This paper presents a novel malposition fusion splice cascade single mode, graded index multimode, and single mode fiber (MS-SMS) structure for simultaneous measurement of strain and temperature. The MS-SMS sensor consists of a 4-period single mode fiber graded refractive index multimode fiber splice with a total length of 4.8 mm. Moreover, higher order cladding patterns are excited by malposition fusion splice. The theoretical analysis simulations are in agreement with the experimental results. Experimental validation showed the high strain and temperature sensitivity of the sensor. The sensor has two resonant dips with strain sensitivities of 7.6 pm/με and -8.7 pm/με, respectively. And the sensitivities of the two resonance depressions reached 48 pm/°C and 55.4 pm/°C, respectively.
A long-period fiber grating based on a D-type multimode fiber (DMF) embedded in a no-core fiber (NCF) has been designed and fabricated. The 5-period NCF-DMF-NCF (NDN-LPG) has a high resonance loss contrast (18dB). The theoretical analysis simulations are in agreement with the experimental results. We investigated the sensing response characteristics of NDN-LPG for refractive index and temperature, and the sensor achieved a wavelength sensitivity of 244.11nm/RIU in the range of 1.344-1.421 RIU with a low temperature sensitivity (22pm/°C).
Sinusoidal phase modulating (SPM) interferometry is a well-established technique for ultra-precise measurements. In SPM interferometry, the phase modulation depth is of crucial importance: it is either a measurand or a key parameter for accurate phase demodulation. For laser diode SPM interferometry, the problem of residual amplitude modulation (RAM) should be considered, thus the measurement of phase modulation depth becomes difficult, especially when the RAM ratio is unknown. In this paper, a novel method is proposed to simultaneously obtain phase modulation depth and RAM ratio: by solving a twelve-variable nonlinear equation set, phase modulation depth and RAM ratio can be retrieved numerically. Preliminary simulations show that this method is rarely influenced by the choice of initial values for the numerical solving process.
Conference Committee Involvement (1)
29th International Conference on Optical Fiber Sensors
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.