JP2009085593A - Photoelectric field sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric field sensor which is easy to assemble and inexpensive, has a high measuring accuracy and can be used for a long time and which is free from dew condensation and freezing even when ambient temperature lowers and has high reliability. <P>SOLUTION: The photoelectric field sensor is constituted of a collimator which emits light to the polarizer side, a polarizer, a quarter wave plate, a Pockels element, an optical analyzer, a collimator which condenses light, a block which has a hole formed in the portion passing light through and to which the polarizer is stuck, a block which has a hole formed in the portion passing the light through and to which the quarter wave plate is stuck, a block to which the Pockels element is stuck, a block which has a hole formed in the portion passing the light through and to which the optical analyzer is stuck, and a base on which the collimators, the polarizer, the quarter wave plate, the Pockels element and the optical analyzer are disposed. The blocks have step-shaped parts which make it possible respectively to set optical azimuth angles that the polarizer, the quarter wave plate, the Pockels element and the optical analyzer need. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power transformer such as a substation or a power plant and an instrument transformer for measuring a voltage of a power system, and in particular, an electric field between a high voltage portion of the power equipment or a system and a ground is used by polarization of light. The present invention relates to an optical electric field sensor for direct measurement.

  When an electric field is applied to the ferroelectric crystal, a Pockels effect is generated in which the refractive index changes in proportion to the strength. A crystal capable of obtaining this effect is called a Pockels element, and an optical electric field sensor that measures the electric field by arranging this in a measurement target part and measuring the electric field has been developed (see Patent Document 1). ).

  An example of such a conventional optical electric field sensor 20 will be described with reference to FIGS. 16 (a) and 16 (b) and FIGS.

  16 (a) is a plan view of the optical electric field sensor 20, and FIG. 16 (b) is a side view. 16A and 16B, the optical electric field sensor 20 includes a collimator 1 that emits light toward the polarizer 2, a polarizer 2, a quarter-wave plate 3, a Pockels element 4, and an analyzer. 5, a prism 6 that reflects light, a collimator 7 that collects light, and a base 8 made of an insulator on which these optical elements are disposed. In order to seal these optical elements, the base 8 provided with the optical elements is housed in a cover 13 made of an insulating material, and the base 8 and the cover 13 are hermetically bonded by an adhesive 18.

  The optical electric field sensor 20 is attached to a power transmission / transformation device and placed in an electric field between a high voltage portion and a ground potential. The optical electric field sensor 20 is used as one component of the power transmission / transformation equipment, and is connected to the light source 9 and the signal processor 10 through the optical fibers 11 and 12 as shown in FIG.

The optical electric field sensor 20 having the above configuration functions as follows. That is, the light from the light source 9 enters the optical electric field sensor 20 through the optical fiber 11. In the optical electric field sensor 20, each optical element is directly attached to the base 8 at the required azimuth angle. The light exiting the collimator 1 becomes linearly polarized light by the polarizer 2, becomes circularly polarized light by the quarter wavelength plate 3, undergoes modulation according to the electric field applied by the Pockels element 4, and becomes elliptically polarized light, The unidirectional component of the analyzer 5 is taken out as linearly polarized light, the light traveling direction is bent by reflection at the prism 6, condensed by the collimator 7, and exits the optical electric field sensor 20. The light exiting the optical electric field sensor 20 passes through the optical fiber 12 and enters the signal processor 10, and the voltage of the high voltage part that creates the electric field to be measured is obtained using the modulation signal.
JP 2003-4776 A

  However, the conventional optical electric field sensor having the above configuration has the following drawbacks. That is, since the polarizer 2, the quarter wavelength plate 3, the Pockels element 4, and the analyzer 5 are directly attached to the base 8, the attaching portion 8a of these optical elements is formed on the base 8 and has a complicated shape. It has become. Further, in order to reduce the size of the optical electric field sensor 20, the interval between the optical elements is extremely narrow. Therefore, when assembling the optical electric field sensor 20, the work space is narrow, so that workability is extremely poor.

  In addition, a portion for determining the azimuth angle of the optical element is not provided on the attachment surface of the optical element of the conventional optical electric field sensor, and much time is required for positioning. 17 and 18 show an example in which the relative angle between the polarizer 2 and the quarter-wave plate 3 is 45 °. Note that the four black circles 2b in FIG. 17 indicate an adhesive portion, and the four black circles 4b in FIG. 18 indicate an adhesive portion. In this case, it is necessary to incline the quarter-wave plate 3 at 45 °, but it is necessary to confirm whether circularly polarized light is formed before adhesion. Therefore, adjustment and confirmation are repeated many times until the final state is reached, and much time is required for the adjustment and confirmation work.

  In addition, even after adjustment and confirmation, there is a problem that misalignment is likely to occur when pasting with an adhesive. The analyzer 4 has a similar problem when pasting.

  The base 8 is made of an insulating material such as an epoxy mold material that can be machined. Such a material has a relative dielectric constant of about 6, and is not equal to the relative dielectric constant of gas (about 1), and therefore distorts the electric field applied to the Pockels element 4. That is, in the vertical modulation optical electric field sensor, the electric field that should be applied perpendicularly to the optical axis contains a component parallel to the optical axis, and the required electric field strength cannot be obtained, resulting in a decrease in accuracy. It was.

  The same phenomenon also occurs in a lateral modulation optical electric field sensor, and the electric field that should be applied in parallel to the optical axis contains a component perpendicular to the optical axis, so that the required electric field strength cannot be obtained and the accuracy decreases. It was the cause.

  Furthermore, since an epoxy-based adhesive is used for the seal portion 18, leaks may occur due to a decrease in adhesive force with the passage of time over a long period of time, and moisture in the atmosphere may enter the sealed space. It was. In addition, since the moisture contained in the epoxy mold material, which is the material of the base 8 and the cover 13, gradually emerges in the sealed space, when the ambient temperature is lowered, the moisture that has entered the surface of the optical element Condensation and icing may occur, which may lead to a decrease in the accuracy of the optical electric field sensor and a situation where it cannot be used.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an inexpensive optical electric field sensor that can be easily assembled. It is another object of the present invention to provide an optical electric field sensor having high measurement accuracy, and further to provide an optical electric field sensor that can be used for a long period of time and has high reliability without condensation or freezing even when the ambient temperature is lowered.

  To achieve the above object, the present invention provides a collimator that emits light toward a polarizer, a polarizer, a quarter-wave plate, a Pockels element, an analyzer, a collimator that collects light, A block where the light passes through the hole and the polarizer is attached, a block where the light passes through the hole and a quarter-wave plate is attached, and the light passes through the hole and the analyzer is attached. In the optical electric field sensor comprising a block to be attached, the collimator, the polarizer, the quarter-wave plate, the Pockels element, and a base on which the analyzer is disposed, the block includes the polarizer and the 1 / A stepped portion is previously provided so that the optical azimuth required by the four-wavelength plate and the analyzer can be set.

  According to the present invention, it is possible to provide an inexpensive optical electric field sensor that can be easily assembled. In addition, it is possible to provide an optical electric field sensor with high measurement accuracy, and further to provide an optical electric field sensor that can be used for a long time and has high reliability without dew condensation or freezing even when the ambient temperature is lowered.

(First embodiment)
A first embodiment of the present invention will be specifically described with reference to FIGS.
FIGS. 1A and 1B are configuration diagrams of the optical electric field sensor 20 according to the first embodiment, which are a horizontal plan view and a side view, respectively. 2 is a detailed view of a portion A in FIG. 1B, showing a state where the polarizer 2 is attached, and FIG. 3 is a detailed view of a portion B, shown in FIG. 1B, where the quarter-wave plate 3 is attached. FIG. 4 is a detailed view of a portion C in FIG. 1B and shows a state where the analyzer 5 is attached.

  As shown in FIGS. 1A and 1B, the optical electric field sensor 20 includes a collimator 1 that emits light toward the polarizer 2, a polarizer 2, a block 2a that attaches the polarizer 2, and a quarter. A wave plate 3, a block 3 a to which the quarter wave plate 3 is attached, a Pockels element 4, an analyzer 5, a block 5 a to which the analyzer 5 is attached, a collimator 7 that collects light, and these are disposed. Consists of a base 8. Also, a prism 6 that bends the traveling direction of light by reflection is disposed after the analyzer 5. The blocks 2a, 3a, and 5a to which the optical elements such as the polarizer 2 are attached form a stepped portion having a predetermined optical azimuth on the end face with a hole through which light passes, and come into contact with the stepped portion. In this state, the required optical azimuth angle can be set by simply pasting the four corners of the optical element. The blocks 2a, 3a, and 5a are attached to the predetermined positions 2c, 3c, and 5c of the base 8 with adhesives.

  The state of setting the azimuth angle of the optical element such as the polarizer 2 will be described with reference to FIGS. FIG. 2 is a detailed view of part A in FIG. 1B, and a portion 2b to which the polarizer 2 is attached is processed into a step shape on the end face of the block 2a, and this portion is the edge portion of the polarizer 2 Can be achieved by affixing them in a state where they are in contact with each other (here, an example of an azimuth angle of 0 ° is shown).

  FIG. 3 is a detailed view of part B of FIG. 1 (b). A part 3b to which the quarter wavelength plate 3 is attached is processed into a step shape on the end face of the block 3a, and this part has a quarter wavelength. The azimuth angle required by the quarter-wave plate 3 can be achieved by pasting the edges of the plate 3 in contact with each other (here, an example of an azimuth angle of 45 ° is shown). ).

FIG. 4 is a detailed view of part C of FIG. 1 (b). A portion 5b to which the analyzer 5 is attached is processed into a step shape on the end surface of the block 5a, and the edge of the analyzer 5 is applied to this portion. The azimuth angle required by the analyzer 5 can be achieved by sticking along the contacted state (here, an example of an azimuth angle of 10 ° is shown. The azimuth angle of the analyzer has the Pockels element, It depends on the temperature characteristics of the Pockels effect and the optical rotation.)
The operations and effects of the optical electric field sensor 20 according to the first embodiment having the above-described configuration are as follows.

  That is, the blocks 2a, 3a, and 5a to which the optical elements such as the polarizer 2 are attached are steps that can set the optical azimuth required by the polarizer 2, the quarter wavelength plate 3, and the analyzer 5. Since the shape portion is formed in advance, the required optical azimuth angle can be achieved simply by attaching the edge of the optical element such as the polarizer 2 in contact with the blocks 2a, 3a, and 5a. Therefore, adjustment / confirmation work is unnecessary, the work time is short, and no positional deviation occurs. Thereby, an inexpensive and accurate optical electric field sensor can be provided.

(Second Embodiment)
An optical electric field sensor 20 according to a second embodiment of the present invention will be specifically described with reference to FIGS. 5 (a) and 5 (b) and FIGS. 6 (a) and 6 (b). The same members as those in the first embodiment will be described with the same reference numerals.

  As shown in FIGS. 5A and 5B, the optical electric field sensor 20 includes a collimator 1 that emits light toward the polarizer 2, a polarizer 2, a quarter wavelength plate 3, and a polarizer 2. A single block 23a for affixing the quarter-wave plate 3, a Pockels element 4, an analyzer 5, a block 5a for affixing the analyzer 5, a collimator 7 for condensing light, and these are disposed. The base 8 is composed of A prism 6 that bends the traveling direction of light is disposed after the analyzer 5. The blocks 23a and 5a to which the optical elements such as the polarizer 2 are attached form a stepped portion having a predetermined optical azimuth on the end face with a hole through which light passes, and are in contact with the stepped portion. By simply pasting the four corners of the optical element, the required optical azimuth angle can be set.

  6 (a) and 6 (b) are diagrams showing the state in which the polarizer 2 and the quarter wavelength plate 3 are attached to the block 23a in FIG. 5 (b), and FIG. FIG. 5B is a view taken in the direction of the arrow A in FIG. 5B, and FIG. 6B is a view taken in the direction of the arrow B in FIG. In the block 23a, the end face on the side of the polarizer 2 of the block 23a to which the polarizer 2 is attached is processed into a step shape, and the edge of the polarizer 2 is in contact with this portion so that the edge is attached. The azimuth angle required by the polarizer 2 (shown here as an example with an azimuth angle of 0 °) can be achieved. The end face of the block 23a to which the quarter wavelength plate 3 is attached is also processed into a step shape, and the edge of the quarter wavelength plate is in contact with this portion. By sticking them together, the azimuth angle required by the quarter-wave plate 3 (here, shown as an example of an azimuth angle of 45 °) can be achieved.

  According to the optical electric field sensor of the second embodiment having the above-described configuration, the polarizer 2 and the quarter-wave plate 3 have a predetermined optical azimuth angle formed in advance on both surfaces of the same block. Since it is attached to the stepped portion, it is possible to reduce one block to be used, to further improve workability, to reduce costs, and to reduce the size of the optical electric field sensor.

(Third embodiment)
An optical electric field sensor 20 according to a third embodiment of the present invention will be specifically described with reference to FIGS. 7 (a), 7 (b) and FIG. The same members as those in the first embodiment will be described with the same reference numerals.
FIGS. 7A and 7B are configuration diagrams of the optical electric field sensor 20 according to the third embodiment, and FIG. 8 is an AA arrow view in FIG. 7A and an attachment state diagram of the Pockels element 4. It is.

  As shown in FIG. 7A, the optical electric field sensor 20 includes a collimator 1 that emits light toward the polarizer 2, a polarizer 2, a quarter wavelength plate 3, a polarizer 2, and a quarter wavelength. A block 23a for attaching the plate 3, a Pockels element 4, a block 4a for attaching the Pockels element 4, an analyzer 5, a block 5a for attaching the analyzer 5, a collimator 7 for collecting light, and It is comprised from the base 8 to arrange | position.

  Also, a prism 6 that bends the traveling direction of light by reflection is disposed after the analyzer 5. The blocks 23a and 5a to which the optical elements such as the polarizer 2 are attached have optical azimuth angles required by simply attaching the optical elements to the end faces with holes through which light passes, in the same manner as in the above-described embodiment. Can be set.

  The attachment state of the Pockels element 4 is shown in FIG. FIG. 8 is an AA arrow view of FIG. In the case of the present embodiment, the Pockels element 4 is cut out in a rectangular parallelepiped shape so that its optical axis is 45 ° with respect to the crystal axis, and the Pockels element 4 is pasted at a predetermined position 4b on the block 4a. The optical azimuth angle of the Pockels element 4 is achieved. The block 4a to which the Pockels element 4 is attached is attached to a predetermined position 4c on the base 8 with an adhesive.

  According to the optical electric field sensor of the third embodiment having the above-described configuration, the distance from the adhesive surface to the optical axis can be shortened by placing the Pockels element 4 on the block 4a, and the expensive Pockels element 4 is optically coupled. Can be made as small as possible. Accordingly, a low-cost optical electric field sensor can be supplied.

(Fourth embodiment)
An optical electric field sensor 20 according to a fourth embodiment of the present invention will be specifically described with reference to FIGS. 9 (a), 9 (b) and FIG. The same members as those in the first embodiment will be described with the same reference numerals.

  FIGS. 9A and 9B are configuration diagrams of the optical electric field sensor 20 according to the fourth embodiment, and FIG. 10 is a view taken along the line AA in FIG. It is.

  As shown in FIG. 10, the optical electric field sensor 20 includes a collimator 1 that emits light toward the polarizer 2, a polarizer 2, a quarter wavelength plate 3, a polarizer 2, and a quarter wavelength plate 3. A block 23a to which the Pockels element 4 is attached, a block 4a to which the Pockels element 4 is attached, an analyzer 5, a block 5a to which the analyzer 5 is attached, a collimator 7 for condensing light, and a base on which these are disposed. 8 is composed. Further, a prism 6 is disposed after the analyzer 5 by bending the light traveling direction by reflection.

  The blocks 23a and 5a to which the optical elements such as the polarizer 2 are attached can be obtained by simply attaching the optical elements to the end faces having holes through which light passes, in the same manner as in the above-described embodiment. It has a stepped part that can set the corner. The block 4a to which the Pockels element 4 is attached is configured such that the optical azimuth angle of the Pockels element 4 is achieved by placing the Pockels element 4 thereon.

  Furthermore, the shape of the base 8 has a stepped portion 8b, and the side surfaces of the blocks 23a, 5a, 6a, to which optics are attached to the stepped portion 8b, are formed so as to rise perpendicularly from the bottom surface of the base 8. The processing is performed with an accuracy that can achieve alignment only by arranging the block in accordance with the side surface of the stepped portion 8b.

  According to the optical electric field sensor of the fourth embodiment having the above-described configuration, a complicated positioning and adjustment is achieved by adopting a structure in which the side surface of the block can be aligned with the side surface of the stepped portion 8b of the base 8. Work is unnecessary, and work time can be further reduced. Therefore, the cost can be further reduced and an inexpensive optical electric field sensor can be provided.

(Fifth embodiment)
An optical electric field sensor 20 according to a fifth embodiment of the present invention will be specifically described with reference to FIGS. 11 (a), 11 (b) and FIG. The same members as those in the first embodiment will be described with the same reference numerals.
FIGS. 11A and 11B are configuration diagrams of the optical electric field sensor 20 according to the fifth embodiment, and FIG. 12 is a detailed view of a part A in FIG.

In the fifth embodiment, Bi ₁₂ GeO ₂₀ or Bi ₁₂ SiO ₂₀ is used as the Pockels element 4 of the lateral modulation optical electric field sensor 20 according to the fourth embodiment, and both end faces thereof are made of transparent indium oxide. The electrode 14 deposited is used.

  According to the optical electric field sensor 20 of the fifth embodiment having the above-described configuration, since the transparent electrodes 14 which are conductive materials are deposited on both end faces of the Pockels element 4, the equipotential surface 14a is uniform. Distributed. As a result, the electric field 14b generated in the Pockels element 4 becomes perpendicular to the optical axis with almost no distortion. Therefore, an electric field having a required strength can be obtained, and high-precision measurement can be performed without degrading measurement accuracy.

(Sixth embodiment)
An optical electric field sensor 20 according to a sixth embodiment of the present invention will be specifically described with reference to FIGS. 13 (a), 13 (b) and FIG. The same members as those in the first embodiment will be described with the same reference numerals.
FIGS. 13A and 13B are configuration diagrams of the optical electric field sensor 20 according to the sixth embodiment, and FIG. 14 is a detailed view of a portion A in FIG.

  The optical electric field sensor 20 according to the sixth embodiment includes a collimator 1 that emits light toward the polarizer 2, a polarizer 2, a ¼ wavelength plate 3, a polarizer 2, and a ¼ wavelength plate 3. A block 23a to which the Pockels element 4 is attached, a block 4a to which the Pockels element 4 is attached, an analyzer 5, a block 5a to which the analyzer 5 is attached, a collimator 8 that collects light, and a base on which these are disposed. 8 is composed. Further, prisms 6 a and 6 b that bend the light traveling direction are disposed in front of the polarizer 2 and after the analyzer 5, respectively.

  The blocks 23a and 5a to which the optical elements are attached can each set the required optical azimuth angle just by attaching the optical element to the end face with a hole through which light passes, as in the above-described embodiment. . Further, the block 4a for attaching the Pockels element by reflection is configured such that the optical azimuth angle of the Pockels element is achieved by placing the Pockels element thereon.

  Furthermore, the shape of the base 8 is stepped, and alignment is performed simply by arranging the block 23a, 4a, 5a with the optical elements attached to these portions so that the side faces of the blocks 8 are aligned with the stepped side faces of the base 8. Is processed with the accuracy that can be achieved.

In the case of this embodiment, since it is a lateral modulation electric field sensor, the electric field is perpendicular to the optical axis. Further, Bi ₄ Ge ₃ O ₁₂ , Bi ₄ Si ₃ O ₁₂ or LiNbO ₃ is used as the Pockels element 4, and a film of the electrode 15 made of gold is vapor-deposited on two surfaces parallel to the optical axis.

  According to the optical electric field sensor 20 of the sixth embodiment having the above configuration, since the gold electrode 15 is deposited on two surfaces parallel to the optical axis in the Pockels element 4, the equipotential surface 14a is uniformly distributed. As a result, the electric field 14b generated in the Pockels element 4 becomes parallel to the optical axis with almost no distortion. Therefore, an electric field having a required strength can be obtained, and high-precision measurement can be performed without degrading measurement accuracy.

(Seventh embodiment)
An optical electric field sensor 20 according to a seventh embodiment of the present invention will be specifically described with reference to FIGS. 15 (a) and 15 (b). In addition, about the member same as said embodiment, the same code | symbol is attached | subjected and demonstrated.
FIGS. 15A and 15B are configuration diagrams of the optical electric field sensor 20 according to the sixth embodiment.

  In the optical electric field sensor 20 according to the seventh embodiment, the base 8 to which the optical unit described in the fifth embodiment is attached is accommodated in the cover 13, and the base 8 and the cover 13 are joined by the solder 16, Nitrogen gas having a dew point below the minimum use temperature is enclosed in the cover 13. Further, the blocks 23a, 4a, 5a, the base 8, and the cover 13 are made of a ceramic that can be machined, which is an insulating material having a moisture content of 0%.

  According to the optical electric field sensor 20 of the seventh embodiment having the above configuration, the moisture permeability can be reduced to 0 because the base 8 and the cover 13 are joined by the solder 16, that is, metal. Moreover, since the adhesiveness is good, the sealing performance does not deteriorate over time.

  Therefore, the amount of moisture inside the sealed interior does not increase. Also, since the dew point of the nitrogen gas initially sealed is lower than the minimum ambient temperature, there is no condensation or freezing even when used at the minimum ambient temperature. Therefore, even if the temperature drops to the minimum ambient temperature during long-term use, condensation and icing will never occur, and measurement will not be impossible, and high reliability can be obtained.

(A), (b) is a block diagram of the optical electric field sensor which concerns on the 1st Embodiment of this invention. It is the A section detail drawing in Drawing 1 (b), and the pasting state figure of the polarizer. FIG. 2B is a detailed view of the B part in FIG. FIG. 2B is a detailed view of a portion C in FIG. (A), (b) is a block diagram of the optical electric field sensor which concerns on the 2nd Embodiment of this invention. (A), (b) is an A and B arrow line view of FIG.5 (b), and is a bonding state figure of a polarizer and a quarter wavelength plate. (A), (b) is a block diagram of the optical electric field sensor which concerns on the 3rd Embodiment of this invention. It is an AA arrow line view of Drawing 6 (b), and a pasting state figure of a Pockels element. (A), (b) is a block diagram of the optical electric field sensor which concerns on 4th Embodiment based on this invention. It is an AA arrow line view in FIG.8 (b), and the attachment state figure of the block which affixed the polarizer. (A), (b) is a block diagram of the optical electric field sensor which concerns on 5th Embodiment based on this invention. FIG. 11 is a detailed view of part A in FIG. (A), (b) is a block diagram of the optical electric field sensor which concerns on the 6th Embodiment of this invention. FIG. 13 is a detailed view of part A in FIG. (A), (b) is a block diagram of the optical electric field sensor which concerns on the 7th Embodiment of this invention. (A), (b) is a block diagram of the conventional optical electric field sensor. It is an AA arrow line view in FIG.16 (b), and the sticking state figure of a polarizer. It is a BB arrow line view in FIG.16 (b), and the affixing state figure of a quarter wavelength plate. Connection diagram when an optical electric field sensor is attached to a power transmission and transformation device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Collimator, 2 ... Polarizer, 2a ... Block (for polarizer), 23a ... Block (for polarizer and 1/4 wavelength plate), 3 ... 1/4 wavelength plate, 3a ... Block (1/4 wavelength plate) 4) Pockels element, 4a ... Block (for Pockels element), 5 ... Analyzer, 5a ... Block (for analyzer), 6 ... Prism, 7 ... Collimator, 8 ... Base, 8a ... Paste, 8b DESCRIPTION OF SYMBOLS ... Base part of base 8, 9 ... Light source, 10 ... Signal processor, 11, 12 ... Optical fiber, 13 ... Cover, 14 ... Transparent electrode, 15 ... Gold electrode, 16 ... Solder, 17 ... Nitrogen gas, 18 ... Adhesive (epoxy), 20... Optical electric field sensor.

Claims (9)

A collimator that emits light toward the polarizer, a polarizer, a quarter-wave plate, a Pockels element, an analyzer, a collimator that collects the light, and a portion through which the light passes has a hole shape. A block for pasting, a block for pasting a quarter-wave plate with a hole-transmitting portion, a block for pasting an analyzer with a hole-passing portion for light, the collimator, the polarizer, and the block In an optical electric field sensor comprising a quarter wavelength plate, the Pockels element, and a base on which the analyzer is disposed,
2. The optical electric field sensor according to claim 1, wherein the block has a stepped portion in advance so that the optical azimuth required by the polarizer, the quarter-wave plate, and the analyzer can be set.   The optical electric field sensor according to claim 1, wherein the polarizer and the quarter-wave plate are attached to both surfaces of the same block.   The optical electric field sensor according to claim 1, wherein the side surface of the base has a stepped portion that can be aligned only by arranging the side surfaces of the block together.   4. The optical electric field according to claim 1, wherein the Pockels element is a vertical modulation Pockels element in which a transparent electrode is deposited on two surfaces perpendicular to the optical axis of the Pockels element. 5. Sensor. The optical electric field sensor according to claim 4, wherein the Pockels element is made of Bi ₁₂ GeO ₂₀ or Bi ₁₂ SiO ₂₀ .   4. The optical electric field sensor according to claim 1, wherein the Pockels element is a lateral modulation Pockels element in which electrodes are deposited on two surfaces parallel to the optical axis of the Pockels element. 5. The optical electric field sensor according to claim 6, wherein the Pockels element is made of Bi ₄ Ge ₃ O ₁₂ , Bi ₄ Si ₃ O _12, or LiNbO ₃ .   The material of the block and the base is an insulator having a moisture content of 0 and is housed in a cover made of an insulator having a moisture content of 0. 8. Optical electric field sensor.   The optical electric field sensor according to any one of claims 1 to 8, wherein the base and the cover are joined by soldering, and a gas having a dew point equal to or lower than a minimum operating temperature is sealed.

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