JP2006023409A - Optical sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sensor which is compact and is hardly affected with a disturbance and with which the speed of measurement is enhanced by eliminating any movable part or reducing it to minimum requirements. <P>SOLUTION: A two arm optical Michelson type interferometer has a low coherent light source 8, a directional coupler 10, a light reflection part 12, a light receiver 13, and optical paths (9-1)-(9-5) optically connecting them. If the low coherent light source 8 is connected to one out of input parts of the directional coupler 10 via the optical path 9-1, the light receiver 13 is connected to the other input part thereof via the optical path 9-5, a variable delay line 11 is arranged within one arm of the interferometer, which connects one output part of the directional coupler 10 with the light reflection part 12 via the optical path (9-3) and (9-4), the other arm terminal connected with the other output part of the directional coupler 10 via the optical path 9-2 and an optical fiber 14 is made to be used for connection of an object to be measured, and the object 15 to be measured is connected to the optical fiber 14, any movable part is eliminated and consequently a distribution type optical sensor which is high-speed and stable, and further has a compact construction and varies delay is constructed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical sensor that performs sensing using interference of light waves. More specifically, the present invention relates to a low coherence reflectometer (OLCR) apparatus that performs sensing using temporal low coherence of light waves.

OLCR is a method for measuring the longitudinal distribution of an object to be measured using the property of causing interference only when the difference in length of the interferometer is less than or equal to the coherence length of the light source.
As an OLCR apparatus, conventionally, as shown in FIG. 14, a Michelson interferometer in which a bulk movable reflecting mirror 5 is arranged on one arm is known (Non-Patent Document 1).
In FIG. 14, 1 is a low coherence light source, 2-1 to 4 are optical paths, 3 is a beam splitter, 4 is an object to be measured, 5 is a movable reflecting mirror, and 6 is a light receiver (O / E converter).

As shown in FIG. 14, the low-coherence light output from the low-coherence light source 1 passes through the optical path 2-1, and is bisected by the beam splitter 3, and one of the low-coherence light passes through the optical path 2-2 and enters the object 4 to be measured. The light is reflected at the reflection point and returns to the optical path 2-2, and the other is reflected by the movable reflecting mirror 5 through the optical path 2-3 and returns to the optical path 2-3.
Here, by moving the movable reflecting mirror 5 as indicated by an arrow in the figure and changing the length of the arm, the reflected light from the movable reflecting mirror 5 in the component of the reflected light from the object 4 to be measured on the other arm. Interference occurs only with those whose lengths are almost the same.

By measuring the interference light intensity with the light receiver 6, the longitudinal state of the DUT 4 can be measured. As a specific example of the DUT 4, consider an optical fiber having a cut portion.
Since a peak occurs in the reflected light intensity at the cut portion, the position of the cut portion can be specified with high accuracy by this method.
The coherence length of the low-coherence light source 1 (also known as coherence distance: a distance that gives an upper limit for the difference in length that causes interference when light is divided into two parts and propagated through different lengths and then combined again. ) L _c is given by the following equation when the spectral shape of the light source is Gaussian.

However,
λ ₀ : central wavelength of the light source,
Δλ: full width at half maximum of light source spectrum,
It is.
When λ ₀ and Δλ of the low-coherence light source 1 are typical values of 1550 nm and 50 nm, respectively, L _c is about 48 μm.
Therefore, by using this light source, since FIG. 14 shows a measurement system having a reflection type configuration, a high measurement resolution of about 24 μm or less can be obtained.
http://www.ando.co.jp/products/mid/mid-index.htm Ando Denki Catalog, “High Resolution Reflectometer AQ7410B.”

In the conventional method described above, a motor-driven bulk component must be used as the movable reflector 5 for adjusting the length.
For this reason, there are drawbacks such as (1) generation of measurement errors due to disturbances such as vibration, (2) enlargement of the apparatus, and (3) difficulty in high-speed measurement.
The present invention has been made in view of the above-described prior art, and provides an optical sensor that eliminates or minimizes a movable part, is small in size and hardly affected by disturbance, and can increase measurement speed. It is intended to provide.

  An optical sensor according to a first aspect of the present invention for solving the above-mentioned problems is a two-arm optical Michelson type having a low coherence light source, a directional coupler, a light reflecting section, a light receiver, and an optical path for optically connecting them. An interferometer, wherein the low coherence light source is connected to one of the input portions of the directional coupler, and the light receiver is connected to the other, and connects the output portion of the directional coupler and the light reflecting portion. A variable delay line is arranged in one arm of the interferometer, and the other arm end connected to the output part of the directional coupler is used for connecting a device under test.

  An optical sensor according to a second aspect of the present invention for solving the above-described problems is a low-coherence light source, an optical switch having two inputs and N outputs (N is an integer of 3 or more), a light reflecting section, a light receiver, and these optically. An N-arm optical Michelson interferometer having an optical path to be connected, wherein the low-coherence light source is connected to one of the input parts of the optical switch, the photoreceiver is connected to the other, and the output part of the optical switch is connected Of the N arms to be connected, a variable delay line is arranged in one arm of the interferometer that connects the output part of the optical switch and the light reflecting part, and the other connected to the output part of the optical switch. The (N-1) arm ends are all for connecting a device under test.

  An optical sensor according to a third aspect of the present invention for solving the above-mentioned problems is a low-coherence light source, an optical splitter with two inputs and N outputs (N is an integer of 3 or more), a light reflector, a light receiver, and these optically. An N-arm optical Michelson interferometer having an optical path to be connected, wherein the low coherence light source is connected to one of the input parts of the optical splitter, the photoreceiver is connected to the other, and the output part of the optical splitter is connected Among the N arms to be operated, a variable delay line is arranged in one arm of the interferometer that connects the output part of the optical splitter and the light reflecting part, and the other arm connected to the output part of the optical splitter. (N-1) Optical modulators are arranged in (N-1) arms, respectively, and the arm ends are all for connecting a device under test.

  An optical sensor according to a fourth aspect of the present invention for solving the above-mentioned problems is a two-arm optical Michelson type having a low-coherence light source, a directional coupler, a light reflector, a light receiver, and an optical path for optically connecting them. An interferometer, wherein the low-coherence light source is connected to one of the input parts of the directional coupler, the light receiver is connected to the other, and the interference connecting the output part of the directional coupler and the light reflecting part A variable delay line is disposed in one arm of the meter, and the other arm end connected to the output portion of the directional coupler is used for connecting an object to be measured that can be moved by a movable mechanism.

  An optical sensor according to a fifth aspect of the present invention for solving the above-mentioned problems is a two-arm optical Mach-Zehnder interferometer having a low coherence light source, two directional couplers, a light receiver, and an optical path for optically connecting them. The two arms of the interferometer connecting the two directional couplers are composed of one arm on which a variable delay line is arranged and the other arm for arranging the object to be measured. And

  An optical sensor according to a sixth aspect of the present invention for solving the above-mentioned problems is a low-coherence light source, an optical switch with 1 input and N output (N is an integer of 3 or more), an optical switch with N input and 1 output, a light receiver, and these N-arm optical Mach-Zehnder interferometers having optical paths that optically connect the optical switches, and the N optical paths connecting the optical switches include (N-1) optical paths for measuring object placement and variable delay. It is characterized by comprising one optical path in which lines are arranged.

  An optical sensor according to a seventh aspect of the present invention for solving the above-mentioned problems is a low-coherence light source, an optical splitter with one input and N outputs (N is an integer of 3 or more), an optical combiner with N inputs and one output, a light receiver, and these N-arm optical Mach-Zehnder interferometer having an optical path for optically connecting the optical splitter, and the N optical paths connecting the optical splitter and the optical combiner are provided with an optical modulator and an object to be measured ( It is characterized by comprising N-1) optical paths and one optical path provided with variable delay lines.

  An optical sensor according to an eighth aspect of the present invention for solving the above-mentioned problems is a two-arm optical Mach-Zehnder interferometer having a low coherence light source, two directional couplers, a light receiver, and an optical path for optically connecting them. The two optical paths connecting between the two directional couplers are composed of one optical path for placing the object to be measured that can be moved by the movable mechanism and the other optical path on which the variable delay line is arranged. It is characterized by that.

The optical sensor according to a ninth aspect of the present invention for solving the above-described problems is the optical sensor according to the first to eighth aspects, wherein the variable delay line has a difference in length of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 A total of K + 1 symmetrical Mach-Zehnder type interferences having a phase adjustment unit on at least one arm between K delay lines that are ^K-1 ΔL (K is an integer of 1 or more) and before and after the delay line pairs at both ends. It is characterized by having a phase adjustment unit at least at one of the input / output unit and the delay line unit.

The optical sensor according to a tenth aspect of the present invention for solving the above-mentioned problems is the optical sensor according to the first to eighth aspects, wherein the variable delay line has a difference in length of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 Two symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm between K delay lines (K is an integer of 1 or more) and before and after a delay line pair at both ends, which are ^K-1 ΔL. One output unit and the other input unit are connected by K + 1 multistage interferometers, which are connected using waveguide pairs having equal lengths having a phase adjustment unit on at least one arm, and an input / output unit, It is characterized by having a phase adjusting unit at least at one position of the delay line unit.

The optical sensor according to an eleventh aspect of the present invention that solves the above-described problems is the optical sensor according to the first to eighth aspects, wherein the variable delay line has a difference in length of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 Two symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm between K delay lines (K is an integer of 1 or more) and before and after a delay line pair at both ends, which are ^K-1 ΔL. Connect each output of both output units with K + 1 multistage interferometers connecting both inputs of a symmetric Mach-Zehnder interferometer having a phase adjustment unit on at least one arm, It is characterized by having a phase adjusting unit at least at one position of the delay line unit.

The optical sensor according to a twelfth aspect of the present invention that solves the above-described problems is the optical sensor according to the first to eighth aspects, wherein the variable delay line has a difference in length of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 ^{Both of K-1} ΔL (where K is an integer equal to or greater than 1) delay line pairs and before and after the delay line pairs at both ends, both of symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm. The output unit is connected by K + 1 interferometers, each of which is connected to one input of both input units of two symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm, an input / output unit, a delay It has a phase adjustment part in at least one place of a line part, It is characterized by the above-mentioned.

  An optical sensor according to a thirteenth aspect of the present invention that solves the above-described problems is that, in the fourth and eighth aspects, the movable mechanism uses a micro-electro-mechanical system (MEMS). It is characterized by.

In the optical sensor of the present invention, by incorporating a variable delay line configuration in a Michelson type or Mach-Zehnder type interferometer that makes full use of the waveguide configuration technology, the movable parts can be eliminated or minimized.
Further, by applying a waveguide material capable of high-speed phase adjustment, the delay can be changed at high speed.
As a result, it is possible to realize an excellent optical sensor that is small in size and hardly affected by disturbance, and that can perform high-speed measurement.

  The present invention relates to an optical sensor that measures the longitudinal distribution of an object based on a Michelson interferometer or a Mach-Zehnder interferometer, for example, by forming a main configuration such as a variable delay line on a planar lightwave circuit, It is a compact optical sensor that is not easily affected by disturbance and capable of high-speed measurement, and various functions can be added as described in the following embodiments.

In other words, in the present invention, the length adjustment portion is configured by a variable delay line having an optical waveguide structure, so that the length is reduced to a minimum sub-μm order by phase adjustment using a refractive index change (<msec) in the waveguide. Thus, it can be changed over a wide range of sub-μm to m with high accuracy.
Therefore, the movable part of the length adjusting part can be removed, and an optical sensor that is small in size and hardly affected by disturbance and can shorten the measurement time can be configured.

FIG. 1 shows a configuration example of a first embodiment (claim 1) of an optical sensor according to the present invention.
The optical sensor of this embodiment includes a quartz planar lightwave circuit 7 formed on a silicon substrate, a low coherence light source 8, quartz waveguides 9-1 to 5, a directional coupler 10, a variable delay line 11, a reflecting mirror 12, a light receiving element. This is a two-arm optical Michelson interferometer provided with a detector 13 and an optical fiber 14.

  As shown in FIG. 1, in the quartz planar lightwave circuit 7, the low coherence light source 8 is connected to one quartz waveguide 9-1 which is an input part of the directional coupler 10, and the other quartz waveguide 9-5. The variable delay line 11 is arranged in the quartz waveguides 9-3 and 9-4 in one arm of the interferometer connecting the output unit of the directional coupler 10 and the reflecting mirror 12 to the optical receiver 13. The quartz waveguide 9-2, which is the other arm end connected to the output portion of the directional coupler 10, was used for connecting the object to be measured. The quartz waveguide 9-2 for connecting the device under test is connected to the device under test 15 via the optical fiber. The loss of both arms can be made the same by changing the coupling ratio of the directional coupler 10 or by arranging a variable optical attenuator such as a symmetric Mach-Zehnder interferometer in any one of the quartz waveguides 9-2 to 9-4. It is possible to perform measurement with high accuracy.

In the present embodiment, for the purpose of miniaturization, stabilization, and low loss, it is variable using a planar lightwave circuit technique for forming a quartz waveguide (clad: SiO ₂ , core: SiO ₂ —GeO ₂ ) on a silicon substrate. It constitutes the main part of the delay line 11 and the like.
The low coherence light source 8 which is a light emitting / receiving element that cannot be realized with a quartz waveguide is a semiconductor or optical fiber element {light emitting diode (LED), high intensity light emitting diode (SLD), rare earth doped optical fiber amplifier or semiconductor laser amplifier spontaneous emission. Light (ASE light source, etc.), the light receiver 13 uses a semiconductor element and is hybrid-integrated in a planar lightwave circuit.

Of course, the quartz waveguide portion may be replaced with a semiconductor, a ferroelectric material such as LiNbO ₃ (LN) or KTa _lx Nb _x O ₃ (KTN), a polymer, an optical fiber, or a waveguide structure in which these are combined. Is possible.
The DUT 15 is connected to the quartz planar lightwave circuit 7 using an optical fiber 14.
Although the object to be measured 15 can be arranged and measured in the quartz planar lightwave circuit 7, an example of simple and general-purpose fiber connection is shown in consideration of replacement of the object to be measured 15.

Note that the lengths of the quartz waveguides 9-2 to 4-4 and the optical fiber 14 are adjusted in advance so that all longitudinal states in the DUT 15 can be measured using the delay variation of the variable delay line 11. .
A configuration example of the variable delay line 11 is shown in FIG.
When the variable delay line of FIG. 2 is used in FIG. 1, it corresponds to an embodiment of claim 9.
The variable delay line in FIG. 2 includes input waveguides 17-1 and 2, thermo-optic phase shift thin film heaters (chromium, tantalum nitride, etc.) 18-1 to K + 1 (K is 1 or more) on one arm (on the clad). Symmetric Mach-Zehnder interferometer type 2 × 2 optical switches 19-1 to 19-K + 1, asymmetric arm pairs 20a-1 to K, 20b-1 to K, output waveguides 21-1, 2 and phase adjustment Part 22.

Either of the input waveguides 17-1 and 17-2 is connected to the quartz waveguide 9-3, and the output waveguide 21-1 is connected to the quartz waveguide 9-4.
The difference ΔL _{K in} length between the asymmetric arm pairs 20a-1 to 20K, 20b-1 to 20K is set to ΔL _K = 2 ^K-1 ΔL _{l in} this configuration example. However, ΔL _l is the difference in length between 20a-1 and 20b-1.
By changing the switching state of the 2 × 2 optical switches 19-1 to 19 -K + 1, the characteristics between the input waveguides 17-1 and 17-2 and the output waveguides 21-1 and 21-2 are set to 0 to (2 ^K −1). ) the range of [Delta] L ₁ the relative delay of the variable can be a total of 2 ^K as can be realized with minimum configuration in [Delta] L ₁ increments. At most K = 10, more than 1000 points can be measured.
Since a reflective structure, in a reciprocating, 0~ (2 ^K -1) the scope of 2.DELTA.L ₁ can be obtained relative delay characteristics of the variable can be a total of 2 ^K Street in 2.DELTA.L ₁ increments.

Since the quartz waveguide can be precisely designed and manufactured, it is possible to set ΔL ₁ to a minimum on the order of μm or sub-μm.
When the coherence length L _c in the waveguide of the low coherence light source 8 is set to be smaller than 2ΔL ₁ , assuming that the equivalent refractive index of the quartz waveguide and the refractive index of 15 are the same for the sake of simplicity, the resolution ΔL ₁ is 15 The longitudinal state can be measured.
Phase adjusting unit 22 is used to correct the production error of [Delta] L _K, similarly to the thermal optical phase shift film heater 18 is a thin film heater is used.
Since the thermo-optic phase shift has a variable range and setting accuracy of about a wavelength and about 1/200 of the wavelength, respectively, the length can be adjusted with an accuracy on the order of nm. Further, as the length adjusting unit in the order of μm or less, a cascade connection configuration of phase shifters can be used.

Note that the same adjustment can be performed by arranging a phase adjustment unit in either of the input waveguides 17-1 and 17, or on the asymmetric arm pair 20.
Further, as the reflecting mirror 12, in addition to a loop mirror (Sagnac mirror) in which two locations of one waveguide are coupled with a 50% coupling directional coupler, a waveguide type grating, metal deposited on the end face of the waveguide, etc. Can also be used.
Here, the measured object scan measurement time T _m when using the configuration of FIGS. 1 and 2 is expressed by the following equation, where 19 switching times are T _s .

However,

J: Necessary number of switching times, L _m : Length of device under test, [y] represents an integer part of positive real number y.
Assuming that a measurement object having a length of 100 mm is measured with a resolution of 20 μm, T _m ≈5 s when a thermo-optic refractive index change (T _s ≈ms) such as a quartz waveguide or a polymer waveguide is used.
When using a high-speed refractive index change such as an electro-optic effect such as a semiconductor waveguide, a ferroelectric waveguide, or a polymer waveguide, it is easy to set T _s <ns, and thus T _m <5 μs.

The measurement speed of the OLCR apparatus AQ7410B (manufactured by Ando Electric Co., Ltd., resolution: 20 μm) using a commercially available movable reflection mirror is about 40 mm / s, so the measurement time of the above-mentioned measurement object is 100 mm / (40 mm / s); 5 s.
Therefore, by using the structure without moving parts shown in FIGS. 1 and 2, when the semiconductor waveguide and the ferroelectric waveguide are applied to the variable delay line section, the measurement speed can be increased by 6 digits or more. Even with the application of a waveguide, measurement at a speed on the order of the conventional configuration is possible with a small device.

Another configuration example of the variable delay line 11 is shown in FIG.
When the variable delay line of FIG. 3A is used in FIG. 1, it corresponds to an embodiment of claim 10.
As shown in FIG. 3A, the variable delay line includes input waveguides 24-1 and 2, interferometer type 2 × 2 optical switches 25-1 to K + 1, and asymmetric arm pairs 26a-1 to K, 26b−. 1 to K, output waveguides 27-1 and 27-2, and a phase adjustment unit 28.
A configuration example of the interferometer type 2 × 2 optical switch 25 is shown in FIG.

As shown in FIG. 3B, the interferometer type 2 × 2 optical switch 25 includes input waveguides 29-1, 2; directional couplers 30-1 to 30-4; symmetrical arm pairs 31a-1 to 31a-3; 31b-1 to 3-3, thin film heaters 32-1 to 3 and output waveguides 33-1 and 33-2.
By adjusting the phase using the thin film heaters 32-1 and 32-3, the phase between the arm 31a-1 and the arm 31b-1 and between the arm 31a-3 and the arm 31b-3 is set to π / 2.
In this case, as a strength characteristic between the input waveguides 29-1 and 29-2 and the arms 31a-2 and 31b-2, and between the arms 31a-2 and 31b-2 and the output waveguides 33-1 and 3, the coupling rate is 50%. A directional coupler (3 dB directional coupler) can be equivalently realized.

In the configuration of FIG. 2, when the coupling ratio (fixed value) of the directional coupler in the symmetric Mach-Zehnder interferometer type 2 × 2 optical switches 19-1 to 19-K + 1 deviates from 50%, the extinction characteristic, that is, the switching characteristic Deteriorates.
On the other hand, in FIG. 3, even when the directional couplers 30-1 to 30-4 are deviated from 50%, a 3 dB directional coupler is obtained as a characteristic of one stage of the symmetric Mach-Zehnder interferometer by adjusting the thin film heaters 32-1 and 32-3. Therefore, switching characteristics with a good extinction ratio can be obtained as the characteristics of the entire interferometer type 2 × 2 optical switches 25-1 to K + 1.
The interferometer type 2 × 2 optical switches 25-1 to K + 1 are two-stage cascaded symmetrical Mach-Zehnders in which two output units of a symmetrical Mach-Zehnder type interferometer and two input units of another symmetrical Mach-Zehnder type interferometer are connected. It can be paraphrased as a type interferometer configuration.

As another specific example of the variable delay line 11, the configuration shown in FIG.
As shown in FIG. 4A, the variable delay line includes input waveguides 34-1 and 34-2, interferometer type 2 × 2 optical switches 35-1 to K + 1, and asymmetric arm pairs 36a-1 to K, 36b−. 1 to K, output waveguides 37-1 and 37, and a phase adjustment unit 38.
A configuration example of the interferometer type 2 × 2 optical switches 35-1 to K + 1 is shown in FIG. 4B or 4C.
When the interferometer type 2 × 2 optical switches 35-1 to K + 1 shown in FIG. 4A are used as shown in FIG. 4B or 4C, the embodiments of claims 11 and 12, respectively, are used. It corresponds to.

In FIG. 4B, interferometer type 2 × 2 optical switches 35-1 to K + 1 include input waveguides 39-1 to 4, directional couplers 40-1 to 6, symmetrical arm pairs 41a-1 to 41b. -1 to 3, thin film heaters 42-1 to 42, and output waveguides 43-1 and 43-2.
In FIG. 4C, the interferometer type 2 × 2 optical switches 35-1 to K + 1 include input waveguides 44-1, 2 and directional couplers 45-1 to 45-6 and symmetrical arm pairs 46a-1 to 46a-1. , 46b-1 to 46b, thin film heaters 47-1 to 47, and output waveguides 48-1 to 48-4.

One of the combinations (39-1, 2), (39-3, 4), (48-1, 2), and (48-3, 4) is used as the input / output unit.
4 (b) or 4 (c) has a configuration in which two stages of symmetric Mach-Zehnder interferometers are cascaded one by one, so that a symmetric Mach-Zehnder interferometer type 2 × 2 optical switch is used. Better extinction characteristics than 19-1 to 19-K + 1 can be obtained.
As the variable delay line 11, a plurality of asymmetric Mach-Zehnder interferometers each having a symmetric Mach-Zehnder type 2 × 2 switch arranged at both ends of a pair of asymmetric arms are prepared, and one arm of each asymmetric Mach-Zehnder type interferometer is provided. Configurations that connect to each other can also be used.

A configuration example of the second embodiment (claim 2) of the optical sensor according to the present invention is shown in FIG.
The optical sensor of the present embodiment includes a waveguide circuit 49 formed on a substrate, a low coherence light source 50, waveguides 51-1 to N + 3, an optical switch 52 with two inputs and N outputs (N is an integer of 3 or more), a variable delay. An N-arm optical Michelson interferometer including a line 53, a reflecting mirror 54, a light receiver 55, and optical fibers 56-1 to N-1.

  As shown in FIG. 5, in the waveguide circuit 49, a low-coherence light source 50 is connected to one of the input portions of a two-input N-output optical switch 52 via a waveguide 51-1, and the other is a waveguide 51-N + 3. Of the N arms connected to the output of the optical switch 52, a variable delay line between the waveguide 51-N + 1 and the waveguide 51-N + 2 in one arm. 53, a reflecting mirror 54 is connected to the waveguide 51-N + 2 which is the arm end, and the waveguides 51-2 to 51-N which are the other (N-1) arm ends are all measured. Used for connecting objects. The measured object 57 is connected to the measured object connecting waveguides 51-2 to 51-N via optical fibers 56-1 to N-1.

A configuration example (two inputs and eight outputs) of the optical switch 52 is shown in FIG.
In FIG. 6, symmetrical Mach-Zehnder type 2 × 2 optical switches 59-1 to 7 having phase adjustment units 58-1 to 5-7 at one port are cascade-connected in a tree shape.
In addition, a configuration in which Y-branch type 1 × 2 digital optical switches are cascade-connected in a tree shape and one output port of the directional coupler is connected to the input portion thereof is also conceivable.
The low-coherence light from the low-coherence light source 50 is switched to one of the waveguides 51-2 to 51-N and the waveguide 51-N + 1 by using the 2-input N-output optical switch 52, and the delay change in the variable delay line 53 is used. The distribution in the longitudinal direction of the measurement object 57 is measured.
This operation is repeated once for each of the different (N-1) waveguides 51-2 to N in total (N-1) times.

Assuming that the connection between the optical fibers 56-1 to N-1 and the object 57 to be measured is a straight line, this operation causes the longitudinal distribution of the object 57 to be measured and the optical fibers 56-1 to N-1 to be measured. Thus, information on the vertical position distribution, that is, two-dimensional distribution information can be obtained.
Note that the resolution of the linear position distribution depends on the arrangement positions of the optical fibers 56-1 to N-1.
When the optical fibers 56-1 to N-1 are connected to the object 57 in a two-dimensional plane, the longitudinal distribution of the object 57 and the optical fibers 56-1 to N-1 are perpendicular to each other. Information on the planar position distribution in the direction, that is, three-dimensional distribution information can be obtained.

FIG. 7A shows a configuration example in which the output section of the optical switch 52 in FIG. 5 is configured in a three-dimensional space by the stacked waveguide technique and the object to be measured is directly connected to the stacked waveguide.
7A shows only a portion corresponding to the broken line portion 6A in FIG. 5, and reference numerals 60-1 to 3 and 61-1 to 3 and 62 denote a phase adjustment unit and a symmetric Mach-Zehnder type 2 × 2 optical switch, respectively. It is a device under test.
For simplicity, an example using a 2 × 4 tree-like switch using a two-layer laminated waveguide structure is shown.

In the figure, thick lines and thin lines are used to represent the upper layer waveguide and the lower layer waveguide, respectively, and do not indicate the waveguide size.
FIGS. 7B and 7C are an AA ′ cross-sectional view and a BB ′ waveguide cross-sectional view in the direction indicated by the arrow in FIG. 7A, respectively. In FIG. 7B, the internal waveguide configuration is indicated by a broken line.
As shown to Fig.7 (a), the directional coupler is comprised in the up-down direction in the part which the thick line and the thin line overlapped.

With this configuration, it is possible to measure the longitudinal distribution of the device under test 62 corresponding to the output points of the symmetrical Mach-Zehnder type 2 × 2 optical switches 61-2 and 3 distributed in a plane.
Although an example using a two-layer laminated waveguide is shown for simplicity, the number of measurement points can be increased by further multilayering.
7 does not use the optical fiber 56 as shown in FIG. 5, the system can be simplified and miniaturized.
The technique for measuring the two-dimensional and three-dimensional distributions described above without moving parts is also not feasible with the prior art.

FIG. 8 shows a configuration example of a third embodiment (claim 3) of the optical sensor according to the present invention.
In the figure, the optical sensor of this embodiment includes a waveguide circuit 63 formed on a substrate, a low coherence light source 64, waveguides 65-1 to N + 3, and an optical splitter 66 having two inputs and N outputs (N is an integer of 3 or more). , Variable delay line 67, reflecting mirror 68, light receiver 69, electrical wiring 70-1 to N + 2, synchronous detector 71, electrical oscillator 72, 1-input multiple-output electrical switch 73, optical modulators 74-1 to N-1, An N-arm optical Michelson interferometer including optical fibers 75-1 to N-1.

  As shown in FIG. 8, in the waveguide circuit 63, a low-coherence light source 64 is connected to one of the input portions of a two-input N-output optical splitter 66 via a waveguide 65-1, and the other is guided to the waveguide 65-N + 3. Of the N arms connected to the output portion of the optical splitter 66, a variable delay line between the waveguide 65-N + 1 and the waveguide 65-N + 2 in one arm. 67 and the reflecting mirror 68 is connected to the waveguide 65-N + 2, which is the arm end, and the optical modulator 74- is connected to the waveguides 65-2 to 65-N in the other (N-1) arms. 1 to N-1 are arranged, and the waveguides 65-2 to 65-N, which are the arm ends, are all used for connecting the device under test. The measured object 76 is connected to the measured object connection waveguides 65-2 to 65 -N via optical fibers 75-1 to N−1.

The low-coherence light from the low-coherence light source 64 is distributed to the waveguides 65-2 to N + 1 by the 2-input N-output optical splitter 66.
The output signal of the electric oscillator 72 is switched using the 1-input multi-output electrical switch 73, and any one of the optical modulators 74-1 to N-1 is driven to modulate the light in intensity or phase.
Using the synchronous detection by the synchronous detector 71, the light passing through the (N−1) waveguides 65-2 to 65 -N is separated and the delay of the variable delay line 67 is used to change the object to be measured 76. Longitudinal distribution is measured.
This operation is repeated once for each of the different waveguides 65-2 to 65 -N for a total of (N−1) times, and the two-dimensional or three-dimensional distribution information of the object to be measured 76 can be obtained.

Compared with the configuration of FIG. 5, the optical modulators 74-1 to N-1 and the electric devices 70 to 73 are increased. However, since it is not necessary to use a tree-like optical switch, the waveguide circuit portion can be reduced in size. .
Note that (N-1) electrical oscillators 72 and corresponding synchronous detectors 71 are prepared, and the optical modulators 74-1 to 74-1 are directly used without using the 1-input multi-output electrical switch 73. By modulating N-1 at different frequencies, (N-1) reflected lights from the device under test 76 can be measured simultaneously.
Therefore, although the number of electrical devices increases, the measurement time can be reduced to 1 / (N-1) or less as compared with the configuration of FIG.

FIG. 9 shows a configuration example of a fourth embodiment (claim 4) of the optical sensor according to the present invention.
The optical sensor of the present embodiment includes a waveguide circuit 77 formed on a substrate, a low coherence light source 78, waveguides 79-1 to 79, a directional coupler 80, a variable delay line 81, a reflecting mirror 82, a light receiver 83, This is a two-arm optical Michelson interferometer provided with a movable mechanism (not shown) for installing the object to be measured 84.

As shown in FIG. 9, in the waveguide circuit 77, a low coherence light source 78 is connected to one of the input portions of the directional coupler 80 via the waveguide 79-1, and the other is connected to the other end via the waveguide 79-5. A variable delay line 81 is provided between the waveguide 79-3 and the waveguide 79-4, which is one arm of the interferometer, connected to the light receiver 83 and connecting the output portion of the directional coupler 80 and the light reflecting portion 82. Is disposed, and the waveguide 79-2, which is the other arm end connected to the output portion of the directional coupler 80, is used for connecting the device under test. An object to be measured 84 that is movable by a movable mechanism is connected to the waveguide 79-2.
If the movable mechanism is MEMS, it corresponds to the embodiment of claim 13.
When the object to be measured 84 is moved in the vertical plane with respect to the waveguide 79-2 by the movable mechanism, the object to be measured 84 is a small system that does not need to contact a plurality of probes (waveguides or fibers). Dimensional distribution can be measured.

FIG. 10 shows a configuration example of a fifth embodiment (claim 5) of the optical sensor according to the present invention.
The optical sensor of this embodiment includes a quartz planar lightwave circuit 85 formed on a silicon substrate, a low coherence light source 86, waveguides 87-1 to 8, two directional couplers 88-1 and 882, and a variable delay line 89. , A two-arm optical Mach-Zehnder interferometer including a light receiver 90 and optical fibers 91-1 and 91-2.

As shown in FIG. 10, in the quartz planar lightwave circuit 85, a low-coherence light source 86 is connected to one of the input portions of the directional coupler 88-1 via a waveguide 87-1, and the directional coupler 88-2. A receiver 90 is connected to one of the output portions of the two interferometers via the waveguide 87-8, and the two arms of the interferometer connecting the two directional couplers 88-1 and 88-2 are one arm. It comprises waveguides 87-6 and 7 in which a certain variable delay line 89 is disposed, waveguides 87-2 and 87-3 which are the other arms, and optical fibers 91-1 and 91-2 for arranging the object to be measured. A device under test 92 is disposed between the optical fibers 91-1 and 91-2.
In this embodiment, distributed interference measurement is performed with a low-coherence light source using the transmitted light instead of the reflected light of the object to be measured.
By changing the coupling rate of the directional couplers 88-1 and 88-2, or by arranging a variable optical attenuator in any one of the waveguides 87-2, 3, 6, and 7, Similarly, the loss of both arms can be made the same, and measurement can be performed with high accuracy.

In FIG. 10, a Mach-Zehnder interferometer is provided in which a variable delay line 89 is arranged on one arm.
By changing the delay amount of the variable delay line 89 and changing the length of the arm, the length of the transmitted light from the variable delay line 89 in the component of the transmitted light from the DUT 92 of the other arm substantially coincided. Interference occurs only with things.
By measuring the intensity of the interference light, the state in the longitudinal direction of the DUT 92 can be measured.

When the variable delay line having the configuration shown in FIG. 2 is used as the variable delay line 89 (corresponding to the embodiment of claim 9), the range of 0 to (2 ^K −1) ΔL ₁ is variable in increments of ΔL _1. A total of 2 ^K possible relative delay characteristics can be obtained.
When the coherence length L _c in the waveguide of the low coherence light source 86 is set to be smaller than ΔL ₁ , assuming that the equivalent refractive index of the quartz waveguide and the refractive index of the DUT 92 are the same for the sake of simplicity, the resolution ΔL ₁ Thus, it is possible to measure the longitudinal state of the DUT 92.

FIG. 11 shows a configuration example of a sixth embodiment (claim 6) of the optical sensor according to the present invention.
The optical sensor of this embodiment includes a quartz planar lightwave circuit 93 formed on a silicon substrate, a low coherence light source 94, waveguides 95-1 to 2N + 4, a 1-input N-output optical switch 96, and an N-input 1-output optical switch 97. , An N-arm optical Mach-Zehnder interferometer including a variable delay line 98, a light receiver 99, and optical fibers 100-1 to 2N-2.

As shown in FIG. 11, in the quartz planar lightwave circuit 93, a low coherence light source 94 is connected to an input portion of a 1-input N-output optical switch 96 via a waveguide 95-1, and an N-input 1-output optical switch 97. A light receiver 99 is connected to the output section via a waveguide 95- (2N + 4), and a waveguide 95-2, which is N optical paths, connecting the 1-input N-output optical switch 96 and the N-input 1-output optical switch 97. To 2N + 3, optical fibers 100-1 to 2N-2 for placing the object to be measured, and a variable delay line 98. A device under test 101 is disposed in the optical fibers 100-1 to 2N-2.
The 1-input N-output optical switch 96 has the configuration example shown in FIG. 6 and can be realized by using one of the input ports.
The N-input 1-output optical switch 97 can be realized by a configuration in which the above configuration is reversed left and right.
In addition, the optical switch 97 may have a simple combiner configuration, but in this case, loss increases as compared with the optical switch configuration.

The low-coherence light from the low-coherence light source 94 is guided to the waveguides 95-2, 4, 6,. . . , 2N-2, 2N and the waveguide 95-2N + 2, and the longitudinal distribution measurement of the device under test 101 is performed using the delay change in the variable delay line 98.
This operation is changed to different (N-1) waveguides 95-2, 4, 6,. . . , 2N-2, 2N are repeated once for a total of (N-1) times.
By this operation, information on the longitudinal distribution of the object to be measured 101 and the position distribution in the direction perpendicular to the optical fiber 100, that is, two-dimensional or three-dimensional distribution information can be obtained.

A configuration example of the seventh embodiment (claim 7) of the optical sensor according to the present invention is shown in FIG.
The optical sensor according to this embodiment includes a waveguide circuit 102 formed on a substrate, a low coherence light source 103, waveguides 104-1 to 2N + 4, an optical splitter 105 having 1 input and N outputs (N is an integer of 3 or more), and N inputs. 1-output optical combiner 106, variable delay line 107, light receiver 108, electrical wiring 109-1 to N + 2, synchronous detector 110, electrical oscillator 111, 1-input multiple-output electrical switch 112, optical modulators 113-1 to N- 1 is an N-arm optical Mach-Zehnder interferometer including optical fibers 114-1 to 2N-2.

As shown in FIG. 12, in the waveguide circuit 102, a low-coherence light source 103 is connected to an input portion of a 1-input N-output optical splitter 105 via a waveguide 104-1, and an N-input 1-output optical combiner 106 is connected. The optical receiver 108 is connected to the output section via the waveguide 104- (2N + 4), and the N optical paths connecting the 1-input N-output optical splitter 105 and the N-input 1-output optical combiner 106 are optical modulators. (N-1) optical paths including waveguides 104-2 to 2N + 1 in which 113-1 to N-1 are arranged and optical fibers 114-1 to 2N-2 for arranging the object to be measured, and a variable delay line 107 are provided. It consists of waveguides 104- (2N + 2) and 104- (2N + 3) which are one optical path arranged. An object to be measured 115 is disposed in the optical fibers 114-1 to 2N-2.
The low-coherence light from the low-coherence light source 103 is guided to the waveguides 104-2, 4, 6,. . . , 2N, 2N + 2.

The output signal of the electric oscillator 111 is switched using the 1-input multi-output electrical switch 112, and any one of the optical modulators 113-1 to N-1 is driven to modulate the light in intensity or phase.
Using the synchronous detection by the synchronous detector 110, (N-1) waveguides 104-3, 5, 7,. . . . , 2N−1, 2N + 1 are separated, and the longitudinal distribution of the object to be measured 115 is measured using the delay change in the variable delay line 107.
This operation is performed by using different waveguides 104-3, 5, 7,. . . , 2N-1, 2N + 1 is repeated once (N-1) times to obtain two-dimensional or three-dimensional distribution information of the DUT 115.

Compared with the configuration of FIG. 11, the optical modulator 113 and the electrical wirings 109-1 to N + 2, the synchronous detector 110, the electrical oscillator 111, and the 1-input multi-output electrical switch 112 are increased, but it is necessary to use the optical switches 96 and 97. Therefore, the waveguide circuit portion can be reduced in size.
Note that (N-1) electrical oscillators 111 and (N-1) corresponding synchronous detectors 110 are prepared, and the optical modulators 113-1 to 113-1 are directly used without using the 1-input multi-output electrical switch 112. By modulating N-1 with different frequencies, (N-1) transmitted lights from the waveguide 104 can be measured simultaneously.
Therefore, although the number of electrical devices increases, the measurement time can be reduced to 1 / (N-1) or less as compared with the configuration of FIG.

FIG. 13 shows a configuration example of an optical sensor according to an eighth embodiment (claim 8) of the present invention.
The optical sensor of the present embodiment includes a waveguide circuit 116 formed on a substrate, a low coherence light source 117, waveguides 118-1 to 118, two directional couplers 119-1 and 119, a variable delay line 120, light reception. 2 is a two-arm optical Mach-Zehnder interferometer equipped with a movable mechanism (not shown) that can move the device 121 and the object 122 to be measured.

As shown in FIG. 13, in the waveguide circuit 116, the two optical paths connecting the two directional couplers 119-1 and 119-1 and 2 are waveguides 118-2 which are one optical path for placing the object to be measured. 118-3 and waveguides 118-6 and 118-7, which are the other optical paths on which the variable delay line 120 is disposed. A device under test 122 movable by a movable mechanism is disposed between the waveguides 118-2 and 118-3.
If the movable mechanism is MEMS, it corresponds to the embodiment of claim 13.
When the object 122 to be measured is moved in a vertical plane with respect to the waveguides 118-2 and 3, the three-dimensional structure of the object 122 to be measured is a small system that does not require a plurality of probes (waveguides or fibers) to be in contact with each other. Distribution can be measured.

  The present invention can be used in the fields of optoelectronics (distribution diagnosis of various optical devices such as integrated optical components and optical fibers), medical / bio field (diagnosis of tomographic distribution of living cells), and the like.

It is a schematic block diagram which shows 1st Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows the structural example of the variable delay line in FIG. 3A is a schematic configuration diagram showing the variable delay line in FIG. 1, and FIG. 3B is a schematic configuration diagram showing the interferometer type 2 × 2 optical switch in FIG. 3A. 4A is a schematic configuration diagram showing the variable delay line in FIG. 1, and FIGS. 4B and 4C are schematic configurations showing the interferometer type 2 × 2 optical switch in FIG. 4A. FIG. It is a schematic block diagram which shows 2nd Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows the optical switch in FIG. FIG. 7A is a schematic configuration diagram showing another embodiment of the optical sensor of FIG. 5, FIGS. 7B and 7C are cross-sectional views taken along line AA ′ in FIG. It is BB 'sectional drawing. It is a schematic block diagram which shows 3rd Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows 4th Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows 5th Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows 6th Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows 7th Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows 8th Embodiment of the optical sensor of this invention. It is a schematic block diagram which shows the conventional optical sensor (OLCR apparatus).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low coherence light source 2-1-4 Optical path 3 Beam splitter 4 Measured object 5 Movable reflector 6 Light receiver (O / E converter)
7 Quartz Planar Lightwave Circuit 8 Low Coherence Light Sources 9-1 to 5 Quartz Waveguide 10 Directional Coupler 11 Variable Delay Line 12 Reflector 13 Light Receiver 14 Optical Fiber 15 Measured Object 17-1, Input Waveguide 18-1 ˜K + 1 Thin Film Heaters 19-1 to 19-K + 1 Symmetric Matternder Interferometer Type 2 × 2 Optical Switches 20a-1 to K, 20b-1 to K Asymmetric Arm Pairs 21-1, 2 Output Waveguide 22 Phase Adjuster 24-1 , 2 input waveguides 25-1 to K + 1 interferometer type 2 × 2 optical switches 26 a-1 to K, 26 b-1 to K asymmetric arm pairs 27-1, output waveguides 28, phase adjustment units 29-1 and 29-2, inputs Waveguides 30-1 to 31-4 Directional couplers 31a-1 to 31 and 31b-1 to 3 Symmetric arm pairs 32-1 to 3 Thin film heaters 33-1 and 2 Output waveguides 34-1 and 2 Input waveguides 35- 1 to K + 1 interferometer type 2 × 2 Switches 36a-1 to K, 36b-1 to K asymmetric arm pairs 37-1 and 2 Output waveguide 38 Phase adjusting section 39-1 to 4 Input waveguide 40-1 to 6 Directional couplers 41a-1 to 41a-3, 41b-1 to 3 Symmetric arm pair 42-1 to 3 Thin film heater 43-1 and output waveguide 44-1 and input waveguide 45-1 to 6 Directional couplers 46a-1 to 46b-1 3 Symmetric Arm Pairs 47-1 to 3 Thin Film Heaters 48-1 to 4 Output Waveguide 49 Waveguide Circuit 50 Low Coherence Light Sources 51-1 to N + 3 Waveguide 52 Optical Switch 53 Variable Delay Line 54 Reflector 55 Light Receiver 56-1 ˜N-1 Optical fiber 57 DUTs 58-1 to 7-7 Phase adjusting units 59-1 to 7 Symmetrical Magenta type 2 × 2 optical switch 60-1 to 3 Phase adjusting units 61-1 to 3 Symmetrical Muntender type 2 × 2 Optical switch 62 Device 63 Wave circuit 64 Low coherence light source 65-1 to N + 3 Waveguide 66 Optical splitter 67 Variable delay line 68 Reflector 69 Light receiver 70-1 to N + 2 Electrical wiring 71 Synchronous detector 72 Electric oscillator 73 1-input multiple-output electrical switch 74-1 N-1 optical modulators 75-1 to N-1 optical fiber 76 device under test 77 waveguide circuit 78 low coherence light source 79-1 to 5 waveguide 80 directional coupler 81 variable delay line 82 reflecting mirror 83 light receiver 84 Measurement object 85 quartz flat light wave circuit 86 low coherence light source 87-1-8 waveguide 88-1, directional coupler 89 variable delay line 90 light receiver 91-1, 2 optical fiber 92 DUT 93 Quartz planar lightwave circuit 94 Low coherence light source 95-1 to 2N + 4 waveguide 96 1 input N output optical switch 97 N input 1 output optical switch 98 variable Delay line 99 light receivers 100-1 to 2N-2 optical fiber 101 device under test 102 waveguide circuit,
103 Low Coherence Light Source 104-1 to 2N + 4 Waveguide 105 Optical Splitter 106 Optical Combiner 107 Variable Delay Line 108 Light Receiver 109-1 to N + 2 Electrical Wiring 110 Synchronous Detector 111 Electric Oscillator 112 1-input Multi-output Electrical Switch 113-1 to N -1 Optical modulator 114-1 to 2N-2 Optical fiber 115 Device under test 116 Waveguide circuit 117 Low coherence light source 118-1 to 8 Waveguide 119-1, Directional coupler 120 Variable delay line 121 Light receiver 122 Object to be measured installed in movable mechanism

Claims (13)

A two-arm optical Michelson interferometer having a low-coherence light source, a directional coupler, a light reflector, a light receiver, and an optical path for optically connecting them, and one of the input parts of the directional coupler The low-coherence light source is connected to the other receiver, and a variable delay line is arranged in one arm of the interferometer that connects the output part of the directional coupler and the light reflecting part, and the direction An optical sensor characterized in that the other arm end connected to the output portion of the sex coupler is used for connecting a device under test. An N-arm optical Michelson interferometer having a low-coherence light source, a 2-input N-output (N is an integer of 3 or more) optical switch, a light reflector, a light receiver, and an optical path for optically connecting them, The low-coherence light source is connected to one of the input parts of the optical switch, the photoreceiver is connected to the other, and of the N arms connected to the output part of the optical switch, the output part of the optical switch and the light A variable delay line is arranged in one arm of the interferometer that connects to the reflecting section, and the other (N-1) arm ends connected to the output section of the optical switch are for connecting the device under test. An optical sensor characterized by that. An N-arm optical Michelson interferometer having a low-coherence light source, a 2-input N-output (N is an integer of 3 or more) optical splitter, a light reflector, a light receiver, and an optical path for optically connecting them, The low-coherence light source is connected to one of the input parts of the optical splitter, the photoreceiver is connected to the other, and of the N arms connected to the output part of the optical splitter, the output part of the optical splitter and the light A variable delay line is disposed in one arm of the interferometer that connects to the reflection section, and an optical modulator is disposed in each of the other (N−1) arms connected to the output section of the optical splitter. In addition, the optical sensor is characterized in that each of the arm ends is used for connecting an object to be measured. A two-arm optical Michelson interferometer having a low-coherence light source, a directional coupler, a light reflector, a light receiver, and an optical path for optically connecting them, and one of the input parts of the directional coupler The low coherence light source is connected to the light receiver on the other side, and a variable delay line is arranged in one arm of the interferometer connecting the output part of the directional coupler and the light reflecting part, and the directionality An optical sensor characterized in that the other arm end connected to the output portion of the coupler is used for connecting an object to be measured that can be moved by a movable mechanism. A two-arm optical Mach-Zehnder interferometer having a low-coherence light source, two directional couplers, a light receiver, and an optical path for optically connecting them, wherein the interference between the two directional couplers The two arms of the total are composed of one arm on which a variable delay line is arranged and the other arm for arranging an object to be measured. An N-arm optical Mach-Zehnder interferometer having a low-coherence light source, an optical switch with 1 input and N output (N is an integer of 3 or more), an optical switch with N input and 1 output, a light receiver, and an optical path for optically connecting them. The N optical paths connecting the optical switches are composed of (N-1) optical paths for placing a device under test and one optical path having a variable delay line. Sensor. An N-arm optical Mach-Zehnder interferometer having a low-coherence light source, a 1-input N-output (N is an integer of 3 or more) optical splitter, an N-input 1-output optical combiner, a light receiver, and an optical path for optically connecting them. The N optical paths connecting the optical splitter and the optical combiner are arranged with an optical modulator, (N-1) optical paths for measuring object arrangement, and one variable delay line. An optical sensor comprising: A two-arm optical Mach-Zehnder interferometer having a low-coherence light source, two directional couplers, a light receiver, and an optical path for optically connecting them, and connecting the two directional couplers The optical path comprises an optical path for placing an object to be measured, which can be moved by a movable mechanism, and an optical path on which the variable delay line is disposed. The variable delay lines have length differences of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 ^K−1 ΔL, between K delay line pairs and at both ends. The delay line pair is connected with a total of K + 1 symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm, and has a phase adjustment unit at least at one of the input / output unit and the delay line unit. 9. The optical sensor according to claim 1, 2, 3, 4, 5, 6, 7 or 8. The variable delay lines have length differences of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 ^K−1 ΔL, between K delay line pairs and at both ends. A length of two symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm, and a phase adjustment unit on at least one arm before and after the delay line pair. 2. The connection is made by using K + 1 multistage interferometers connected by using waveguide pairs of equal length, and has a phase adjustment unit at least at one of an input / output unit and a delay line unit. , 2, 3, 4, 5, 6, 7 or 8. The variable delay lines have length differences of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 ^K−1 ΔL, between K delay line pairs and at both ends. Before and after the delay line pair, one output of each of the output parts of two symmetrical Mach-Zehnder interferometers having a phase adjustment unit on at least one arm, and a symmetrical Mach-Zehnder having a phase adjustment unit on at least one arm 2. A multi-stage interferometer connected to both input units of a type interferometer is connected by a K + 1 multi-stage interferometer, and has a phase adjusting unit at least at one of an input / output unit and a delay line unit. , 2, 3, 4, 5, 6, 7 or 8. The variable delay lines have length differences of ΔL, 2ΔL, 4ΔL,..., 2 ^K−2 ΔL, 2 ^K−1 ΔL, between K delay line pairs and at both ends. Both the output part of the symmetric Mach-Zehnder interferometer having a phase adjustment unit on at least one arm, and two symmetric Mach-Zehnder type interferometers having a phase adjustment unit on at least one arm, before and after the delay line pair The input unit is connected by K + 1 interferometers connected to one of the inputs, and has a phase adjustment unit at least at one of the input / output unit and the delay line unit. The optical sensor according to 2, 3, 4, 5, 6, 7 or 8. The optical sensor according to claim 4 or 8, wherein the movable mechanism uses a micro-electro-mechanical systems (MEMS) mechanism.

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