Device

Abstract

To provide an optical component capable of reducing the loss of signal light.SOLUTION: An optical component provided herein is designed to be attached to an optical fiber and comprises a lens with a refractive index distribution, where a portion between the lens and the optical fiber, where signal light travels, is provided with a gap to be filled with a liquid.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device that is used under high pressure. Device It is related to. [Background technology]

[0002] Conventional optical fiber hydrophones (optical fiber acoustic sensors) shown in Figure 4 of Non-Patent Document 1 use a sensing fiber to detect underwater sounds, as well as optical components such as an optical coupler and Faraday Rotator Mirror (FRM) that constitute a sensing interferometer. Furthermore, when wavelength-division multiplexing signals from multiple hydrophones, optical components such as a multiplexer / demultiplexer are also used. These optical components function to emit signal light from the optical fiber into the air, branch it, and then input it into the optical fiber. In this process, curved lenses are often used in these optical components to convert the divergence angle of the signal light emitted from the optical fiber into parallel light close to 0 degrees, efficiently input the signal light into the optical fiber core, and reduce loss between the emission and input of the signal light. However, while curved lenses are intended for use in air, the optical components in Non-Patent Document 1 are intended for use underwater, requiring them to be housed in a pressure-resistant container to withstand water pressure.

[0003] When optical components are used under high pressure, the usual method is to make the pressure-resistant container that the optical components are placed in heavier, but this causes the problem of the pressure-resistant container becoming larger.In addition to making the pressure-resistant container that the optical components are placed in heavier, when optical components are used under high pressure, there is also the method of emitting the signal light into a liquid, branching it, etc., and then inputting it into an optical fiber, but because the refractive index of a liquid changes with temperature and pressure, the refraction angle changes in a curved lens, increasing the loss until it is coupled to the optical fiber.

[0004] In addition to the use of a curved lens in the method of releasing signal light into a liquid, branching it, and then inputting it into an optical fiber, there is also a method of fusion splicing a GI (Graded Index) fiber to the end of an SM (Single Mode) fiber that propagates the signal light and using it as a lens (hereinafter referred to as a GI lens), as shown in Fig. 2 of Non-Patent Document 2. By making the light closer to parallel light inside the GI lens, changes in the refraction angle are suppressed even if the refractive index of the liquid changes, and loss until input to the optical fiber can be reduced.

[0005] An example of the configuration of an optical fiber hydrophone 200 considered in the prior art is shown in Figure 4. The example of the configuration of the optical fiber hydrophone 200 shown in Figure 4 has a structure in which a sensing interferometer consisting of an optical coupler, two FRMs, and a sensing fiber is installed in a container filled with a liquid that transmits acoustic signals. The signal light coming from the light source passes through a wavelength division multiplexer / demultiplexer and is input to the sensing interferometer. The signal light input to the sensing interferometer is split by the optical coupler, one of which is input to the FRM via the sensing fiber and the other to another FRM. The signal light reflected by each FRM then propagates in the opposite direction through the optical coupler and demultiplexer toward the O / E converter. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] JJAP, 52, 012501,“Expansion of dynamic range in interferometric fiber optic hydrophone” [Non-patent document 2] IEEE Photonics J. Vol. 2, No. 3, June 2010,“Fringe Visibility Enhanced Extrinsic Fabry?Perot Interferometer Using a Graded Index Fiber Collimator” Summary of the Invention [Problem to be solved by the invention]

[0007] In a conventional optical fiber hydrophone 200 such as that shown in Figure 4, which is an optical component that has the function of releasing signal light into a liquid or the function of injecting signal light into an optical fiber, when the SM fiber and the GI lens are fusion-spliced, the refractive index distribution of the molten part is disturbed, which also disturbs the intensity distribution of the signal light released into the liquid. As a result, the proportion of light that enters the optical fiber and enters the core and propagates farther decreases, resulting in an increase in loss of signal light.

[0008] The present disclosure has been made to solve the above problems, and is capable of reducing loss of signal light. Device The purpose is to provide. [Means for solving the problem]

[0009] The apparatus according to the present disclosure is an apparatus having optical components used under high pressure, and includes the optical components, an optical fiber, and a container for storing the optical components, the optical components including a fixing portion for attaching the optical fiber and a lens using a refractive index gradient, the fixing portion fixes the optical fiber such that a gap for liquid to enter is provided in a portion where light propagates between the lens and the optical fiber attached to the fixing portion, the container is filled with the liquid, and the optical components include a Faraday rotator and A reflecting surface is installed perpendicular to the incident direction of the light that has passed through the Faraday rotator so as to reflect the light that has passed through the Faraday rotator and pass it in the opposite direction along the same path. A FRM equipped with a mirror is housed inside the container. [Effects of the Invention]

[0010] The present disclosure DeviceAccording to the method, a gap through which liquid can enter is provided in the portion where the signal light propagates between the lens and the optical fiber, and by allowing the liquid to enter the gap, disturbances in the refractive index distribution are eliminated, thereby reducing the loss of the signal light. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a configuration of an optical component according to a first embodiment. [Figure 2] FIG. 10 is a diagram illustrating a configuration of an optical component according to a second embodiment. [Figure 3] FIG. 10 is a diagram illustrating a configuration of an optical component according to a third embodiment. [Figure 4] FIG. 1 is a diagram showing an example of the configuration of a conventional optical fiber hydrophone. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. Also, the size relationships of the components in the drawings may differ from those in reality.

[0013] Embodiment 1 FIG. 1 is a diagram showing a configuration of an optical component according to the first embodiment. In the first embodiment, an FRM 10 will be described as an example of an optical component that handles signal light of an optical fiber hydrophone.

[0014] [FRM10 Configuration] The FRM 10 includes an SM (Single Mode) fiber 11 as an optical fiber, a GI (Graded Index) lens 12 that uses a refractive index gradient, a Faraday rotator 13, a mirror 14, a spacer 15, and a substrate 16. The FRM 10 is mounted in a container 101 filled with a liquid. The GI lens 12 converts the signal light emitted from the SM fiber 11 into parallel light with a divergence angle close to 0 degrees or gently converging light, thereby reducing the diffusion loss of the signal light. To prevent damage to the optical components due to freezing, the liquid filled in the container 101 is an oil or the like that remains liquid within the storage and operating temperatures.

[0015] An SM fiber 11 and a GI lens 12, which emit signal light arriving from a light source, are arranged side by side, with a narrow gap G1 between the end face of the SM fiber 11 and the GI lens 12. By providing the narrow gap G1 between the SM fiber 11 and the GI lens 12 in this way, liquid fills the gap G1, resulting in a structure in which no air remains in the portion of the gap G1 through which the signal light propagates. Regarding the above structure, if there is a downward depression in the portion of the gap G1 through which the signal light propagates, air may remain in the downward depression when liquid flows into the gap G1, causing the signal light to be refracted. Therefore, it is desirable to have a structure in which the top of the gap G1 is open and there is no downward depression. However, if air remains in the portion of the gap G1 through which the signal light propagates, it is possible to remove the air by repeatedly pressurizing and depressurizing the gap G1 after filling it with liquid. Therefore, it is not essential to have a structure in which the top of the gap G1 is open and there is no downward depression. Furthermore, it is desirable to have a narrower gap G1, but if the gap G1 is made too narrow when using a highly viscous liquid, air is more likely to remain when the liquid is poured into the gap G1, so it is desirable to ensure a width that makes it difficult for air to remain.

[0016] The SM fiber 11 is fixed to a substrate 16 with a spacer 15 sandwiched therebetween, and the GI lens 12, Faraday rotator 13, and mirror 14 are fixed directly to the substrate 16. A liquid is filled in the portion (path) along which the signal light propagates from the GI lens 12 to the mirror 14. The GI fiber that forms the GI lens 12 and the SM fiber 11 are not fused together, and the GI lens 12 and the SM fiber 11 are separated from each other.

[0017] The Faraday rotator 13 and the mirror 14 are arranged so that the signal light emitted from the GI lens 12 passes through the Faraday rotator 13 , is reflected by the mirror 14 , and returns along the same path in the opposite direction to be incident on the SM fiber 11 .

[0018] [FRM10 Operation] The signal light emitted from the SM fiber 11 propagates through the liquid in gap G1 and enters the GI lens 12, where it is converted into parallel light with a divergence angle close to 0 degrees or gently converging light and emitted into the liquid. The signal light emitted from the GI lens 12 propagates through the liquid, the Faraday rotator 13, and again into the liquid, reflected by mirror 14, and then propagates in the reverse direction through the liquid, the Faraday rotator 13, the liquid, the GI lens 12, and again into the liquid, before entering the SM fiber 11.

[0019] [EFFICIENCY OF FRM10] In a method of mounting optical components in a container 101 filled with liquid to provide high pressure resistance to optical components without using a heavy pressure-resistant container, when the SM fiber 11 and the GI lens 12 are fusion-spliced ​​using conventional technology, the refractive index distribution of the fused portion is disturbed, which also disturbs the intensity distribution of the signal light emitted into the liquid, resulting in a problem of reduced coupling when the signal light enters the optical fiber. To address this problem, in the first embodiment, the SM fiber 11 and the GI lens 12 are not fusion-spliced, but the GI lens 12 and the SM fiber 11 are separated, and a gap G1 into which liquid can enter is provided between them, thereby eliminating the disturbance in the refractive index distribution and reducing the loss of the signal light.

[0020] The divergence angle of the signal light emitted from the SM fiber 11 into the liquid in the gap G1 is determined by the refractive index ratio between the SM fiber 11 and the liquid, and the divergence angle of the signal light incident on the GI lens 12 from the liquid in the gap G1 is determined by the refractive index ratio between the liquid and the GI lens 12. Here, when the width of the gap G1 is narrow, the refractive index ratio between the SM fiber 11 and the GI lens 12 dominates the divergence angle and diameter of the signal light incident on the GI lens 12, and the influence of the refractive index of the liquid is negligible. Therefore, when the width of the gap G1 is narrow, even if the divergence angle in the gap G1 changes due to changes in temperature and pressure, the influence on the diameter of the signal light emitted from the GI lens 12 is negligible. As a result, a decrease in coupling when the signal light is incident on the SM fiber 11 is suppressed, and an increase in loss of the signal light is mitigated.

[0021] Furthermore, since the signal light emitted from the GI lens 12 is parallel light with a divergence angle close to 0 degrees or gently converging light, the increase in loss of the signal light due to the change in refractive index between the GI lens 12 and the mirror 14, which increases the distance it propagates through the liquid, is slight.

[0022] In the prior art, changes in temperature and pressure change the refractive index of the liquid, causing changes in the angle of incidence and diameter of the signal light that is reflected by the mirror 14, propagates through the liquid, and enters the Faraday rotator 13, the GI lens 12, and the SM fiber 11. In the first embodiment, the width of the gap G1 through which the signal light propagates in the liquid is narrowed in the portion where the angle of incidence is not close to 0 degrees, i.e., between the SM fiber 11 and the GI lens 12. Also, in the first embodiment, the divergence angle of the GI lens 12 is set to close to 0 degrees in the portion where the propagation distance in the liquid is long, i.e., between the GI lens 12 and the mirror 14. Therefore, in the first embodiment, even if changes in temperature and pressure change the refractive index of the liquid, changes in the angle of incidence and diameter of the signal light that is reflected by the mirror 14, propagates through the liquid, and enters the SM fiber 11 are small, thereby suppressing an increase in the loss of the signal light.

[0023] According to the first embodiment, by taking measures as described above to address the cause of increased loss of signal light that occurs when optical components are immersed in liquid, it is possible to realize optical components that combine high water pressure resistance and low loss of signal light without using a heavy pressure-resistant container.

[0024] As described above, the optical component according to the first embodiment is an optical component that is attached to an SM fiber 11 and has a GI lens 12 that uses a refractive index distribution, and a gap G1 that is a gap into which a liquid can enter is provided in the portion where the signal light propagates between the GI lens 12 and the SM fiber 11.

[0025] According to the optical component of embodiment 1, a gap G1 into which liquid can enter is provided in the portion where the signal light propagates between the GI lens 12 and the SM fiber 11. By filling the gap G1 with liquid, the disturbance in the refractive index distribution is eliminated, and the loss of the signal light can be reduced.

[0026] Embodiment 2 The second embodiment will be described below, but explanations of parts that overlap with those of the first embodiment will be omitted, and parts that are the same as or equivalent to those of the first embodiment will be given the same reference numerals.

[0027] FIG. 2 is a diagram illustrating a configuration of an optical component according to the second embodiment. In the second embodiment, an optical coupler 20 will be described as an example of an optical component that handles signal light from an optical fiber hydrophone.

[0028] [Configuration of optical coupler 20] The optical coupler 20 includes an SM fiber 21, a GI lens 22, a half mirror 24, a spacer 25, a substrate 26, and a uniform medium 28. The optical coupler 20 is mounted in a container 101 filled with a liquid.

[0029] The SM fiber 21 is fixed to a substrate 26 with a spacer 25 sandwiched therebetween, and the GI lens 22, the half mirror 24, and the uniform medium 28 are fixed directly to the substrate 26.

[0030] The half mirror 24 is configured in the same manner as the optical coupler of the prior art shown in FIG. 4, that is, configured to split the signal light input to the optical coupler 20 into two different directions.

[0031] As in the first embodiment, the GI fiber forming the GI lens 22 and the SM fiber 21 are not fused together, but are separated from each other. However, a uniform medium 28 is provided between the GI lens 22 and the SM fiber 21. The uniform medium 28 is a medium with a uniform refractive index that does not have a core for propagating signal light, such as an optical fiber. The uniform medium 28 is made of a material such as silica glass, whose refractive index changes less with temperature and pressure than a liquid. The length of the uniform medium 28 and the size and refractive index distribution of the GI lens 22 are set so that the diameter of the signal light emitted from the SM fiber 21 expands in the uniform medium 28 and is emitted as light with a divergence angle close to 0 degrees by the GI lens 22.

[0032] Furthermore, narrow gaps G21 and G22 are provided between the end face of the SM fiber 21 and the uniform medium 28, and between the uniform medium 28 and the end face of the GI lens 22, respectively, as in the first embodiment, and liquid is filled in these gaps G21 and G22.

[0033] [Operation of optical coupler 20] 4, i.e., it splits the signal light input to the optical coupler 20 into two different directions. The GI lens 22 and other components, as well as the gaps G21 and G22, operate in the same manner as in the first embodiment. The uniform medium 28 expands the diameter of the signal light propagating from the SM fiber 21 to the GI lens 22, and also reduces the diameter of the signal light propagating from the GI lens 22 to the SM fiber 21.

[0034] [Effect of Optical Coupler 20] The optical coupler 20 provides the same effects as those of the first embodiment. Furthermore, by providing the uniform medium 28 between the GI lens 22 and the SM fiber 21, even if the intensity distribution of the signal light changes due to small irregularities on the surfaces of the GI lens 22 and the half mirror 24, or small impurities floating in the liquid, the uniform medium 28 widens the diameter of the signal light propagating from the SM fiber 21 to the GI lens 22. Furthermore, because the diameter of the signal light emitted from the GI lens 22 is wider than the size of the small irregularities and the size of the small impurities, an effect of reducing an increase in loss of the signal light is obtained.

[0035] As described above, in the optical component according to the second embodiment, the uniform medium 28, which is a medium with a uniform refractive index, is provided in the portion between the GI lens 22 and the SM fiber 21 through which the signal light propagates.

[0036] According to the optical component of the second embodiment, by providing the uniform medium 28 as described above, even if the intensity distribution of the signal light changes due to minute irregularities on the surface of the GI lens 22 or fine impurities floating in the liquid, the uniform medium 28, which is a medium with a uniform refractive index, expands the diameter of the signal light propagating from the SM fiber 21 to the GI lens 22. Furthermore, since the diameter of the signal light emitted from the GI lens 22 is wider than the size of the above-mentioned fine irregularities and the size of the fine impurities, an effect of reducing an increase in loss of the signal light is obtained.

[0037] Embodiment 3 Hereinafter, the third embodiment will be described, but explanations of parts that overlap with the first and second embodiments will be omitted, and parts that are the same as or equivalent to the first and second embodiments will be given the same reference numerals.

[0038] FIG. 3 is a diagram illustrating a configuration of an optical component according to the third embodiment. In the third embodiment, a multiplexer / demultiplexer 30 will be described as an example of an optical component that handles signal light from an optical fiber hydrophone.

[0039] [Configuration of multiplexer / demultiplexer 30] The multiplexer / demultiplexer 30 includes an SM fiber 31, a GI lens 32, a multilayer filter 34, a spacer 35, a substrate 36, a uniform medium 38, and a uniform medium 39. The multiplexer / demultiplexer 30 is mounted in a container 101 filled with a liquid.

[0040] The multilayer filter 34 is configured in the same manner as the prior art multiplexer / demultiplexer of FIG. 4, that is, configured to transmit only specific wavelengths of the signal light input to the multiplexer / demultiplexer 30 and reflect other wavelengths.

[0041] As in the first embodiment, the GI fiber that forms the GI lens 32 and the SM fiber 31 are not fused together, but the GI lens 32 and the SM fiber 31 are separated. However, a uniform medium 38 is provided between the GI lens 32 and the SM fiber 31. Here, like the uniform medium 28 in the second embodiment, the uniform medium 38 is a medium with a uniform refractive index that does not have a core for propagating signal light, such as an optical fiber. Furthermore, the material of the uniform medium 38 is, for example, quartz glass, whose refractive index changes less with temperature and pressure than a liquid.

[0042] A uniform medium 39 is provided between the GI lens 32 and the multilayer filter 34, where the signal light emitted from the GI lens 32 propagates as parallel light with a divergence angle close to 0 degrees or as gently converging light. Similar to the uniform medium 38, the uniform medium 39 is a medium with a uniform refractive index that does not have a core for propagating the signal light, such as an optical fiber. The material of the uniform medium 39 is, for example, quartz glass, which has lower absorption of the signal light than a liquid.

[0043] Furthermore, narrow gaps G31 and G32 are provided between the end face of the SM fiber 31 and the uniform medium 38, and between the uniform medium 38 and the end face of the GI lens 32, respectively, as in the second embodiment, and liquid is filled in these gaps G31 and G32.

[0044] [Operation of multiplexer / demultiplexer 30] The multilayer filter 34 operates in the same manner as the conventional optical demultiplexer shown in Fig. 4, i.e., it transmits only specific wavelengths of the signal light input to the multiplexer / demultiplexer 30 and reflects other wavelengths. The GI lens 32 and other components, as well as the narrow gaps G31 and G32, operate in the same manner as in the first embodiment. The uniform medium 38 expands the diameter of the signal light propagating from the SM fiber 31 to the GI lens 32 and reduces the diameter of the signal light propagating from the GI lens 32 to the SM fiber 31. The uniform medium 39 has low absorption of the signal light and allows the signal light emitted from the GI lens 32 to propagate.

[0045] [Effects of the multiplexer / demultiplexer 30] The multiplexer / demultiplexer 30 achieves the same effects as in the second embodiment. Furthermore, a uniform medium 39 with a uniform refractive index is provided in the portion where the signal light emitted from the GI lens 32 propagates as parallel light with a divergence angle close to 0 degrees or as gently converging light. This reduces changes in the intensity distribution of the signal light due to impurities floating in the liquid, and shortens the propagation distance through the liquid, thereby reducing the absorption of the signal light by the liquid, thereby reducing loss of the signal light. Furthermore, by using a material for the uniform medium 39 that absorbs signal light less than the liquid, loss of the signal light can be further reduced.

[0046] As described above, the optical component according to the third embodiment has a uniform medium 39, which is a medium with a uniform refractive index, provided in a portion where the signal light emitted from the GI lens 32 propagates as parallel light with a divergence angle close to 0 degrees or as gently converging light.

[0047] According to the optical component of the third embodiment, by providing the uniform medium 39 as described above, the change in the intensity distribution of the signal light caused by impurities floating in the liquid is reduced, and the shorter the propagation distance in the liquid, the less the absorption of the signal light by the liquid, so that the loss of the signal light can be reduced.

[0048] In addition, as examples of optical components, FRM 10 is used in embodiment 1, optical coupler 20 is used in embodiment 2, and multiplexer / demultiplexer 30 is used in embodiment 3, but the present disclosure can also be applied to other optical components such as optical circulators.

[0049] Furthermore, in the first to third embodiments, examples have been shown in which the GI lens or the like is attached to a substrate, but it may also be attached to a non-plate-shaped object such as a cylinder.

[0050] Furthermore, in the first to third embodiments, examples of optical components attached to SM fibers have been shown, but the present disclosure can also be applied to other light propagation means such as multimode fibers.

[0051] Furthermore, in embodiments 1 to 3, examples of optical components that handle signal light from an optical fiber hydrophone are shown, but the present disclosure can also be applied to optical components that handle signal light from other sensors or optical components that handle signal light for communications. [Explanation of symbols]

[0052] 10 FRM, 11 SM fiber, 12 GI lens, 13 Faraday rotator, 14 mirror, 15 spacer, 16 substrate, 20 optical coupler, 21 SM fiber, 22 GI lens, 24 half mirror, 25 spacer, 26 substrate, 28 uniform medium, 30 multiplexer / demultiplexer, 31 SM fiber, 32 GI lens, 34 multilayer filter, 35 spacer, 36 substrate, 38 uniform medium, 39 uniform medium, 101 container, 200 optical fiber hydrophone.

Claims

1. An apparatus having an optical component used under high pressure, The optical component; a container for storing the optical fiber and the optical component, The optical component comprises: a fixing portion for attaching the optical fiber; a lens using a refractive index gradient, The fixing portion is the optical fiber is fixed so that a gap for a liquid to enter is provided in a portion where light propagates between the lens and the optical fiber attached to the fixing portion; The container is filled with the liquid, The optical component is an FRM including a Faraday rotator and a mirror whose reflective surface is installed perpendicular to the incident direction of the light that has passed through the Faraday rotator so as to reflect the light that has passed through the Faraday rotator and pass it in the opposite direction along the same path, and is stored inside the container. Device.

2. the optical component includes a medium having a uniform refractive index in the portion where light propagates between the lens and the optical fiber, The medium having a uniform refractive index expands the diameter of the light propagating through the medium having a uniform refractive index from the optical fiber toward the optical component.

10. The apparatus of claim 1.

3. The liquid filled in the container is oil.

10. The apparatus of claim 1.

4. The container is filled with the liquid without containing air.

10. The apparatus of claim 1.

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