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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

The RI sensitivity of two in-line MIs based on: (a) the fiber taper; (b) the core-offset structure, respectively.
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f14-sensors-12-10430: The RI sensitivity of two in-line MIs based on: (a) the fiber taper; (b) the core-offset structure, respectively.

Mentions: So far, several kinds of in-line MIs have been reported based on special fibers, for instance, reference [75] fabricated an in-line MI by simply splicing a section of MMF to SMF, and reference [80] proposed an in-line MI which consists of a section of two-core fiber (TCF) and SMF. Meanwhile, the in-line MIs based on air-holes collapsing of the PCF have been demonstrated by reference [86,90,91]. Such kind of PCF-based MIs have higher RI sensitivity and low temperature sensitivity due to the special air-hole silicon structures. However, these in-line MIs require special fibers, which make it expensive to use in industry. On the contrary, the other ways to achieve the low-cost in-line MIs in SMF include LPFG [60,61], fiber taper [67], core-offset structure [70]. Although the LPFG can realize coupling and re-coupling between the core and cladding modes in the MI, the fabrication of the LPFG require precise (and often expensive) photolithographic alignment equipment and amplitude masks. Figure 13 shows two in-line MIs formed in SMF based on the fiber taper and core-offset structures, respectively. As shown in Figure 13(a), light in the core will be partially coupled into the cladding by the abrupt taper and gradually attenuated. However, since a layer of gold is coated on the fiber end facet, the core and cladding modes will be reflected by the mirror and then be re-coupled together by the same abrupt taper. In Figure 13(b), the core-offset structure has the same effects on coupling and re-coupling between the core and the cladding modes. Figure 14 shows that two in-line MIs with the same interferometer length of ∼38 mm have similar RI sensitivities of ∼290 nm/RIU (based on taper) and ∼333 nm/RIU (based on core-offset), which are comparable to that of a pair of LPFGs based MZI (∼252 nm/RIU) [59].


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

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

The RI sensitivity of two in-line MIs based on: (a) the fiber taper; (b) the core-offset structure, respectively.
© Copyright Policy
Related In: Results  -  Collection

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

f14-sensors-12-10430: The RI sensitivity of two in-line MIs based on: (a) the fiber taper; (b) the core-offset structure, respectively.
Mentions: So far, several kinds of in-line MIs have been reported based on special fibers, for instance, reference [75] fabricated an in-line MI by simply splicing a section of MMF to SMF, and reference [80] proposed an in-line MI which consists of a section of two-core fiber (TCF) and SMF. Meanwhile, the in-line MIs based on air-holes collapsing of the PCF have been demonstrated by reference [86,90,91]. Such kind of PCF-based MIs have higher RI sensitivity and low temperature sensitivity due to the special air-hole silicon structures. However, these in-line MIs require special fibers, which make it expensive to use in industry. On the contrary, the other ways to achieve the low-cost in-line MIs in SMF include LPFG [60,61], fiber taper [67], core-offset structure [70]. Although the LPFG can realize coupling and re-coupling between the core and cladding modes in the MI, the fabrication of the LPFG require precise (and often expensive) photolithographic alignment equipment and amplitude masks. Figure 13 shows two in-line MIs formed in SMF based on the fiber taper and core-offset structures, respectively. As shown in Figure 13(a), light in the core will be partially coupled into the cladding by the abrupt taper and gradually attenuated. However, since a layer of gold is coated on the fiber end facet, the core and cladding modes will be reflected by the mirror and then be re-coupled together by the same abrupt taper. In Figure 13(b), the core-offset structure has the same effects on coupling and re-coupling between the core and the cladding modes. Figure 14 shows that two in-line MIs with the same interferometer length of ∼38 mm have similar RI sensitivities of ∼290 nm/RIU (based on taper) and ∼333 nm/RIU (based on core-offset), which are comparable to that of a pair of LPFGs based MZI (∼252 nm/RIU) [59].

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