PMID- 30018260
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20180720
LR  - 20181114
IS  - 1424-8220 (Electronic)
IS  - 1424-8220 (Linking)
VI  - 18
IP  - 7
DP  - 2018 Jul 17
TI  - Optical Strain Measurement with Step-Index Polymer Optical Fiber Based on the 
      Phase Measurement of an Intensity-Modulated Signal.
LID - 10.3390/s18072319 [doi]
LID - 2319
AB  - Polymer optical fibers (POFs) have been proposed for optical strain sensors due 
      to their large elastic strain range compared to glass optical fibers (GOFs). The 
      phase response of a single-mode polymer optical fiber (SM-POF) is well-known in 
      the literature, and depends on the physical deformation of the fiber as well as 
      the impact on the refractive index of the core. In this paper, we investigate the 
      impact of strain on a step-index polymer optical fiber (SI-POF). In particular, 
      we discuss the responsivity of an optical strain sensor which is based on the 
      phase measurement of an intensity-modulated signal. In comparison to the phase 
      response of an SM-POF, we must take additional influences into account. Firstly, 
      the SI-POF is a multi-mode fiber (MMF). Consequently, we not only consider the 
      strain dependence of the refractive index, but also its dependency on the 
      propagation angle thetaz. Second, we investigate the phase of an intensity-modulated 
      signal. The development of this modulation phase along the fiber is influenced by 
      modal dispersion, scattering, and attenuation. The modulation phase therefore has 
      no linear dependency on the length of the fiber, even in the unstrained state. 
      For the proper consideration of these effects, we rely on a novel model for 
      step-index multi-mode fibers (SI-MMFs). We expand the model to consider the 
      strain-induced effects, simulate the strain responsivity of the sensor, and 
      compare it to experimental results. This led to the conclusion that the 
      scattering behavior of a SI-POF is strain-dependent, which was further proven by 
      measuring the far field at the end of a SI-POF under different strain conditions.
FAU - Becker, Thomas
AU  - Becker T
AD  - Polymer Optical Fiber Application Center, Technische Hochschule Nurnberg Georg 
      Simon Ohm, Wassertorstrasse 10, 90489 Nurnberg, Germany. 
      thomas.becker@pofac.th-nuernberg.de.
FAU - Ziemann, Olaf
AU  - Ziemann O
AD  - Polymer Optical Fiber Application Center, Technische Hochschule Nurnberg Georg 
      Simon Ohm, Wassertorstrasse 10, 90489 Nurnberg, Germany. 
      olaf.ziemann@pofac.th-nuernberg.de.
FAU - Engelbrecht, Rainer
AU  - Engelbrecht R
AUID- ORCID: 0000-0001-7243-3647
AD  - Polymer Optical Fiber Application Center, Technische Hochschule Nurnberg Georg 
      Simon Ohm, Wassertorstrasse 10, 90489 Nurnberg, Germany. 
      rainer.engelbrecht@pofac.th-nuernberg.de.
FAU - Schmauss, Bernhard
AU  - Schmauss B
AUID- ORCID: 0000-0002-6615-370X
AD  - Institute of Microwaves and Photonics (LHFT), Friedrich-Alexander-Universitat 
      Erlangen-Nurnberg, Wetterkreuz 15, 91058 Erlangen, Germany. 
      bernhard.schmauss@fau.de.
LA  - eng
PT  - Journal Article
DEP - 20180717
PL  - Switzerland
TA  - Sensors (Basel)
JT  - Sensors (Basel, Switzerland)
JID - 101204366
PMC - PMC6069075
OTO - NOTNLM
OT  - SI-POF
OT  - multi-mode fiber
OT  - phase sensing
OT  - strain sensing
COIS- The authors declare no conflict of interest.
EDAT- 2018/07/19 06:00
MHDA- 2018/07/19 06:01
PMCR- 2018/07/01
CRDT- 2018/07/19 06:00
PHST- 2018/06/20 00:00 [received]
PHST- 2018/07/11 00:00 [revised]
PHST- 2018/07/13 00:00 [accepted]
PHST- 2018/07/19 06:00 [entrez]
PHST- 2018/07/19 06:00 [pubmed]
PHST- 2018/07/19 06:01 [medline]
PHST- 2018/07/01 00:00 [pmc-release]
AID - s18072319 [pii]
AID - sensors-18-02319 [pii]
AID - 10.3390/s18072319 [doi]
PST - epublish
SO  - Sensors (Basel). 2018 Jul 17;18(7):2319. doi: 10.3390/s18072319.