High-sensitivity vector bend sensor based on a fiber directional coupler inscribed by a femtosecond laser.
Opt Lett
; 48(6): 1498-1501, 2023 Mar 15.
Article
in En
| MEDLINE
| ID: mdl-36946962
ABSTRACT
In this Letter, we demonstrate a high-sensitivity vector bend sensor based on a fiber directional coupler. The fiber directional coupler is composed of two parallel waveguides inscribed within a no-core fiber (NCF) by a femtosecond laser. Since the two written waveguides have closely matched refractive indices and geometries, the transmission spectrum of the fiber directional coupler possesses periodic resonant dips. Such a fiber directional coupler exhibits a good bending-dependent spectral shift response due to its asymmetric structure. Experimental results show that bending sensitivities of -97.11â
nm/m-1 and 58.22â
nm/m-1 are achieved for the 0° and 180° orientations in the curvature range of 0-0.62â
m-1, respectively. In addition, the proposed fiber directional coupler is shown to be insensitive to external humidity changes, thus improving its suitability in high-accuracy bending measurements.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Type of study:
Diagnostic_studies
Language:
En
Journal:
Opt Lett
Year:
2023
Type:
Article