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In-line fiber optic interferometric sensors in single-mode fibers.

Zhu T, Wu D, Liu M, Duan DW - Sensors (Basel) (2012)

Bottom Line: Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers.It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost.Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China. zhutao@cqu.edu.cn

ABSTRACT
In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

No MeSH data available.


Related in: MedlinePlus

Measured reflection spectra of the FPI at different temperatures.
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f2-sensors-12-10430: Measured reflection spectra of the FPI at different temperatures.

Mentions: For temperature measurement, the in-line FPI is a popular sensor owing to its high sensitivity and good stability at high temperature. Zhu et al. spliced a section of special PCF to SMF to form a FPI, which could be heated up to 1,200 °C [47]. Wei et al. made a fiber in-line FPI with a femtosecond laser for high temperature measurement (up to 1,100 °C) [31]. Also, Choi et al. fabricated a FPI by fusion-splicing a short piece of holey optical fiber (HOF) between SMF and a piece of multimode fiber (MMF) to measure the temperature up to 500 °C [44]. However, these FPIs need a femtosecond laser or special optical fibers. Recently, Duan et al. proposed a low-cost FPI, as shown in Figure 1(a) [95]. The FPI is formed by simply splicing two sections of SMF together with large intentional lateral offset (∼62.5 μm). The formation of the FPI needs only two steps and inexpensive SMF, making it extremely low-cost. As shown in Figure 1(a), the first FPI mirror is formed due to the Fresnel reflection of part of SMF core uncovered by the next section of SMF, while the second FPI mirror is formed due to the Fresnel reflection at the next section of SMF cladding end. Figure 1(b) shows the reflective spectrum of such a FPI with a cavity geometry length L of ∼1.65 mm. The typical interference fringe has a visibility around 15 dB, which is sufficient for the sensing application. To characterize the high temperature response, the FPI was put into a temperature furnace whose temperature error is ±1 °C for temperature measurement. Figure 2 shows the test results of the FPI with a cavity geometry length L of 1.65 mm. It can be seen that in the first heating cycle, the FPI shows a poor high temperature response of the OPD; while in the later heating and cooling cycles, the linearity become better and repeatable. Thus, pre-annealing this kind of FPI up to 1,000 °C can greatly improve its linearity and the repeatability of the high temperature response. We can also see that the OPD temperature sensitivity of the FPI is ∼41 nm/°C, which is comparable with that of FPIs based on special PCFs [47].


In-line fiber optic interferometric sensors in single-mode fibers.

Zhu T, Wu D, Liu M, Duan DW - Sensors (Basel) (2012)

Measured reflection spectra of the FPI at different temperatures.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472836&req=5

f2-sensors-12-10430: Measured reflection spectra of the FPI at different temperatures.
Mentions: For temperature measurement, the in-line FPI is a popular sensor owing to its high sensitivity and good stability at high temperature. Zhu et al. spliced a section of special PCF to SMF to form a FPI, which could be heated up to 1,200 °C [47]. Wei et al. made a fiber in-line FPI with a femtosecond laser for high temperature measurement (up to 1,100 °C) [31]. Also, Choi et al. fabricated a FPI by fusion-splicing a short piece of holey optical fiber (HOF) between SMF and a piece of multimode fiber (MMF) to measure the temperature up to 500 °C [44]. However, these FPIs need a femtosecond laser or special optical fibers. Recently, Duan et al. proposed a low-cost FPI, as shown in Figure 1(a) [95]. The FPI is formed by simply splicing two sections of SMF together with large intentional lateral offset (∼62.5 μm). The formation of the FPI needs only two steps and inexpensive SMF, making it extremely low-cost. As shown in Figure 1(a), the first FPI mirror is formed due to the Fresnel reflection of part of SMF core uncovered by the next section of SMF, while the second FPI mirror is formed due to the Fresnel reflection at the next section of SMF cladding end. Figure 1(b) shows the reflective spectrum of such a FPI with a cavity geometry length L of ∼1.65 mm. The typical interference fringe has a visibility around 15 dB, which is sufficient for the sensing application. To characterize the high temperature response, the FPI was put into a temperature furnace whose temperature error is ±1 °C for temperature measurement. Figure 2 shows the test results of the FPI with a cavity geometry length L of 1.65 mm. It can be seen that in the first heating cycle, the FPI shows a poor high temperature response of the OPD; while in the later heating and cooling cycles, the linearity become better and repeatable. Thus, pre-annealing this kind of FPI up to 1,000 °C can greatly improve its linearity and the repeatability of the high temperature response. We can also see that the OPD temperature sensitivity of the FPI is ∼41 nm/°C, which is comparable with that of FPIs based on special PCFs [47].

Bottom Line: Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers.It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost.Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing 400044, China. zhutao@cqu.edu.cn

ABSTRACT
In-line fiber optic interferometers have attracted intensive attention for their potential sensing applications in refractive index, temperature, pressure and strain measurement, etc. Typical in-line fiber-optic interferometers are of two types: Fabry-Perot interferometers and core-cladding-mode interferometers. It's known that the in-line fiber optic interferometers based on single-mode fibers can exhibit compact structures, easy fabrication and low cost. In this paper, we review two kinds of typical in-line fiber optic interferometers formed in single-mode fibers fabricated with different post-processing techniques. Also, some recently reported specific technologies for fabricating such fiber optic interferometers are presented.

No MeSH data available.


Related in: MedlinePlus