absorption occurs because SrRuO ₃ itself is black. .

Therefore, an object of the present invention is to drive a light deflection element using the electro-optic effect at a low voltage without deteriorating the light propagation characteristics.

[0010]

FIG. 1 is an explanatory view of the principle configuration of the present invention. Here, the means for solving the problems in the present invention will be described with reference to FIG. In order to solve the above problems, the present invention provides an electro-optic effect element using a lead zinc niobate-lead titanate mixed crystal ferroelectric single crystal, in which at least one cladding layer 1 is made of P
b {(Zn _1-u Nb _u ) _1-v Ti _v } _w O ₃ ,
Moreover, the core layer 2 is made of Pb {(Mg _1-x Nb _x ) _1-y T
It is characterized by having an optical waveguide structure made of i _y } _z O ₃ .

Thus, at least one of the cladding layers 1
As a lead zinc niobate-lead titanate mixed crystal system having a Pb-based perovskite structure, that is, Pb {(Zn _1-u N
b _u ) _{1- v} Ti _v } _w O ₃ [PZNPT], a lead magnesium niobate-lead titanate mixed crystal system having a high Pockels constant can be obtained as the core layer 2, that is, P
b {(Mg _1-x Nb _x ) _1-y Ti _y } _z O ₃ [PMNP
T] can be epitaxially grown, which makes it possible to obtain a high deflection angle at a low voltage.

In this case, Pb {(Z
u, v, w in n _1-u Nb _u ) _1-v Ti _v } _w O ₃
Respectively 0.5 <u <1,0 ≦ v <0.5,0.8
By setting <v <1.2, the refractive index of PZNPT which becomes the cladding layer 1 can be set to 2.561 and the refractive index of PMNPT which becomes the core layer 2 can be set to 2.612, so that a good optical waveguide structure can be obtained. Can be configured.

In order to epitaxially grow the PMNPT layer, Pb {(Zn _1-u Nb _u ) _1-v T
The main surface of the i _{v} w} O ₃ is a perovskite structure (10
(0) plane, (001) plane, (101) plane, and (11
1) It is desirable to have one of the faces.

In this case, in order to narrow the electrode interval,
One cladding layer 1 is Pb {(Zn _1-uNb_u)_1-vT
i_v}_wO₃Consisting of a first PZNPT substrate consisting of
Then, the first PZNPT substrate is connected to the second substrate through the conductive material 5.
Configured to be bonded to the PZNPT substrate 4 of
The thickness of the ZNPT substrate should be 0.5-100 μm
It is desirable to thin the layer by polishing, etc.
Further lower voltage driving becomes possible.

On the main surface of such an electro-optical effect element, a triangular electrode 6 having an emitting surface inclined with respect to an incident surface,
Typically, by providing a prismatic electrode, it is possible to configure a light deflection element that deflects incident light by the electro-optic prism effect.

In this case, the optical waveguide having Pb {(Mg _1-x Nb _x ) _1-y Ti _y } _z O ₃ having a high Pockels coefficient as the core layer 2 has a high electro-optical effect by applying an electric field. The wavelength λ of the light passing through the optical waveguide is shown by
_n (= λ / n; where n is the refractive index) greatly changes as the refractive index n changes.

The light deflection element as described above is used as a collimator system,
An optical switch that can be driven at a low voltage can be configured by combining a common waveguide and the like.

In order to form the electro-optical effect element having a narrow electrode interval as described above, a PZNPT substrate is used, for example, 1
After polishing to about 50 μm, the conductive material 5 such as Au is used to bond to the second PZNPT substrate, which is a supporting substrate,
Further, for example, after mechanically or chemically polishing to 20 μm, the PMNPT layer to be the core layer 2 may be epitaxially grown.

Alternatively, the PMN is deposited on the first PZNPT substrate.
After the core layer 2 made of PT and the cladding layer 3 are sequentially epitaxially grown, a second PZN serving as a supporting substrate is formed.
The PT substrate is bonded by the conductive material 5, and then the first
The back surface of the PZNPT substrate is polished to, for example, 20 μm.
It may be thin.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A light deflecting element according to a first embodiment of the present invention will now be described with reference to FIGS. 2 to 5. First, with reference to FIGS. The manufacturing process of the first embodiment of the invention will be described. See FIG. 2 (a). First, commercially available Pb {(Zn _0.33 Nb _0.67 ) _0.91 T
Two PZNPs with a composition of i _0.09 } O ₃ and a thickness of 0.3 mm
Both sides of the T substrate are mirror-polished, one of which is the first for waveguide fabrication.
The PZNPT substrate 11 is used, and the other one is used as the second PZNPT substrate 13 serving as a supporting substrate.

Next, after mechanically and chemically polishing the first PZNPT substrate 11 to have a thickness of, for example, 150 μm, the entire surface of one side is DC sputtered to a thickness of
For example, a Ti layer of 100 nm and a thickness of 500
nm Pt layer and A with a thickness of, for example, 300 nm
u layers are sequentially formed to form the conductive adhesive layer 12. Similarly, for the second PZNPT substrate 13, the conductive adhesive layer 14 of Au / Pt / Ti structure is formed from the outermost surface side.

Next, referring to FIG. 2 (b), the conductive adhesive layers 12 and 14 are made to face each other and brought into contact with each other, and then the first PZNPT substrate 11 and the second PZNPT substrate 13 are bonded in a vacuum chamber by a surface active bonding method. To do.

That is, in the surface active bonding method, the first P
The ZNPT substrate 11 and the second PZNPT substrate 13 are housed in, for example, a vacuum chamber of 1 × 10 ⁻⁶ Torr, and then the conductive adhesive layers 12 and 14 on the surface are irradiated with an Ar beam so that the conductive adhesive layers 12 and 14 are irradiated. The conductive adhesive layer 1 having an activated surface by removing oxides and the like from the surface of the
2 and 14 are brought into contact with each other and heated at a substrate temperature of 500 to 900 ° C. to bond them. In this case, the conductive adhesive layers 12 and 14 are integrated to form the substrate-side electrode 15.

Next, the surface of the second PZNPT substrate 13 opposite to the bonding surface is mechanically polished to a thickness of, for example, 30 μm, and then the thickness is further increased by using an ICP (inductively coupled plasma) etching device. However, for example, the PZNPT clad layer 16 is obtained by polishing to 20 μm.

Next, referring to FIG. 3D, the surface of the PZNPT clad layer 16 polished by the RF magnetron sputtering method has a thickness of, for example,
A 2.4 μm PMNPT core layer 17 and a PLZT cladding layer 18 having a thickness of, for example, 1.0 μm are sequentially epitaxially grown. When forming the film, the film is formed using a mask so that deposition does not occur on the exposed surface of the substrate-side electrode 15.

The film forming conditions in this case are PMNPT core layer
In case of 17, {Pb_1.2(Mg _0.33Nb_0.67)
O₃}_0.65(Pb_1.2TiO₃)_0.35  8 inches of composition
Substrate heating using the ceramic sintered body of
The temperature is 400 to 900 ° C, for example, 650 ° C, Ar90.
% + O₂The gas pressure of the atmosphere consisting of 10% is 20 mTorr
r and the film formation time of 4 hours, the film thickness of 2.4 μm
The PMNPT core layer 17 was obtained.

In the case of the PLZT clad layer 18,
Is (Pb_0.91La_0.09)_1.1(Zr _0.65Ti_0.35) O
₃Targeting an 8-inch ceramic sintered body of composition
Substrate heating temperature is 400 to 900 ° C., for example, 6
50 ° C, Ar 90% + O₂Atmosphere gas consisting of 10%
The pressure was set to 20 mTorr and the film formation time was 1.5 hours.
To obtain a PZNPT clad layer 18 having a thickness of 1.0 μm.
It was

Next, referring to FIG. 3 (e), for example, on the surface of the PLZT cladding layer 18 using the RF magnetron sputtering method using a mask having a prism-shaped opening having a base of 1 mm and a height of 5 mm,
A prismatic element electrode 19 made of ITO having a thickness of 0.2 μm, for example, is formed.

The film forming conditions in this case are (I
Using an 8-inch ceramic sintered body of n _0.95 Sn _0.05 ) O ₃ composition as a target, for example, the substrate heating temperature is room temperature, the gas pressure of the atmosphere consisting of Ar 90% + O ₂ 10% is ₂₀ mTorr, and the temperature is 1 hour. The prismatic element electrode 19 having the above-mentioned film thickness of 0.2 μm was obtained in film time.

Finally, the pads 20 and 21 made of solder are formed on the substrate-side electrode 15 and the prism-shaped element electrodes 19, respectively, to complete the basic structure of the optical deflection element.

In this case, the refractive index n ₁ and relative permittivity ε _{r1 of} the PZNPT cladding layer 16, the refractive index n ₂ and relative permittivity ε _{r2 of} the PMNPT core layer 17, and the PLZT cladding layer 18 are used.
Has a refractive index n ₃ and a relative permittivity ε _r3 of n ₁ = 2.561, ε
_{r1 = 3000, n 2 = 2.612} , ε r2 = 1500, n
₃ = 2.430 and ε _r3 = 1000.

FIG. 4 FIG. 4 is an explanatory diagram of the deflection characteristics of the optical deflecting element according to the first embodiment of the present invention, in the case where a voltage of 100 V is applied between the pad 20 and the pad 21 by the power source 22. , PZNP
T-clad layer 16, PMNPT core layer 17, and PL
Each of the ZT cladding layers 18 has a thickness and a relative dielectric constant ε.
72V, 17.2V, 10.8 depending on the value of _r
V will be applied.

In this way, the PMNPT core layer 17 is formed with 17.
By applying the voltage of 2 V, the incident light 23 having a wavelength of 0.633 nm from the He—Ne laser is 1.83 when passing through the optical waveguide below the prismatic element electrode 19.
The output light 24 is deflected by ° (= θ).

FIG. 5 is a dispersion curve of the optical waveguide of the optical deflecting element according to the first embodiment of the present invention. The normalized propagation constant b of each order mode is shown in FIG.
Shows the dependence of the core thickness on the core layer. By setting the thickness of the core layer to be 2.4 μm as in the present invention, it is possible to propagate only the zero-order mode.

When the thickness of the core layer is 5 μm,
The multi-mode is composed of three modes, that is, the 0th-order mode, the 1st-order mode, and the 2nd-order mode, and the signal light waveform becomes dull, which makes high-frequency optical communication difficult. Note that, in the respective modes, the TE mode and the TM mode have substantially the same characteristics and overlap with each other. Therefore, the difference is neglected in the drawing.

The PMNPT forming the core layer is a mixed crystal perovskite type oxide of rhombohedral Pb (Mg _1/3 Nb _2/3 ) O ₃ [PMN] and tetragonal PbTiO ₃ [PT]. The PMN 65% -PT 35% has a rhombohedral and tetragonal phase boundary, and the relative dielectric constant takes the maximum value at this phase boundary, and the electromechanical coupling coefficient and the piezoelectric constant at room temperature become maximum.

Further, the refractive index of the crystal is a change in electron density in the crystal, and the Pockels effect representing the applied voltage dependence of the change in the refractive index is maximized in the composition having the largest piezoelectric constant. Wavelength of propagating light λ ₂ (= λ
/ N ₂ ) will change significantly during propagation.

As described above, in the first embodiment of the present invention, the PZNPT substrate is provided with the conductive material to serve as the substrate side electrode and then bonded to the supporting substrate, and in that state, the PZNPT substrate is thinned to one side. Since it is a clad layer, the distance between the electrodes for applying a voltage to the core layer can be made sufficiently thin, which enables low voltage driving. When thinning the layer, since it is bonded to the supporting substrate and then polished, the PZN forming the optical waveguide structure is formed.
There is no problem in handling the PT substrate.

Next, the manufacturing process of the second embodiment of the present invention will be described with reference to FIGS. See FIG. 6A. First, commercially available Pb {(Zn _0.33 Nb _0.67 ) _0.91 T
Two PZNPs with a composition of i _0.09 } O ₃ and a thickness of 0.3 mm
Both sides of the T substrate are mirror-polished, one of which is the first for waveguide fabrication.
The PZNPT substrate 31 is used, and the other one is used as the second PZNPT substrate 35 (illustrated in and after FIG. 6B) which serves as a support substrate.

Next, after mechanically and chemically polishing the first PZNPT substrate 31 to have a thickness of, for example, 220 μm, the PMNP in the first embodiment described above is polished.
The PMNPT core layer 32 having a thickness of, for example, 2.4 μm and the PLZT having a thickness of, for example, 1.0 μm are formed under the same conditions as the film forming conditions of the T core layer and the PLZT clad layer.
The cladding layer 33 is sequentially epitaxially grown.

Next, referring to FIG. 6B, the PLZT clad layer 33 is formed by the DC sputtering method.
A Ti layer having a thickness of, for example, 100 nm, a Pt layer having a thickness of, for example, 500 nm, and an Au layer having a thickness of, for example, 300 nm are sequentially formed on the surface of the conductive adhesive layer 3
Set to 4. On the other hand, similarly for the second PZNPT substrate 35, the conductive adhesive layer 36 having the Au / Pt / Ti structure is formed from the outermost surface side.

Next, as shown in FIG. 6 (c), the conductive adhesive layers 34 and 36 are made to face each other and brought into contact with each other. Then, in the vacuum chamber, the surface active bonding method is carried out in the same manner as in the first embodiment. First using
The PZNPT substrate 31 and the second PZNPT substrate 35 are bonded together. At this time, the conductive adhesive layer 34 and the conductive adhesive layer 36 are integrated to form the substrate side electrode 37.

Next, referring to FIG. 7D, the back surface of the first PZNPT substrate 31 is mechanically polished to a thickness of, for example, 30 μm, and then the thickness is further reduced by using an ICP (inductively coupled plasma) etching apparatus. However, for example, PZNPT is polished until it becomes 20 μm.
The clad layer 38 is used.

Next, referring to FIG. 7 (e), for example, by using the RF magnetron sputtering method using a mask having a prism-shaped opening having a base of 1 mm and a height of 5 mm, the above-described first embodiment is used. A prismatic element electrode 39 made of ITO having a thickness of, for example, 0.2 μm is formed on the surface of the PLZT clad layer 38 under exactly the same film forming conditions.

Finally, the basic structure of the optical deflector is formed by forming the solder pads 40 (the bumps on the prismatic element electrode 39 side are not shown) on the substrate side electrode 37 and each prismatic element electrode 39, respectively. Complete.

Also in the light deflecting element of the second embodiment, a light deflection of 1.83 ° can be obtained by applying a voltage of 100V.

As described above, in the second embodiment of the present invention, since the first PZNPT substrate serving as the clad layer is thinned by polishing after the epitaxial growth, low voltage driving becomes possible.

Next, with reference to FIG. 8, an optical switch of the third embodiment of the present invention constructed by incorporating the above-mentioned optical deflection element will be described. See FIG. 8. FIG. 8 is a schematic plan view of the optical switch according to the third embodiment of the present invention, in which the optical input side and the optical output side are symmetrically configured.

First, as the optical deflecting elements 51 and 55, the optical deflecting elements of the above-described first or second embodiment are configured in multiple stages, and in the figure, they are configured in two stages. , Each prismatic electrode 52, 53, 5
By combining 6 and 57 in point symmetry, the deflection direction of the deflection angle is arbitrary.

The light deflecting element 51 on the light input side and the light deflecting element 55 on the light output side are used as the common waveguide 5 of the slab waveguide structure.
4 and the input side optical fiber 60 and the individual waveguide 5 are provided on the input side of the optical deflection element 51 on the optical input side.
9 and a two-dimensional lens 58 are provided, while the output side optical fiber 6 is provided on the output side of the optical deflection element 55 on the optical output side.
3, the individual waveguide 62 and the two-dimensional lens 61 are arranged.

Also in the third embodiment, since the light deflecting element having the structure of the first embodiment or the second embodiment is used as the light deflecting element, low voltage driving becomes possible. .

Although the respective embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the respective embodiments, and various modifications can be made. For example, in each of the above-mentioned embodiments, the shape of the deflection element electrode is a right-angled triangular prism-shaped electrode, but it is not limited to such a shape, and the hypotenuse in which the light emitting surface is inclined with respect to the light incident surface. The element electrode may have any shape, for example, a trapezoidal truncated triangular shape.

Further, in each of the above embodiments, the RF magnetron sputtering method is used for growing the core layer and the cladding layer, but the invention is not limited to the RF magnetron sputtering method, and metal organic chemical vapor deposition is possible. Law (MO
A CVD method) or a laser ablation method may be used.

Further, in the above-mentioned first and second embodiments, the prismatic element electrode is formed of the transparent electrode made of ITO to reduce the scattering of light at the electrode interface. When the clad layer on which the prismatic element electrode is provided is thick as in the second embodiment, it is not necessary to use a transparent electrode such as ITO.

Also in the first embodiment described above, when the PLZT clad layer is thickly formed, it is not necessary to form the prismatic element electrode by the transparent electrode.

In each of the above embodiments, the optical waveguide structure has a double-hetero structure in which both sides of the core layer are sandwiched by the cladding layers. When the prismatic element electrode is formed of a transparent electrode, the transparent prismatic element electrode also serves as a clad layer, and thus the upper clad layer is not always necessary.

Further, in each of the above-mentioned embodiments, the optical deflecting element is described, but the present invention is not limited to the optical deflecting element and is also applied to other electro-optical effect elements such as a light modulating element. It is a thing.

For example, a distributed Bragg reflector (DBR) can be constructed by forming a diffraction grating structure in the core layer or one of the cladding layers, and the effective wavelength λ _n (by applying a voltage to this DBR. = Λ / n)
Changes drastically, so that the diffraction condition is no longer satisfied, and thereby a light modulation function can be provided.

Here, referring again to FIG. 1, the book is read again.
Detailed features of the invention will be described. See Figure 1 (Supplementary Note 1) At least one cladding layer 1 is Pb
{(Zn_1-uNb_u)_1-vTi_v}_wO₃Consists of, and
The core layer 2 is Pb {(Mg_1-xNb_x)_1-yTi _y}
_zO₃It is characterized by having an optical waveguide structure consisting of
Uses lead zinc niobate-lead titanate mixed crystal ferroelectric single crystal
The electro-optic effect element that was used. (Appendix 2) Pb {(Zn_1-uNb_u)_1-vT
i_v}_wO₃U, v, and w in 0.5 are respectively 0.5
<U <1,0 ≦ v <0.5, 0.8 <v <1.2
Lead zinc niobate-titanium according to appendix 1, characterized in that
Electro-optic effect element using lead oxide mixed crystal type ferroelectric single crystal. (Supplementary Note 3) Pb {(Zn_1-uNb_u)_1-vT
i_v}_wO₃Has a perovskite structure (10
(0) plane, (001) plane, (101) plane, and (11
1) Note 1 characterized by being one of the faces or
2. Lead zinc niobate-lead titanate mixed crystal ferroelectric according to 2.
An electro-optic effect element using a single crystal. (Supplementary Note 4) The one clad layer 1 is Pb {(Zn
_1-uNb_u)_1-vTi_v}_wO₃First PZN consisting of
It is composed of a PT substrate, and the first PZNPT substrate is conductive.
It is bonded to the second PZNPT substrate 4 via the electric substance 5.
In any one of appendices 1 to 3, characterized in that
Lead Zinc Niobate-Lead Titanate Mixed Crystal Ferroelectric Single Crystal
Electro-optical effect element using. (Supplementary Note 5) The thickness of the first PZNPT substrate is 0.
5 to 100 μm, the subordinate according to appendix 4
Lead lead niobate-lead titanate mixed crystal ferroelectric single crystal
Electro-optical effect element. (Supplementary Note 6) At least one of the electro-optical effect elements
A shape in which the main surface has a slope with the output surface inclined with respect to the input surface
-Shaped electrode 6 is formed, and the light incident on the optical waveguide is electrically
The feature is that the light is deflected by the optical prism effect.
The lead zinc niobate-titanium according to any one of items 1 to 5.
Electro-optic effect element using lead crystal mixed crystal ferroelectric single crystal
Child. (Supplementary Note 7) Pb {(Mg_1-xNb_x)_1-yT
i_y}_zO₃The optical waveguide with the core layer 2 applies an electric field
Shows an electro-optical effect by passing through an optical waveguide
Note 1 to 5 characterized in that the wavelength of the light
The lead zinc niobate-lead titanate mixed crystal system described in item 1
An electro-optic effect element using a dielectric single crystal. (Supplementary Note 8) A plurality of optical waveguides and optical signals of the respective waveguides
Collimating section for individually collimating
Switch the propagation direction of each optical signal that has passed through
Lead zinc niobate-lead titanate mixed crystal system according to appendix 6
A plurality of first electrodes composed of electro-optic effect elements using an electric single crystal.
1 optical deflecting element and the plurality of first optical deflecting elements
A common waveguide for propagating each optical signal passing through
The propagation direction of each signal that has passed through the through waveguide is individually
The lead zinc niobate-lead titanate mixture described in appendix 6
Consists of an electro-optic effect element using a cubic ferroelectric single crystal
A plurality of second light deflecting elements and the second light deflecting elements
Fewer light condensing units that individually collect each passed signal
And a first light deflection element and a second light deflection element.
Each child has one or more pairs of prism groups
An optical switch characterized by being configured. (Appendix 9) Pb {(Zn_1-uNb_u)_1-vTi_v}_w
O₃The first PZNPT substrate consisting of the conductive material 5
And Pb {(Zn_1-uNb_u)_1-vTi_v}_wO₃From
After being bonded to the second PZNPT substrate 4
The PZNPT substrate is made into a thin layer to form the clad layer 1. Next,
And at least Pb {(Mg_1-x
Nb_x)_1-yTi_y}_zO₃The core layer 2 consisting of
Zinc characterized by having a process of axial growth
Using lead niobate-lead titanate mixed crystal ferroelectric single crystal
Manufacturing method of electro-optical effect element. (Appendix 10) Pb {(Zn_1-uNb_u)_1-vTi_v}
_wO₃At least P on the first PZNPT substrate consisting of
b {(Mg_1-xNb_x)_1-yTi_y}_zO₃Consisting of
Epitaxial growth of layer 2 and cladding layer 3
Then, the first PZNPT substrate and Pb {(Zn
_1-uNb_u)_1-vTi_v}_wO₃Second PZN consisting of
The PT substrate is bonded by the conductive material 5, and then the first
The back surface of the PZNPT substrate is thinned to form the clad layer 1.
Zinc lead niobate-tita
Electro-optic effect element using lead acid mixed crystal ferroelectric single crystal
Manufacturing method.

[0060]

As described above, by manufacturing the optical waveguide having the PZNPT substrate / cladding layer and the PMNPT core layer, the driving voltage can be made higher than that of the conventional optical modulator and optical deflector using LiNbO _3. Can be greatly reduced,
In particular, a low voltage drive can be realized by thinning the PZNPT substrate / cladding layer, which in turn greatly contributes to the spread and development of the wavelength division multiplexing optical communication system.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a principle configuration of the present invention.

FIG. 2 is an explanatory diagram of a manufacturing process up to the middle of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of the manufacturing process after FIG. 2 of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a deflection characteristic of the optical deflection element according to the first embodiment of the present invention.

FIG. 5 is a dispersion curve of an optical waveguide of the optical deflecting element according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram of a manufacturing process up to the middle of the second embodiment of the present invention.

FIG. 7 is an explanatory diagram of the manufacturing process after FIG. 6 according to the second embodiment of the present invention.

FIG. 8 is a schematic plan view of an optical switch according to a third embodiment of the present invention.

[Explanation of symbols]

1 Clad layer 2 core layers 3 Clad layer 4 Second PZNPT substrate 5 Conductive substance 6 Electrodes with a slope 11 First PZNPT substrate 12 Conductive adhesive layer 13 Second PZNPT substrate 14 Conductive adhesive layer 15 Substrate side electrode 16 PZNPT clad layer 17 PMNPT core layer 18 PLZT clad layer 19 Prism element electrode 20 pads 21 pads 22 power 23 Input light 24 output light 31 First PZNPT substrate 32 PMNPT core layer 33 PLZT clad layer 34 Conductive adhesive layer 35 second PZNPT substrate 36 Conductive adhesive layer 37 Substrate side electrode 38 PZNPT clad layer 39 Prism element electrode 40 pads 51 Optical deflection element 52 prismatic electrode 53 Prism electrode 54 Common Waveguide 55 Optical deflection element 56 Prism electrode 57 Prism electrode 58 two-dimensional lens 59 Individual Waveguide 60 Input side optical fiber 61 Two-dimensional lens 62 individual waveguide 63 Output side optical fiber

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Claims (5)

[Claims] 1. At least one cladding layer is Pb
{(Zn_1-uNb_u)_{1- v}Ti_v}_wO₃Consists of, and
The core layer is Pb {(Mg_1-xNb_x)_1-yTi _y}_z
O₃The optical waveguide structure consisting of
Lead lead niobate-lead titanate mixed crystal ferroelectric single crystal
Electro-optical effect element. 2. The one clad layer is Pb {(Zn
_1-uNb_u)_1-vTi _v}_wO₃First PZN consisting of
It is composed of a PT substrate, and the first PZNPT substrate is conductive.
Bonded to the second PZNPT substrate via an electrically conductive material
The lead-zinc-niobate-chi according to claim 1, characterized in that
Electro-optic effect element using lead titanate mixed crystal ferroelectric single crystal
Child. 3. The thickness of the first PZNPT substrate is:
The electro-optic effect element using the lead zinc niobate-lead titanate mixed crystal ferroelectric single crystal according to claim 2, having a thickness of 0.5 to 100 μm. 4. An electrode having a shape in which an emitting surface is inclined with respect to an incident surface is formed on at least one main surface of the electro-optical effect element, and light incident on an optical waveguide is generated by an electro-optical prism effect. The lead zinc niobate according to any one of claims 1 to 3, which is deflected.
An electro-optical effect element using a lead titanate mixed crystal type ferroelectric single crystal. 5. The zinc niobate according to claim 4, wherein a plurality of optical waveguides, a collimating section for individually collimating the optical signals of the respective waveguides, and a propagation direction of each optical signal passing through the collimating section are switched. A plurality of first optical deflection elements composed of electro-optical effect elements using a lead-lead titanate mixed crystal type ferroelectric single crystal, and optical signals propagated through the plurality of first optical deflection elements, respectively. 5. The electro-optic effect using the lead zinc niobate-lead titanate mixed crystal ferroelectric single crystal according to claim 4, wherein the common waveguide and the propagation direction of each signal passing through the common waveguide are individually switched. At least a plurality of second light deflecting elements each including an element and a light condensing unit that individually condenses each signal that has passed through the second light deflecting element, and includes the first light deflecting element and the second light deflecting element. All of the light deflection elements An optical switch characterized by being composed of one or more pairs of prism groups.