Optical coherence tomography

Abstract

To provide a new improved optical coherence tomographic device capable of, for example, inhibiting decrease in measurement accuracy due to manufacturing variations or the like.SOLUTION: The optical coherence tomographic device comprises: a light source part outputting light, capable of changing the wavelength of light to be outputted; a branch part splitting light from the light source part into irradiation light and reference light; a reference optical system transmitting the reference light from the branch part; an irradiation optical system transmitting the irradiation light from the branch part to irradiate an object therewith, and transmitting reflected light of irradiation light from the object; an interference part generating interference light generated by interference of the reflected light from the irradiation optical system and the reference light from the reference optical system; an interference light output part outputting interference light; and a coupling element functioning as the branch part and interference part. The reference optical system, the coupling element and the interference light output part are configured by a waveguide formed on a substrate and integrated on the substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical coherence tomography. [Background technology]

[0002] BACKGROUND ART Conventionally, optical coherence tomography devices have been known that have a wavelength-tunable light source, and each functional unit is configured by a waveguide and integrated on a substrate (for example, Patent Document 1).

[0003] The optical coherence tomography device of Patent Document 1 has, as integrated functional units, a branching unit, a reference optical system, an irradiation optical system, an interference unit, and an interference light output unit. The branching unit branches light from the light source unit into reference light for the reference optical system and irradiation light for the irradiation optical system. The reference optical system transmits the reference light to the interference unit after delaying it, for example. The irradiation optical system irradiates the irradiation light onto an object and transmits the reflected light of the irradiation light from the object to the interference unit. The interference unit causes interference between the reference light from the reference optical system and the reflected light from the irradiation optical system. The interference light output unit outputs the interference light to a detection unit. The optical signal received by the detection unit is subjected to predetermined processing to obtain a tomographic image of the object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-111062 Summary of the Invention [Problem to be solved by the invention]

[0005] In the optical tomographic interferometer disclosed in Patent Document 1, the branching section and the interference section are configured separately. Therefore, if a difference occurs between the branching ratio of the branching section and the branching ratio of the interference section due to manufacturing variations or the like, there is a risk that the difference will result in a decrease in measurement accuracy.

[0006] Therefore, one object of the present invention is to provide a new and improved optical coherence tomography device that can suppress a decrease in measurement accuracy due to, for example, manufacturing variations. [Means for solving the problem]

[0007] The optical coherence tomography of the present invention includes, for example, a light source unit that outputs light and is capable of changing the wavelength of the light it outputs; a branching unit that splits the light from the light source unit into illumination light and reference light; a reference optical system that transmits the reference light from the branching unit; an illumination optical system that transmits the illumination light from the branching unit to illuminate an object and transmits reflected light from the object of the illumination light; an interference unit that generates interference light resulting from interference between the reflected light from the illumination optical system and the reference light from the reference optical system; an interference light output unit that outputs the interference light; and a coupling element that functions as the branching unit and the interference unit, wherein the reference optical system, the coupling element, and the interference light output unit are configured by waveguides formed on a substrate and are integrated on the substrate.

[0008] In the optical coherence tomography, the coupling element may be a variable coupler that can change a branching ratio between 0 and 100%.

[0009] In the optical coherence tomography, the reference optical system may include a loop mirror formed of a waveguide.

[0010] In the optical coherence tomography, the reference optical system may include a variable optical attenuator formed by a waveguide.

[0011] In the optical coherence tomography, the reference optical system may include a variable delay device formed of a waveguide.

[0012] In the optical coherence tomography, the variable delay device may have a heater, and a heat insulating groove may be provided surrounding the variable delay device.

[0013] In the optical coherence tomography device, the interference light output section may include an arrayed waveguide grating.

[0014] In the optical coherence tomography, the reference optical system may include a variable optical attenuator formed by a waveguide, and the arrayed waveguide diffraction grating may be positioned away from the variable optical attenuator in a direction intersecting an output direction of unwanted light from the variable optical attenuator.

[0015] The optical coherence tomography device may include a switching unit provided between the light source unit and the coupling element, capable of switching between inputting light from the light source unit to the coupling element and inputting light to the interference light output unit, and the switching unit may be formed by a waveguide on the substrate and integrated on the substrate.

[0016] In the optical coherence tomography device, a matching agent container capable of containing a refractive index matching agent may be provided between the switching unit and the interference light output unit.

[0017] In the optical coherence tomography, the irradiation optical system may be provided with an object container capable of containing the object.

[0018] In the optical coherence tomography, the object storage unit may be provided in the irradiation optical system between the coupling element and the output end of the irradiation light in the optical coherence tomography, and the object storage unit may be configured such that when the object is not stored in the object storage unit, light from the coupling element can pass through the object storage unit and be output from the output end.

[0019] In the optical coherence tomography device, the object accommodation unit may be configured to accommodate a refractive index matching agent. [Effects of the Invention]

[0020] According to the present invention, it is possible to obtain a new and improved optical coherence tomography device that can suppress a decrease in measurement accuracy due to, for example, manufacturing variations. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is an exemplary block diagram of an optical coherence tomography device according to the first embodiment. [Figure 2] FIG. 2 is an exemplary schematic plan view of the optical coherence tomography device according to the first embodiment. [Figure 3] FIG. 3 is a schematic diagram illustrating an exemplary configuration of a Mach-Zehnder interferometer included in the optical coherence tomography device of the first embodiment. [Figure 4] FIG. 4 is an exemplary block diagram of the optical coherence tomography device according to the second embodiment. [Figure 5] FIG. 5 is an exemplary schematic plan view of the optical coherence tomography device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, several exemplary embodiments of the present invention will be disclosed. The configurations of the embodiments shown below, as well as the actions and results (effects) brought about by the configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

[0023] The following embodiments have similar configurations. Therefore, according to the configurations of each embodiment, similar actions and effects based on the similar configurations can be obtained. Furthermore, in the following, similar configurations are given similar reference numerals, and duplicated descriptions may be omitted.

[0024] 2 and 5, the X direction is represented by an arrow X, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X direction, Y direction, and Z direction intersect and are perpendicular to each other. In addition, in these Figures 2 and 5, the internal structure is drawn with solid lines.

[0025] Furthermore, each drawing is a schematic diagram, and the dimensions in the drawing may differ from the actual dimensions.

[0026] [First embodiment] FIG. 1 is a block diagram showing a schematic configuration of an optical coherence tomography device 100A (100) according to the first embodiment.

[0027] As shown in FIG. 1, the optical coherence tomography device 100 includes an optical integrated circuit 10A (10), a light source unit 20, an isolator 30, and a detection unit .

[0028] The light source unit 20 has, for example, a semiconductor laser element that outputs light (laser light). The light source unit 20 is a wavelength-variable light source that can change the wavelength of the light that it outputs.

[0029] The isolator 30 transmits light traveling from the light source unit 20 to the optical integrated circuit 10 and blocks light traveling from the optical integrated circuit 10 to the light source unit 20. In other words, the isolator 30 suppresses light from returning from the optical integrated circuit 10 to the light source unit 20.

[0030] The optical integrated circuit 10 is an integrated circuit integrally including a substrate 11 and a structure stacked on the substrate 11. The optical integrated circuit 10 can be configured as, for example, a known planar lightwave circuit (PLC). In this case, the substrate 11 is, for example, a glass substrate or a silicon substrate. The structure on the substrate 11 has, for example, a core and a cladding surrounding the core. The cladding is made of a silica-based glass material, and the core is made of a silica-based glass material having a refractive index higher than that of the cladding. The core may contain, for example, germania (GeO2) or zirconia (ZrO2) as a dopant that increases the refractive index. In the optical integrated circuit 10, the core formed in the structure on the substrate 11 constitutes a waveguide 12. The optical integrated circuit 10 may also be a silicon photonics device having a waveguide structure made of a silicon-based material.

[0031] The optical integrated circuit 10 has a coupling element 13, a reference optical system 14, an irradiation optical system 15, and an interference light output unit 16. The coupling element 13, the reference optical system 14, the irradiation optical system 15, and the interference light output unit 16 are all configured with a waveguide 12.

[0032] The combining element 13 splits the light from the light source unit 20 into reference light to be directed to the reference optical system 14 and irradiation light to be directed to the irradiation optical system 15. In other words, the combining element 13 functions as a splitter.

[0033] The reference optical system 14 transmits the reference light. The reference optical system 14 has a variable delay device 141, a variable optical attenuator 142, and a mirror 143. The reference light that has passed through the variable delay device 141 and the variable optical attenuator 142 is reflected by the mirror 143, and passes through the variable optical attenuator 142 and the variable delay device 141 again to return to the coupling element 13.

[0034] The illumination optical system 15 has a waveguide 12 that transmits illumination light. The illumination light that has passed through the waveguide 12 is output from an end of the waveguide 12 at the end face 10a of the optical integrated circuit 10 and is illuminated onto the object 200, and at least a portion of the light reflected from the object 200 in response to the illumination light is input to the waveguide 12. The reflected light passes through the waveguide 12 again and is input to the coupling element 13. In other words, the illumination optical system 15 transmits the illumination light and the reflected light.

[0035] The combining element 13 generates interference light by causing interference between the reference light from the reference optical system 14 and the reflected light from the irradiation optical system 15. In other words, the combining element 13 functions as an interference section.

[0036] As described above, the coupling element 13 also functions as a branching section. That is, the coupling element 13 functions as both a branching section and an interference section. If the branching section and the interference section are configured separately as in Patent Document 1, differences in specifications such as dimensions will occur between the branching section and the interference section, which will result in differences between the branching ratio of the branching section and the interference section, and ultimately, the accuracy of the measurement results may be reduced. In this regard, according to the present embodiment, the coupling element 13 functions as both a branching section and an interference section, and this can eliminate differences in specifications between the branching section and the interference section, and ultimately the differences in branching ratio, thereby suppressing the reduction in measurement accuracy caused by the branching section and the interference section being configured separately.

[0037] The interference light from the coupling element 13, which functions as an interference unit, passes through the interference light output unit 16 and is input to the detection unit 40. The detection unit 40 converts the interference light into an electrical signal, and then performs AD conversion to output a digital signal. The digital signal is subjected to Fourier analysis in a signal processing unit (not shown), and a tomographic image of the object 200 is obtained.

[0038] Next, a specific example of the configuration of each part of the optical integrated circuit 10A (10) will be described. FIG. 2 is a schematic plan view of the optical coherence tomography device 100A (100). The optical integrated circuit 10 as a whole extends in a direction perpendicular to and intersects with the Z direction. The optical integrated circuit 10 also has a surface 10b facing the Z direction. The surface 10b is also referred to as the front surface. In the optical integrated circuit 10, the waveguide 12 extends in a curved manner intersecting the Z direction.

[0039] The coupling element 13 can be configured as, for example, a Mach-Zehnder interferometer 50. FIG. 3 is a plan view showing a schematic configuration of the Mach-Zehnder interferometer 50. The Mach-Zehnder interferometer 50 has two waveguides 12 and two coupling portions 50a and 50b that are spaced apart from each other and optically couple the two waveguides 12. These coupling portions 50a and 50b have a branching ratio of 1:1 and can be configured by, for example, a directional coupler or a multimode interference (MMI) waveguide. In the Mach-Zehnder interferometer 50, one end of the waveguide 12 is a port pa, pb, and the other end of the waveguide 12 is a port pc, pd.

[0040] The Mach-Zehnder interferometer 50 is also equipped with a heater 51, which is configured to heat one of the two waveguides 12 between the coupling portions 50a and 50b. The heater 51 is, for example, an electric heater having an electrical resistance that generates heat when electricity is applied, and generates heat when electricity is applied between two terminals 52. In this case, the heating by the heater 51 changes the refractive index of the heated waveguide 12, thereby generating an appropriate optical path difference between the light passing through the heated waveguide 12 and the light passing through the unheated waveguide 12, thereby making it possible to eliminate output from port pd when light is input from port pa. In this case, for example, the branching ratio from port pa to port pd is 0%.

[0041] When the Mach-Zehnder interferometer 50 of FIG. 3 is applied to the coupling element 13, port pa is an input port for light from the isolator 30 (light source unit 20), port pb is an output port for light to the interference light output unit 16, port pc is an input / output port for light with the reference optical system 14, and port pd is an input / output port for light with the irradiation optical system 15. In this case, by heating the heater 51, it is possible to obtain a state in which no light is output from port pd without stopping the light output from the light source unit 20. This makes it possible to obtain a state in which no irradiation light is output from the irradiation optical system 15 with a relatively simple configuration and relatively easily. In other words, the coupling element 13 is an example of a variable coupler that can switch the branching ratio between 0 and 100% and can function as a switch that stops the output of irradiation light.

[0042] As shown in FIG. 2 , the reference optical system 14 includes a curved waveguide 12 and a heater 141a that heats at least a portion of the curved waveguide 12 as the variable delay device 141. With this configuration, the refractive index of the waveguide 12 can be changed by heating the heater 141a, thereby changing the delay amount of the reference light. The optical integrated circuit 10 also includes a groove 141b recessed from the surface 10b in the opposite direction to the Z direction. The groove 141b extends so as to surround the variable delay device 141 when viewed in the opposite direction to the Z direction. The groove 141b can prevent heat from being transferred from the variable delay device 141 to its surroundings. Heat loss from the variable delay device 141 to its surroundings may reduce the heating efficiency of the heater 141a, increasing power consumption, or may heat the waveguide 12, which should not be heated, resulting in unintended changes in the optical characteristics of the light passing through the waveguide 12. In this regard, according to the present embodiment, by providing groove 141b, it is possible, with a relatively simple configuration, to prevent the above-mentioned inconvenience caused by heat escaping to the periphery of variable delay device 141. Groove 141b is an example of a heat insulating groove.

[0043] The reference optical system 14 also has a Mach-Zehnder interferometer 50 having the same configuration as that shown in FIG. 3 as the variable optical attenuator 142, and a loop mirror as the mirror 143. The reference light that reaches the mirror 143 via the variable optical attenuator 142 is reflected by the mirror 143, returns to the variable delay device 141 via the variable optical attenuator 142 again, and is input to the coupling element 13. The variable optical attenuator 142 also has a heater 51 (see FIG. 3), and the proportion of the reference light that passes through can be changed by adjusting the amount of heat generated by the heater 51. That is, the variable optical attenuator 142 can adjust the proportion of the reference light that returns to the coupling element 13 out of the reference light input from the coupling element 13, i.e., the power of the reference light that returns to the coupling element 13. The mirror 143 is not limited to a loop mirror.

[0044] The interference light output unit 16 can be configured as, for example, an arrayed waveguide grating (AWG). The interference light output unit 16 has a plurality of parallel waveguides 12 that function as channel waveguides, and can demultiplex the interference light into individual wavelengths. The arrayed waveguide grating can be configured with high precision in the optical integrated circuit 10.

[0045] Here, as shown in FIG. 2, unwanted light is output from the variable optical attenuator 142 in a direction Ds (see FIG. 2). In this embodiment, the direction Ds in which the unwanted light is output is the X direction or the direction opposite to the X direction. If this unwanted light (stray light) unintentionally propagates within the optical integrated circuit 10 and reaches the interference light output unit 16, there is a risk of measurement accuracy decreasing, which is undesirable. Therefore, in this embodiment, the interference light output unit 16 is provided away from the variable optical attenuator 142 in a direction intersecting the direction Ds (X direction), for example, in the direction opposite to the Y direction. With this configuration, it is possible to prevent measurement accuracy from decreasing due to unwanted light from the variable optical attenuator 142.

[0046] As described above, the optical coherence tomography device 100 of this embodiment includes the coupling element 13 that functions as both a branching section and an interference section. Therefore, according to this embodiment, it is possible to suppress a decrease in measurement accuracy caused by the branching section and the interference section being configured separately.

[0047] Furthermore, according to this embodiment, the optical integrated circuit 10 has a Mach-Zehnder interferometer 50 as the coupling element 13, a variable delay device 141 formed by the waveguide 12, a Mach-Zehnder interferometer 50 as the variable optical attenuator 142, a loop mirror as the mirror 143, and an AWG as the interference light output unit 16. With these configurations, the optical integrated circuit 10 and therefore the optical coherence tomography device 100 can be realized with a smaller size and a more mass-producible configuration.

[0048] [Second embodiment] 4 is a block diagram showing a schematic configuration of an optical coherence tomography device 100B (100) according to the second embodiment. The optical coherence tomography device 100B according to this embodiment also has a configuration similar to that of the optical coherence tomography device 100A according to the first embodiment. Therefore, this embodiment also provides the same effects as those of the first embodiment.

[0049] However, in this embodiment, a switching unit 17 is provided. The switching unit 17 is provided in the optical integrated circuit 10B(10) so as to be interposed between the light source unit 20 and the coupling element 13. The switching unit 17 switches between a state in which light from the light source unit 20 is input to the coupling element 13 and a state in which light is input to the interference light output unit 16 via the waveguide 12B. By inputting light from the light source unit 20 to the interference light output unit 16 using the switching unit 17 and detecting the light from the interference light output unit 16 using the detection unit 40, it is possible to examine the optical characteristics of the interference light output unit 16 itself, and thereby, for example, to perform measurement calibration or correct the measurement results.

[0050] 5 is a schematic plan view of the optical coherence tomography device 100B (100). As shown in FIG. 5, the switching unit 17 includes a switch 17a configured as a Mach-Zehnder interferometer 50 and a matching agent container 18.

[0051] The switch 17a also has a heater 51 (see FIG. 3 ), and the branching ratio of light can be changed by switching the heating state of the heater 51. Specifically, the switch 17a can switch between a case where the proportion of light directed toward the coupling element 13 and the proportion of light directed toward the interference light output unit 16, out of the light input from the light source unit 20, is 100[%] and a case where the proportion of light directed toward the coupling element 13 is 0[%] and the proportion of light directed toward the interference light output unit 16 is 100[%]. With this configuration, for example, before performing a measurement using the optical coherence tomography device 100B, an inspection of the interference light output unit 16 can be performed with the proportion of light directed toward the interference light output unit 16 set to 100[%], and the measurement can be calibrated or the measurement result can be corrected based on the inspection result.

[0052] The matching agent container 18 is formed, for example, as a bottomed recess opening on the surface 10b of the optical integrated circuit 10B and is configured to contain a refractive index matching agent such as matching oil. In this case, by appropriately setting specifications such as the refractive index of the refractive index matching agent and the dimensions of the matching agent container 18, the optical integrated circuit 10B can be configured so that when a refractive index matching agent is contained, light from the light source 20 is transmitted to the interference light output unit 16 via the matching agent container 18, and when a refractive index matching agent is not contained, the light from the light source 20 is diffused in the matching agent container 18 and is not transmitted to the interference light output unit 16. This configuration can more reliably prevent light from leaking from the switching unit 17 to the interference light output unit 16, for example, during measurement.

[0053] Furthermore, in this embodiment, the irradiation optical system 15 is provided with an object accommodation section 19 capable of accommodating the object 200. The object accommodation section 19 is provided in the optical integrated circuit 10B as a bottomed recess that opens on the surface 10b, and is configured to be capable of accommodating the object 200. With this configuration, for example, the position of the object 200 can be determined in advance within a certain range, making it easier or faster to perform more accurate measurement than when the object 200 is located outside the optical integrated circuit 10B (optical coherence tomography 100).

[0054] Furthermore, in this embodiment, the object container 19 is provided in the irradiation optical system 15 between the coupling element 13 and the end face 10a of the optical integrated circuit 10B, i.e., the end (output end) of the waveguide 12 in the optical coherence tomography device 100B. In this configuration, by appropriately setting specifications such as the refractive index of the refractive index matching agent and the dimensions of the object container 19, the optical integrated circuit 10B can be configured so that, when the object 200 is not contained but a refractive index matching agent is contained, the irradiation light and the reflected light are transmitted through the object container 19. In this case, as in the first embodiment, the irradiation light from the coupling element 13 passes through the waveguide 12, the object container 19, and the waveguide 12, is output from the end face 10a of the optical integrated circuit 10, and is irradiated onto the object 200, and at least a portion of the reflected light of the irradiation light from the object 200 is input to the waveguide 12. The reflected light passes through the waveguide 12 , the object container 19 , and the waveguide 12 again and is input to the coupling element 13 .

[0055] On the other hand, when the object 200 is accommodated in the object accommodation section 19, the irradiated light from the coupling element 13 is irradiated onto the object 200 from the end of the waveguide 12 facing the object accommodation section 19, and at least a part of the light reflected from the irradiated light by the object 200 is input to the waveguide 12 from the end. The reflected light passes through the waveguide 12 again and is input to the coupling element 13.

[0056] Therefore, according to this embodiment, the optical coherence tomography device 100B can perform measurements both when the object 200 is positioned opposite the output end of the waveguide 12 and when the object 200 is contained in the object container 19.

[0057] While the embodiments of the present invention have been described above, they are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

[0058] For example, the coupling element may be realized by a configuration other than a Mach-Zehnder interferometer, such as a directional coupler or an MMI.

[0059] Furthermore, the attitude of the variable optical attenuator, the layout of the variable optical attenuator and the interference light output unit, etc. are not limited to those in the above embodiment, and the configuration, attitude, arrangement, etc. of other functional units are also not limited to those in the above embodiment. [Explanation of symbols]

[0060] 10, 10A, 10B... Optical integrated circuit 10a…End face (output end) 10b...side 11... Circuit board 12,12B…Waveguide 13...Coupling element (variable coupler) 14...Reference optical system 15…Irradiation optical system 16...Interference light output section (arrayed waveguide grating) 17...Switching section 17a...Switch 18...Matching agent container 19...Object storage section 20…Light source section 30...Isolator 40...Detection unit 50...Mach-Zehnder interferometer 50a,50b…Joining part 51...Heater 52...Terminal 100, 100A, 100B...Optical coherence tomography 141...Variable delay 141a...Heater 141b... Groove (insulating groove) 142...Variable optical attenuator 143...Mirror (loop mirror) 200...Object pa, pb, pc, pd...port Ds…direction X…direction Y...direction Z…direction

Claims

1. a light source unit that outputs light and is capable of changing the wavelength of the light that it outputs; a branching unit that branches the light from the light source unit into irradiation light and reference light; a reference optical system that transmits the reference light from the branching unit; an irradiation optical system that transmits the irradiation light from the branching unit to irradiate an object and transmits reflected light of the irradiation light from the object; an interference unit that generates interference light resulting from interference between the reflected light from the irradiation optical system and the reference light from the reference optical system; an interference light output unit that outputs the interference light; a coupling element that functions as the branching unit and the interference unit; a switching unit provided between the light source unit and the coupling element, capable of switching between inputting the light from the light source unit to the coupling element and inputting the light to the interference light output unit; Equipped with An optical coherence tomography device, wherein the reference optical system, the coupling element, the interference light output unit, and the switching unit are configured by waveguides formed on a substrate and are integrated on the substrate.

2. The optical coherence tomography device according to claim 1 , further comprising a matching agent container capable of containing a refractive index matching agent, disposed between the switching unit and the interference light output unit.

3. 3. The optical coherence tomography device according to claim 1, wherein the coupling element is a variable coupler that can change a branching ratio between 0 and 100%.

4. 4. The optical coherence tomography system according to claim 1, wherein the reference optical system includes a loop mirror formed of a waveguide.

5. 5. The optical coherence tomography system according to claim 1, wherein the reference optical system includes a variable optical attenuator formed by a waveguide.

6. 6. The optical coherence tomography system according to claim 1, wherein the reference optical system includes a variable delay device formed by a waveguide.

7. the variable delay device has a heater; The optical coherence tomography device of claim 6 , further comprising an insulating groove surrounding the variable retarder.

8. 8. The optical coherence tomography device according to claim 1, wherein the interference light output section includes an arrayed waveguide grating.

9. the reference optical system includes a variable optical attenuator formed by a waveguide, 9. The optical coherence tomography device according to claim 8, wherein the arrayed waveguide grating is positioned away from the variable optical attenuator in a direction intersecting an output direction of unwanted light from the variable optical attenuator.

10. The optical coherence tomography device according to any one of claims 1 to 9, wherein the irradiation optical system is provided with an object accommodation unit capable of accommodating the object.

11. the object accommodation unit is provided in the irradiation optical system between the coupling element and an output end of the irradiation light in the optical coherence tomography device, 11. The optical coherence tomography according to claim 10, wherein the object storage unit is configured such that, when the object is not stored in the object storage unit, light from the coupling element can pass through the object storage unit and be output from the output end.

12. The optical coherence tomography apparatus according to claim 11 , wherein the object container is configured to be able to contain a refractive index matching agent.

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