JPS5862530A - Photosensor - Google Patents

Abstract

PURPOSE:To improve sensitivity and reliance, by a method wherein a polarizer and an analizer are provided within a sensing element. CONSTITUTION:A polarizer 10 having a multilayer film as an interference film and an analyzer 11 having a multilayer film as an interference film are arranged so that they cut a Faraday element made of lead glass in fixed shaped. Said polarizer 10, analyzer 11 and Faraday element 9 are formed in one body by forming films in said cut portions by evaporation etc. and again covering the cut portions by lead glass. A photosensor according to this structure has the advantage that sensitivity of a photo-magnetic field sensor is improved, as the polarizer and analizer are formed within the optical-Faraday element having multilayer films, and further, that the reliability is improved and the size can be minimized, as each optical-components are formed monoblockly.

Description

[Detailed Description of the Invention] □ The present invention relates to an optical sensor that applies light deflection.

□Figure 1 is a diagram showing an optical i-field measurement device using a conventional optical sensor. In the figure, (1) is the light source, (2) is the optical fiber, and (3) is the optical sensor% (4) (4 ) represents a microlens, (5) represents a polarizer, (6) represents an optical Faraday element as a sensing element whose light is deflected by an external magnetic field, (7) represents an analyzer, and (8) represents a light receiver. .

Next, the operation will be explained. Light emitted from a light source (1) is guided to a light sensor (3) by an optical fiber (2). In the optical sensor (3), the light emitted from the optical fiber is
The emitted light is converted into parallel light by a microlens (4), and linearly polarized by a polarizer (5). When there is an external magnetic field parallel to the traveling direction of the light, the polarization plane of the linearly polarized light wave propagating inside the optical Faraday element (6) undergoes Faraday rotation depending on the strength of the magnetic field.7 This rotation angle is converted into intensity modulation by analyzer (7), microlens (4')
, through an optical fiber (2), and undergoes optical/electrical conversion at a photoreceiver (3). By measuring this electrical output, it is possible to measure the external magnetic field around the optical sensor (3).

The above example uses a Faraday element made of lead glass as a sensing element, but instead of a Faraday element, a Lim
When a Pockels element such as b's or B112sio2o is used, the voltage and current around the element can be measured. In addition, if the photoelastic effect of tellurium glass or epoxy resin is used instead of a Faraday element, and t = wood, the pressure applied to the element, insects.

Vibration, acceleration, etc. can be measured.

Since the conventional optical measurement device is configured as described above, sensing elements such as a polarized analyzer (5 buffs) and an optical Faraday element (6) are separately arranged inside the optical sensor (3). However, there are drawbacks such as a large coupling loss within the optical sensor (3) and optical axis misalignment of each optical component due to temperature or vibration, which reduces reliability.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and the purpose is to provide an optical sensor with improved sensitivity and reliability by forming a polarizer and an analyzer inside the sensing element. It is said that

Hereinafter, a description will be given of FIG. 2 in which an embodiment of the present invention is applied to a magneto-optical field measuring device. In Figure 2, (1) is a light source, (2) is an optical fiber, (3) is a light sensor, and (4) is a light source.
(4") is a microlens, and (9) is an optical Faraday element which is a sensing element with a built-in polarizer and analyzer. 8th
The figure shows the details of this optical Faraday element, where Moe is a polarizer using a multilayer film as an interference film, and 0υ is an interference 12
．． This represents an analyzer using a thin multilayer film. That is, and fL
For the polarizer O0 and analyzer Ov, a lead glass Faraday element is cut into a predetermined shape, a film is formed on the part by vapor deposition, etc., and the cut part is covered with lead glass again.
and an analyzer αυ and a Faraday element (9) are integrated.

Next, the operation of the present invention will be explained with reference to FIGS. 2 and 8.

2 and 8, the output light from light # (1) is coupled into the optical fiber (2) and the optical magnetic field sensor (
3) Be guided within. In the optical sensor (3), the beam is first converted into a parallel beam by the microlens (4), and only the electric field component in one direction is extracted by the polarizer QO. That is, the light emitted from the polarizer 01 becomes linearly polarized light. When light propagates within the Faraday element (9) to which a magnetic field is applied, the plane of polarization of the light rotates as shown in the following equation.

ΔX=VIH (1) In the equation (1), ΔX is the rotation angle of the plane of polarization, ■ is Beherde's constant for optical Faraday elements, l is the optical path length, and H is the external magnetic field. The analyzer aυ has the same function as the polarizer Ql, but the direction of the passing electric field is rotated. That is, the output light from the Faraday element (9) is converted into light intensity modulation by the analyzer 0υ. The analyzer output is focused by a microlens (4') onto the core surface of an output optical fiber (2), and guided through the optical fiber to a light receiver (8). The rotation angle ΔX of the plane of polarization within the optical faraday element, that is, the magnetic field H can be determined from the electrical signal converted from light to electricity by this light receiver.

In this invention, as shown in FIG. 8, the polarizing analyzer is fabricated within the optical faraday element using a multilayer film or the like, so that the sensitivity of the optical magnetic field sensor is improved. Now, in the conventional optical magnetic field sensor, the optical path length of the polarized analyzer using calcite etc. is I
P, and the optical path length of the optical Faraday element is /F, then the sensitivity improvement rate η of the sensor of the present invention compared to the conventional sensor is:
lp+ly η;α□ (2) Approximate by p. α represents the improvement in sensitivity due to the effect of eliminating reflection loss occurring between the 4M analyzer and the optical faraday element, and α>l. For example, 1p-2txa.

jy-1am, axl, 2, η=1.8.

In the above embodiments, a magneto-optical field sensor and an applied measurement device thereof have been described, but these can of course also be applied to current measurement.

In addition, in the above embodiments, an optical magnetic field sensor and an optical measurement device using an optical Faraday element were described, but it can also be applied to any sensor using a polarizer, an analyzer, or both, and their applied devices. can. For example, photovoltage and electric field sensors using the Pockels effect of LiNbO3, Bi128102o, etc. as in the past.

It can also be applied to optical acceleration, pressure, strain sensors, etc. that utilize the photoelastic effect of tellurium glass or epoxy resin.

Further, in the above embodiment, a sensor in which light travels straight within the optical faraday element has been described, but the sensor can also be miniaturized by reflecting the light as shown in FIG. In Fig. 4, 2 indicates a reflective gold film.

1123, in the above example, the polarized analyzer gate light, A5 f
- Although the optical sensor built into the system has been described, this can be applied not only to measuring devices but also to optical devices such as optical isolators and optical circulators that require polarized analyzers.

As described above, according to the present invention, a light polarizer and an analyzer are formed within a sensing element such as an optical Faraday element, a Pockels element, or a photoelastic effect element, so that the sensitivity of the optical sensor is improved and each This has the effect of improving reliability due to the integration of optical components and reducing the size of the optical sensor.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a magnetic field measuring device using a conventional optical sensor, Fig. 2 is a schematic diagram of an optical magnetic field measuring device using an optical sensor of the present invention, and Fig. 8 is a schematic diagram of an optical magnetic field measuring device using an optical sensor of the present invention. FIG. 4 is a detailed view of the optical sensor shown in FIG. 4, which is a configuration diagram of an optical sensor according to another embodiment of the present invention. In the figure, (1) is a light source, (2) is an optical fiber, and (3) is a light source.
) is an optical sensor, (4) (4') is a microlens,
(8) is a light receiver, (9) is an optical Faraday element which is a sensing element with a built-in polarized photon, 0Q is a polarizer using a multi-layer film, OIJ is an analyzer using a multi-layer film, and (2) is an optical Faraday element that is a sensing element with a built-in polarized photon. reflective gold k1
There will be 4 exhibitions. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Thousand-Continued Amendment (from III) Director General of the Patent Office 1, Case (7) Display Patent Application Sho Be-16225'
No. 2 2. Title of the invention Optical sensor 3. Person making the amendment Claims of the specification and detailed description of the invention column 6. Contents of the amendment (1) Claims of the specification should be submitted in the attached document. correct. (2) On page 2, line 16, the phrase ``is deflected'' should be corrected to ``change the deflection state of.'' (3) In the 14th line of page 3, replace "current" with "electric field"
I am corrected. 7. Attachment Catalog of Class 11 (1) One or more documents stating the amended scope of claims Claims (1) Polarizer and sensing that propagates light and changes the polarization state of light by surrounding medium An optical sensor comprising an element and an analyzer, characterized in that a polarizer and an analyzer are formed in a multilayer film in the sensing element, and the polarizer, analyzer, and sensing element are integrated. . (2) The optical sensor according to claim 1, wherein the sensing element is constituted by an optical Faraday element. (3) The optical sensor according to claim 1, characterized in that the sensing element is constituted by a Pockels element. (4) Claim, characterized in that the sensing element is constituted by a photoelastic effect element. The optical sensor according to item 1. (6) The optical sensor according to claim 1, wherein the sensing element is configured so that light propagating therein is reflected. (6) Polarizer and analyzer are optical sensors that transmit light through optical fibers. (7) Optical isolator created by applying a constant external magnetic field such that the rotation angle within the optical 7 Alladay element is 45@
The optical sensor according to item 2 of the range of ltM requirements.

Claims (7)

[Claims] (1) In an optical sensor consisting of a polarizer, a sensing element that propagates light and deflects the light by a surrounding medium, and an analyzer, the polarizer and analyzer are formed in the sensing element by a multilayer film, and the polarizer An optical sensor characterized by integrating photons and a sensing element. (2) The optical sensor according to claim 1, wherein the sensing element is constituted by an optical Faraday element. (3) The optical sensor according to claim 1, wherein the sensing element is constituted by a Pockels element. (4) The optical sensor according to claim 1, wherein the sensing element is constituted by a photoelastic effect element. (5) The optical sensor according to claim 1, wherein the sensing element is configured so that light propagating therein is reflected. (6) The optical sensor according to any one of claims 1 to 6, wherein the polarizer and the analyzer are arranged so as to emit cis light from the light source and the light receiver through an optical fiber. (7) The optical sensor according to claim 2, which is made into an optical isolator by applying a constant external magnetic field such that the rotation angle within the optical faraday element is 45 degrees.