JP2015225030A - Optical rotation characteristic measuring method of living body using polarization modulating interferometer system and optical rotation characteristic measuring device of living body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-invasive glucose measuring device of a living body that has not been put into a practical use so far.SOLUTION: A problem has been solved in such a manner that, in the system arranging a specimen material (sample) such as a living body in an optical fiber ring interferometer and measuring a phase difference between right and left circularly polarized light beams, a polarization control device is used in a ring optical path, and a polarized light state of signal light beams incident from both sides of the sample is switched to at least a pair of orthogonal polarized light beams in a constant period. A method of controlling the polarized light beams is adopted so that the polarized light beams incident from both sides of the sample are always orthogonal to each other. A positional relationship of the lenses for controlling a plane of polarization preserving optical fiber used for an opposing optical system that nips the sample is optimized, and a beam waist in the sample is set between 30 μm and 50 μm.

Description

  The present invention relates to a living body optical rotation characteristic measuring device and a living body optical rotation characteristic measuring method, and more specifically, it can measure the concentration of carbohydrates in a living body, and irradiates a finger, ear or skin of a living body with laser light. In addition, the present invention relates to a low-cost biological optical rotation characteristic measuring device and a biological optical rotation characteristic measurement method that can measure the glucose concentration of a specimen with high measurement accuracy without measuring the transmitted light and / or reflected light and collecting blood from the biological body. .

  The first method known as a method for measuring the glucose concentration in blood is to irradiate a part of a living body such as a finger with infrared laser light as described in Patent Document 1, and to scatter light from a blood vessel. And glucose in blood is measured. This utilizes the fact that scattered light is reduced in proportion to the glucose concentration. However, this method has a problem that the light intensity of scattered light depends on temperature, moisture of the skin, an oil component, etc., and is not widely used. As described in Non-Patent Document 1, Patent Document 2, and the like, the second method is to propagate a polarized component orthogonal to glucose and measure the birefringence in an open loop. However, this method has a large error when a sample having a blood glucose level of about 0.1 g / dL, which is a blood glucose level of a healthy person, is measured with a sample (glucose) having a length of about 10 mm. Moreover, it is impossible to measure the optical rotation of a living body having a thickness of about 1 mm. In particular, in a living body having a very large light scattering loss, the glucose concentration cannot be measured. The third method is a method of measuring with a birefringence measuring apparatus described in Patent Document 3. In this method, a nonreciprocal optical system is provided in the ring optical path of the interferometer, and the optical rotation characteristic of the specimen is measured inside the specimen. In this method, a glucose level of 0.1 g / dL, which is a healthy subject's blood glucose level, can be measured with sufficient accuracy with glucose having a cell length of about 1 mm, but an optical path difference of a beam propagating in both directions in a living body occurs. Because the output of the ring interferometer has a constant bias, the optical rotation of the living body to be measured could not be measured correctly.

  That is, a so-called non-invasive measuring apparatus that measures the glucose concentration of a living body without collecting blood from the living body has not been put into practical use.

JP 2004-31554 A JP 2007-093289 A JP 2005-274380 A

Masayuki Yokota et al., “Glucose Sensor Using Lead Glass Fiber Polarization Modulator”, 31st Lightwave Sensing Technology Research Group LST31-8, PP. 51-56, August 2003 Tsujioka, Oho, "Development of optical fiber gyroscope", 3rd Lightwave Sensing Technology Study Group, LST3-9, PP. 55-62, June 1989

  The problem to be solved by the present invention is to provide a biological optical rotation characteristic measuring device and a biological optical rotation characteristic measurement method that can measure the glucose concentration of a living body in a non-invasive manner with high measurement accuracy. is there.

A feature of the biological optical rotation characteristic measuring method and the biological optical rotation characteristic measuring device according to the present invention made to solve the problem is that a specimen such as a living body (hereinafter referred to as a sample) is placed in an optical fiber ring interferometer. In a system that measures the phase difference of left and right circularly polarized light transmitted through a sample with a ring interferometer, a polarization controller is used in a part of the ring optical path, and the polarization state of the signal light incident on the sample from both sides is constant. Employs a method of controlling the polarization state so that at least one pair of orthogonally polarized lights is obtained, and a polarization plane preserving optical fiber (hereinafter referred to as PMF) used for the opposed optical system sandwiching the sample and the position of the lens for controlling the beam diameter The problem was solved by optimizing the relationship and setting the beam waist in the sample to be between 30 μm and 50 μm.
Hereinafter, embodiments and invention examples of the present invention will be described in detail.

  The first invention (hereinafter referred to as invention 1) as an embodiment of the present invention made to solve the problem is to measure the optical rotation characteristic in the ring optical path of the optical fiber ring interferometer using the PMF. A specimen (hereinafter referred to as a sample) such as a living body, blood, or a saccharide solution is arranged, the light emitted from the light source is guided to the ring optical path, and is emitted toward the sample from the end face of the PMF facing the sample. An optical system that converts light into collimated light or condensed light directly or with a lens and makes it incident on the sample perpendicularly or at an angle is used, and at least one pair of orthogonally polarized light is incident on the sample from both directions of the sample. An optical rotation characteristic measuring device according to the present invention is characterized in that the optical rotation characteristic of the sample is measured by measuring a plurality of phase differences of bi-directional light propagating in the ring optical path.

  A second invention (hereinafter referred to as invention 2) as an embodiment of the invention developed by developing invention 1 is an optical rotation characteristic measuring apparatus according to invention 1, in which the emitted light from the PMF is a lens. In an optical system that converts the light into condensed light and makes it incident on the sample perpendicularly or at an angle, the end face of the PMF is set in a direction away from the focal position of the lens, and the distance between the lenses is inserted by a tool for gripping the sample It is an invention of an optical rotation characteristic measuring apparatus characterized in that the beam waist diameter (hereinafter also referred to as BW) of the signal light propagating through the sample is designed to be between 30 μm and 50 μm.

  A third invention (hereinafter referred to as invention 3) as an embodiment of the present invention developed by developing invention 1 or 2 is an optical rotation characteristic measuring apparatus according to invention 1 or 2, wherein the end portion of the PMF The optical rotation characteristic is characterized in that the core is expanded (hereinafter also referred to as TEC), and the TEC-processed end portion is formed by TEC processing of PMF having the same specifications as the main part of the optical path forming portion of the PMF. It is an invention of a measuring device.

  In a fourth invention (hereinafter referred to as invention 4) as an embodiment of the present invention made to solve the problem, a sample is placed in a ring optical path using PMF, and light emitted from a light source is emitted. System that guides light to the ring optical path, and converts the light emitted from the PMF from both directions of the sample toward the sample into collimated light or condensed light directly or with a lens, and enters the sample vertically or at an angle Is used to control a polarization control device or an optical device (hereinafter collectively referred to as a polarization control device) in which light incident from both directions of the sample is arranged on both sides of the sample, and at least one set in a predetermined cycle It is an invention of an optical rotation characteristic measuring apparatus characterized by measuring a phase difference of light propagating in both directions on the ring optical path so as to be polarized perpendicular to each other.

  A fifth invention (hereinafter referred to as invention 5) as an embodiment of the present invention developed by developing invention 4 is an optical rotation characteristic measuring apparatus according to invention 4, in which light is applied to the sample from both directions of the sample. An optical rotation characteristic measuring device according to the present invention is characterized in that the tip portion of the PMF to which the light enters is composed of a TEC-processed end surface.

  The sixth invention (hereinafter referred to as invention 6) as an embodiment of the present invention developed by developing invention 5 is the optical rotation characteristic measuring device according to invention 5, in which the vicinity of the end surface of the PMF subjected to TEC processing is It is an invention of an optical rotation characteristic measuring device comprising a TEC processed PMF having the same specifications as the main optical path forming portion of the PMF.

  A seventh invention (hereinafter referred to as invention 7) as an embodiment of the present invention developed by developing inventions 4 to 6 is an optical rotation including the polarization control device according to any one of inventions 4 to 6. In the characteristic measurement apparatus, the main part of the optical rotation characteristic measurement apparatus constitutes a part of the ring optical path of the ring light interference system with the sample and an optical system including a polarization controller facing the sample with the sample interposed therebetween, It is an invention of an optical rotation characteristic measuring apparatus characterized in that the optical rotation characteristic of the sample can be measured by measuring the phase difference of light propagating in both directions along the ring optical path.

  The eighth invention (hereinafter referred to as invention 8) as an embodiment of the present invention developed by developing invention 7 is the optical rotation characteristic measuring apparatus according to invention 7, wherein the light in the ring optical path of the ring optical interferometer is used. The fiber part propagates as the right-handed signal light and the left-handed signal light through the same optical fiber in the same polarization mode with the linearly polarized light as the clockwise signal light and the linearly polarized light as the left-handed signal light, respectively. A nonreciprocal polarization conversion optical system including Faraday rotation elements on both sides of the sample so that the clockwise signal light and the counterclockwise signal light are incident in polarization states orthogonal to each other and propagated as the clockwise signal light and the counterclockwise signal light, respectively. It is an invention of an optical rotation characteristic measuring device characterized by having.

  The ninth invention (hereinafter referred to as invention 9) as an embodiment of the present invention developed by developing inventions 4-8 is the optical rotation characteristic measuring device according to any one of inventions 4-8, The present invention is an optical rotation characteristic measuring device invention including a polarization control device characterized in that the polarization control device is an optical device that controls polarization by applying a voltage to a liquid crystal.

  The tenth invention (hereinafter referred to as invention 10) as an embodiment of the present invention developed by developing inventions 4 to 9 is the optical rotation characteristic measuring device according to any one of inventions 4 to 9, The polarization control device includes a polarization control device including a polarizer disposed on both sides of a sample and a half-wave plate having a rotation or attachment / detachment function.

  The eleventh invention (hereinafter referred to as invention 11) as an embodiment of the present invention developed by developing inventions 4 to 10 is the optical rotation characteristic measuring device according to any one of inventions 4 to 10, The optical rotation characteristic measuring apparatus guides laser light as signal light emitted from a light source to a second optical coupler via a first optical coupler or an optical circulator and a polarizer, and mainly by the second optical coupler. A ring optical path configured by connecting an opposing optical system including the polarization control device in the middle of the ring optical path made of PMF is branched as signal light propagating in both directions, and an optical phase is proximate to the second optical coupler in the ring optical path. A modulator is provided, and the signal light propagating in both directions on the ring optical path is received through the second optical coupler, the polarizer, the first optical coupler, or the optical circulator, and the light receiver and / or the signal processing. At least one set that is guided to a circuit, extracts a phase difference of signal light propagating in the ring optical path in both directions as a signal synchronized with the phase modulation signal, and enters the signal light from both sides of the sample via the polarization controller Measuring the phase difference when switched to orthogonal polarization, and estimating the sugar concentration of the sample with reference to the phase difference when switching to at least one set of orthogonal polarization when there is no sample. This is an invention of an optical rotation characteristic measuring device.

  A twelfth invention (hereinafter referred to as invention 12) as an embodiment of the present invention developed from invention 11 is the optical rotation characteristic measuring device according to invention 11, wherein the sample is a part of a living body. When the blood glucose level is known, the phase difference of the optical interferometer when a plurality of sets of orthogonal polarized light is incident on the sample from both sides is measured in advance, and the phase difference of the optical interferometer is measured based on the phase difference. From the above, it is an invention of an optical rotation characteristic measuring apparatus characterized in that a change in optical rotation of the sample is estimated.

  The thirteenth invention (hereinafter referred to as invention 13) as an embodiment of the present invention developed by developing inventions 4 to 12 is the optical rotation characteristic measuring apparatus according to any one of inventions 4 to 12, In the optical system in which the emitted light from each of the opposing PMFs is magnified and collimated by the first lens, converted into the condensed light by the second lens, and incident on the sample perpendicularly or at an angle. The optical rotation characteristic is characterized in that the distance between the lenses of the eye is a distance at which a forceps-like tool for holding the sample can be inserted, and the BW of the signal light propagating through the sample is between 30 μm and 50 μm It is an invention of a measuring device.

  14th invention (henceforth the invention 14) as embodiment of this invention made | formed by developing invention 4-13 WHEREIN: The optical rotation characteristic measuring apparatus of any one of invention 4-13 WHEREIN: When the sample is a part of a living body, the living body is grasped from a direction perpendicular to the beam propagation direction by a dielectric flat plate.

  A fifteenth invention (hereinafter referred to as invention 15) as an embodiment of the present invention developed by developing the invention 14 is the optical rotation characteristic measuring apparatus according to the invention 14, in which the sample gripping portion by the flat plate and the facing The optical rotation characteristic measuring apparatus is characterized in that an output optical system from the PMF is mechanically separated.

  A sixteenth invention (hereinafter referred to as invention 16) as an embodiment of the present invention made to solve the problem is a sample arranged in a ring optical path of an optical fiber ring interferometer made of PMF. In the method for measuring the optical rotatory characteristics, the optical rotatory characteristics measuring method converts the light emitted from the end faces of the PMF facing each other with the sample into the sample directly or with a lens into collimated light or condensed light. The sample is made incident perpendicularly or at an angle, and at least one set of orthogonally polarized lights from both directions of the sample is made incident on the sample, and a plurality of phase differences of both-direction light propagating in the ring optical path are measured to measure the phase difference of the sample. It is an invention of a method for measuring optical rotation characteristics, comprising a step of measuring optical rotation characteristics.

  The seventeenth invention (hereinafter referred to as invention 17) as an embodiment of the present invention developed by developing the invention 16 is the optical rotation characteristic measuring method according to the invention 16, wherein the light emitted from the PMF is converted into a lens. In an optical system that converts the light into condensed light and makes it incident on the sample perpendicularly or at an angle, the end face of the PMF is set in a direction away from the focal position of the lens, and the distance between the lenses is inserted by a tool for gripping the sample It is an invention of a method for measuring optical rotatory characteristics, characterized by comprising a step of setting the distance of the signal light so that the BW of the signal light propagating through the sample is between 30 μm and 50 μm.

  An eighteenth invention (hereinafter referred to as invention 18) as an embodiment of the present invention made to solve the problem is a light emitted from a light source by arranging a sample in a ring optical path using PMF. Optical rotation characteristics in which the light emitted from the PMF from both directions of the sample toward the sample is converted into collimated light or condensed light directly or with a lens, and is incident on the sample perpendicularly or at an angle In the measurement method, on the optical path of the light, the polarization control device in which light incident from both directions of the sample is arranged on both sides of the sample is controlled, and the polarized light is at least one set of orthogonally polarized light with a predetermined period. An optical rotation characteristic measuring method comprising a step of including a polarization controller characterized by measuring a phase difference of light propagating in both directions on the ring optical path. It is bright.

  A nineteenth invention (hereinafter referred to as invention 19) as an embodiment of the present invention developed by developing the invention 18 is the optical rotation characteristic measuring method according to the invention 18, in which the emitted light from the PMF is transmitted through a lens. In an optical system that converts the light into condensed light and makes it incident on the sample perpendicularly or at an angle, the end face of the PMF is set in a direction away from the focal position of the lens, and the distance between the lenses is inserted by a tool for gripping the sample It is an invention of a method for measuring optical rotatory characteristics, characterized by comprising a step of setting the distance of the signal light so that the BW of the signal light propagating through the sample is between 30 μm and 50 μm.

  A twentieth invention (hereinafter referred to as invention 20) as an embodiment of the present invention developed by developing the invention 18 or 19 is the optical rotation characteristic measuring method according to the invention 18 or 19, wherein the end portion of the PMF Is an invention of an optical rotation characteristic measuring method characterized by comprising a step of using a TEC-processed optical fiber.

  The twenty-first invention (hereinafter referred to as invention 21) as an embodiment of the present invention developed by developing the inventions 18 to 20 is the optical rotation characteristic measuring method according to any one of the inventions 18 to 20, The optical fiber part of the ring optical path of the ring optical interferometer is a right-handed signal light and a left-handed signal light through the same optical fiber in the same polarization mode where the linearly polarized light as the clockwise signal light and the linearly polarized light as the counterclockwise signal light are the same. A non-reciprocal polarization conversion optical system including Faraday rotation elements on both sides of the sample so that the sample part is incident on the sample part in a polarization state orthogonal to each other and propagates as a clockwise signal light and a counterclockwise signal light, respectively. It is invention of the optical rotation characteristic measuring method containing the polarization control apparatus characterized by having a process.

  The twenty-second invention (hereinafter referred to as invention 22) as an embodiment of the present invention developed by developing inventions 18 to 21 is the optical rotation characteristic measuring method according to any one of inventions 18 to 21, It is an invention of a method for measuring optical rotation characteristics, comprising a step of using a polarization control device including an optical device that controls the polarization by applying a voltage to a liquid crystal.

  A twenty-third invention (hereinafter referred to as invention 23) as an embodiment of the present invention developed by developing invention 22 is a polarizer disposed on both sides of a sample in the optical rotation characteristic measuring method according to invention 22. And a step of using a polarization control device comprising a half-wave plate having a rotation or detachment function.

  The twenty-fourth invention (hereinafter referred to as invention 24) as an embodiment of the present invention developed by developing inventions 18-23 is the optical rotation characteristic measuring method according to any one of inventions 18-23, In the optical rotation characteristic measuring method, laser light as signal light emitted from a light source is guided to a second optical coupler via a first optical coupler or an optical circulator and a polarizer, and mainly by the second optical coupler. A ring optical path configured by connecting an opposing optical system including the polarization control device in the middle of the ring optical path made of PMF is branched as signal light propagating in both directions, and an optical phase is proximate to the second optical coupler in the ring optical path. A modulator is provided, and the signal light propagating in both directions on the ring optical path is received through the second light coupler, the polarizer, the first optical coupler or the optical circulator, and / or a light receiver. A signal processing circuit, extracting the phase difference of the signal light propagating in the ring optical path in both directions as a signal synchronized with the phase modulation signal, and entering the signal light from both sides of the sample via the polarization controller; Measuring a phase difference when switching to a pair of orthogonal polarizations, and estimating a sugar concentration of the sample with reference to a phase difference when switching to at least one set of orthogonal polarizations when there is no sample It is invention of the optical rotation characteristic measuring method characterized by having.

  A twenty-fifth invention (hereinafter referred to as invention 25) as an embodiment of the present invention developed by developing the invention 24 is the optical rotation characteristic measuring method according to the invention 24, wherein the sample is a part of a living body. When the blood glucose level is known, the phase difference of the optical interferometer when a plurality of sets of orthogonal polarized light is incident on the sample from both sides is measured in advance, and the phase difference of the optical interferometer is measured based on the phase difference. The method of measuring the optical rotation characteristic, comprising the step of estimating the change in optical rotation of the sample from the above.

  The twenty-sixth invention (hereinafter referred to as invention 26) as an embodiment of the present invention developed by developing the inventions 18 to 25 is the optical rotation characteristic measuring method according to any one of the inventions 18 to 25, In the optical system in which the emitted light from each of the opposing PMFs is magnified and collimated by the first lens, converted into the condensed light by the second lens, and incident on the sample perpendicularly or at an angle. And a step of designing the distance between the lenses of the eye so that a forceps-like tool for gripping the sample can be inserted and the BW of the signal light propagating through the sample is between 30 μm and 50 μm. It is invention of the optical rotation characteristic measuring method to do.

  A twenty-seventh invention (referred to as invention 27) as an embodiment of the present invention developed by developing inventions 18 through 26 is the optical rotation characteristic measuring method according to any one of inventions 18 through 26, wherein the sample Is a part of a living body, the invention comprises a method of measuring an optical rotation characteristic, comprising the step of grasping a living body from a direction perpendicular to the beam propagation direction with a dielectric flat plate.

  Since the living body optical rotation characteristic measuring method and the living body optical rotation characteristic measuring apparatus of the present invention can measure the biological glucose concentration related to the blood glucose level without blood collection, first, there is no trouble and pain associated with blood collection with a needle. Secondly, the disposal of the blood collection needle is unnecessary and hygienic, and thirdly, the reagent that reacts with glucose used at the time of blood collection is unnecessary, so that the running cost of 100,000 yen or more per year is unnecessary. Fourth, it can be easily measured, and blood glucose level can be monitored any number of times a day. It can be used for the health management of diabetics, their reserves, and healthy people. To demonstrate. If the biological optical rotation characteristic measuring apparatus and biological optical rotation characteristic measurement method of the present invention are used in general households, the number of diabetic patients that are increasing worldwide can be reduced, and the cost required for the treatment is reduced. Can be greatly reduced.

1 is a basic configuration diagram of an optical rotation characteristic measuring device for a living body as an embodiment of the present invention. FIG. It is a detailed block diagram of the nonreciprocal polarization conversion optical system as an Example of this invention. It is another detailed block diagram of the nonreciprocal polarization conversion optical system as an Example of this invention. It is a conceptual diagram of the polarization | polarized-light propagation condition of a biological body. 1 is a basic configuration diagram of a biological optical rotation characteristic measuring device using a polarization control device and a spatial optical system. FIG. It is a basic block diagram of the biological optical rotation characteristic measuring apparatus using an optical fiber type polarization control apparatus. It is a block diagram of a living body reflection type optical rotation characteristic measuring apparatus using an optical fiber type optical rotation characteristic measurement apparatus.

  Examples of embodiments of the present invention will be described below with reference to the drawings. The drawings used for the description schematically show the dimensions, shapes, arrangement relationships, and the like of the constituent components to such an extent that the embodiments of the present invention can be understood. For convenience of explanation of the present invention, there may be cases where the enlargement ratio is partially changed, and the drawings used to describe the embodiments of the present invention are not necessarily similar to the actual objects and descriptions of the embodiments. There is also. Moreover, in each figure, about the same component, it attaches and shows the same number, The overlapping description may be abbreviate | omitted. Further, in the description of the present invention, the description of the optical rotation characteristic measuring device for the optical rotatory substance may also serve as the description of the optical rotation characteristic measuring method, and vice versa.

  FIG. 1 is a basic configuration diagram of an optical rotation characteristic measuring apparatus such as a living body as an embodiment of the present invention. Laser light emitted from a broadband light source 1 such as an SLD propagates through an optical fiber type polarizer 3 via a first optical fiber directional coupler, that is, a 2 × 2 optical coupler 2-1, and a second 2 × 2 optical coupler. Light that propagates in the clockwise direction from the direction of the optical fiber 4-1 to the direction of the optical fiber 4-2 (also referred to as clockwise light) and the direction of the optical fiber 4-2 from the direction of the optical fiber 4-2 by the optical fiber 4-2. It is branched into light propagating counterclockwise in the direction of 1 (also referred to as counterclockwise light). Here, the wavelength of the light source is in the 1300 nm band. The optical fiber is a 1300 nm band PMF, and the optical couplers are all composed of a 1300 nm band PMF. The first directional coupler 2-1 may be replaced with an optical circulator. However, when using an optical circulator, it is preferable to use a two-stage type with excellent isolation.

  The light propagating in the clockwise direction propagates through a PMF 4-1 having a length of 400 m, and a holding plate 9-made up of a lens optical system 7-1, a polarizer 6-1, a polarization conversion optical system 8-1, and a sapphire disk. 1 is incident on the sample 10. Similarly, the light propagating in the counterclockwise direction is modulated by the optical phase modulator 11 placed in the vicinity of the optical coupler of the PMF 4-2, and the PMF 4-2, the lens optical system 7-2, and the polarizer 6-2. Then, the light is incident on the sample 10 through the polarization conversion optical system 8-2 and a pressing plate 9-2 made of a sapphire disk for pressing the sample. Here, the sample holding plates 9-1 and 9-2 are formed of a sapphire plate having a thickness of 0.2 to 0.3 mm whose surface is AR-coated or a glass plate instead of sapphire.

  The polarization conversion optical systems 8-1 and 8-2 are optical systems that generate left and right circularly polarized light from linearly polarized light, respectively, and their configurations are shown in FIGS. 2 and 3, respectively. That is, the polarization conversion optical systems 8-1 and 8-2 are composed of 45-degree Faraday rotators 17-1 and 17-2 and quarter-wave plates 18-1 and 18-2, and linearly polarized light is incident thereon. In this case, it has a function of generating left and right circularly polarized light. In the figure, reference numerals 16-1 and 16-2 denote propagation light as signal light.

  Thus, the signal light propagated in both the clockwise and counterclockwise directions on the ring optical path propagates in both directions, and then passes through the second optical coupler 2-2, the polarizer 3, and the first optical coupler 2-1. Propagated, propagated from the first optical coupler 2-1 to the light receiver 12, converted into an electrical signal by the light receiver 12, and input to the signal processing circuit 13. A sine wave signal 14 is sent from the signal processing circuit 13 to the phase modulator 11 as a phase modulation signal of 20 KHz. In the signal processing circuit 13, when the phase difference of light propagating in the left and right directions on the ring optical path is θ, the 20 KHz component is detected as sin θ and the 40 KHz component is detected as a component proportional to cos θ. Taking these ratios, the arc tan θ is calculated by a microcomputer included in the signal processing device 13. Details are described in Non-Patent Document 2.

  Here, the principle and experimental results for measuring the optical rotation characteristics of a sample with the configuration of FIG. 1 actually implemented as an embodiment will be described. The part of the living body used in the experiment is the base of the thumb and the index finger, and the thickness of the living body is about 1.0 mm.

  In the above experiment, when the living body was the base of the finger and the thickness of the living body was 1 mm, the optical power returned to the light receiver 12 was found to be −27 dBm (2 μW). Since the output of SLD1 is +13 dBm, the loss of the ring interferometer is 5 dB, and the light transmission loss of the living body is 35 dB, this is a reasonable value.

  Next, it was confirmed that the phase measurement sensitivity of the 1300 nm ring optical interferometer used is 0.0001 degrees or less. This was confirmed by reversing the fiber coil used in the ring upside down and measuring twice the rotational angular velocity of the earth.

  In FIG. 1, the working distance of the lens system is 20 mm. The thickness of the living body was measured with a holding plate with a micrometer. In this state, a so-called glucose tolerance test was performed in which glucose was ingested while monitoring the output of the ring interferometer. A sugar solution in which 50 g of glucose was dissolved in 100 g of pure water was ingested, and the blood glucose level measured with a conventional blood glucose meter increased by 100 mg / dl after 40 minutes. The inventor monitored the output of the polarimeter for 40 minutes.

  Originally, there should have been a phase change of approximately 0.0002 degrees, but the actual measured values varied by 0.001 degrees or more and could not be measured correctly. Usually, the phase change is 0.0005 degrees when the glucose is 100 mg / dL and the cell length is 1 mm. Here, assuming that the polarization preserving distance is 0.4 mm, the phase change is considered to be 0.0002 degrees.

  In general, when linearly polarized light is incident on an optical rotatory material and the optical rotation angle per unit length of the polarization plane is Φ, the phase difference between the left and right circularly polarized light of the propagating light when the left and right circularly polarized light is incident on the sample Is known to be polarization optics. However, when a sample is placed in a loop of a ring interferometer and left and right circularly polarized light is propagated in both directions, the phase difference measured by the ring interferometer becomes Φ instead of 2Φ. Here, when the thickness of the living body (sample length) is 1 mm and +52 degrees is applied as the specific rotation of glucose, when the glucose concentration changes by 100 mg / dl, the corresponding change in the rotation angle becomes about 0.0005 degrees. .

  As described above, in the measurement system of FIG. 1, the relative optical rotation of the living body can be measured in principle, but in practice, the phase fluctuation significantly exceeding the phase difference to be originally obtained was measured. The inventor considered this cause as follows. The first cause is that when a living body is gripped by a pressing plate, the gripping state changes during a long-time measurement, and a subtle phase difference is generated in both left and right light. Second, a phase bias inherent to a ring interferometer including a living body is generated during a long-time measurement.

  An object of the present invention is to measure the phase difference of laser light propagating through a living body in both directions and quantitatively measure the optical rotation due to a sugar component contained in the living body. However, the phase difference of the laser light propagating in both directions through the living body is affected not only by the polarization state propagating in both directions in the biological sample but also by the state of holding the living body with the holding plate. Here, the phase difference generated in the optical rotation measuring apparatus of the present invention will be considered quantitatively. FIG. 4 shows a conceptual diagram of the polarization propagation state of the living body. When the sample is a part of the living body, the incident light is scattered by the cells and tissues constituting the living body, and the polarized component is depolarized while propagating through the living body by multiple reflection. That is, the incident circularly polarized light is partially converted to non-polarized light after propagating a certain distance. In the figure, reference numerals 16-3 and 16-4 indicate propagating light.

Here, the distances LR, LL, LL ′, LR ′ are defined as follows.
LR: Distance where polarized light is preserved when right circularly polarized light is incident from the left direction of the sample (reference numeral 24-1)
LL: Distance at which polarized light is preserved when left circularly polarized light is incident from the right direction of the sample (reference numeral 24-2)
LL ′: Distance where polarized light is preserved when left circularly polarized light is incident from the left direction of the sample (reference numeral 24-1)
LR ': Distance where polarized light is preserved when right circularly polarized light is incident from the right direction of the sample (reference numeral 24-2)
Here, reference numerals 23-1 and 23-2 represent distances at which light propagates with random polarization.

但し試料の長さをＬとする。またここでは、ある距離ＬR，ＬLを偏光度が１で伝搬し、その後は偏光度がゼロで伝搬するステップ状の円偏光度モデルを仮定する。
αは試料の固定方法によって生じる位相差で試料内の両方向伝搬光の光路差によって発生する位相差である。 Next, let NL and NR be the equivalent refractive indices of the sample for left and right circularly polarized light, respectively. The equivalent refractive index of the sample with respect to random polarization is N0.
When defined in this way, the phase difference θ1 of the light propagating through the sample in the right direction and the left direction when the right circularly polarized light from the left and the left circularly polarized light is incident from the right is expressed by Equation (1).

However, the length of the sample is L. Here, a step-like circular polarization degree model is assumed in which a certain degree of polarization LR, LL propagates with a degree of polarization of 1 and thereafter propagates with a degree of polarization of zero.
α is a phase difference caused by the method of fixing the sample, and is a phase difference generated by the optical path difference of the bi-directionally propagated light in the sample.

Similarly, the phase difference θ2 of the light propagating through the sample in the right direction and the left direction when the left circularly polarized light is incident from the left and the right circularly polarized light is incident from the right is expressed by Equation (2).

Therefore, θ1-θ2 is expressed as Θ in the equation (3).

（４）式は試料の旋光性に基づく試料を両方向に伝搬する光の位相差である。 Here, for the sake of simplicity, LR and LL ′, which are polarization preservation distances for the left and right circularly polarized light at the left end of the sample, are equal, and LL and LR ′, which are polarization preservation distances for the left and right circularly polarized light, at the right end of the sample are measured. Assuming that they are equal, equation (3) becomes equation (4).

Equation (4) is a phase difference of light propagating through the sample in both directions based on the optical rotation of the sample.

（５）式の第１項は生体の旋光度による位相差である。ＬRとＬLはほぼ等しいと考えられるので生体に入射する偏光を切り替えないときの大凡２倍である。またβは試料の両端部にある非相反光学系（ファラデー回転素子および４分の１波長板）を左から右円偏光、右から左円偏光が伝搬するときのリング干渉計の位相差と左から左円偏光、右から右円偏光が伝搬するときのリング干渉計の位相差を差し引いた場合の位相差である。すなわちβはリング干渉計に生体などの試料がない場合の両方向に直交する円偏光を伝搬させた場合の非相反光学系の位相差である。したがって試料を挟む前にβを求めておき、試料を挿入したときの（５）式からβを差し引くことで生体の旋光度を求めることができる。 Considering ΘT, which is the phase difference of light propagating in both directions through the entire loop of the ring interferometer, equation (5) is obtained.

The first term of the equation (5) is a phase difference due to the optical rotation of the living body. Since LR and LL are considered to be substantially equal, they are approximately twice that when the polarized light incident on the living body is not switched. Β is the phase difference of the ring interferometer and the left when the circularly polarized light propagates from the left to the right circularly polarized light and from the right to the left circularly polarized light in the nonreciprocal optical system (Faraday rotator and quarter wave plate) at both ends of the sample. The phase difference is obtained by subtracting the phase difference of the ring interferometer when the left circularly polarized light propagates from the right and the right circularly polarized light propagates from the right. That is, β is a phase difference of the nonreciprocal optical system when circularly polarized light orthogonal to both directions is propagated when there is no sample such as a living body in the ring interferometer. Therefore, β can be obtained before the sample is sandwiched, and the optical rotation of the living body can be obtained by subtracting β from the equation (5) when the sample is inserted.

  In actual measurement, when the polarization state incident on the sample is changed with the period t, the output of the ring interferometer also changes with the period t. The amplitude of the change is equation (5).

  In the above measurement, it is considered that α does not change during the measurement even if the polarized light incident on the sample is switched.

FIG. 5 shows a specific method for canceling the phase difference α generated by the optical path difference between the two-way propagating light in the sample generated by the sample fixing method as described above.
FIG. 5 is a basic configuration diagram of a biological optical rotation characteristic measuring device using a polarization control device and a spatial optical system.
The feature of FIG. 5 is that a bulk-type polarization control unit 26 including a polarizer 6-5 and a half-wave plate 20 is provided between the sensor optical unit 5 and the optical interferometer core unit 25. The bulk-type polarization control unit 26 and the sensor optical unit 5 are coupled by a spatial optical system by total reflection mirrors 19-1 and 19-2.

  Next, the function of FIG. 5 will be described. The output polarization direction of the PMF of the interferometer core unit 25 and the direction of the polarizing plate 6-3 are made to coincide with each other, and the half-wave plate 20 is rotated to change the polarization state of the propagating light 16-5 and 16-6. . Here, the Faraday elements of the nonreciprocal polarization conversion optical systems 8-1 and 8-2 rotate the magnetic field so that the light propagating from both directions is rotated by 45 degrees (16-5 is clockwise and 16-6 is counterclockwise). Therefore, polarized light incident on the sample 10 from both sides is always orthogonal.

  Here, a case is considered in which the azimuth of the half-wave plate 20 is changed to two types of azimuth of 0 (which does not rotate the polarization) and 45-degree azimuth by the half-wave plate control signal 21. If the propagating light 16-5 and 16-6 incident on the sample 10 when the azimuth of the half-wave plate 20 is 0 degrees are right circularly polarized light and left circularly polarized light, respectively, When the azimuth is 45 degrees, 16-5 and 16-6 are switched to left circular polarization and right circular polarization, respectively.

  Thus, by switching the direction of the half-wave plate 20 in two stages, the polarization state incident on the sample can be switched to left and right circularly polarized light. Taking the difference of the output of the ring interferometer in each case, the output corresponding to the above equation (5) can be measured.

  When there is no sample, the optical polarization of only the sample can be measured by switching the same polarization state in two stages and calculating the change in the output of the ring interferometer (β in equation (5)).

  What is important here is that, firstly, since the time for switching between the two polarization states is short, the time characteristic of the phase bias inherent to the optical interferometer is negligible. Second, the influence of the phase bias due to the gripping state (α in equation (2)) can be canceled. Third, since the difference between the positive optical rotation and the negative optical rotation of the sample can be measured, the measurement sensitivity is doubled.

  In general, in an all-fiber optical ring interferometer, both-way light is confined in the optical fiber, and therefore propagates through the same path, so that there is no phase difference between the left-and-right both-way light. However, in the system of FIG. 5, there is a spatial optical system including a sample in the loop of the ring optical path. Depending on the gripping state of the sample, there is a possibility that a path difference may occur in both the left and right light and a phase difference of 0.001 degree or more may occur. However, the phase error based on the change in the gripping state of the sample can be canceled by changing the two types of polarized light incident on the sample and taking the difference in the measured phase difference as described above. In actual measurement, the substantial phase change was about 0.0002 degrees when the polarized light incident on the sample from both directions was switched to the left and right circularly polarized light. This indicates that the polarization preservation distance is about 0.2 mm.

  This measurement is performed by a glucose tolerance test, and a reference table of the relationship between the value of the conventional blood collection type blood glucose meter and the value measured as equation (4) is created in advance, and the sample is incident on the sample in the measurement system of FIG. The blood glucose level can be estimated from the output phase information of the ring interferometer by switching the left and right circularly polarized light.

  FIG. 6 is a basic configuration diagram of a biological optical rotation characteristic measuring apparatus using an optical fiber type polarization controller. The difference from FIG. 5 is that optical fiber polarization controllers 27-1 and 27-2 are used instead of the half-wave plate 20. Further, optical fiber polarizers 6-4a and 6-4b are used in place of the polarizing plate 6-3. In this way, the optical system other than the sensor optical unit 5 becomes an all-fiber type. As the optical fiber type polarization controllers 27-1, 27-2, for example, All-Fiber Polarization Switch sold by Phoenix Photonics, UK can be used. The device consists of a liquid crystal that switches incident polarization to orthogonal polarization with a voltage between opposing PMFs. Reference numerals 4-3 and 4-4 denote PMFs forming the respective optical paths. Reference numerals 22, 22-1, 22-2 indicate control signals of the optical fiber type polarization controller.

  FIG. 7 is a block diagram of a living body reflection type optical rotation characteristic measuring apparatus using an optical fiber type polarization controller. In FIG. 7, the pressing plates 9-1 and 9-2 used in FIG. 1 are not used. In FIG. 7, the signal light propagated clockwise through the PMF 4-1 in the ring optical path is refracted toward the sample 10 by the prism 15, and obliquely enters the sample 10 at a predetermined angle via the sample holding plate 9-3. Is done. On the other hand, the signal light propagated counterclockwise through the PMF 4-2 in the ring optical path is refracted toward the sample 10 by the prism 15 and is obliquely incident on the sample 10 at a predetermined angle via the sample holding plate 9-3. The These two lights are reflected by the skin part of the living body, the signal light propagating clockwise is coupled to PMF4-2, and the signal light propagating counterclockwise is coupled to PMF4-1.

  The prism 15 in FIG. 7 is slidable up and down or left and right, and adjusted so that the light beams 16-7 and 16-8 can be directly coupled when the prism 15 is not provided. Reference numerals 7-3 and 7-4 denote lens optical systems, and 8-3 and 8-4 denote nonreciprocal polarization conversion optical systems.

  There are two merits of this method. The first merit is that the sensor optical system is simplified because the sample arrangement portion of the apparatus is not a structure for sandwiching the sample but a structure for placing the sample. The second merit is that the distance that the signal light beam propagates through the living body can be set.

  In the above embodiment, the phase difference due to the rotation of the living body is obtained by changing two kinds of polarization states. However, as a modification of the embodiment, a method of calculating the rotation of the living body by expressing the living body by Mueller determinant Is also promising. In this case, the direction of the half-wave plate 20 in FIG. 5 is changed in 22.5 degree steps, for example, and the polarization states of the beams 16-5 and 16-6 are switched to three or more stages, and various polarization states are applied to the sample Is incident.

  In this way, the 16 elements of the Mueller matrix can be determined by making various polarized light beams orthogonal to each other from both sides of the living body and measuring the phase difference of the output of the optical interferometer in that case.

  In order to measure the optical rotation of a living body using the measurement system shown in FIGS. 5 and 6, the following conditions are required. The first is a reduction in light transmission loss of the living body. Secondly, a sufficient interval is required between the lenses of the sensor optical unit 5 so that the sample can be gripped. As a method for realizing these simultaneously, the working distance of the lens was increased to some extent so that the beam waist was in the middle of the sample, and the beam waist (BW) was optimized.

  As a result of repeating the experiment by changing BW to 10, 20, and 33 μm, it was very subtle and unstable to bond the opposing PMF when BW was 10 μm and 20 μm. At 30 μm, the living body thickness was 1 mm, and 30 to 35 dB could be achieved. Furthermore, as a result of repeating the experiment while changing BW to 50 μm and 100 μm, when the thickness exceeded 50 μm, the biopermeation loss increased. It has been experimentally found that if BW is too large, it is affected by the scattering of the living body.

  From the above experimental results, it is preferable that the BW of the beam of the sensor optical unit in measuring the optical rotation of the living body is between 30 μm and 50 μm.

  As a result of repeating the experiment of efficiently transmitting light to a light scattering medium such as a living body, that is, the present inventor, as a result of expanding the core of the tip portion of the PMF facing the sample with the sample interposed therebetween, the present inventor is a so-called TEC ) I experimentally grasped that the processing is powerful. However, this method cannot optimize the working distance and BW. In the case of adopting the TEC system, it was found that the BW can be optimized by increasing the working distance with the second lens system and the second lens system.

  The optical rotation of the interstitial fluid could be measured with a ring interferometer using the optical rotation measurement device described above.

  The present invention has been described above with some examples, but the present invention is not limited to this, and many variations can be made in accordance with the above technical idea of the present invention. .

  As described above, according to the present invention, it is possible to measure a noninvasive blood sugar level that has not been realized so far. As a result, diabetics are freed from the pain and annoyance of blood sampling several times a day. In addition, by utilizing the blood glucose level measuring instrument derived from the present invention in a preventive and conservative manner, it is possible to reduce the number of diabetic patients that are currently increasing worldwide, and to significantly reduce the cost required for the treatment. it can.

  The present invention can provide a non-invasive blood sugar level measuring device and can be widely used as a medical device or a health device. The present invention can greatly contribute to the development of the health device field, the medical device field including nursing care. Is.

1: Light source (SLD, ASE)
2-1, 2-2: 2 × 2 directional coupler or circulator 3: Fiber-type polarizer 4-1, 4-2: PMF
5: Sensor optical part 6-1, 6-2, 6-3, 6-4a, 6-4b, 6-5a, 6-5b: Polarizing plates 7-1, 7-2, 7-3, 7-4 : Lens optical system 8-1, 8-2, 8-3, 8-4: Nonreciprocal polarization conversion optical system 9-1, 9-2, 9-3: Sample holding plate 10: Sample 11: Optical phase modulator 12: light receiving element 13: signal processing circuit 14: phase modulation signal 15: prism 16-1, 16-2, 16-3, 16-4, 16-5, 16-6, 16-7, 16-8: light 17-1, 17-2, 17-3, 17-4: Faraday element 18-1, 18-2: 1/4 wavelength plate 19-1, 19-2: Total reflection mirror 20: 1/2 wavelength Plate 21: Half-wave plate rotation or attachment / detachment control signal 22, 22-1, 22-2, 22-3, 22-4: Optical fiber type polarization switch control signal 23-1 23-2: Propagation distance with random polarization 24-1, 24-2: Distance where polarization is preserved 25: Optical interferometer core unit 26: Bulk polarization control optical system 27-1, 27-2, 26-3 , 26-4: Optical fiber type polarization controller

Claims (27)

  A living body (hereinafter referred to as a sample) whose optical rotation characteristics are to be measured is placed in the ring optical path of an optical fiber ring interferometer using a polarization plane preserving optical fiber (hereinafter referred to as PMF), and the light emitted from the light source is transmitted into the ring optical path. Optical system that directs light emitted from the end face of the PMF facing the sample across the sample toward the sample to be collimated or condensed light directly or with a lens, and makes the sample enter the sample perpendicularly or at an angle To measure at least one set of orthogonally polarized light from both directions of the sample and to measure the optical rotation characteristics of the sample by measuring a plurality of phase differences of the two-way signal light propagating in the ring optical path. Characteristic optical rotation characteristic measuring device.   2. The optical rotation characteristic measuring apparatus according to claim 1, wherein the light emitted from the PMF is converted into condensed light by a lens and incident on the sample at an angle or at an angle. It is set in a direction away from the focal position, and the distance between the lenses is a distance that can be inserted by the tool for gripping the sample, and the beam waist (diameter, hereinafter referred to as BW) of the signal light propagating through the sample is between 30 μm and 50 μm. An optical rotation characteristic measuring device characterized by being designed as follows.   3. The optical rotation characteristic measuring apparatus according to claim 1, wherein an end portion of the PMF is subjected to core enlargement (hereinafter referred to as TEC) processing, and the end portion subjected to the TEC processing is a main portion of an optical path forming portion of the PMF. An optical rotatory characteristic measuring device comprising TEC processed PMF of the same specification.   A living body (hereinafter referred to as a sample) whose optical rotation characteristics are to be measured is placed in a ring optical path using a polarization-maintaining optical fiber (hereinafter referred to as PMF), and light emitted from a light source is guided to the ring optical path. From both directions of the sample by using an optical system in which the light emitted from the PMF toward the sample from both directions is converted into collimated light or condensed light directly or with a lens and is incident on the sample vertically or at an angle. By controlling a polarization control device or an optical device (hereinafter collectively referred to as a polarization control device) in which incident light is disposed on both sides of the sample, at least one set of orthogonal polarizations is obtained at a predetermined period. An optical rotation characteristic measuring apparatus for measuring a phase difference of signal light propagating in both directions on the ring optical path.   5. The optical rotation characteristic measuring apparatus according to claim 4, wherein a tip end portion of the PMF for allowing light to enter the sample from both directions of the sample is composed of an end surface processed with a core enlarged (hereinafter referred to as TEC). Characteristic measuring device.   6. The optical rotation characteristic measuring apparatus according to claim 5, wherein the TEC-processed end face vicinity of the PMF is made of TEC-processed PMF having the same specifications as the main optical path forming portion of the PMF.   The optical rotation characteristic measuring device including the polarization control device according to any one of claims 4 to 6, wherein a main part of the optical rotation characteristic measurement device includes an optical device including a polarization control device facing the sample with the sample interposed therebetween. A part of the ring optical path of the ring optical interference system, and the optical rotation characteristic of the sample can be measured by measuring the phase difference of the signal light propagating in both directions on the ring optical path. Optical rotation characteristic measuring device.   8. The optical rotation characteristic measuring apparatus according to claim 7, wherein the optical fiber portion of the ring optical path of the ring optical interferometer has the same light in the same polarization mode in which linearly polarized light as clockwise signal light and linearly polarized light as counterclockwise signal light are the same. Propagating through the fiber as clockwise signal light and counterclockwise signal light, respectively, and entering the sample portion with clockwise signal light and counterclockwise signal light in polarization states orthogonal to each other, respectively, as clockwise signal light and counterclockwise signal light, respectively. An optical rotation characteristic measuring apparatus having a nonreciprocal polarization conversion optical system including Faraday rotation elements on both sides of the sample so as to propagate.   The optical rotation characteristic measuring apparatus according to any one of claims 4 to 8, including the polarization control apparatus, wherein the polarization control apparatus is an optical device that controls the polarization by applying a voltage to the liquid crystal. Optical rotation characteristic measuring device characterized by.   10. The polarization control device according to claim 4, wherein the polarization control device includes a polarizer disposed on both sides of the sample and a half-wave plate having a rotation or attachment / detachment function. An optical rotation measuring device comprising the device.   The optical rotation characteristic measuring device according to any one of claims 4 to 10, wherein the optical rotation characteristic measuring device converts a laser beam as signal light emitted from a light source into a first optical coupler or an optical circulator and a polarizer. To the second optical coupler, and a signal propagating in both directions through the ring optical path formed by connecting the opposing optical system including the polarization control device in the middle of the ring optical path mainly made of PMF by the second optical coupler. An optical phase modulator is provided in the vicinity of the second optical coupler in the ring optical path. The signal light propagating in both directions through the ring optical path is transmitted to the second optical coupler, the polarizer, and the first optical coupler. The signal is guided to a light receiver and / or a signal processing circuit via an optical coupler or an optical circulator, and a phase difference of the signal light propagating in both directions on the ring optical path is synchronized with the phase modulation signal. Extracting and measuring the phase difference when the signal light is switched to at least one set of orthogonal polarized light incident from both sides of the sample via the polarization controller, and at least one set of orthogonal when there is no sample An optical rotation characteristic measuring apparatus characterized in that the sugar concentration of the sample is estimated on the basis of a phase difference when switched to polarized light.   12. The optical rotation characteristic measuring apparatus according to claim 11, wherein when the sample is a part of a living body and a blood glucose level is known, a plurality of sets of orthogonal polarized light are incident on the sample from both sides. An optical rotation characteristic measurement apparatus characterized in that a phase difference is measured in advance, and a change in optical rotation of the sample is estimated from a measurement phase difference of an optical interferometer with the phase difference as a reference.   The optical rotation characteristic measuring apparatus according to any one of claims 4 to 12, wherein the emitted light from each of the opposing PMFs is enlarged and collimated by a first lens, and converted into condensed light by a second lens. Then, in the optical system that makes the sample enter the sample vertically or at an angle, the distance between the second lens is the distance at which a forceps-like tool that holds the sample can be inserted, and the beam of signal light that propagates through the sample An optical rotation characteristic measuring apparatus designed to have a waist (diameter, hereinafter referred to as BW) between 30 μm and 50 μm.   The optical rotation characteristic measuring apparatus according to any one of claims 4 to 13, wherein when the sample is a part of a living body, the living body is held by a dielectric flat plate from a direction perpendicular to the beam propagation direction. An optical rotation characteristic measuring device characterized by that.   15. The optical rotation characteristic measuring apparatus according to claim 14, wherein a sample gripping part by the flat plate and an emission optical system from the opposing PMF are mechanically separated.   Place a specimen (hereinafter referred to as a sample) such as a living body or blood or a sugar solution whose optical rotation characteristics are to be measured in the ring optical path of an optical fiber ring interferometer made of a polarization-maintaining optical fiber (hereinafter referred to as PMF). In the method for measuring the optical rotatory characteristics, the optical rotatory characteristics measuring method converts the light emitted from the end faces of the PMF facing each other with the sample into the sample directly or with a lens into collimated light or condensed light. The sample is incident perpendicularly or at an angle, and at least one set of orthogonally polarized light is incident on the sample from both directions of the sample, and a plurality of phase differences of both-direction signal light propagating through the ring optical path are measured. And a method for measuring the optical rotation characteristic of the optical rotation characteristic.   17. The optical rotation characteristic measuring method according to claim 16, wherein the light emitted from the PMF is converted into condensed light by a lens and incident on the sample at a vertical angle or at an angle. It is set in a direction away from the focal position, the distance between the lenses is a distance that allows the tool for gripping the sample to be inserted, and the beam waist (diameter, hereinafter referred to as BW) of the signal light propagating through the sample is between 30 μm and 50 μm. An optical rotation characteristic measuring method comprising the step of:   Light emitted from a light source by placing a living body or a specimen such as blood or a sugar solution (hereinafter referred to as a sample) whose optical rotation characteristics are to be measured in a ring optical path using a polarization-maintaining optical fiber (hereinafter referred to as PMF) Optical rotation characteristics in which the light emitted from the PMF from both directions of the sample toward the sample is converted into collimated light or condensed light directly or with a lens, and is incident on the sample perpendicularly or at an angle In the measurement method, on the optical path of the light, controlling a polarization control device or an optical device (hereinafter collectively referred to as a polarization control device) in which light incident from both directions of the sample is arranged on both sides of the sample, The phase difference of the signal light propagating in both directions on the ring optical path is measured by making the polarized light into at least one set of orthogonally polarized lights with a predetermined period. Optical rotation characteristic measuring method characterized by comprising the step of including a polarization controller to.   19. The optical rotation characteristic measuring method according to claim 18, wherein the light emitted from the PMF is converted into condensed light by a lens and incident on the sample at an angle or at an angle. It is set in a direction away from the focal position, the distance between the lenses is a distance that allows the tool for gripping the sample to be inserted, and the beam waist (diameter, hereinafter referred to as BW) of the signal light propagating through the sample is between 30 μm and 50 μm. An optical rotation characteristic measuring method comprising the step of:   20. The optical rotation characteristic measurement method according to claim 18, further comprising a step of using an optical fiber in which an end portion of the PMF is processed to expand a core (hereinafter referred to as TEC).   21. The optical rotation characteristic measuring method according to claim 18, wherein the optical fiber portion of the ring optical path of the ring optical interferometer has the same linear polarization as the clockwise signal light and the linear polarization as the counterclockwise signal light. Are propagated through the same optical fiber as a clockwise signal light and a counterclockwise signal light, respectively, and are incident on the sample portion in polarization states orthogonal to each other to propagate as a clockwise signal light and a counterclockwise signal light, respectively. And a step of using a nonreciprocal polarization conversion optical system including a Faraday rotator on both sides of the sample.   The optical rotation characteristic measurement method according to any one of claims 18 to 21, further comprising a step of using a polarization control device including an optical device that controls polarization by applying a voltage to a liquid crystal. Method.   23. The optical rotation characteristic measuring method according to claim 22, comprising a step of using a polarization control device comprising a polarizer disposed on both sides of a sample and a half-wave plate having a rotation or attachment / detachment function. Degree measurement method.   The optical rotation characteristic measurement method according to any one of claims 18 to 23, wherein the optical rotation characteristic measurement method uses a first optical coupler or an optical circulator and a polarizer as laser light as signal light emitted from a light source. To the second optical coupler, and a signal propagating in both directions through the ring optical path formed by connecting the opposing optical system including the polarization control device in the middle of the ring optical path mainly made of PMF by the second optical coupler. An optical phase modulator is provided in the vicinity of the second optical coupler in the ring optical path. The signal light propagating in both directions through the ring optical path is coupled to the second optical coupler, the polarizer, and the first optical coupler. A signal that is guided to a light receiver and / or a signal processing circuit via an optical coupler or an optical circulator, and the phase difference of the signal light propagating in both directions on the ring optical path is synchronized with the phase modulation signal. The phase difference when the signal light is switched to at least one set of orthogonal polarized light incident from both sides of the sample via the polarization control device is measured, and at least one set of orthogonal when there is no sample An optical rotation characteristic measuring method comprising a step of estimating a sugar concentration of the sample on the basis of a phase difference when switched to polarized light.   25. The optical rotation characteristic measuring method according to claim 24, wherein when the sample is a part of a living body and a blood glucose level is known, a plurality of sets of orthogonal polarized light are incident on the sample from both sides. An optical rotation characteristic measuring method comprising a step of measuring a phase difference in advance and estimating a change in optical rotation of the sample from a measurement phase difference of an optical interferometer with the phase difference as a reference.   The optical rotation characteristic measuring method according to any one of claims 18 to 25, wherein the emitted light from each of the opposing PMFs is enlarged and collimated by a first lens, and converted into condensed light by a second lens. Then, in the optical system that makes the sample enter the sample vertically or at an angle, the distance between the second lens is the distance at which a forceps-like tool that holds the sample can be inserted, and the beam of signal light that propagates through the sample An optical rotation characteristic measuring method comprising a step of designing a waist (diameter, hereinafter referred to as BW) to be between 30 μm and 50 μm.   The optical rotation characteristic measuring method according to any one of claims 18 to 26, wherein when the sample is a part of a living body, the living body is held by a dielectric plate from a direction perpendicular to the beam propagation direction. An optical rotation characteristic measuring method comprising: a step.

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