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(a) Fabrication of silicone-cladding/silica-core composite optical fiber; (b) Scanning Electron Microscope photo of the fabricated composite fiber; (c) field distribution of several modes inside the composite fiber.
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We have fabricated a composite optical fiber with hyperelastic silicone cladding and silica core, and demonstrated a simple and highly sensitive pressure sensor based on the light coupling between two such composite fibers twisted together. The hyperelastic silicone has very low Young's modulus which makes the fiber deformation easier even under sm...
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... the Young's modulus of conventional polymer optical fiber made by Polymethyl Methacrylate Resin (PMMA) is still large, limiting further improvement of the pressure sensitiv- ity. Moreover, the relatively high loss makes PMMA polymer fiber not suitable in long-distance sensing. In this paper we fabricate a hyperelastic silicone-cladding/silica-core composite optical fiber and develop a simple and highly sensitive pressure sensor based on it. Silica is used as the material of the fiber core, while hyperelastic silicone (Sylgard184, Dow Corning Ltd.) with very low Young's modulus, is used as the cladding material. Two such composite fibers are twisted together such that light coupling between them takes place when external pressure deforms the soft silicone claddings and makes the silica cores approach each other. By simply measuring the light intensity coupled from one fiber to the other, we can monitor the pressure applied to the fiber. The use of hyperelastic silicone as the cladding material gives rise to high sensitivity because the cores of the composite fibers can be more easily compressed closely to enhance the light coupling. And silica core offers lower loss than polymer fiber. Moreover, no post-processing of the fiber to form particular fiber structures like FBGs and interferometers etc is needed, which simplifies the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethyl- siloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber with core diameter of 85 µm. The coating material is silicone (Sylgard184, Dow Corning Ltd.), which is mixed with curing agent at a weight ratio of 10:1. During the coating process, the pure silica core passes through the coating cup filled with mixed silicone and curing agent. As the surface tension of the silicone is low (20.4 mN/m for Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) and much larger than 100 dB/km beyond 850 nm [21]- [24], the loss of our composite optical fiber is quite low. The thermo-optic coefficient for the silicone cladding of the composite fiber is negative, i.e., −4.5 × 10 −4 / • C, whose magnitude is about will be slightly changed by temperature, making the composite fiber also potential in temperature sensing. However, in this paper we focus on pressure ...
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... the Young's modulus of conventional polymer optical fiber made by Polymethyl Methacrylate Resin (PMMA) is still large, limiting further improvement of the pressure sensitiv- ity. Moreover, the relatively high loss makes PMMA polymer fiber not suitable in long-distance sensing. In this paper we fabricate a hyperelastic silicone-cladding/silica-core composite optical fiber and develop a simple and highly sensitive pressure sensor based on it. Silica is used as the material of the fiber core, while hyperelastic silicone (Sylgard184, Dow Corning Ltd.) with very low Young's modulus, is used as the cladding material. Two such composite fibers are twisted together such that light coupling between them takes place when external pressure deforms the soft silicone claddings and makes the silica cores approach each other. By simply measuring the light intensity coupled from one fiber to the other, we can monitor the pressure applied to the fiber. The use of hyperelastic silicone as the cladding material gives rise to high sensitivity because the cores of the composite fibers can be more easily compressed closely to enhance the light coupling. And silica core offers lower loss than polymer fiber. Moreover, no post-processing of the fiber to form particular fiber structures like FBGs and interferometers etc is needed, which simplifies the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethyl- siloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber with core diameter of 85 µm. The coating material is silicone (Sylgard184, Dow Corning Ltd.), which is mixed with curing agent at a weight ratio of 10:1. During the coating process, the pure silica core passes through the coating cup filled with mixed silicone and curing agent. As the surface tension of the silicone is low (20.4 mN/m for Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) and much larger than 100 dB/km beyond 850 nm [21]- [24], the loss of our composite optical fiber is quite low. The thermo-optic coefficient for the silicone cladding of the composite fiber is negative, i.e., −4.5 × 10 −4 / • C, whose magnitude is about will be slightly changed by temperature, making the composite fiber also potential in temperature sensing. However, in this paper we focus on pressure ...
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... the Young's modulus of conventional polymer optical fiber made by Polymethyl Methacrylate Resin (PMMA) is still large, limiting further improvement of the pressure sensitiv- ity. Moreover, the relatively high loss makes PMMA polymer fiber not suitable in long-distance sensing. In this paper we fabricate a hyperelastic silicone-cladding/silica-core composite optical fiber and develop a simple and highly sensitive pressure sensor based on it. Silica is used as the material of the fiber core, while hyperelastic silicone (Sylgard184, Dow Corning Ltd.) with very low Young's modulus, is used as the cladding material. Two such composite fibers are twisted together such that light coupling between them takes place when external pressure deforms the soft silicone claddings and makes the silica cores approach each other. By simply measuring the light intensity coupled from one fiber to the other, we can monitor the pressure applied to the fiber. The use of hyperelastic silicone as the cladding material gives rise to high sensitivity because the cores of the composite fibers can be more easily compressed closely to enhance the light coupling. And silica core offers lower loss than polymer fiber. Moreover, no post-processing of the fiber to form particular fiber structures like FBGs and interferometers etc is needed, which simplifies the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethyl- siloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber with core diameter of 85 µm. The coating material is silicone (Sylgard184, Dow Corning Ltd.), which is mixed with curing agent at a weight ratio of 10:1. During the coating process, the pure silica core passes through the coating cup filled with mixed silicone and curing agent. As the surface tension of the silicone is low (20.4 mN/m for Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) and much larger than 100 dB/km beyond 850 nm [21]- [24], the loss of our composite optical fiber is quite low. The thermo-optic coefficient for the silicone cladding of the composite fiber is negative, i.e., −4.5 × 10 −4 / • C, whose magnitude is about will be slightly changed by temperature, making the composite fiber also potential in temperature sensing. However, in this paper we focus on pressure ...
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... the Young's modulus of conventional polymer optical fiber made by Polymethyl Methacrylate Resin (PMMA) is still large, limiting further improvement of the pressure sensitiv- ity. Moreover, the relatively high loss makes PMMA polymer fiber not suitable in long-distance sensing. In this paper we fabricate a hyperelastic silicone-cladding/silica-core composite optical fiber and develop a simple and highly sensitive pressure sensor based on it. Silica is used as the material of the fiber core, while hyperelastic silicone (Sylgard184, Dow Corning Ltd.) with very low Young's modulus, is used as the cladding material. Two such composite fibers are twisted together such that light coupling between them takes place when external pressure deforms the soft silicone claddings and makes the silica cores approach each other. By simply measuring the light intensity coupled from one fiber to the other, we can monitor the pressure applied to the fiber. The use of hyperelastic silicone as the cladding material gives rise to high sensitivity because the cores of the composite fibers can be more easily compressed closely to enhance the light coupling. And silica core offers lower loss than polymer fiber. Moreover, no post-processing of the fiber to form particular fiber structures like FBGs and interferometers etc is needed, which simplifies the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethyl- siloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber with core diameter of 85 µm. The coating material is silicone (Sylgard184, Dow Corning Ltd.), which is mixed with curing agent at a weight ratio of 10:1. During the coating process, the pure silica core passes through the coating cup filled with mixed silicone and curing agent. As the surface tension of the silicone is low (20.4 mN/m for Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) and much larger than 100 dB/km beyond 850 nm [21]- [24], the loss of our composite optical fiber is quite low. The thermo-optic coefficient for the silicone cladding of the composite fiber is negative, i.e., −4.5 × 10 −4 / • C, whose magnitude is about will be slightly changed by temperature, making the composite fiber also potential in temperature sensing. However, in this paper we focus on pressure ...
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... the Young's modulus of conventional polymer optical fiber made by Polymethyl Methacrylate Resin (PMMA) is still large, limiting further improvement of the pressure sensitiv- ity. Moreover, the relatively high loss makes PMMA polymer fiber not suitable in long-distance sensing. In this paper we fabricate a hyperelastic silicone-cladding/silica-core composite optical fiber and develop a simple and highly sensitive pressure sensor based on it. Silica is used as the material of the fiber core, while hyperelastic silicone (Sylgard184, Dow Corning Ltd.) with very low Young's modulus, is used as the cladding material. Two such composite fibers are twisted together such that light coupling between them takes place when external pressure deforms the soft silicone claddings and makes the silica cores approach each other. By simply measuring the light intensity coupled from one fiber to the other, we can monitor the pressure applied to the fiber. The use of hyperelastic silicone as the cladding material gives rise to high sensitivity because the cores of the composite fibers can be more easily compressed closely to enhance the light coupling. And silica core offers lower loss than polymer fiber. Moreover, no post-processing of the fiber to form particular fiber structures like FBGs and interferometers etc is needed, which simplifies the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethyl- siloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber with core diameter of 85 µm. The coating material is silicone (Sylgard184, Dow Corning Ltd.), which is mixed with curing agent at a weight ratio of 10:1. During the coating process, the pure silica core passes through the coating cup filled with mixed silicone and curing agent. As the surface tension of the silicone is low (20.4 mN/m for Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) and much larger than 100 dB/km beyond 850 nm [21]- [24], the loss of our composite optical fiber is quite low. The thermo-optic coefficient for the silicone cladding of the composite fiber is negative, i.e., −4.5 × 10 −4 / • C, whose magnitude is about will be slightly changed by temperature, making the composite fiber also potential in temperature sensing. However, in this paper we focus on pressure ...
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... the Young's modulus of conventional polymer optical fiber made by Polymethyl Methacrylate Resin (PMMA) is still large, limiting further improvement of the pressure sensitiv- ity. Moreover, the relatively high loss makes PMMA polymer fiber not suitable in long-distance sensing. In this paper we fabricate a hyperelastic silicone-cladding/silica-core composite optical fiber and develop a simple and highly sensitive pressure sensor based on it. Silica is used as the material of the fiber core, while hyperelastic silicone (Sylgard184, Dow Corning Ltd.) with very low Young's modulus, is used as the cladding material. Two such composite fibers are twisted together such that light coupling between them takes place when external pressure deforms the soft silicone claddings and makes the silica cores approach each other. By simply measuring the light intensity coupled from one fiber to the other, we can monitor the pressure applied to the fiber. The use of hyperelastic silicone as the cladding material gives rise to high sensitivity because the cores of the composite fibers can be more easily compressed closely to enhance the light coupling. And silica core offers lower loss than polymer fiber. Moreover, no post-processing of the fiber to form particular fiber structures like FBGs and interferometers etc is needed, which simplifies the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethyl- siloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber with core diameter of 85 µm. The coating material is silicone (Sylgard184, Dow Corning Ltd.), which is mixed with curing agent at a weight ratio of 10:1. During the coating process, the pure silica core passes through the coating cup filled with mixed silicone and curing agent. As the surface tension of the silicone is low (20.4 mN/m for Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) and much larger than 100 dB/km beyond 850 nm [21]- [24], the loss of our composite optical fiber is quite low. The thermo-optic coefficient for the silicone cladding of the composite fiber is negative, i.e., −4.5 × 10 −4 / • C, whose magnitude is about will be slightly changed by temperature, making the composite fiber also potential in temperature sensing. However, in this paper we focus on pressure ...
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... the sensing configuration. It is worth mentioning that hyperelastic organic silicon materials, e.g., polydimethylsiloxane and silicone etc, have been recently used in developing soft electronic skin and skin-like pressure sensors for highly intuitive human-computer user interfaces due to their flexibility and biocompatibility [17]- [20]. Fig. 1(a) depicts the fabrication process of the hyperelastic silicone-cladding/silica-core composite optical fiber used in the experiment by using fiber drawing tower. Note that the figure is plotted along horizontal direction for convenience. The pure silica preform is heated up to 1950 °C in the furnace and then is drawn into optical fiber ...
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... Sylgard184), coating silicone to the surface of pure silica core becomes easy. After this process, pure silica core is coated with a thin liquid silicone film. Finally the coated fiber immediately passes through a curing oven with temperature kept at 250 °C. The process takes 10 second and the liquid silicone is completely cured during that time. Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. ...
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... Fig. 1(b) shows the Scanning Electron Microscope (SEM) photo of the fabricated silicone/silica composite optical fiber. The core and cladding radii of the composite fiber are 42.5 µm and 73.8 µm, respectively. At 1550 nm region the refractive index of silicone and silica are 1.40 and 1.45, and the composite fiber supports multimode transmission. Fig. 1(c) depicts the field distribution of the fundamental mode and several higher-order modes inside the composite fiber. The attenuation coefficient of the composite fiber is measured to be 23 dB/km at 850 nm and 83 dB/km at 1550 nm. Compared with the loss of POF which is around the level of 100 dB/km at visible light region (below 650 nm) ...
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