JPH11231002A - Optical sensor element - Google Patents

Abstract

(57) [Problem] To provide an optical sensor element having an optical modulation function. An optical sensor element that modulates and outputs incident light according to a measurement voltage. The optical sensor element includes a waveguide layer 24 including a core portion 2 for guiding the incident light,
4 on both sides of the substrate 20 holding the waveguide layer 24,
And a pair of electrodes 4u and 4d opposed to each other so as to apply the measurement voltage to the core portion. The core part 24
Is formed of a polymer material whose refractive index changes due to an electromagnetic field, and the change shows optical nonlinearity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sensor element used for optically measuring an electromagnetic quantity such as a voltage and an electromagnetic field intensity.

[0002]

2. Description of the Related Art In today's advanced information age, electromagnetic waves have become increasingly important as an information transmission medium for broadcasting and communication, and their strength and frequency have been increasing. There is a tendency.

On the other hand, the problem of malfunction of electronic devices caused by the electromagnetic wave is also increasing. Therefore, development of a method for accurately and easily evaluating the electromagnetic wave is desired.

Conventionally, there has been proposed a device for optically measuring such an electromagnetic wave. This device includes:
An optical sensor element that modulates and outputs measurement light in accordance with the magnitude of an electromagnetic wave is used, and by measuring light that is modulated and output by this element, the intensity of an electromagnetic field can be measured.

FIG. 8 shows an example of a conventional optical sensor element. In this optical sensor element, a waveguide structure 110 for guiding measurement light is provided on a substrate 100. Then, on the upper surface side of the waveguide structure portion 110, an electrode 120,
122 are arranged at a predetermined interval.
2, a voltage corresponding to the electromagnetic field strength measured by an antenna or the like is applied.

The waveguide structure 110 is composed of a core formed by a method such as Ti diffusion using a material having a large electro-optic effect such as LiNbO ₃ and a clad surrounding the core. With such a configuration, the waveguide structure 110 can confine the light inside the core and guide the light.

[0007] Such a waveguide structure 110 is provided with the electrode 12.
When a voltage is applied to 0 and 122, it modulates the measurement light propagated inside the core. Therefore, by measuring the measurement light output from the optical sensor element, the electromagnetic field intensity detected by the antenna or the like can be optically measured.

However, in the conventional optical sensor element, the waveguide structure 110 is formed using the above-mentioned inorganic material. For this reason, there were the following problems.

In the case of an optical sensor element using an inorganic material, it is very difficult to make the waveguide structure 110 thinner.
As shown in FIG. 8, it is inevitable to adopt a surface-loaded electrode structure as the configuration of 20 and 122. In this case, when an attempt is made to measure a low-frequency electric field or an electrostatic field, electric charges are generated in the material, a leak current is generated between the electrodes 120 and 122, and as a result, the light intensity drifts and the measurement accuracy are reduced. This causes problems such as a decrease in the temperature.

Another problem with using an inorganic material is that the dielectric constant is large.

When the permittivity is large, in the case of a measuring instrument for measuring an electromagnetic field as in the present invention, the influence on the electromagnetic field becomes large, and there arises a problem that high-precision measurement is difficult.

In the case of measuring a high-frequency electric field, it is necessary to use a traveling-wave electrode as an electrode structure. In this case, it is necessary to match the phase of the measured electric field with the phase of the guided light. In order to achieve these phase matchings, it is desirable that the dielectric constant of the waveguide be low. However, as described above, the conventional sensor has a large dielectric constant, so that a high-frequency electric field,
In particular there is a problem that is not suitable for measurement of high-frequency electric field of GH _Z level.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and has as its object to provide an optical sensor element capable of measuring electromagnetic quantity with high accuracy in a wide frequency band including an electrostatic field. Is to do.

[0014]

In order to achieve the above object, the present invention provides a thin film layer made of a polymer material, comprising a core portion for guiding incident light, and a cladding portion surrounding the core portion. The waveguide structure portion formed as, and electrodes disposed opposite to both surfaces of the thin film layer, including at least one or all of the region in contact with the core portion of the cladding portion and the core portion, The refractive index changes due to the electromagnetic field,
The change is made of a material including a polymer material exhibiting optical nonlinearity.

The material forming the waveguide structure must be a material whose refractive index changes with an electromagnetic field. A typical example of such a material is a nonlinear optical material having the Pockels effect.

In the present invention, as such a material, a material containing a polymer material whose refractive index changes due to an electromagnetic field and the change shows optical nonlinearity is used. Since such a material is a material that can be thinned, the waveguide structure can be formed as a thin film layer.

Therefore, the electrodes can be arranged to face each other via the thinned core portion, and the distance between the electrodes can be made sufficiently small, and the two electrodes can be more insulated by the thin film layer. Is done.

Thus, according to the present invention, the light intensity drift caused by the surface-loading type electrode configuration as in the prior art,
A low-frequency electric field (voltage) or an electrostatic field (voltage) can be measured without considering a problem such as a decrease in measurement accuracy.

In addition, according to the present invention, since the waveguide structure is formed of a material including a polymer material, the dielectric constant of the waveguide structure is reduced.

Thus, the electric field (voltage) can be measured without affecting the electromagnetic field.

When a high-frequency electric field (voltage) is measured, it is necessary to adopt a traveling-wave electrode configuration.
It is advantageous to use a low dielectric constant material for the phase matching of the measurement electric field and the phase of the guided light. In the present invention, due to the low dielectric constant of the waveguide structure as described above, a high frequency (several tens of GH _Z
Above) can be measured.

Further, according to the present invention, for example, by applying a voltage corresponding to the electromagnetic field strength detected by an antenna or the like to between the opposed electrodes, the electromagnetic field strength can be measured as a voltage. . In addition, by applying a voltage generated at a certain detection site to the electrode, the voltage itself can be measured.

In the present invention, at least one of the clad portion and the core portion is formed of a material containing a polymer material exhibiting optical nonlinearity as described above. The portion may be formed of a material including the above-described polymer material exhibiting optical nonlinearity. Thereby, the incident light can be modulated and output more effectively according to the measurement voltage.

It is preferable that the optical sensor element of the present invention is formed so as to include a base holding the thin film layer, if necessary.

One embodiment of the polymer material exhibiting the optical nonlinearity is an electric field oriented polymer material. When this material is used, a poling process may be performed on this region after forming the core portion or the clad portion. Thereby, the optical nonlinearity can be developed in the core portion or the clad portion.

Of course, another material may be used as long as it is a polymer material exhibiting optical nonlinearity.

[0027]

Next, a preferred embodiment of the present invention will be described.

(1) Polymer material exhibiting optical nonlinearity As a material whose refractive index changes by an electromagnetic field, a nonlinear optical material having a Pockels effect is typical.

A non-linear optical material is most suitable as a material having a high responsiveness that enables voltage measurement at a frequency of gigahertz or higher.

Nonlinear optical materials are roughly classified into inorganic crystals typified by lithium niobate and organic materials typified by electric field oriented polymers.

In the present embodiment, an electric field oriented polymer material is generally selected as a material whose refractive index change due to an electromagnetic field is indicated by optical nonlinearity.

In the present invention, the electrodes are formed so as to sandwich the core of the waveguide structure. In order to induce a strong electric field between the electrodes and cause a desired change in the refractive index, the waveguide structure needs to be a thin film so that the distance between the electrodes can be sufficiently reduced. For this reason, in the present embodiment, the waveguide structure is formed as a thin film layer having a thickness of up to about 10 μm including the core and the clad. It is very difficult to form such a thin film using an inorganic nonlinear crystal. As a material for such a thin film, a polymer material that can form a thin film by a spin coating method or the like is suitable.

Further, since the present invention aims at measuring a voltage in a wide band, the electric field oriented polymer which has a low dielectric constant, easily matches the phase of an optical electric field with an external electromagnetic wave, and does not require a complicated element structure, is used. Suitable as a material for forming a wave layer.

In this embodiment, an electric field oriented polymer is described as an example of the polymer material. However, if the polymer material can be formed into a thin film and exhibits nonlinearity, the electric field oriented high The material used in the present invention is not limited to the molecule.

In the following, a material exhibiting optical nonlinearity used in the present embodiment will be described in detail.

In order to exhibit optical non-linearity,
Π-electron conjugated systems having mobile electrons, such as benzene rings, naphthalene rings, azobenzene rings, etc., have electron-withdrawing functional groups such as nitro groups and cyano groups, and electron-donating functional groups such as amino groups and alkoxy groups. A molecule in which such functional groups are simultaneously introduced can be employed. These can exhibit relatively large optical nonlinearity.

In order to actually impart optical nonlinearity, it is necessary to orient these molecules in order to break the central symmetry in the molecular arrangement. In order to perform this molecular orientation,
A poling process for orienting molecules by applying an electric field can be employed. In this case, it is preferable to perform the heating while heating the thin film layer constituting the waveguide structure in order to smooth the orientation of the molecules.

It is preferable that the material having the above-described properties has low waveguide loss. Generally, the wavelength range used as an optical sensor element is a range from visible to near-infrared, and therefore, it is preferable that loss in the wavelength area where the optical sensor element is used is low. That is, it is sufficient that the loss is low in the region when the wavelength is used in the visible wavelength range and in the near-infrared wavelength range.

(2) Structure of Sensor Element In the optical sensor element of the present invention, at least one of the core and the clad is formed using a material exhibiting optical nonlinearity. Therefore, the refractive index can be controlled by applying an electric field to the core portion.

In the optical sensor element of the present embodiment, the core portion is formed of a polymer material exhibiting optical nonlinearity, and the refractive index of the core portion is changed according to the application of an electric field, so that the light transmitted through the core portion is changed. The optical modulator which performs the modulation of the above. Note that an optical modulator that modulates light transmitted through the core portion by changing the refractive index of a part of the cladding portion surrounding the core portion with the application of an electric field may be configured. At this time, the core may be made of the polymer material showing the optical nonlinearity, or may be made of the polymer material showing no optical nonlinearity.

The core can be formed by a photobleaching method using light irradiation, or by a general reactive ion etching method.

Generally, an electrode is mounted in a region constituting the core portion.

FIG. 1 shows a main part of an example of the optical sensor element of the embodiment. FIG. 2A schematically shows a cross section thereof. In this example, an under clad layer 22 is laminated on a substrate 20 as a base, a waveguide layer 24 is laminated thereon, and an over clad layer 5 is further laminated thereon.

FIG. 2A shows a cross section of the sensor element.

The waveguide layer 24 includes a core portion 2 for guiding light,
And a side clad portion disposed on both sides of the core portion. Accordingly, the core portion 2 is surrounded by the side cladding portions 3 and 3 located on both sides thereof and the cladding layers 5 and 22 located above and below the core portion 2. Layers 5, 22
Constitutes a waveguide structure for confining light in the core 2 and transmitting the light.

Here, the waveguide structure is formed as a thin film layer 100 using a polymer material. The lower electrode 4 (4d) formed by vapor deposition or the like is disposed between the substrate 22 and the under cladding layer 22. An upper electrode 4 (4u) formed by vapor deposition or the like is mounted on the upper clad layer 5 so as to face the core portion 2.

When an optical modulator is formed, the waveguide layer 24
By introducing a portion having the above-mentioned optical non-linearity into the material constituting the core portion 2 and supplying a DC voltage to the electrode 4 and performing an electric field application process also called a poling process, the core portion 2 is formed. Molecular orientation is induced in the constituent materials. As a result, the core 2 whose refractive index can be controlled by the electro-optic effect can be formed. Alternatively, the electrode 4u may be provided after molecular orientation is performed by a corona poling technique.

When light modulation is performed, the electrodes 4 (4d, 4d,
If an external electric field is applied to the core unit 2 by supplying an AC voltage to 4u), light modulation by the external electric field becomes possible based on a change in the external electric field.

The light modulation in the linear waveguide exemplified here is an operation in which a change in retardation caused by a phase change caused by application of an electric field of light transmitted through the core 2 is replaced by a change in intensity through a polarizer. The optical modulation is not limited to the operation in the form of the linear waveguide, and even if the modulation operation uses interference in the form of the Mach-Zehnder waveguide, the directional coupler-type waveguide is used. A modulation operation using a coupling change in the form of a wave path may be used.

The electrode 4 according to the present embodiment can be used for both the application of an electric field in the poling process and the application of the electric field in the light modulation.

In this embodiment, the case where only the core portion 2 is formed by using a polymer material exhibiting optical nonlinearity has been described as an example. All or a part of the regions 22 and 5 in contact with the core portion 2 may be formed using the above-described polymer material exhibiting optical nonlinearity.

FIGS. 2B and 2C show an example in which a polymer material exhibiting such optical nonlinearity is used for the cladding region. FIG. 2B shows a configuration in which the overcladding layer 5 has a configuration in which two layers 5a and 5b are stacked, and the cladding layer 5a in contact with the waveguide layer 24 is formed using a polymer material exhibiting optical nonlinearity. The upper clad layer 5b was formed using a normal polymer material.

On the contrary, as shown in FIG. 2C, the under cladding layer 22 is
2b, the cladding layer 22a in contact with the waveguide layer 24 is formed using a polymer material exhibiting optical nonlinearity, and the lower cladding layer 22b is formed using a normal polymer material. I have.

By doing so, the core 2
Good light modulation can be performed on the measurement light passing through the inside.

As described above, in the present embodiment, the electrodes 4u and 4d of the optical sensor element are opposed to each other so as to sandwich the core 2A. By adopting this configuration, the electrodes 4u and 4d are completely insulated, so that high-precision measurement is possible, and furthermore, it is possible to measure the voltage in the DC range. For example, it is possible to measure an electrostatic field.

That is, in a configuration in which the electrodes are arranged adjacent to each other, for example, as in the conventional optical sensor element shown in FIG. 8, when an electrostatic field is applied, the light intensity drifts due to the effect of the surface current, and the electrostatic field is correctly corrected. Cannot be measured.

However, by employing the electrode configuration as in the present embodiment, it is possible to accurately measure a voltage in a DC range, for example, an electrostatic field.

In the optical sensor element, the core 2 is formed as shown in FIG.
As shown in FIG. 2, these may be of a buried channel type or of a ridge type. In some cases, like a fiber, a configuration of a cylindrical core portion and a clad portion may be used.

As shown in FIG. 2, the over cladding layer 5 may be present above the waveguide layer 24. In this case, the material of the over cladding layer 5 may be the same as the refractive index of the cladding portion 3 in the horizontal direction, or may be a material having another refractive index.

(3) Manufacturing Method In manufacturing the above-described optical sensor element, a poling process for performing molecular orientation for light modulation can be employed.

In order to develop optical nonlinearity, a molecular orientation operation is performed by applying a DC electric field to the material forming the waveguide layer 24. In this case, corona poling using a needle electrode or poling using a parallel plate electrode may be used. Generally, as the degree of molecular orientation increases, the optical non-linearity increases. Therefore, in order to more easily orient the molecules, usually, the material for forming the waveguide layer is heated. Although depending on the material, the heating temperature is generally preferably equal to or higher than the glass transition point.

FIGS. 3 and 4 are conceptual diagrams of the polling process. FIG. 3 illustrates the concept of corona polling. In this case, an electrode arranged below the waveguide layer M and a needle electrode arranged above the waveguide layer M are used, and both electrodes are connected to a DC high-voltage power supply. An electric field is applied to. FIG. 4 shows the concept of poling using parallel plate electrodes. In this case, an electrode disposed below the waveguide layer M and an electrode disposed above the waveguide layer M are used, and both electrodes are similarly connected to a DC high-voltage power supply. An electric field is applied to M.

(4) Another Embodiment FIG. 6 shows another embodiment of the optical sensor element of the present invention. Note that members corresponding to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

The feature of the optical sensor element of this embodiment is that a light reflecting portion 30 is formed on the other end of the waveguide layer 24 as shown in FIG. Thus, the measurement light incident from one end of the core 2 propagates through the core 2, is reflected at the other end, and is output again from one end of the core 2. Therefore, the measurement light propagating in the core 2 undergoes two round-trip modulations, and as a result, it is possible to realize a small-sized optical sensor element capable of high-precision measurement.

In this embodiment, the light reflecting portion 30 is provided on the polished surface on the other end side of the optical sensor element, for example, by A
It can be manufactured by depositing a thin film such as a metal such as 1 or Au or a dielectric or the like by a method such as vapor deposition or sputtering.

Further, the present invention can be applied to a case where the optical modulator is formed as a branch interference type optical modulator. When Mach-Zehnder type is adopted, the waveguide (core part)
May be configured as disclosed in, for example, Japanese Patent Application Laid-Open No. 4-172261.

As a method of forming the waveguide (core portion), for example, a reactive ion etching method using a reactive gas such as oxygen may be used in addition to the photobleaching method described in the above embodiment. .

The wavelength of the measurement light used in the optical sensor element of the present embodiment may be any wavelength if the light intensity is not impaired to the extent that measurement is not possible during the propagation of the measurement light through the core 2. May be used. Usually, a wavelength in a visible region to an infrared region is selected.

[0069]

Embodiments of the present invention will be described below.

First, a method for synthesizing a material having optical non-linearity constituting the core portion 2 used in the embodiment will be described, and then a method for manufacturing an optical sensor element will be described for each item. In this example, the confirmation of the molecular structure is based on the infrared absorption spectrum,
H nuclear magnetic resonance spectrum. The measurement of the melting point and the glass transition temperature was performed by a differential scanning calorimeter. The refractive index was determined from the mode angle when light was incident on the waveguide layer using a coupling prism to excite the waveguide mode.

The manufacturing method of this embodiment is an example of forming the optical sensor element shown in FIGS.

As a substrate 20 functioning as a substrate, a single-sided mirror-surfaced 4-inch silicon wafer having a thickness of about 500 μm and cut by a crystal axis <100> (manufactured by Mitsubishi Materials; n
Was divided into four parts.

The divided wafer was subjected to HF: pure water = 1: 50
For about 1 minute to wash the surface. Next, the substrate was washed with running pure water for about 5 minutes, dried with a spin drier, and provided for the next electrode deposition step.

In the electrode vapor deposition step, Cr was vapor-deposited on the silicon wafer at a thickness of 100 angstroms and then A1 was vapor-deposited at a thickness of 2000 angstroms using an EB vapor deposition apparatus (manufactured by Anelva; EVD-500B) to form a lower electrode 4d. At this time, a mask was placed on a silicon wafer in a portion which is considered to be used as the mode filter A, so that the lower electrode was not deposited.

Next, as the under cladding layer 22, polyimide (manufactured by Hitachi Chemical; PlX2400) was used.
That is, polyimide is directly applied to the lower electrode 4d obtained as described above, and heat-treated (at 150 ° C. for 1 hour, 300 hours).
C. for 1.5 h) to form the under cladding layer 22.

The thickness of the thin film formed on the glass under the same conditions is measured by using a stylus type surface roughness needle (SloanTechnology).
y Corp .; DEKTAKII) and used as the sample thickness. The film thickness was similarly determined in the following steps. The thickness of the polyimide layer which is the under cladding layer 22 is about 7 μm.
m.

The sample was cut with a dicing saw so that the width was fixed at 10 mm and the longitudinal direction was a rectangle having an appropriate length of 40 mm or more.

In forming the polymer thin film portion corresponding to the waveguide layer 24, the material produced as described above is mixed with pyridine as a solvent to form a pyridine solution having a relatively low concentration (1% by weight). did. The pyridine solution was filtered with a 0.2 μm Teflon filter (Advantech Toyo; DISMIC13P), and then concentrated with an evaporator to obtain a high-concentration solution (about 10% by weight).
Thereafter, this high concentration solution was laminated on the under cladding layer 22 by spin coating using a photoresist spinner.

After spin coating, at room temperature for about 6 hours, 8
Vacuum drying was performed at 0 ° C. for about 20 hours and at 150 ° C. for 2 hours. The thickness of the obtained waveguide layer 24 was 2.8 μm.

Next, a light irradiation process called photobleaching was performed. That is, an ultra-high pressure mercury lamp (USH-250BY manufactured by USHIO Inc.) is used as a light source, and a light source unit for an exposure apparatus (manufactured by USHIO Inc .; Multilight ML-251A / B) capable of irradiating parallel light is used to guide light on a substrate. Layer 24
The region corresponding to the core portion 2 was irradiated with ultraviolet light (UV). The irradiation power was 80 mW / cm ² . At the time of light irradiation, a linear core part 2 having a size of 10 μm width is used.
A photomask (manufactured by Toppan Printing Co., Ltd.) in which a pattern for forming is formed on quartz glass with low reflection chrome was used. This photomask is brought into contact with the sample surface, and the sample is heated to 130 ° C.
And irradiated for 4 hours through the mask from above the sample.

The sample was placed on an A1 substrate equipped with a heating device, and an electric field orientation treatment was performed with a needle electrode from above while heating. In this treatment, the heating temperature is 170 ° C. and the distance between the electrodes is 50 m.
m, and an applied voltage of 20 kV. As a result, optical non-linearity is imparted to the portion of the waveguide layer 24 that constitutes the core 2.

Thereafter, a fluorine-based polymer solution for spin coating (CYTOP-805A manufactured by Asahi Glass Co., Ltd.) was applied to a photoresist spinner (K-33359SD-1 manufactured by Kyowa Riken).
Was spin-coated on the waveguide layer at a rotation speed of 1000 rpm to laminate a protective film. Then, vacuum drying at 80 ° C,
Dried for 1 hour. The thickness of the protective layer was 0.65 μm.

Next, a polymethyl methacrylate (PMM) is used as the over cladding layer 5 covering the upper side of the waveguide layer 24.
A, manufactured by Aldrich) in an acetone-methanol system. That is, a 5 wt% PMMA chloroform solution was prepared, and the number of rotations was set to 1000 using a photoresist spinner (K-3359SD-1 manufactured by Kyowa Riken).
Spin coating was performed on the sample coated with the protective film at rpm. Subsequently, it was dried at room temperature for 2 hours in a vacuum dryer. The thickness of the over cladding layer 5 was 1.5 μm.

Next, the sample was immersed in liquid nitrogen to cool the sample. The sample was cleaved including the waveguide layer 24 in the <010> and <001> directions in the crystal plane which had been damaged in advance, exposing the end face.

The waveguide was cut so as to have a length of 25 mm.

Al was vapor-deposited on the core portion of the waveguide of the sample by about 2,000 angstroms using an EB vapor deposition apparatus (manufactured by Anelva; EVD-500B) to form an upper electrode 4u. The sample was masked with a mask for vapor deposition to deposit electrodes only at desired positions. After the lower electrode 4d was exposed, a lead wire was bonded to each of the upper electrode 4u and the lower electrode 4d with a silver paste.

(Light Modulation Experiment) A light modulation experiment was performed using the sample manufactured as described above. In this case, a semiconductor laser having a wavelength of 1.3 μm was used as a light source. Basically, a semiconductor laser, a lens, an optical fiber, a lami-ball fiber polarizer (Sumitomo Osaka Cement), and an optical sensor element are arranged in this order, and one end of the optical sensor element is coupled to the lami-ball fiber polarizer as an incident portion. The other end of the optical sensor element was arranged at the emission part.

In the light modulation experiment, the light intensity from the emission end of a lami-ball fiber polarizer (manufactured by Sumitomo Osaka Cement) was changed in the vertical direction (corresponding to TM mode) and the horizontal direction
(Corresponding to the mode) so as to be equal to each other, and this was coupled to the incident part of the core part 2 of the optical sensor element as the sample.

The light emitted from the emission end opposite to the core 2 was magnified by an objective lens, and the intensity was measured by a photodetector through a polarizing filter.

A high frequency was generated by a high frequency transmitter, amplified by an amplifier, and an AC voltage was applied between the lower electrode 4d and the upper electrode 4U of the sample. As a result, the change in light intensity could be measured. It can be seen that the amount of change is proportional to the magnitude of the voltage, and the voltage can be measured.

(Electromagnetic Field Measurement System) FIG. 5 shows an example of an electromagnetic field measurement system constituted by using the optical sensor element 1 according to this embodiment.

This system includes a light emitting section 200 for outputting measurement light, and a photodetector 202. The light emitting section 200 and one end of the core section 2 constituting the waveguide of the optical sensor element 1 are connected to the incident fiber 210. The other end of the core 2 of the optical sensor element and the photodetector 202 are connected by a light receiving fiber 212.

The incident fiber 210 uses the Ramipole fiber polarizer and the light receiving fiber 212
Was used with the tip fixed with a ferrule and a Ramipole fiber polarizer attached to the tip.

The electrodes 4u and 4d of the optical sensor element 1 are
Each pair is connected to a pair of dipole antennas 220 for detecting an electromagnetic field, and configured to apply a voltage corresponding to an external electromagnetic field.

Further, the dipole antenna 220 and the optical sensor element 1 are integrally mounted and fixed using a plastic package 430, and the optical integrated element 1 is housed in the package 430.

In such a measurement system, the plastic package 430 was set in a TEM cell, and a high-frequency electric field of 400 MHz was generated, and the measurement was performed. As a result of the measurement, the light detection unit 202 was able to confirm the modulation of the light intensity following the frequency of the high-frequency electric field.

(Supplementary Note) The following technical idea can be understood from the above description.

A step of forming a waveguide structure section including a core section and a cladding section surrounding the core section as a thin film layer on a substrate by using an electric field oriented polymer material as a material exhibiting optical nonlinearity; A step of forming electrodes facing each other on both sides of the thin film layer so as to apply the measurement voltage to the core portion, and after forming the thin film layer, subject the core region to a poling process to form a core portion; And a step of developing optical nonlinearity.

(Other Embodiments) FIG. 7 shows an example of a measurement system constituted by using the reflection type optical sensor element shown in FIG. Members corresponding to those of the measurement system shown in FIG. 5 are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, the light sensor element 1
Is configured to reflect the measurement light incident on the core unit 2 from one end through the optical fiber 214 by the light reflection unit 30 provided on the other end, and to output the measurement light from the optical fiber 214 again.

Therefore, only one optical fiber 214 needs to be used, and the optical fiber 214 can be connected to one end of the optical sensor element 1 to form a single beam structure. The part can be formed small.

In this embodiment, the optical sensor element 1 is integrally fixed in the plastic package 430, and the end of the optical fiber 214 is also integrally fixed to the plastic package 430.

Then, on the other end side of the plastic package 430, a voltage measuring lead, for example, a pair of measuring leads 52a provided with crocodile clips 50a, 50b at the ends,
52b is provided. Then, the pair of measurement leads 52
a and 52b are connected to the electrodes 4u, 4
d.

As described below, by attaching the crocodile clips 50a and 50b to a predetermined object to be measured, a voltage generated between the attachment portions can be optically measured.

In such a measurement system, the light emitting section 20
It is necessary to separate the measurement light output from 0 and the measurement light to the light detection unit 202. To this end, an optical system that connects the light emitting unit 200 and the light detecting unit 202 with the light sensor element 1 includes a beam spiriter 440, a lens 442, and an optical fiber 214.

The measuring light output from the light emitting section 200 is transmitted through the beam
The light is output after being divided into two at a right angle and a reflection direction at right angles. That is,
The measurement light output from the light emitting unit 200 is divided into a direction α transmitting through the beam spiriter 204 and a reflection direction perpendicular thereto, and only the measurement light transmitting through the beam spiriter 400 is transmitted through the lens 442. Optical fiber 2
14 is output.

Further, from the optical sensor element 1 to the optical fiber 2
14. The measurement light output through the lens 442 is divided into two directions: a direction transmitting the beam spiriter 24 and a reflection direction β perpendicular thereto, and only the measurement light reflected at a right angle is supplied to the photodetector 202. Is entered.

In this manner, the voltage at the portion where the crocodile clips 50a and 50b are attached is output from the optical sensor element 1 as measurement light modulated according to the voltage. Thus, the photodetector 202 can optically measure the voltage at the measurement site.

[0109]

[Brief description of the drawings]

FIG. 1 is a perspective view showing the general concept of an optical sensor element.

FIGS. 2A to 2C are cross-sectional explanatory views of an optical sensor element.

FIG. 3 is a configuration diagram illustrating a concept of a corona poling process using a needle electrode.

FIG. 4 is a configuration diagram showing the concept of a poling process using parallel plate electrodes.

FIG. 5 is an explanatory diagram of a measurement system configured using the optical sensor element according to the present embodiment.

FIG. 6 is a perspective view illustrating the concept of an optical sensor element having a light reflecting section.

7 is an explanatory diagram of a measurement system using the optical sensor element shown in FIG.

FIG. 8 is an explanatory diagram showing an example of a conventional optical sensor element.

[Explanation of symbols]

 2A core part 3A, 3B sand clad 4d, 4u electrode 5, 22 clad layer 20 substrate 24 conductive layer 30 light reflection part 100 thin film layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Ito 41-41, Yokomichi, Nagakute-cho, Aichi-gun, Aichi-gun, Toyota-Chuo Research Institute, Inc. (72) Inventor Tadashi Ichikawa, Nagakute-cho, Nagakute-cho, Aichi, Aichi 41, Yokomichi, Toyota Central Research Institute, Inc.

Claims (1)

[Claims] 1. A waveguide structure portion including a core portion for guiding incident light, a cladding portion surrounding the core portion, formed as a thin film layer using a polymer material, and both surfaces of the thin film layer And at least one of the core portion and the whole or a part of the region of the cladding portion that is in contact with the core portion, the refractive index of which is changed by an electromagnetic field, and the change is optically non-linear. An optical sensor element formed of a material containing a polymer material having a property.